CON_015 Ovation Link Controller (LC) Modbus Interface User Guide

Ovation Link Contro ller (LC) Modbus Interface U ser Guid e for Ovation Windows and Solaris Pla tform s CON_015 Version 1 August 2005

Copyright Notice Since the equipment explained in this manual has a variety of uses, the user and those responsible for applying this equipment must satisfy themselves as to the acceptability of each application and use of the equipment. Under no circumstances will Emerson Process Management be responsible or liable for any damage, including indirect or consequential losses resulting from the use, misuse, or application of this equipment. The text, illustrations, charts, and examples included in this manual are intended solely to explain ® the use and application of the Ovation unit. Due to the many variables associated with specific uses or applications, Emerson Process Management cannot assume responsibility or liability for actual use based upon the data provided in this manual. No patent liability is assumed by Emerson Process Management with respect to the use of circuits, information, equipment, or software described in this manual. No part of this publication may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, including electronic, mechanical, photocopying, recording or otherwise without the prior express written permission of Emerson Process Management. The document is the property of and contains Proprietary Information owned by Emerson Process Management and/or its subcontractors and suppliers. It is transmitted in confidence and trust, and the user agrees to treat this document in strict accordance with the terms and conditions of the agreement under which it was provided. This manual is printed in the USA and is subject to change without notice. Ovation and WEStation are registered trademarks of Emerson Process Management. All other trademarks or registered trademarks are the property of their respective holders. Copyright © Emerson Process Management Power & Water Solutions, Inc. All rights reserved. Emerson Process Management Power & Water Solutions 200 Beta Drive Pittsburgh, PA 15238 USA E-Mail: [email protected] Website: http://www.EmersonProcess.com

Contents 1

Introduct ion to Ovation Link Contro ller Modbus Interfa ce

1.1

What is the Ovation LC Modbus Interface? ........................................................................1

2

Hardware Configu ration

2.1

What is the Ovation LC Module? ........................................................................................ 3

2.2

What are the Interface Connections? ................................................................................. 4 2.2.1 Terminal Block Connections.............................................................................. 5 2.2.2 Pin Assignments................................................................................................ 6 2.2.3 Cabling Schemes ..............................................................................................8 2.2.4 Cable Choices ................................................................................................. 10

3

Software C onfig uration

3.1

What Software is Required for the LC Modbus Interface? ...............................................11

3.2

Software Configuration Overview ..................................................................................... 11

3.3

Creating a 3.3.1 3.3.2 3.3.3 3.3.4 3.3.5

3.4

1

3

11

Configuration File ............................................................................................12 Configuration File Guidelines ..........................................................................12 To Create a Configuration File ........................................................................13 Sample Configuration File ...............................................................................14 Overall Parameters .........................................................................................15 Group Operation Parameters..........................................................................17

3.3.6 Modbus Address and Point Mapping Parameters........................................... 18 3.3.7 Modbus Command Mnemonic Keywords .......................................................20 3.3.8 Modbus Addresses.......................................................................................... 21 3.3.9 Modbus Data Type Specifiers .........................................................................22 3.3.10 How Modbus Protocol Represents 32-bit Quantities ......................................24 3.3.11 Data Conversion.............................................................................................. 27 Creating an AUTOEXEC.BAT File ....................................................................................27 3.4.1 To Create the AUTOEXEC.bat File.................................................................28

4

Operation o f LC Modbus Interfa ce

4.1

Initializing the Link Controller Modbus Interface ...............................................................29

4.2

Troubleshooting LC Modbus Operation ............................................................................29 4.2.1 Displaying Error Messages ............................................................................. 30 4.2.2 Runtime Diagnostics ....................................................................................... 31 4.2.3 Interpreting the Ovation Link Controller Module LEDs.................................... 32

CON_015

29

i

Table of Contents

5

Ovation Link Contr oller Module Re dundancy

5.1

What is Redundancy? ....................................................................................................... 33

5.2

What Configuration File Parameters are Used for Redundancy?..................................... 33

5.3

What Algorithms are Used for Redundancy?....................................................................34

5.4

Configuring Redundant Hardware ....................................................................................34

5.5

LC Modbus Interface Redundancy Operation................................................................... 35

5.6

5.7

Bumpless Transfer ............................................................................................................35 5.6.1 Sending Data from the Controller to Field Devices......................................... 36 5.6.2 Sending Data from the Field Devices to the Controller ...................................36 Backup Mode Action .........................................................................................................36

6

Interfa ce Timing Considerations

6.1

Interface Timing ................................................................................................................ 37

6.2

Balancing Communication Priorities with the interval parameter......................................37

6.3

Using InterMsgDelay to Throttle Communication ............................................................. 38

6.4

Setting MessageTimeout ..................................................................................................38

6.5

Significance of watchdog_time ......................................................................................... 39

7

Using Multi-Drop Ne twork s

7.1

What is a Multi-Drop Network? .........................................................................................41

7.2

Multi-Drop Interface Configuration ....................................................................................41

8

Modbus Protocol

8.1

Modbus Protocol Messages.............................................................................................. 43

9

Configuration File E xamples

9.1

Configuration File Examples Included in This Section......................................................49

9.2

Configuration File Example 1 ............................................................................................50

9.3


9.4


9.5


9.6


10

Glossary of Terms

Index

ii

33

37

41

43

49

57

79

CON_015

S

ECTION

1

INTRODUCTION TO OVATION L INK CONTROLLER MODBUS INTERFACE

IN THIS SECTION What is the Ovation LC Modbus Interface? ........................................................................ 1

1.1

W

HAT IS THE

O VATION L C M ODBUS I NTERFACE ?

The Ovation Link Controller Modbus Interface provides communication between an Ovation Link Controller (LC) module (also know as an RLC module) and one or more external devices. This communication is performed through a single RS-232, RS-422, or RS-485 link using Modbus communication protocol. Throughout the remainder of this document, the Ovation Link Controller Modbus Interface is referred to as the LC Modbus Interface. The Ovation Link Controller module is the Modbus master and the external device(s) are the slaves. The LC Modbus Interface software interprets a configuration file which defines messages between Modbus registers, coils, and inputs, and Link Controller (LC) module memory locations. The interface then sends requests to the Modbus slaves to read and write Modbus data. Modbus is an open protocol which is used by many manufacturers of industrial controls. Parts of this document, particularly those concerning connection of the LC Module to the field device(s), are writtenappropriate in generic terms. Therefore, and you must consult the field device documentation in order to design cable connectors to limit the Modbus configuration to the functions that the field device supports.

CON_015

1

S

2

ECTION

HARDWARE CONFIGURATION

IN THIS SECTION What is the Ovation LC Module? ........................................................................................ 3 What are the Interface Connections? ................................................................................. 4

2.1

W

HAT IS THE

O VATION L C M ODULE ?

The Ovation Distributed Control System provides modulating control, sequential control, and data acquisition for a variety of system applications. This system consists of a configurable mix of functional Input/Output (I/O) modules that communicate on an I/O bus to the Ovation Controller. I/O modules provide an interface between the Ovation Controller and the processes in the plant. Ovation I/O modules are “plug-in” components with built-in fault tolerance and diagnostics. They are able to operate on a wide range of signals and perform a multitude of functions. The Ovation I/O modules are locked into base units. These base units are housed in the Controller cabinets where they are mounted on DIN rails and wired to the appropriate field devices. (See Ovation I/O Reference Manual.) The standard Ovation modular components typically consist of the following:   

Electronics module Personality module Base Unit (containing the field terminations)

There is one Electronics module group for the Link Controller module: 

1C1166G01 provides for communication to a field device or another system.

There are two Personality module groups for the Link Controller module: 



CON_015

Group 1 module (Emerson part number 1C31169G01) 

Provides an RS-232 electrical interface.



Appropriate for installations where the distance between the LC module and the other Modbus speaking device is 50 feet (15 meters) or less.

Group 2 module (Emerson part number 1C31169G02) 

Provides an RS-422/RS-485 electrical interface.



Appropriate for distances up to 4000 feet (1220 meters).

3

2.2 What are the Interface Connections?

2.2

W

HAT ARE THE

I NTERFACE

C ONNECTIONS ?

The Modbus protocol is used by many control manufacturers. The cable between the LC module and the field device must be designed to match the device manufacturer’s serial port connection. The connector pin-out information should be available in the manufacturer’s documentation. The field connection to the LC module can be made either at the nine-pin J2 connector of the Ovation Personality module or at the terminal block of the Base Unit. It is common for RS-422 and RS-485 connections to use field wiring rather than a premanufactured cable. This is because the cable length field wiring is typically longer than a premanufactured cable. An interface connection consists of the following:

4



Terminal block connections (see page 4)



Pin assignments (see page 6)



Cabling Schemes (see page 8)



Cable choices (see page 10)

CON_015


2.2.1 T ERMINAL B LOCK C ONNECTIONS The Base Unit terminal block connection is the most convenient connection for field-wiring connections and is illustrated in the following figure. Note: Do no t use unmarked terminal block locations.

Terminal Blo ck Notes: 1.

COM is the galvanically isolated common terminal of the Applications Port.

2.

Use an overall shield conductor for the Applications Port cable:

3.

4.



To ground the cable shield locally, connect the cable shield to terminal C17 (Earth Gnd).



To ground the cable shield remotely, connect the cable shield to terminal C16 (SH).

Connect a wire jumper for the following: 

To boot up from an external PC, connect a jumper between SEL and BT.



To set Programming Port baud rate to 9600, (default is 19200), connect a jumper between SEL and BAU.

For RS-485 four-wire applications, connect a wire jumper for the following: 

To use a transmitter termination resistor, connect a jumper between RES (B14) and TX+ (B15).



To use a receiver termination resistor, connect a jumper between RES (A14) and RX+ (A15).

For a four wire RS-485 communication network, a termination resistor is recommended if the receiver is located at the end of the communications transmitter termination resistor is recommended if the transmitter is at the end oflink. the A communication link and if the transmitter is tri-stated (disabled) when data is not being transmitted. Otherwise, a transmitter termination resistor is not necessary.

CON_015

5


2.2.2 P IN A SSIGNMENTS The J2 connector pin assignments for the Group 1 RS-232 Personality Module are listed in the following table. Pin Assi gnment s for J 2 RS-232 Interface P I N N UMBER

6

S IGNAL N A M E ( F UNCTION )

S IGNAL D IRECTION

1

DCD (Data Carrier Detect)

Input

2

RX/ (Receive Data)

Input

3

TX/ (Transmit Data)

Output

4

DTR (Data Terminal Ready)

Output

5

Com (Isolated Common)

6

DSR (Data Set Ready)

Input

7

RTS (Request to Send)

Output

8

CTS (Clear to Send)

Input

9

RI (Ring Indicator)

Input

CON_015


The J2 connector pin assignments for the Group 2 RS-422/RS-485 Personality Module are listed in the following table. Pin As sig nments for J2 RS-422/RS-485 Four-Wire Interface P I N N UMBER

S IGNAL N A M E ( F UNCTION )

S IGNAL D IRECTION

1

RX-

Input

2

RX+

Input

3

TX+

Output

4

TX-

Output

5

Com (Isolated Common)

6 7 8 9

CON_015

7


2.2.3 C A B L IN G S CHEMES Once the pin-out assignment of the field device has been determined, a cable can be made to connect the device to the LC module. The module’s transmit signal (RS-232) or signal pair (RS485) must be connected to the receive signal (RS-232) or signal pair (RS-485) of the other device. Likewise, the LC receive signal or signal pair is connected to the transmit signal of the other device. The Ovation LC/Modbus interface does not require any of the control signals (that is, RTS, CTS, DTR, DSR, DCD, or RI) to be connected for proper operation. Some field devices will require logically complementary pairs of control signals to be looped back (for example, the device’s own Request To Send signal is connected to satisfy its Clear To Send signal). Generic RS-232 and RS-485 cables are shown in the following figures. Many manufacturers use DB-9 or DB-25 connectors for the serial connection. Terminal blocks instead of connectors are also commonly used for RS-485. These figures show no pin numbers for the other Modbus speaking device since there is considerable variation among manufacturers.

Figure 1: Generic RS-2 32 Cablin g Scheme

8

CON_015


Figure 2: Generic RS-4 85 LC Cabling Scheme The following figure shows a more specific cabling diagram for a multi-drop two-wire RS-485 network. This configuration is common for electric meters and protective relays. The transmit and receive terminals are connected together so that the LC module can both transmit and receive on the sametherefore cable pair. LC module is usually at one of the pair when usingthat a multi-drop network, theThe module’s terminating resistor is end shown jumpered in. Note there is another terminating resistor at the other end of the network. Rt is approximately 150 Ω.

Figure 3: Multi -drop 2-wire RS -485 Networ k

CON_015

9


2.2.4 C A B L E C HOICES The following cable choices are recommended: 

Cable for RS-232 serial communication should be multiple conductor with a shield. The shield drain wire should be used for the ground connection.



Cable for RS-422/RS-485 serial communication should be multiple twisted pairs, overall or individually shielded. Each signal’s two differential connections should be made within a twisted pair; signals should not cross pairs.



The RS-485 Group 2 Personality Module includes terminating resistors which can be placed across each signal pair by jumpering the base unit Terminal Block (see page 4) between B14 and B15 for transmit and between A14 and A15 for receive. Some field devices will have resistors which can be switched in. For other devices, terminating resistors may need to be added. A typical value is 120 ohms across the (+) and () pins. In particularly noisy environments, the resistor can be split into 60 ohms from (+) to ground and 60 ohms from (-) to ground.

10

CON_015

S

3

ECTION

SOFTWARE CONFIGURATION

IN THIS SECTION What Software is Required for the LC Modbus Interface? ...............................................11 Software ..................................................................................... 11 Creating aConfiguration ConfigurationOverview File ............................................................................................ 12 Creating an AUTOEXEC.BAT File.................................................................................... 27

3.1

W

HAT

S OFTWARE IS

R EQUIRED FOR THE

L C M ODBUS I NTERFACE ?

You need the following software to implement the LC Modbus interface: 

DOS operating system Install a DOS operating system version 5.0 on the LC module. DOS is loaded during module testing, however a copy should be available in the event that the LC module RAM memory becomes corrupted.



Configuration file Create a configuration file and install it on the LC module.



AUTOEXEC.BAT f il e Create an AUTOEXEC.BAT file and install it on the LC module so the interface will start





automatically. LC Module utilities 

RLCEXTPC.EXE (disk RLC10A)



RLCFLASH.EXE (disk RLC20A)

MODBUS.EXE Install this executable program on the LC module. MODBUS.EXE is provided on the distribution CD.

3.2

S

OFTWARE

C ONFIGURATION

O VERVIEW

The following software processes must be performed in order to successfully use the LC Modbus Interface: 

Create a configuration file.



Create an AUTOEXEC.BAT file.



Copy the MODBUS.EXE program, the configuration file, and the AUTOEXEC.BAT file to the Link Controller module.

CON_015

11

3.3 Creating a Configuration File

3.3

C

REATING A

C ONFIGURATION

FIL E

The configuration file used with the LC Modbus interface is often referred to as the “point group file.” It contains groups of statements which specify communication parameters and describe the correspondences between Modbus addresses and the LC addresses. These Modbus addresses are ultimately mapped to process points in the Ovation Controller. A sample configuration file is provided with the LC Modbus release. You can use it as a template to create the configuration file that you desire for your LC Modbus interface. Once the configuration file has been created and verified, load it along with the driver executable file named MODBUS.EXE to the LC module. (See Ovation Link Controller (LC) User Guide for instructions on the operation of the LC module.)

3.3.1 C ONFIGURATION F ILE G UIDELINES 

The configuration file is an ASCII text file that is case-insensitive.



The format of the file is a parameter keyword followed by a parameter value.



Commas, equal signs, tabs, spaces, and line breaks, may all be used as separators between parameter keywords and parameter values. All the following examples for entering a baud parameter are valid: baud,9600 baud = 9600 baud 9600 baud 9600



Many of the keywords have aliases.



Comments may be inserted in the file using an asterisk "*". All text from the asterisk to the end of the line is ignored. A configuration file has three types of parameters:







Overall communication parameters (see page 15).



Group operation parameters (see page 17).



Modbus address mapping parameters (see page 18).

The configuration file format is as follows: a) Overall parameters are placed at the top of the file. b) Next, group operation parameters introduce a point group. c)

Then the Modbus address specific parameters provide mapping for the group.

This pattern of group operation parameters followed by Modbus address parameters repeats until the entire mapping is complete.

12

CON_015


3.3.2 T O C REATE A C ONFIGURATION F IL E 1.

Locate the sample configuration file that is provided with the LC Modbus Interface.

2.

Load the sample file into a text editor.

3.

Name the file an appropriate name that will identify its uses. For example, BOILER2. CFG.

Note: Use the DOS file naming conventions for the file name. Use no more than eight character for the file name and the characters are not case sensitive (can be upper of lower case). 4.

Make the desired edits, save the file, and verify it.

5. 6.

Use the suggested guidelines (see page 12) while editing the file. Load the edited file, along with MODBUS.EXE, to the LC module.

CON_015

13


3.3.3 S AM PL E C ONFIGURATION F IL E A sample configuration file is provided with the LC Modbus Interface. An example of an LC Modbus configuration file is shown in the sample below. Additional configuration file examples are provided in Configuration File Examples (see page 49). pl at f or m PC baud 9600 sysl og 3 gr oup "t hi s i s grou p one" oper at i on per i odi c islntave er val 1000 2 f unc RHR poi nt I 0000 address 0000 poi nt I 0001 address 0001 poi nt I 0002 address 0002 gr oup "t hi s i s grou p t wo" oper at i on per i odi c i nt er val 2000 sl ave 1 f unct i on RHR poi nt F0100 addr ess 0100 poi nt F0102 addr ess 0102 dat a_t ype f l oat conv_t ype 1 1v 10. 00 2v 100. 00 sl ave 1 f unct i on PMR poi nt F0110 addr ess 0110 poi nt F0112 addr ess 0112 dat a_t ype f l oat conv_t ype 1 1v 10. 00 2v 100. 00 gr oup " group t hr ee" oper at i on per i odi c i nt er val 3000 sl ave 20 f unct i on RHR poi nt F0200 addr ess 0200 dat a_t ype f l oat r ev gr oup " t he f our t h gr oup" operat i on gat ed gat er eg 1000 gr oupst at r eg D2000 sl ave 100 f unc RHR poi nt D0300 addr 0900. 00 poi nt D0301 addr 0900. 01 poi nt D0302 addr 0900. 02 poi nt D0303 addr 0900. 03 poi nt D0304 addr 0900. 04 poi nt D0305 addr 0900. 05 poi nt D0306 addr 0900. 06 poi nt D0307 addr 0900. 07 gr oup "f i ve" oper at i on t r i gger t r i ggerr eg 1500 gr oupst at r eg D2020 sl ave 1 f unc RHR poi nt D0500 addr 0500

14

CON_015


3.3.4 O VERALL P AR A ME TE RS The first parameters in the configuration file are the Overall parameters. They specify attributes that pertain to the entire link, such as port settings. The platform parameter is used to indicate the hardware on which the interface software will run. The software can run on a WDPF QLC card, an Ovation LC module, or it can be run on a PC for testing before the Ovation hardware is available. The following table defines the Overall parameters (valid aliases for the Overall parameters are shown in parentheses): Overall Parameters PA RAMETER (AL IAS)

D ESCRIPTION

V A L U E /R A N G E

platform

Hardware platform

PC=Personal Computer platform=RLC QLC=Q-line card RLC=Ovation module Default=RLC

baud (bit_rate)

Communication rate between LC module and Modbus slaves

110 through 19200 bits per second. Default=9600

baud=9600

data_bits (data)

Number of data bits per character frame

7 or 8 Default=7

data=7

parity

Type of parity checking Odd, Even, None Default=Even

parity=odd

stop_bits (stopbits)

Number of stop bits per character frame

stop_bits=2

retries

Number of attempts of 0 to 65535 a single transaction Default=3 before going on

retries=3

flow_ctl

Specifies hardware flow control

set, reset, [off, false, no], [on, true, yes], [rts_only, rtsonly, rts_on_tx] There is no default

flow_ctl=rts_on_tx

duplex

Used to specify half duplex, that is, 2-wire (so discard echo)

full, half Default=full

duplex=half

MessageTimeout

Time in milliseconds to 0 to 65535

MessageTimeout

(timeout)

wait for response from Default=5000 slave

3000

CON_015

1, 1.5, or 2 Default=1

E XAMPLE

15


16

PA RAMETER (AL IAS)

D ESCRIPTION


E XAMPLE

InterMsgDelay (inter_msg_delay)

Specifies a delay (in milliseconds) between transactions

0 to 65535 Default=0

InterMsgDelay 250

syslog

Debug severity

1 (low) to 7 (high) Default=3

syslog=5

link_stat_reg

Register number at

0 to 2044

link_stat_reg=2000

(linkstatreg) (qlcstatusreg)

which SLCSTATUS algorithm is located.

There is no default

status_hold_time (loop_time)

Time (in milliseconds) to hold SLCSTATUS values in memory

0 to 2147483647 Default=1000 (1 second)

watchdog_time (watchdogtime) (watch_dog_time)

Watchdog time setting 0 to 65535 in milliseconds Default=5000 (5 seconds)

watchdog_time= 1000

control_reg (controlreg)

Address of register used to control redundancy

control_reg=2000

0 to 2047 There is no default

status_hold_time=50 00

executedoncereg Address of redundancy 0 to 2047 (executed_once_reg) feedback register There is no default

executedoncereg= 2001

backupmodeaction

read_only, mute, never

backupmodeaction

(backup_mode_action mode )

Redundancy backup

Default=never

mute

DiagReg (diag_reg)

Address at which to place diagnostic counters


DiagReg=1500

list

Enables listing of point [off, false, no], [on, true, list=on database as yes] interpreted from Default=off configuration file

CON_015


3.3.5 G ROUP O PERATION P AR AM ET ER S The Group Operation parameters introduce a point group which specifies the mapping between LC Module registers and Modbus addresses. Group Operation parameters also define the Modbus commands used to make the data transfers implied by those mappings. The following table defines the Group Operation parameters (valid aliases for the Group Operation parameters are shown in parentheses): Group Operation Parameters PA RAMETER (AL IAS)

D ESCRIPTION


E XAMPLE

group

Group introducer, followed by group name

Valid character string

group=Unit 1 inputs

operation

Group operation periodic, triggered, specifies when a group gated is transacted Default=periodic

operation=triggered

interval

Specifies how often (in 0 through 3600000 milliseconds) periodic Default=0 group operation is attempted

interval=10000

triggerreg (trigger) (triggerpnt)

Address of register used to trigger a triggered group

triggerreg=500

gatereg (gate)

Address of register 0 to 2047 used to enable a gated There is no default

(gatepnt)

group

slave (slave_address)

Modbus slave address 1 to 255 There is no default

function (func)

Modbus function code mnemonic

CON_015


gatereg=510

slave=5

RCS,RIS,RHR,RIR,FSC func=RHR ,PSR,RES,FMC,PMR There is no default

17


3.3.6 M ODBUS A DDRESS AND P OINT M A PPIN G P AR AM ET ER S The address mapping parameters that specify correspondences between Modbus addresses and LC module registers appear after the group operation parameters. The following table defines the Modbus point mapping parameters (valid aliases for the Modbus point mapping parameters are shown in parentheses): Modbus Point Mapping Paramete rs PA RAMETER

D ESCRIPTION


E XAMPLE

point (pnt)

Ovation LC module style pseudo-point name

See Pseudo-Point Name table.

point D0100

address (addr)

Modbus address number

0 through 65535

address 1234

data_type

Specifies interpretation int16, short, uint16, of Modbus data values word, int32, long, uint32, ulong, int32rev, uint32rev, bcd4, bcd8, float, floatrev

data_type uint16

conv_type (cv)

Conversion type (See 0=no conversion Ovation Record Types 1=linear Reference Manual.) 2=fifth order poly 3=square root 4=exponential

conv_type 1

(AL IAS)

5=square root of fifth order polynomial

18

1v (C0)

Conversion Coefficient float 1

1v=1.0

2v (C2)


2v=.375

3v (C3)


3v=10.00

4v (C4)


4v=3.14159

5v (C5)


5v=50

6v (C6)


6v=-100

CON_015


The point parameter for each Modbus address is entered as though it were an Ovation point name (a pseudo point name). Analog values and digital states are exchanged between the Ovation Controller and the Ovation LC module through a shared memory region which is thought of as consisting of 16-bit registers. The point reference consists of an initial letter which indicates the type of reference, and a four digit number which specifies an LC register address, or offset into the shared memory region. This is described in the following table. Pseudo-Point Names as LC Addresses P OINT N A M E P OINT TYPE

#L C REGS

VA L UE TYPE

R EAD A LGORITHM A N D F ORMAT 1

2

W RITE A LGORITHM A N D F ORMAT 1

2

D0000 to D2047

Digital

1

I0000 to I2047

Analog

1

integer

SLCAIN -0 3 format

SLCAOUT - 0 3 format

F0000 to F2046

Analog

2

float (IEEEE)

SLCAIN -1 4 format

SLCAOUT - 1 4 format

S0000 to S2045

Analog

3

float (IEEEE)

SLCAIN SLCAOUT 5 5 2 or 3 format 2 format

SLCDIN

SLCDOUT

1

See Ovation Algorithm Reference Manual for more information about the SLC algorithms and their formats. 2

The interface software and algorithm use a single 16 bit word to represent the digital status word. (See Ovation Record Types Reference Manual.) The state of the point is represented as the least significant bit of the word. When reading a digital using the SLCDIN algorithm, some of the remaining bits of the digital status word are used to set the quality of the point. 3

When using the SLCAIN or SLCAOUT algorithm with format 0 and an I0000 style point designator, the interface software and algorithm pass a single 16 bit word treated as a signed integer. 4

When using the S LCAIN or SLCAOUT algorithm with format 1 and an F0000 style point designator, the interface software and algorithm pass a four byte (two word or two register) IEEE format floating point value. 5

The interface software and algorithm pass a 16 bit word which represents the Analog Status Word followed by a four byte (two word or two register) IEEE format floating point value. A single S0000 style point uses three LC registers. This must be taken into account when laying out the data.

CON_015

19


3.3.7 M ODBUS C OMMAND M NEMONIC K EYWORDS A mnemonic keyword is used to represent each of the supported Modbus commands in the LC Modbus link configuration or point-group file. These keywords and their corresponding Modbus commands are detailed in the following table. Modbus Commands

20

MNEM

M ODBUS C OMMAND

F UNCTION CODE

D ESCRIPTION

RCS

Read Coil Status

01

Reads Modbus Coil Statuses such as C0001

RIS

Read Input Status

02

Reads Modbus Input Statuses such as I10002

RHR

Read Holding Registers

03

Reads Modbus Holding Registers such as HR40001

RIR

Read Input Registers

04

Reads Modbus Input Registers such as IR30001

FSC

Force Single Coil

05

Writes a Modbus Coil such as C0001

PSR

Preset Single Register

06

Writes a Modbus Holding Register such as HR40001

RES

Read Exception Status

07

Reads Modbus Exception Status

FMC

Force Multiple Coils

15

Writes multiple Modbus Coils such as C0001

PMR

Preset Multiple Registers

16

Writes multiple Modbus Holding Registers such as HR40001

CON_015


3.3.8 M ODBUS A DDRESSES The Modbus data space is divided into four types: 

Discrete inputs known as inputs.



Discrete outputs known as coils.



Sixteen-bit inputs known as input registers.



Sixteen-bit outputs known as holding registers.

The address field of Modbus messages is sixteen bits and so 65536 of each type can be addressed. This style of sixteen-bit numeric address is used in the LC/Modbus interface configuration file. Modbus has a traditional way of referring to these types. Each of the types is thought of as starting with a particular tens of thousands. For example the Input Registers start at IR30001 and continue to IR39999 while the Holding Registers start at HR40001 and continue to HR49999. It should be obvious that using this scheme, addresses for each space above 9999 are not available so the entire sixteen bit address space is not available. Therefore the traditional way of referring to Modbus addresses has been amended to allow addresses such as HR465534. The Modbus messages do not use the tens of thousands scheme to differentiate the types. The type is known explicitly because the messages contain function codes that specify the types. It is useful to be aware of the Modbus nomenclature because project documents specifying the data to be mapped with the interface have been known to use the traditional notation as well as the sixteen-bit address. The following table lists the traditional addresses in both the srcinal and the so-called six- digit version, the resultant protocol addresses as they would appear in the Modbus messages, and the Modbus functions used to move each type of Modbus storage. Note that the traditional addresses begin with one while the protocol addresses begin at zero. This is a common source of confusion when translating project documents into interface configuration files. Modbus Addresses M ODBUS S TORAGE

T RADITIONAL A DDRESS

P ROTOCOL A DDRESS

M ODBUS F UNCTIONS

Coils

C0001 to C9999

0 to 65535

RCS, FSC, FMC

0 to 65535

RIS

0 to 65535

RIR

0 to 65535

RHR, PSR, PMR

C00001 to C65534 Inputs

I10001 to I19999 I100001 to I165534

Input Registers

IR30001 to IR39999 IR300001 to IR365534

Holding Registers

HR40001 to HR49999 HR400001 to HR465534

CON_015

21


3.3.9 M ODBUS D AT A T YPE S PECIFIERS The Modbus Data Type field in each of the point group records specifies how the data in the Modbus messages is used. Several keywords may be recognized for each type. This field is optional. If the field is not entered, the value defaults to int16 . The specifiers and corresponding data format are listed in the following table. Modbus Data Type Specifiers S PECIFIER

D ESCRIPTION

int16, short

Treat two consecutive bytes as a sixteen bit signed integer.

uint16, word

Treat two consecutive bytes as a sixteen bit unsigned integer.

int32, long

Treat four consecutive bytes as a thirty-two bit signed integer.

int32rev

Treat four consecutive bytes as a thirty-two bit signed integer, least significant word first.

int32_bs

Treat four consecutive bytes as a thirty-two bit signed integer, most significant word first, bytes swapped within each word.

int32_ws_bs,

Treat four consecutive bytes as a thirty-two bit signed integer, least significant word first, bytes swapped within each word.

int32_enron uint32, ulong

Treat four consecutive bytes as a thirty-two bit unsigned integer.

uint32rev

Treat four consecutive bytes as a thirty-two bit unsigned integer, least significant word first.

uint32_bs

Treat four consecutive bytes as a thirty-two bit unsigned integer, most significant word first, bytes swapped within each word.

uint32_ws_bs,

Treat four consecutive bytes as a thirty-two bit unsigned integer, least significant word first, bytes swapped within each word.

uint32_enron bcd4

Treat two consecutive bytes as four binary coded decimal (bcd) digits.

bcd8

Treat four consecutive bytes as eight binary coded decimal (bcd) digits

float

Treat four consecutive bytes as a four byte IEEE format floating point number.

floatrev

Treat four consecutive bytes as a four byte IEEE format floating point number, least significant word first.

float_bs

Treat four consecutive bytes as a four byte IEEE format floating point number, most significant word first, bytes swapped within each word.

float_ws_bs,

Treat four consecutive bytes as a four byte IEEE format floating point number, least significant word first, bytes swapped within each word.

float_enron

22

CON_015


Modbus protocol (see page 24) provides more detail about these Modbus data types. Several values and the corresponding message representation are shown for each data type. Note the differences between a signed and unsigned value of the same length and the difference between a normal and reversed representation of the same value. For example, the message representation FF FF FF FF is -1 if the specifier is int16 (signed) and 65535 if the specifier is uint16 (unsigned).

CON_015

23


3.3.10 H OW M ODBUS P ROTOCOL R EPRESENTS 32- BIT Q UANTITIES The Modbus protocol defines no data object larger than a 16-bit register. Thirty-two bit quantities are represented at the application level by placing them in two consecutive 16-bit registers. Manufacturers of devices that support the Modbus protocol have placed the halves of the 32-bit quantity into Modbus messages in various orders. The Modbus protocol specifies that the high order byte of a 16-bit register is placed in the Modbus message first, the low order byte is second. Therefore, when the Modbus data type specifiers (as listed in the Modbus Data Types (see page 22)) int32, uint32, and float are used, the high order word of the 32-bit quantity is placed in the message first in an extension of the Modbus byte order. Many manufacturers of devices that use the Modbus protocol place the low order word into the Modbus message first. These include Modicon, the srcinator of the Modbus protocol. This word order is accommodated by using the LCModbus data type specifiers int32rev , uint32rev , and floatrev , where the rev suffix indicates the reverse of the order in which the Modbus byte order is extended to word order. Some manufacturers violate the byte order specified by the Modbus protocol when placing 32-bit quantities into Modbus messages. The combination of two suffixes, _bs for byte swap, and _ws for word swap is used to specify these. This yields int32_bs, in32_ws_bs, uint32_bs, uint32_ws_bs, float_bs, and float_ws_bs. Perhaps the most frequently used of these Modbus-violating representations is when both the two 16-bit words are swapped and the bytes composing those words are swapped. This results in exactly the opposite byte order of the data specifiers without suffixes. This is the byte order that would be produced by ignoring the Modbus specification and using a “C” programming language pointer de-reference to move the quantity into the Modbus message buffer if the machine uses the intel order in memory as PC-compatible computers do. Enron produced a Modbus implementation that uses this opposite byte order and also uses the Daniel floating point protocol violation. The LC Modbus data type specifiers int32_ws_bs, uint32_ws_bs, and float_ws_bs are therefore synonymous with the specifiers int32_enron, uint32_enron, and float_enron. Examples of 32-bit quantities placed in Modbus messages in each of these orders can be found in the following table. When the 32 bit data type specifiers int32, uint32, int32rev, uint32rev, bcd8, float, floatrev, int32_bs, int32_ws_bs, uinit32_bs, uint32_ws_bs, float_bs, and float_ws_bs are used, two consecutive Modbus registers from the message are interpreted and a Modbus address should be skipped in the point group. Modbus Data Type Examples DA TA TYPE int16

24

I NTERNAL

VA L UE

M ESSAGE 1

00 01

-32768

80 00

-1

FF FF

CON_015


DA TA TYPE uint16

int32

int32rev

int32_bs

int32_ws_bs

I NTERNAL

VA L UE

M ESSAGE 1

00 01

32768

80 00

65535

FF FF

1

00 00 00 01

32768

00 00 80 00

-2147483648

80 00 00 00

-1

FF FF FF FF

1

00 01 00 00

32768

80 00 00 00

-2147483648

00 00 80 00

-1

FF FF FF FF

1

00 00 01 00

32768

00 00 00 80

-2147483648

00 80 00 00

-1

FF FF FF FF

1

01 00 00 00

32768

00 80 00 00

-2147483648

00 00 00 80

-1 uint32

uint32rev

uint32_bs

uint32_ws_bs

CON_015

FF FF FF FF

1 32768

00 00 00 01 00 00 80 00

2147483648

80 00 00 00

4294967295

FF FF FF FF

1

00 01 00 00

32768

80 00 00 00

2147483648

00 00 80 00

4294967295

FF FF FF FF

1

00 00 01 00

32768

00 00 00 80

2147483648

00 80 00 00

4294967295

FF FF FF FF

1

01 00 00 00

32768

00 80 00 00

2147483648

00 00 00 80

4294967295

FF FF FF FF

25


DA TA TYPE bcd4

bcd8

float

floatrev

float_bs

float_ws_bs

26

I NTERNAL

VA L UE

M ESSAGE 1

00 01

1234

12 34

5555

55 55

1

00 00 00 01

12345678

12 34 56 78

66666666

66 66 66 66

0.0

00 00 00 00

1.0

3F 80 00 00

-1.0

BF 80 00 00

3.1415927

40 49 0F DB

-3.1415927

C0 49 0F DB

6000000

4A B7 1B 00

0.0

00 00 00 00

1.0

00 00 3F 80

-1.0

00 00 BF 80

3.1415927

0F DB 40 49

-3.1415927

0F DB C0 49

6000000

1B 00 4A B7

0.0

00 00 00 00

1.0 -1.0

80 3F 00 00 80 BF 00 00

3.1415927

49 40 DB 0F

-3.1415927

49 C0 DB 0F

6000000

B7 4A 00 1B

0.0

00 00 00 00

1.0

00 00 80 3F

-1.0

00 00 80 BF

3.1415927

DB 0F 49 40

-3.1415927

DB 0F 49 C0

6000000

00 1B B7 4A

CON_015

3.4 Creating an AUTOEXEC.BAT File

3.3.11 D AT A C ONVERSION The data conversion specified by fields Conversion Type and Conversion Factors 0 through 5 is applied to data coming from the Modbus slave before it is placed in LC registers. These fields are optional. If the fields are not entered, data conversion defaults to no conversion. A list of these types and the equation used with each is provided in the following table. Data Conversions N UMBER

C ONVERSION

TYP E

E QUATION

0

No Conversion (Default)

Y=X

1

Linear

Y = C1X + C2

2

Fifth Order Polynomial

Y = C1 + C2X + C3X2 + C4X3 + C5X4 + C6X5

3

Square Root (SQRT)

Y = C1 [SQRT (X + C2)] + C3

4

Exponential (EXP)

Y = C1 [EXP (C2X)] + C3

5

SQRT of Fifth Order Polynomial

Y = SQRT (C1 + C2X + C3X2 + C4X3 + C5X4 + C6X5)

The Ovation LC Module has a 12 MHz 80186 equivalent CPU with no floating point co-processor. Specifying a non-zero data conversion in the LC/Modbus configuration file therefore imposes a severe performance penalty on the interface. Total transfer times have in the past been seen to double for configurations where most of the points were analog and all were scaled in the LC Module, hence throughput was halved. The scaling can easily be done instead in the Ovation controller without incurring a performance penalty.

3.4

C

REATING AN

A UTOEXEC.B A T F I L E

You must create an AUTOEXEC.BAT file so the interface will start automatically when you apply power to the LC Module or when you reset the LC module. After you have created the file, you must install it on the LC module. The AUTOEXEC.BAT file contains two lines: 

The first line sets an environment variable that informs the run-time library that the module has no floating point co-processor.

set NO87= where = any text string 

The second line invokes the interface executable program and specifies the configuration file name:

modbus - f

CON_015

27

3.4 Creating an AUTOEXEC.BAT File

3.4.1 T O C REATE THE A UTOEX EC. BAT F IL E 1.

Create the AUTOEXEC.bat file in a text editor.

2.

Refer to the example AUTOEXEC.bat file:

set NO87=pr oj ect modbus - f pr oj . cf g - d 3.

Several command line options are available for debugging purposes. Use the options that are applicable for your interface functions. These options are described in the following table:

Command Line Options for Debugging AUTOEXEC.BAT

28

O PTION

D ESCRIPTION

-f

Specifies the name of the configuration file. This parameter is required .

-p

Specifies the platform on which the interface is loaded: PC, QLC, or RLC.

-d

Enables display of the LC module registers. This register display slows down the operation or the interface and should be used only while debugging.

-a

Enables display of the Modbus messages transferred between the LC module and the Modbus slaves. The message display slows down the operation of the interface and should only be used while debugging.

-l

Causes the interface software to list the point database as interpreted from the configuration file.

-e

Specifies the level of the syslogging parameter, that is, sets the debug message level (1 - 7).

4.

Make the desired edits, save the file, and verify it.

5.

Load the edited file, along with the configuration file, to the LC module.

CON_015

S

ECTION

4

OPERATION OF LC MODBUS INTERFACE

IN THIS SECTION Initializing the Link Controller Modbus Interface ...............................................................29 Troubleshooting LC Modbus Operation ............................................................................ 29

4.1

I

NITIALIZING THE

L INK C ONTROLLER

M ODBUS I NTERFACE

Before you can begin to use the LC Modbus, you need to ensure that the LC module ram disk has been formatted and the DOS operating system has been loaded. These steps are typically performed by Emerson during factory testing and do not need to be repeated. (See Ovation I/O Reference Manual and Ovation Link Controller (LC) User Guide for information for information about these processes. After DOS has been installed on the LC module and the LC disk has been formatted, use the following steps to prepare the Ovation LC module for operation as a Modbus master:

4.2

1.

Copy the Ovation LC/Modbus executable program modbus.exe to the Ovation LC module ram disk.

2.

Prepare the configuration file (see page 17) and copy it to the Ovation LC module ram disk.

3.

Copy the autoexec.bat file (see page 27) to the LC ram disk.

4.

Copy the ram disk image to the non-volatile Ovation LC module flash memory using the utility rlcflash.exe .

5.

Reset the Ovation LC module by removing the LC electronics module from the base unit and reinstalling it. Alternatively, the module may be reset by pressing the key sequence Ctrl-ShiftDel.

6.

Monitor the PC host to ensure the LC module starts, boots DOS, and starts the link software successfully.

T

ROUBLESHOOTING

L C M ODBUS O PERATION

During LC Modbus interface operation, several features are available for confirming interface operation and diagnosing problems. These features are implemented using the following functions: 

syslog parameter (see page 30) determines what error messages are displayed.



Keyboard driven diagnostics (see page 30) used during interface operation



LEDs (see page 32) on the LC module

CON_015

29

4.2 Troubleshooting LC Modbus Operation

4.2.1 D ISPLAYING E RROR M ESSAGES The parameter syslog is used to select the severity of messages that will display, with on e being most severe and seven being least severe. This attribute can also be set using the command line parameter -e. The severity levels are listed in the following table. The interface software generates messages at levels log_info, log_err, log_notice, and log_debug. The interface will display those messages at or below the level set by syslog. Therefore, if syslog is set to one, only those messages associated with errors that cause the interface to abort are displayed. If syslog is set to seven, all messages are displayed. The default value of syslog is three , which means messages of severity log_err and below will be displayed. Syslog Message Severity Levels L EVEL

30

S EVERITY

D ESCRIPTION

0

log_emerg

Emergency

1

log_abort

Abort

2

log_crit

Critical

3

log_err

Errors

4

log_warning

Warnings

5

log_notice

Notices

6

log_info

Informative

7

log_debug

Debugging (Verbose)

CON_015


4.2.2 R UNTIME D IAGNOSTICS There are keyboard driven diagnostics available during interface operation. These diagnostics are selected at the keyboard of the external PC host which is used to initialize the Ovation Link Controller module. The diagnostic information appears on the external host PC screen. The information comes to the host PC through the serial connection between the PC and the Ovation LC module. The keystrokes used to operate the diagnostics are listed in the following table. Those marked with an asterisk (*) are active only when register display is enabled. Diagnostic Keys K EY

A CTION ESC

Exit the Ovation LC/Modbus interface program

t

Toggle display (of registers)

a

Toggle analyze mode (Modbus messages)

PgUp *

Page up through registers

PgDn *

Page down through registers

h*

Display registers in hexadecimal notation

d*

Display registers in decimal notation

f*

Display registers pairs as floating point

c*

Clear all registers (set to zero)

i*

Set registers to consecutive numbers

g*

Go to a specific page number (prompts for page)

m

Modify a memory location (prompts for location)

x

Examine specified point (prompts for point name)

2*

25 line display

5*

50 line display

+

Increase SysLogPriority by one

-

Decrease SysLogPriority by one

* Indicates key only active when registers are displayed.

CON_015

31


Sample Debugging Session The following debugging actions provide a sample of using the keystrokes for debugging: 1.

Press the t key to enable the display of registers. The Page Up and Page Down keys are used to page through the registers. The keys h, d, and f can be used to change the way registers are displayed to hexadecimal, decimal, and floating point respectively.

2.

Choose to change the value of a register by pressing the m key. You are prompted to enter a register number and value. You might choose to look at a register specified by a pseudo-point name by pressing the x key. You will then be prompted to enter a pseudo- point number and the value will be displayed.

3.

After using the register display to investigate a problem, in order to see the outgoing Modbus message and the subsequent response, press the t key to disable the register display and the a key to enable analyze mode. The messages are displayed on the external host PC screen.

The Modicon Modbus Protocol Reference Guide PI-MBUS-300 provides the detailed protocol information needed to interpret the messages. The Modbus protocol specification is also available on the World Wide Web at: http://www.modicon.com

4.2.3 I NTERPRETING THE O VATION L INK C ONTROLLER M ODULE L ED S The row of LEDs on the face of the LC electronics module displays information about the operation of the interface. These LEDs are labeled 1 through 8 on the module case. The meaning of each LED is shown in the following table: LED Significance LED

S IGNIFICANCE LED 1

Interface is transmitting a Modbus message

LED 2

Interface is receiving

LED 3 - LED 7 LED 8

No significance Ovation Link Controller module is in control (when configured as one of a redundant pair)

As can be seen in the table, LED 1 indicates that a message is being sent. LED 2 indicates that characters are being received. During normal operation, LED 1 and LED 2 alternate rapidly. If LED 1 appears to be on for a very short time and LED 2 is never illuminated, this usually indicates the interface software is timing out on every message because no responses are received. When two Ovation LC modules are configured as a redundant pair (see page 33), LED 8 is used to indicate that the LC module is the one in control. .

32

CON_015

S

5

ECTION

OVATION L INK CONTROLLER MODULE REDUNDANCY

IN THIS SECTION What is Redundancy? ....................................................................................................... 33 What Parameters are Used for Redundancy?.....................................3 3 What Configuration Algorithms areFile Used for Redundancy?.................................................................... 34 Configuring Redundant Hardware .................................................................................... 34 LC Modbus Interface Redundancy Operation...................................................................35 Bumpless Transfer ............................................................................................................ 35 Backup Mode Action ......................................................................................................... 36

5.1

W

HAT IS

R EDUNDANCY ?

Redundancy is used throughout the Ovation system as a safeguard against a complete system failure whenever a single component of the system fails. For example, if a Controller fails, the redundant backup Controller takes over the Controller functions and the system continues to function.. In the same manner, using two redundant Link Controller modules prevents failure of the LC Module Interface if one LC module fails. A redundant LC/Modbus link uses two LC modules to communicate with the field devices. One of the modules is designated the primary module; the other is the secondary module. During operation, the primary LC module communicates with the field devices and moves the data to/from the Ovation Controller. If communication between the primary module and the field devices fails, the secondary module takes over communication.

5.2

W

HAT

C ONFIGURATION

F ILE P A R A M E T E R S

A RE

U SED FOR R EDUNDANCY ?

The following configuration file parameters are used to configure redundancy: 

controlreg (see page 35) - Address of register used to control redundancy



ExecutedOnceReg (see page 35) - Address of redundancy feedback register



backupmodeaction (see page 36) - Redundancy backup mode



watchdog_time (see page 39) - Specifies time to satisfy watchdog after last good transaction. Used with SLCSTATUS algorithm to determine communication success.

CON_015

33

5.3 What Algorithms are Used for Redundancy?

5.3

W

HAT

A LGORITHMS ARE

U SED FOR R EDUNDANCY ?

The SLC algorithms include support for redundant links. (See Ovation Algorithms Reference Manual.) The algorithms which provide data I/O for the Ovation LC module have the ability to transfer the data between the Controller and either of a redundant pair of LC modules. These algorithms include the following: 

SLCAIN



SLCAOUT



SLCDIN SLCDOUT

 

SLCGPIN



SLCGPOUT

The hardware addresses of both LC modules are provided to the algorithm as parameters. The digital inputs, PSTA and SSTA, are used to select the primary or secondary module for the data transfer. The SLCSTAT algorithm is used in the redundancy scheme to determine if the selected module is still communicating with the field devices. The LC module’s hardware watchdog timer state indicates the success or failure of the communication.

5.4

C

ONFIGURING

R EDUNDANT

HA RDWA RE

You need to consider the connection of redundant LC modules to field devices. Devices designed for redundancy haveports. two independent serial ports. In this case, connect each Ovation LC module to one ofoften the serial Some multi-drop serial networks can accommodate multiple masters. In this case, connect the two LC modules to the one network by using the RS-485 Group 2 personality module. Consult the field device manufacturer’s documentation to determine the appropriate connection for redundant LC modules.

34

CON_015

5.5 LC Modbus Interface Redundancy Operation

5.5

LC M ODBUS I NTERFACE

R EDUNDANCY

O PERATION

Ovation LC Modbus Interface redundancy involves coordinating the data flow between the Ovation Controller and the Ovation LC modules and enabling/disabling communication between each module and the field devices. Redundancy is driven by the Ovation Controller. The Controller decides which module should transfer data and which module should communicate with the field devices. The Controller bases these decisions on feedback from each module about the state of the communication. A redundant LC Modbus link uses SLC algorithms to move data to and from the LC module just as a non-redundant link does, but with these exceptions: 

The algorithms which transfer data to the LC module (that is, SLCAOUT and SLCDOUT) must be repeated for the secondary LC, because these algorithms cannot transfer data to both cards simultaneously.



The algorithms which transfer data from the LC module (that is, SLCAIN and SLCDIN) must have both cards’ hardware addresses entered and must use the inputs PSTA and SSTA to select which of the card’s data to transfer.



An SLCDOUT algorithm is used to send a digital state to the LC register specified with the controlreg attribute in the interface configuration file. This digital is used to tell the LC module to communicate or not to communicate. One algorithm is entered for each of the modules so that each can be enabled independently.



An SLCDIN algorithm is added to read the LC register specified as ExecutedOnceReg . This register goes true when the LC module has successfully completed all the configured transactions once.



The SLCSTAT algorithm must be included in the Controller’s configuration with both LC modules’ hardware addresses entered. The watchdog timer bit (bit 0) of variables PSTA and SSTA is monitored to ascertain the success of the communication.

In practice, the Controller selects the primary LC module to communicate with the field devices by setting its controlre g true . The Modbus interface program, which has been testing this digital, begins to communicate with the field devices. After the primary LC has successfully made each of the configured transactions once, it signals back to the Controller via the ExecutedOnceReg . If communication is successful, the interface program updates the hardware watchdog timer. If communication fails, the timer expires and the Controller, which is monitoring the watchdog, sets the primary LC module’s controlreg false and the secondary module’s controlreg true . The secondary LC module then takes over communicating with the field devices.

5.6

B

UMPLESS

T RANSFER

The danger exists that during the transfer of control from either LC module to its redundant partner, bad data could be transferred to either the Controller or to the field devices. This possibility is overcome by two techniques, one for each data transfer direction: 

Controller to Field Devices (see page 36)



Field Devices to Controller (see page 36)

CON_015

35

5.7 Backup Mode Action

5.6.1 S ENDING D AT A FR OM THE C ONTROLLER TO F IELD D EVICES For data going from the Controller to the field devices, the algorithms SLCAOUT and SLCDOUT are doubled for the second LC module. A single set of these algorithms could be used to send the data to the SLCs by juggling the states of the PSTA and SSTA inputs to the algorithm. If an LC module’s communication was enabled before PSTA and SSTA were switched, the newly enabled module would send either invalid or old data to the field devices. This is avoided by doubling the algorithms for each LC module’s hardware address and always setting PSTA to true .

5.6.2 S ENDING D AT A FR OM THE F IELD D EVICES TO THE C ONTROLLER For data coming from the field devices to the Controller, a single set of algorithms with both modules’ hardware addresses entered is used. By juggling the states of PSTA and SSTA, the data is received from one or the other of the LC modules. If, however, these states were changed when control was passed from one LC to the other, there would be a period of time before the newly enabled LC had completed all transactions with the field devices. During this time, old or invalid data would be read from the LC registers. This problem is alleviated by logic in the Controller that waits until the executedoncereg has gone true to switch the incoming algorithms from one module to the other.

5.7

B

A CK UP

M ODE A CTION

The backupmodeaction parame ter tells the interface program what to do with a module in a redundant pair. The backupmodeaction 

attribute can have one of the following values:

never When backupmodeaction is configured never , the LC module ignores the control_reg parameter and never goes out of control. This is for standalone LCs which are not part of a redundant link.



mute When bakupmodeaction is configured mute , the LC module makes no attempt to communicate when the Controller has disabled the card via the control_reg.



read_only When backupmodeaction is configured read_only, the LC module continues to read data when it is not in control. The LC does not attempt to write data to the field devices. This is used in those few cases where the hardware allows both LCs to communicate with the field devices at the same time. When the switchover is made from one redundant pair to the other, the newly enabled card will already have current data and algorithms and will not have to be skipped (see page 35).

36

CON_015

S

ECTION

6

INTERFACE TIMING CONSIDERATIONS

IN THIS SECTION Interface Timing................................................................................................................. 37 Balancing Communication Priorities with the interval parameter ......................................3 7 Using InterMsgDelay to Throttle Communication ............................................................. 38 Setting MessageTimeout .................................................................................................. 38 Significance of watchdog_time.......................................................................................... 39

6.1

I

NTERFACE

T IMING

The following overall parameters and group operation parameters affect the interface timing:

6.2



interval - Specifies an interval in milliseconds for a periodic group



InterMsgDelay - Used to specify a delay between transactions



MessageTimeout - Time the interface waits for a response before giving up



watchdogtime - Interval after which, if there are no good transactions, watchdog expires

B

A L A NCING

C OMMUNICATION

P RIORITIES WITH TH

E INTERVAL

PARAMETER

The sample configuration file (see page 14) shows a periodic group with interval = 1000, another with interval = 2000, and a third with no interval specified. A group with no interval specified defaults to an interval of zero milliseconds. The intervals assigned to the groups are used to balance the communication between more and less important data or between data that changes more quickly or more slowly. For example, an interface which is conveying both rapidly changing contact closures and slowly changing temperature values might have the point groups representing the contact closures defaulted to an interval of zero milliseconds while the point groups representing the temperature values might be assigned an interval of five seconds (5000 milliseconds). During operation, the interface software traverses the list of point groups and examines each to determine if the transactions specified by the group should be performed. For periodic groups, if the elapsed time since the last performance is greater than the specified interval, the transactions are performed. The transaction of messages with the Modbus slaves takes finite time. The time for a transaction depends on the baud rate, the length of each message, and any processing time the slave needs to interpret the request and build a response. It should be clear that the intervals specified for the groups are a minimum interval. For example, a configuration with two point groups each with a specified interval of five seconds should have no trouble processing both transactions within five seconds. By contrast, a configuration with 100 groups each with a specified interval of one second will not result in all the transactions represented by the 100 groups being transacted within one second because 100 transactions will undoubtedly take longer than one second.

CON_015

37

6.3 Using InterMsgDelay to Throttle Communication

6.3

U

SING

I NTER M S G D ELAY TO

T HROTTLE C OMMUNICATION

Some field devices which communicate as Modbus slaves cannot tolerate constant traffic from the master. The LC/Modbus interface will, in the absence of non-zero intervals for periodic groups, attempt the next transaction in sequence as soon as the previous transaction has completed either successfully with a good response or unsuccessfully with a bad response or time-out. Some slaves require a delay between subsequent transactions of perhaps a few hundred milliseconds. Some manufacturers specify a maximum number of transactions per unit time. Some users of the LC/Modbus interface have attempted to use the interval group operation parameter slow down communication with They setHowever, the interval of all the groups to to attempt perhapstoseveral seconds in an attempt to the slowslave(s). communication. there is no way to add an offset into the interval and so when the interval expires,all the groups are attempted in quick succession and the slave is still overwhelmed. The InterMsgDelay group attribute, specified in milliseconds, alleviates the problem. Setting InterMsgDelay to 250 will result in a quarter of a second delay between transactions. The delay can be tuned to meet the requirements of the field device. Note that even when the InterMsgDelay is being used to throttle communication, the interval attribute of periodic groups can be used to favor certain data as described in the previous section.

6.4

S

ETTING

M ESSAGE T IMEOUT

When communicating using the Modbus protocol, the LC module as master sends a request to a slave and waits for a response from the slave. When the response is received, it is checked for validity, interpreted, and the data is used. If the slave does not respond, the interface must eventually stop waiting and go to the next transaction. The MessageTimeout overall parameter tells the interface software how long to wait for a response from the slave. The default value for the message timeout is 5000 milliseconds (five seconds). For some applications this will be too short. In general, the timeout should be set to the worst case response time of the slave. For example, if a field device needs a ten second timeout, the device may become busy performing its control task and not reply to a request. However the request is still in its buffer, and the device sends the old response after the LC/Modbus interface sends the next request. This violates the Modbus protocol. Modbus has no way to differentiate one message from another, so the LC/Modbus interface assumes the response is associated with its most recent request and the data is written to the wrong process points. The solution is to set the timeout to ten seconds, even though that may seem to be an unusually long timeout period.

38

CON_015

6.5 Significance of watchdog_time

6.5

S

IGNIFICANCE OF WATCHDOG

_ TIME

The LC Module’s hardware watchdog timer is used to discern the successful or unsuccessful operation of the interface. The most important use of the watchdog is for module redundancy (see page 33). The Ovation Controller monitors the watchdog via the SLCSTATUS algorithm. It uses the algorithm to determine when to switch from the primary LC module to the secondary LC module. The Controller accomplishes the switch by setting control_reg of the primary LC module to false and control_reg of the secondary LC module to true. Some users of the LC Modbus interface have attempted to alleviate timing problems by using the watchdog_time overall parameter. Setting the watchdog_time parameter will not eliminate link timing problems other than those connected with redundancy.

CON_015

39

S

7

ECTION

USING MULTI-DROP NETWORKS

IN THIS SECTION What is a Multi-Drop Network? ......................................................................................... 41 Multi-Drop Interface Configuration .................................................................................... 41

7.1

W

HAT IS A

M ULTI -D ROP N ETWORK ?

In the context of the LC Modbus interface, an RS-485 multi-drop network is a connection of the LC module as Modbus master and multiple field devices as Modbus slaves. The module serving as master polls each of the field devices to send or receive data. The majority of LC Modbus interfaces connect to one Modbus field device. Some connect to multiple field devices (see page 41) using a multi-drop RS-485 network. When the device that is communicating with the interface fails, the interface software waits for a response for the configured MessageTimeout time, then tries again for the configured number of retries. During this time the interface cannot communicate with the other field devices. The performance of the interface becomes unacceptable. You can perform certain recommended configurations (see page 41) for a multi-drop Modbus network to improve performance.

7.2

M

ULTI

-D ROP I NTERFACE

C ONFIGURATION

The multi-drop network will be either a four-wire (full-duplex) connection or a two-wire (halfduplex) connection. The four-wire connection has a separate transmit pair as well as a receive pair. The master communicates to the slaves on the transmit pair and the slaves reply on the receive pair. The four-wire connection is easier to configure, and a working configuration which supports an RS-232 connection (the most common) will work for a four-wire RS-485 connection without alteration. A two-wire connection has a single pair on which the LC module serves as master and the field devices serve as slaves both to transmit and to receive. Using a two-wire connection, the devices on the network must not drive the RS-485 line unless they are transmitting a message. This means that the interface software must control the RS-485 line driver via the RTS handshake signal internal to the personality module. You can control the RTS line by setting the flow_ctl overall parameter to rts_on_tx . Each device hears all the traffic on the line, including its own transmission. This means that the interface software must expect to receive and discard an echo of its own transmissions. You can direct the interface software to discard the echoes by setting the duplex overall parameter to half . This combination is illustrated in the following sample configuration file fragment:

* A t wo- wi r e mul t i - dr op RS- 485 net wor k pl at f or m RLC f l ow_ctl r t s_o n_t x dupl ex hal f

CON_015

41

S

ECTION

8

MODBUS PROTOCOL

IN THIS SECTION Modbus Protocol Messages.............................................................................................. 43

8.1

M

ODBUS

P ROTOCOL M ESSAGES

This section provides a brief overview of the Modbus protocol messages. A more detailed description is available in PI-MBUS-300 “Modicon Modbus Protocol Reference Guide” and on the world wide web at: http://www.modicon.com

CON_015

43

8.1 Modbus Protocol Messages

Modbus is a registered trademark of Modicon, Inc. The following figures are depictions of the Modbus functions supported by the LC Modbus Interface. The RTU protocol is depicted in the figures. The messages passed between the LC and the Modbus slave(s) can be seen during operation by enabling analyzer mode.

Figure 4: Functi on 01 - Read Output (Coil) Status

44

CON_015


Figure 5: Functi on 02 - Read Input Status

Figure 6: Function 03 - Read Holding Registers

CON_015

45


Figure 7: Functi on 04 - Read Input Registers

Figure 8: Functi on 05 - Forc e Sing le Coil

46

CON_015


Figure 9: Functi on 06 - Preset Single Register

Figure 10: Function 15- Force Multiple Coils

CON_015

47


Figure 11 : Functi on 16- Preset Multip le Registers

48

CON_015

S

ECTION

9

CONFIGURATION FILE EXAMPLES

IN THIS SECTION Configuration File Examples Included in This Section......................................................49 Configuration 50 Configuration File File Example Example 1 2 ............................................................................................ ............................................................................................ 52 Configuration File Example 3 ............................................................................................ 53 Configuration File Example 4 ............................................................................................ 54 Configuration File Example 5 ............................................................................................ 55

9.1

C

ONFIGURATION

F ILE E XAMPLES

I NCLUDED IN

T HIS S ECTION

The example files are: 

Example 1 (see page 50) illustrates an interface to a Controller that communicates using the Modbus protocol.



Example 2 (see page 52) illustrates reading sixteen bit Modbus registers into all four LC address name types.



Example 3 (see page 53) illustrates driving a large multi-segment BCD display from the LC module via Modbus.



Example 4 (see page 54) illustrates digital statuses that are read from a Modbus slave’s coils and inputs.



Example 5 (see page 55) is an example of a redundant LC/Modbus link.

CON_015

49

9.2 Configuration File Example 1

9.2

C

ONFIGURATION

F ILE E XAMPLE 1

An interface is needed to a Controller which communicates using the Modbus protocol. The Controller has analog values in registers HR40001 through HR40009 representing two temperatures and a pressure for each of three units. The 16-bit Modbus registers are holding data from twelve bit I/O and so range from 0 to 4095 counts. For the temperatures, 0 represents -50 degrees Fahrenheit, 4095 represents 250 degrees. For the pressures, 0 represents 0 psi and 4095 represents 200 psi. HR40010 bit 0 represents the running state for Unit 1, bits 1 and 2 represent the same for Units 2 and 3. Bits 3, 4, and 5 represent an alarm condition for each of the three units. In addition, coils C10001, C10002, and C10003 are used to start/stop Units 1, 2, and 3, respectively. In this example, the interface will operate at 9600 baud with no parity and eight data bits. The Controller is at Modbus unit address 5. Remember that the asterisk character (*) introduces a comment. * Exampl e 1 pl at f or m RLC baud 9600 * co ul d expl i ci t l y speci f y par i t y and dat a bi t s her e but "none" * and 8 are t he def aul t s gr oup " Uni t s 1 t hr ough 3 i n" oper at i on per i odi c sl ave 5 f unct i on RHR poi nt S0000 address 00 00 dat a_t ype conv_t ype 1 1v 0. 007326 2v - 50. 0 poi nt S0003 address 00 01 dat a_t ype conv_t ype 1 1v 0. 007326 2v - 50. 0 poi nt S0006 address 00 02 dat a_t ype conv_t ype 1 1v 0. 004884 2v 0. 0 poi nt S0009 address 00 03 dat a_t ype conv_t ype 1 1v 0. 007326 2v - 50. 0 poi nt S0012 address 00 04 dat a_t ype conv_t ype 1 1v 0. 007326 2v - 50. 0 poi nt S0015 address 00 05 dat a_t ype conv_t ype 1 1v 0. 004884 2v 0. 0 poi nt S0018 address 00 06 dat a_t ype conv_t ype 1 1v 0. 007326 2v - 50. 0 poi nt S0021 address 00 07 dat a_t ype conv_t ype 1 1v 0. 007326 2v - 50. 0 poi nt S0024 address 00 08 dat a_t ype conv_t ype 1 1v 0. 004884 2v 0. 0 poi nt D0030 address 0009. 00 poi nt D0031 address 0009. 01 poi nt D0032 address 0009. 02 poi nt D0033 address 0009. 03 poi nt D0034 address 0009. 04 poi nt D0035 address 0009. 05

50

ui nt 16

* 1 i nl et t emp

ui nt 16

* 1 out l et t emp

ui nt 16

* 1 press ure

ui nt 16

* 2 i nl et t emp

ui nt 16

* 2 out l et t emp

ui nt 16

* 2 press ure

ui nt 16

* 3 i nl et t emp

ui nt 16

* 3 out l et t emp

ui nt 16

* 3 press ure

* * * * * uni * uni

uni t 1 r unni ng uni t 2 r unni ng uni t 3 r unni ng uni t 1 al ar m t 2 al ar m t 3 al ar m

CON_015

9.2 Configuration File Example 1 gr oup "Uni t s 1 t hr ough 3 out " oper at i on per i odi c sl ave 5 poi nt poi nt poi nt

f unct i D0040 D0041 D0042

on FMC addr ess 0000 addr ess 0001 addr ess 0002

* uni t 1 r un * uni t 2 r un * uni t 3 r un

In Group One of the example, all the data to be read from the Controller is specified. The Modbus function Read Holding Registers will be used to retrieve the data from Slave 5. The first nine lines specify the analogs. An analysis of the first line shows that the Unit 1 inlet temperature will be placed in LC module register 0 in a format suitable for use with algorithm SLCAIN format 3. The holding register to be read is HR40001 (represented by zero in the protocol as explained in Section 3). The data will be read as a 16-bit unsigned integer, and converted by the equation y = ((250-(-50))/4095) * x + (-50) or y = 0.007326 * x + (-50.0). The next six lines read in the digitals. An analysis of the first of these shows the Unit 1 running signal will be placed in LC module register 30 in a format suitable for use with algorithm SLCDIN. The holding register to be read is HR40010 (represented by 0009 in the protocol). The zero bit of the register is used. The next five lines use bits 1 through 5. Group Two of the example specifies the signals to be sent to the Controller. The Modbus function Force Multiple Coils will be used to send the data to Modbus unit 5. An analysis of the first line shows the signal “unit 1 run” will be had from LC module register 40 using SLCDOUT. The state will be sent to coil C10001 (represented by 0000 in the protocol).

CON_015

51


9.3

C

ONFIGURATION

F ILE E XAMPLE 2

This example illustrates reading 16-bit Modbus registers into all four LC address name types. A mix of Modbus holding registers and input registers is used. Remember that the asterisk character (*) introduces a comment. * Exampl e 2 pl at f or m= RLC baud= 9600 gr oup "al l t ypes" oper at i on per i odi c sl ave 1 f unc RHR poi poi poi poi poi poi poi poi poi poi poi poi poi poi poi poi

nt nt nt nt nt nt nt nt nt nt nt nt nt nt nt nt

D0100 D0101 D0102 D0103 D0104 D0105 D0106 D0107 D0108 D0109 D0110 D0111 D0112 D0113 D0114 D0115

addr ess addr ess addr ess addr ess addr ess addr ess addr ess addr ess addr ess addr ess addr ess addr ess addr ess addr ess addr ess addr ess

0000. 00 0000. 01 0000. 02 0000. 03 0000. 04 0000. 05 0000. 06 0000. 07 0000. 08 0000. 09 0000. 10 0000. 11 0000. 12 0000. 13 0000. 14 0000. 15

f unct i on RI R poi nt I 0120 address 0000 poi nt I 0121 address 0001

* * * * * * * * * * * * * * * *

HR40001 HR40001 HR40001 HR40001 HR40001 HR40001 HR40001 HR40001 HR40001 HR40001 HR40001 HR40001 HR40001 HR40001 HR40001 HR40001

bi bi bi bi bi bi bi bi bi bi bi bi bi bi bi bi

t t t t t t t t t t t t t t t t

0 i 1 i 2 i 3 i 4 i 5 i 6 i 7 i 8 i 9 i 10 11 12 13 14 15

nt o LC r eg 100 nt o LC r eg 101 nt o LC r eg 102 nt o LC r eg 103 nt o LC r eg 104 nt o LC r eg 105 nt o LC r eg 106 nt o LC r eg 107 nt o LC r eg 108 nt o LC r eg 109 i nt o LC r eg 110 i nt o LC r eg 111 i nt o LC r eg 112 i nt o LC r eg 113 i nt o LC r eg 114 i nt o LC r eg 115

* I R30001 i nt o LC r eg 120 f or f or mat 0 * I R30002 i nt o LC r eg 121 f or f or mat 0

gr oup "mor e t ypes" oper at i on per i odi c sl ave 1 f unct i on RHR * next l i ne t r eat s HR40101 as si gned i nt eger and put s i n * LC r egi st er 1000 as f l oat i ng poi nt sui t abl e f or f or mat 1 poi nt F1000 addr ess 0100 * not e t hi s c onsumes t wo r egs f unct i on RI R poi nt F1002 addr ess 0100 * same as above but I R30101 f unct i on RHR * next l i ne t r eat s HR40102 and HR40103 as f our byt e f l oat poi nt S1004 address 01 01 dat a_t ype f l oat poi nt S1007 address 01 03 dat a_t ype f l oat

52

CON_015


9.4

C

ONFIGURATION

F ILE E XAMPLE 3

This example configuration file fragment illustrates driving a large multi-segment BCD display from the LC module via Modbus. The values to be displayed are sent to the LC as integers via SLCAOUT format 0. The interface software converts the values to BCD to send to Modbus holding registers (note Modbus input registers cannot be written to). The values are sent using Modbus function Preset Multiple Registers. * ei ght val ues t o ei ght hol di ng r egi st er s HR40201 t o HR40208 sl ave poi poi poi poi poi poi poi poi

CON_015

7 f unct i on PMR nt I 0000 addr ess nt I 0001 addr ess nt I 0002 addr ess nt I 0003 addr ess nt I 0004 addr ess nt I 0005 addr ess nt I 0006 addr ess nt I 0007 addr ess

0200 0201 0202 0203 0204 0205 0206 0207

dat a_t ype dat a_t ype dat a_t ype dat a_t ype dat a_t ype dat a_t ype dat a_t ype dat a_t ype

bcd4 bcd4 bcd4 bcd4 bcd4 bcd4 bcd4 bcd4

53


9.5

C

ONFIGURATION

F ILE E XAMPLE 4

In this example, digital statuses are read from a Modbus slave’s coils and inputs. The request is made every five seconds. A feedback is written to the slave’s coils at the same rate. The functions used in this example are Read Coil Status, Read Input Status, and Force Single Coil. Remember that the asterisk character (*) introduces a comment. gr oup " r ead st at uses" oper at i on per i odi c i nt erva l = 5 sl ave 1 f unc RI poi nt D0000 poi nt D0001 poi nt D0002 poi nt D0003 poi nt D0004 poi nt D0005 sl ave poi poi poi poi poi

S addr ess addr ess addr ess addr ess addr ess addr ess

0000 0001 0002 0003 0004 0005

* * * * * *

i i i i i i

1 f unc RCS nt D0006 addr ess nt D0007 addr ess nt D0008 addr ess nt D0009 addr ess nt D0010 addr ess

0000 0001 0002 0003 0004

* * * * *

c oi l c oi l c oi l c oi l coi l

0009 0010 0011 0012

* * * *

LC LC LC LC

nput nput nput nput nput nput

I 0001 I 0002 I 0003 I 0004 I 0005 I 0006

i i i i i i

C10001 C10002 C10003 C10004 C10005

nt o nt o nt o nt o nt o nt o

LC LC LC LC LC LC

r eg r eg r eg r eg r eg r eg

0 1 2 3 4 5

i nt o i nt o i nt o i nt o i nt o

LC LC LC LC LC

r eg r eg r eg r eg r eg

6 7 8 9 10

gr oup "wr i t e coi l s" oper at i on per i odi c i nt er val = 5 sl ave 1 f unc FSC poi nt D0020 addr ess poi nt D0021 addr ess poi nt D0022 addr ess poi nt D0023 addr ess

54

r eg r eg r eg r eg

20 21 22 23

to to to to

coi coi coi coi

l l l l

C10001 C10002 C10003 C10004

CON_015


9.6

C

ONFIGURATION

F ILE E XAMPLE 5

This is an example of a redundant LC/Modbus link. It is assumed that the Controller’s hardware has the ability to communicate with two LC modules. Remember that the asterisk character (*) introduces a comment. * r edundant l i nk pl at f or m RLC baud 19200 wat chdog_t i me 2000 l i nk_stat _r eg 1500 st at us_hol d_t i me 1100 cont r ol _r eg execut edoncer eg backupmodeact i on

1600 1700 mut e

gr oup "Di gi t al I ns" oper at i on per i odi c sl ave poi poi poi poi poi poi poi poi poi poi poi poi poi poi poi poi poi poi poi

1 f unct i on RHR nt D0000 addr ess nt D0001 addr ess nt D0002 addr ess nt D0003 addr ess nt D0004 addr ess nt D0005 addr ess nt D0006 addr ess nt D0007 addr ess nt D0008 addr ess nt D0009 addr ess nt D0010 addr ess nt D0011 addr ess nt D0012 addr ess

0700. 00 0700. 01 0700. 02 0700. 03 0700. 04 0700. 05 0700. 06 0700. 07 0700. 08 0700. 09 0700. 10 0700. 11 0700. 12

nt nt nt nt nt nt

0700. 13 14 0700. 15 0701. 00 0701. 01 0701. 02 0701. 03

D0013 D0014 D0015 D0016 D0017 D0018 D0019

addr ess addr ess addr ess addr ess addr ess addr ess

gr oup "Di gi t al Out s" oper at i on per i odi c sl ave poi poi poi poi poi poi poi poi poi poi

CON_015

1 f unct i on PMR nt D0100 addr ess nt D0101 addr ess nt D0102 addr ess nt D0103 addr ess nt D0104 addr ess nt D0105 addr ess nt D0106 addr ess nt D0107 addr ess nt D0108 addr ess nt D0109 addr ess

0800. 00 0800. 01 0800. 02 0800. 03 0800. 04 0800. 05 0800. 06 0800. 07 0800. 08 0800. 09

55

GLOSSARY OF TERMS A A PORT Port on a dual-attached Ovation station where the primary ring enters and the secondary ring exits. A DMIN TOOL The Administrative Tool is an Emerson utility that configures and downloads software to the drops through the use of GUIs. (Do not confuse this tool with the Sun utility also named Admin Tool.) A LARM A message or other signal intended to draw attention to a non-normal plant condition; for displays at user interfaces, an alarm reflects a point status. A LGORITHM 1) A set of rules, procedures, and mathematical formulas that define a desired control strategy. 2) Software provided with a Controller to automatically apply a specified algorithm during the system scan. 3) Ovation record type (LC) used to store tuning or data configuration for an algorithm in the system. A NALOG 1) Conditions or values that continuously vary across some range, represented by more than one bit. 2) A point that is an analog record type. Analog points are typically associated with I/O hardware that converts a field signal (for example, voltage) to a low-level signal used by the processor. Can be Long or Deluxe (Contrast with digital.) A PERIODIC POINTS Points whose values are scanned only as needed or as requested. See also periodic points. API Application Programming Interface, a set of routines or functions a program calls to tell the operating system to perform a task. A PPLICATION PROGRAM 1) Emerson-supplied programs that perform frequently required functions. 2) A series of loops, ladders, and/or algorithms run in a processor to control plant functions. Also known as an Application. 3) Userdefined or commercially available software that performs a specific task. A PPLY GUI button that accepts changes and window remains open.

CON_015

57

Glossary of Terms

ASCII American Standard Code for Information Interchange, a standard for representing computer characters. The set consists of 128 characters numbered from 0 to 127 and includes all the letters, numbers and punctuation marks. A SYNCHRONOUS Data communication that is not time critical. Typically provided on demand only and provided at different times (Contrast with synchronous). AUI CABL E Attachment Unit Interface Cable that interfaces the PCRR card to the MAU module in Ovation and WDPF migrated remote I/O applications. It contains four sets of individually shielded twisted pairs.

B B PORT Port on a dual-attached Ovation station where the secondary ring enters and the primary ring exits. B ANDWIDTH This is a description of how much information can be sent through a connection, usually measured in bitsper-second. B ASE A LARM SYSTEM Standard package used for viewing and acknowledging alarms. B ASE UNIT Hardware that consists of a printed circuit board, various connectors, and plastic housing and provides a mechanism for the user to land field wiring, and connects the field signals to the I/O module. The unit enables the I/O module to receive power, and also provides a low-impedance earth ground connection. Each Base Unit can house two sets of I/O modules, along with the associated field wiring. B AUD RATE Number of bits-per-second a modem can send or receive. BG See Packed Group Alarm. B IT A single digit number in base-2, either a 1 or a zero. This is the smallest unit of computerized data. B ITMAP FILE A file type that is used to define which icons will be shown when using iconic alarming.

58

CON_015

Glossary of Terms

B OOTSTRAP A software routine used to start computer operation (sometimes abbreviated ‘boot’). The bootstrap routine will typically occur automatically after a reset or power cycle, but may require manual keying. B RANCH Set of Base Units configured consecutively on a DIN rail with a local bus being connected to the Ovation I/O controller. B RIDGE Device that connects two or more network components and transmits data with source and destination addresses on different network components. B ROADCAST Process of sending information across the Ovation network. Broadcasts may be periodic (every second or every 0.1 of a second) or non-periodic (broadcast on demand only). B YTE A set of bits that represent a single character. Typically, 8 or 10 bits in a byte.

C CANCEL GUI button that cancels changes and dismisses window. CDDI Copper Distributed Data Interface (See FDDI). CDE Common Desktop Environment. A windowing system that runs on a Sun-compatible workstation under SunOs™ or Solaris™ CHARACTERISTICS A set of 8 alphanumeric characters associated with a point, used to represent user-defined aspects of the controlled process. Characteristics are used in alarm processing and point review/search functions. CLIENT A computer, or software program that is used to contact and obtain data from a server software program on a networked computer. COIL A ladder diagram element that represents either a real-world output field device (for example, a motor starter, solenoid, etc.) or an internal calculated point. (See discrete output.)

CON_015

59

Glossary of Terms

COLLISION Garbling of data when two or more nodes on the same network segment transmit data simultaneously. COLLISION DETECTION Switches are used to buffer simultaneous data messages and transmit them one at a time. COMPACT I/O MODULES Ovation I/O modules that do not contain a Personality module, only an Electronics module.

CONCENTRATOR FDDI node used to connect multiple Ovation stations to dual rings. Must have an “A” port, a “B” port, and at least one “M” port. CONDUCTING The state of a ladder diagram circuit when there is a continuous current path condition caused by closed contacts. CONFIGURATION Entering initial data into a processor, including definition of associated hardware. The configuration process typically includes downloading the drop database and other required software, and may involve editing configuration files(s). CONFIGURATION FILE Typically, an ASCII file containing statements that specify the configuration of a drop or function. These files may use standard operating system formats or may use an Emerson source language. CONTACT A ladder diagram element that represents either a real-world input device (for example, a push-button, switch, etc.) or an internal calculated point. (See discrete input.) CONTROL B UILDER AutoCAD based Power tool package used to build control drawings and generate source code from the drawings. CONTROL SHEET AutoCAD drawing that contains a graphical representation of a control scheme. CONTROL TASK Specific Controller area where all control sheets in that area are scanned at the same frequency. CONTROLLER A drop used to control a process. The Controller passes process control information over the network to other drops or devices that need it.

60

CON_015

Glossary of Terms

CPU Central Processing Unit, a microprocessor chip that powers a computer. May also refer to the case that holds the chip. CRT Cathode-Ray Tube, a tube of a monitor that produces images on the screen. Often used as a generic term for a computer monitor. CURSOR A character on a display screen indicating the current active location.

D DAC/DAS Dual Attachment Concentrator/Dual Attachment Station. Provides dual attachment to the FDDI or Fast Ethernet network. DATA HIGHWAY The communication link used to transfer time-critical information between drops or stations; also called a Local Area Network (LAN) or network. DATA STRUCTURES Four portions of an Ovation point record type.See also Dynamic Data, Static Data, Flash Data, and MMI Data. DATAB ASE A structured set of data, especially the point database in each Ovation drop (which defines srcinated and received points) and the Ovation master database (which defines the attributes of all points in the system). DCS Distributed Control System (such as Ovation). DEADBAND Range of values through which an input signal may vary without initiating an action that causes an observable change in the output signal. DEFAULT POINTS Points created by the Control Builder that have a defined naming convention. DEFAULT VALUE Used by a program when no specific value has been entered by the user. In the context of an interactive window or program, default may refer to a value specified in the function’s configuration file; in the context of configuring a function, default refers to the value used when there is no valid parameter entry.

CON_015

61

Glossary of Terms

DELUXE RECORD TYPE Optional Ovation record type. Has same functions as Long record type, plus plant mode limits and scan time displays. DESTINATION 1) The location in memory (such as a holding register) into which data is placed after the completion of certain programmable functions. (Contrast with source.) 2) A method of determining which alarms will be displayed at a specific user interface drop, based on the first point characteristic (typically representing the plant area).

DEVELOPER STUDIO Common interface that houses all of the integrated engineering tools necessary for a Microsoft Windows based Ovation system. DEVICE 1) Peripheral equipment connected to the Ovation system. 2) Algorithm specifically designed to simplify operation of open/close or stop/start devices, using feedback signals to monitor command completion. DHC Data Highway Controller. Printed-circuit board(s) in each drop that manage Data Highway communication. DIAGNOSTICS Functions that examine hardware or software to isolate malfunctions and errors. In the Ovation system, each drop incorporates automatic self-test diagnostics. If faulty operation is detected, a message or alarm is usually initiated. DIAGRAM A graphic depiction ofa plant process (or other data), displayed on a CRT at a user interface. DIALOG B OX A user interface window that prompts the user to enter information needed by a process. DIGITAL 1) Signals or conditions that are either on or off, represented by one bit. 2) A point that is a digital record type. Digital points are typically associated with discrete I/O hardware. Can be Long or Deluxe. (Contrast with analog.) DIN German standards organization (Deutsche Industrie Norm). DIP Integrated circuit enclosed in a plastic or ceramic housing and connected to pins. (Dual Inline Package)

62

CON_015

Glossary of Terms

DISCRETE I/O Individual hard-wired circuits connecting real-world field devices with the processor. Each discrete input provides the processor with a single digital signal based on a single state in the field device. Each discrete output sends a single digital signal to the field based on a single bit of data in the processor. DISTRIBUTED DATAB ASE Contains a subset of the information stored on the Master Database and is stored locally on a drop to allow that drop to operate if the Master Database is unavailable. A Distributed Database is present on each drop in the system and is continually updated as point information changes.

DISTRIBUTED I/O Hardware used to communicate between the processor and I/O modules located outside the processor chassis (also called Remote I/O). DOMAIN Logical collection of computers and users on a network that share a common security database. DOWNLOAD The process of transferring data to the memory or disk of a drop. DROP A station on the Ovation system. DROP L OADER Power Tool used to load control and srcinating point information into drops in an Ovation system. Links the Master Database with all the drops in the system. DROP POINT (DU) Record type used to store status information for a drop. Every drop must be configured with at least one point of type DU. DYNAMIC DATA Portion of an Ovation point record that is broadcast periodically in Dynamic Data Blocks (DDBs )by the srcinating drop and stored in volatile memory. DDB size is configured through the Ovation configuration tools (Admin Tool or Developer Studio).

E EDB

HISTORIAN

A drop on an Ovation control system that will collect, process, archive, and retrieve information that srcinates locally or throughout a geographically diverse set of process control sites.

CON_015

63

Glossary of Terms

ELECTRONICS MODULE Part of Ovation I/O that contains the electronics for processing I/O signals. Fits into the Base Unit and is typically configured by a Personality Module. EMS Expanded Memory Specification, a bank-switched memory management scheme that allows applications to access vast quantities of memory. ENGINEERING STATION An Ovation drop used for configuration and entry of system programs. ETHERNET A standard network protocol. Used to transfer non-time-critical information between drops.

F FAST ETHERNET Standard for transmitting data at 100 megabits per second. Similar to FDDI, but uses switches instead of concentrators, and dual-channel Ethernet NIC cards instead of dual-attachment FDDI NIC cards (Contrast to FDDI). FDDI Fiber Distributed Data Interface, a standard for transmitting data. Typically consists of a dual fiber-optic counter-rotating ring capable of carrying synchronous and asynchronous messages. Ring provides automatic “wrap-back” reconfiguration if a segment of the highway fails (Contrast to Fast Ethernet). FIREWALL Security system intended to protect an organization's computer network from external threats. All communication between the internal computer network and the outside world is routed through a server that determines if a message is safe to pass to the internal network. FLASH DATA Portion of an Ovation point record that is stored in the srcinating drop’s flash (or disk) memory and copied to receiving drop’s periodically. FORCE VALUE To set the value of a coil or contact to a desired state (on/off; 0, 1), regardless of other values in the ladder diagram. FOUNDATION FIELDBUS Digital, two-way, multi-drop communication link among intelligent measurement and control devices.

64

CON_015

Glossary of Terms

FTP File Transfer Protocol, a set of rules that allows one computer to download a file from another computer via a network connection. FULLY QUALIFIED POINT NAME Point name that specifically identifies a point by combining three parameters. Format is pointname.unit@network where point name contains a maximum of 16 characters, unit contains a maximum of 6 characters, network contains a maximum of 8 characters. Do not use when inserting a new point in Developer Studio, only insert point name parameter.

G GATEWAY Hardware or software that translates between two dissimilar protocols. GP See Packed Group. GRAPHICS B UILDER Power Tool used to create and edit System Process Diagrams that display on the Operator Station. GUI Graphical User Interface, an industry-standard term used to describe a user interface based on a windowing system such as Microsoft Windows™.

H HISTORIAN Dedicated drop in the Ovation system that collects and stores process point data and other information. HMI Human Machine Interface. Refers to drops that provide user interface functions. HOST Any computer on a network that is available for services to other computers. HYPERTEXT Any text that contains “links” to other documents-words or phrases in the document that can be chosen by the reader and which cause another document to be retrieved and displayed.

I I/O Input/Output, a general term for reading and writing data on a computer. Digitizes information from plant processes and passes it to the Controller for use in control strategies.

CON_015

65

Glossary of Terms

I/O B UILDER Power Tool used to define the I/O modules used in an Ovation system. I/O CONTROLLER Interface between the Network and the I/O. The Controller is located in the Ovation I/O cabinet. I/O MODULE Typically made up of an Electronics module and a Personality module. Performs the interface between the I/O Controller and the field devices. I/O NODES Ovation record types ICON A small graphic on a windowing system display that represents an active process or available function. Typically, an icon can be expanded into a window. ICONIC A LARMING Provides a mechanism to group alarms based on their priority and their plant area. Each group of alarms is represented by a preconfigured bitmap on the display. INIT TOOL Initialization Tool. Ovation utility that defines the system drops and the software packages on the drops through the use of GUIs. IOIC CARD Generic name for the Ovation I/O Interface card. Also known as PCI card. Options are PCQL, PCRL, and PCRR cards. IP A DDRESS A unique number consisting of 4 parts separated by dots, (for example, 129.228.36.38). Every computer that is on the Internet has a unique IP address. ISA Industry Standard Architecture, the 8- and 16-bit bus design used in most PCs.

K KB Kilobyte, A thousand bytes, (actually 1024 bytes).

66

CON_015

Glossary of Terms

L L ADDER 1) A diagram representing relay-type control logic (see coil, contact). 2) The user's control application program written in a variation of relay logic representation. LAN Local Area Network, A computer network limited to the immediate area, usually the same building. L ICENSE A necessary permission to use certain Emerson Process Control software products. L OG SERVER Utility used to define and modify custom reports for an Ovation system. Also known as Report Builder or Report Server. L OGIN 1) The account name used to gain access to a computer system. 2) The act of entering into a computer system. L ONG RECORD TYPE Default record type for Ovation points. Has full alarming and I/O capabilities. L OOP 1) A diagram representing a modulating or continuous process control. 2) The modulating control system for a particular physical process. L OOP INTERFACE MODULE (LIM) M/A Station interface connected to QLI card.

M M PORT Port on a Concentrator that attaches to a drop or station. M/A STATION Manual/Automatic Station. May be a diagram (sometimes called a “soft” M/A Station) that simulates the functions of a traditional panel-mounted control device. The M/A Station allows the operator to select manual or automatic control of the output, and to manipulate the set point or output value (depending on the selected control mode).

CON_015

67

Glossary of Terms

MAN PAGES UNIX on-line documentation for operating system functions. Type “man” and the desired topic. MASTER DATAB ASE Contains the entire process database. It is used for creating, modifying, and verifying control strategies and process points. At runtime, it supports queries of the process database, captures changes made to control and point attributes, and propagates those changes to the distributed database. MAU Media Attachment Unit. Interfaces the PCRR card (via the AUI cable) to an Ovation RNC card or a WDPF QOR card. MB Megabyte, A million bytes, a thousand Kilobytes. MENU A screen display representing a set of functions available to the user. MIGRATION Process where Q-Line I/O is interfaced to an Ovation Controller. MMI Man-Machine Interface. Refers to drops that provide user interface functions (such as the Operator Station). MMI DATA Portion of the Ovation point record that is saved in the Distributed Database in every Ovation workstation. MODEM MOdulator and DEModulator, A device that connects to a computer and to a phone line that allows the computer to talk to other computers through the phone system. MODULE POINT (RM) Ovation record type used to configure and monitor status of Ovation I/O modules. MONITOR 1) To observe the operation of a process without influencing it. 2) A computer terminal or CRT. MULTIPLE NETWORKS Function that enables separate Ovation Networks to communicate with each other, share data, and perform control actions.

68

CON_015

Glossary of Terms

N NETWORK Two or more computers connected together so they can share resources. NETWORK FOLDER A subfolder of the System folder in the Ovation Developer Studio. Only one Network folder can exist in the system. The Network folder is the parent folder to all files, objects, and folders that pertain to the Network. NIC Network Interface Card. Located in Ovation Controller cabinets, Stations, or HMIs. NODE 1) Any single computer connected to a network. 2) Active element on an FDDI or Fast Ethernet network that has an address. Can be a station or a concentrator. Up to 1000 nodes are permitted per network. NODE POINT (RN) Node point is used to configure and monitor PCRL, PCRR, PCRQ cards, and remote I/O nodes.

O OPENWINDOWS A windowing system that runs on a Sun-compatible workstation under SunOs™ or Solaris™.

OPERATOR STATION A drop in an Ovation system used to control and monitor plant operation. ORIGINATED POINTS Points that were created in the current drop. OVATION I/O Line of Emerson I/O modules. OVATION K EYBOARD Also known as the Membrane Keyboard, a specialized keyboard that is connected to an Ovation Operator Station serial port and allows the user to execute a set of standard functions from the keyboard. OVATION NETWORK Redundant, deterministic, high-speed network used for process control. Based on Fast Ethernet standards, it supplies input and output data to all the stations and Controllers connected to it.

CON_015

69

Glossary of Terms

OVATION SYSTEM An open architecture Emerson Process Control System that is based on ANSI and ISO network standards. Uses snap-in modules for I/O.

P PACKED DIGITAL POINT (PD) A point that is a packed digital record type. Holds either 32 separate digital values or two 16-bit register (analog) values. PACKED POINT A point that is a packed point record type. Packs up to 16 digital (logical) bits in one point record. Each bit may be separately configured for I/O scanning. Can be Long or Deluxe. PASSWORD A code used to gain access to a locked system. PC 1) Common acronym for personal computer 2) Common acronym for programmable controller. PCI Peripheral Component Interconnect. Generic name for the Ovation I/O Interface card. Also known as IOIC card. Options are PCQL, PCRL, and PCRR cards. PCL Printer Control Language. Printer language that drives most laser and inkjet printers. PCQL CARD Ovation IOIC card used to interface with Q-Line modules. PCRL CARD Ovation IOIC card used to interface with local Ovation modules. PCRR CARD Ovation IOIC card used to interface with remote Ovation modules and remote Q-Line I/O modules in migrated systems. PDS Process Diagram System. Contains graphics that are displayed on the Ovation Operator Station.

70

CON_015

Glossary of Terms

PERIODIC POINTS Points whose values are scanned periodically at a defined frequency such as every 1 second or every 0.1 of a second. See also aperiodic points. PERSONALITY MODULE Part of Ovation I/O that configures the Electronics Module. Fits into the Base Unit beside the Electronic Module that it configures. PID Proportional, Integral, Derivative. A type of closed-loop, modulating control function. It acts according to an algorithm that detects deviations between a predetermined set point and an actual process variable input condition or value. PLANT MODE Defines the current state of a plant (value range 1 - 6). Alarm limits can be defined that are based on plant mode. Can be defined in Deluxe points. POINT A record in the Ovation master database containing a value (such as an input or output) and related data. POINT B UILDER Power Tool used to create, modify, and delete Ovation points. POKE FIELD A location in a diagram where the cursor can be placed, allowing the operator to select an option. PORT 1) A connection where information goes into or out of a computer. 2) Translating a piece of software to bring it from one type of computer system to another. POWER TOOLS Set of unified and flexible engineering tools used to configure and maintain the Ovation system. All objects (such as points) created by the tools are stored in a master database. PROCESS DIAGRAMS Graphical images that represent actual plant process control equipment. Part of the Process Diagram System (PDS) used at the Operator Station. PROCESSING TIME The time, in milliseconds, required to make one complete pass through a Controller application program.

CON_015

71

Glossary of Terms

Q Q-L INE Legacy line of Emerson I/O modules. QUALITY Indicates point condition to Operator Station and to the algorithms.

R RADIO B UTTON Button appears as a small circle that, when selected, has a smaller, filled circle inside it. Selecting one button in a set deselects the previously selected button so one and only one of the options in a set can be selected at any given time. RAM Random Access Memory, the generic term for memory that can be written to and read from. RECEIVED POINTS Points that were not created in the current drop. RECORD The set of data associated with a point, including the point name, System ID, value, status, and various other fields, depending on the point record type.

REFRESH Refreshes the display to the current contents of the object's database values. REGISTER A data storage area in memory. In the Controller, there are four types: input registers (R), output registers (O), holding registers (H), and dynamic holding registers (G). At times, however, input groups (I) and output groups (C) are used as if they were an input or output register. RELATIONAL DATAB ASE Central database (Oracle) for Ovation systems. Uses tables to store and locate information. REMOTE I/O A hardware configuration where the I/O is located remotely from the Controller. REMOTE NODE A grouping of I/O modules that communicates with the Controller via media that can carry control signals over a long distance (for example, fiber-optic).

72

CON_015

Glossary of Terms

REVIEW Data retrieved from the Ovation network. Reviews can be retrieved based on point status requests and/or point characteristics. RING Set of nodes where data is passed sequentially between nodes, examined or copied, and returned to the srcinating node. RISC Reduced Instruction-Set Computing, a microprocessor architecture that contains a smaller instruction set in order to increase processor speed. RNC Remote Node Controller (RNC) is an alternate name for the Ovation module containing the Remote Node Electronics module and Remote Node Personality module. The RNC interfaces the I/O modules in the Remote Node to an MAU module at the Controller via a fiber-optic communication link ROM Read-Only Memory, the generic term for memory that can read from but not be written to. ROP I/O hardware transition panel. ROUTER A hardware or software set-up that handles the connection between two or more networks.

S S PORT Port on a station that connects to an M port. SAC/SAS Single Attachment Concentrator/Single Attachment Station. Provides a single attachment to the FDDI or Fast Ethernet network. SCAN The processor module's sequential and ongoing examination of each contact circuit, control relay, special function, and process control loop in the application program. During the scan, the processor accesses data stored in memory and the current states of the field I/O. The result is the energizing or de-energizing of the coils and the determination of analog output information. SCSI Small Computer System Interface, a peripheral-connect interface used to connect hard drives, CDROM drives, and other storage devices to a computer.

CON_015

73

Glossary of Terms

SECURITY B UILDER Ovation Power Tool that defines, configures, and manages security for an Ovation system. SELECT 1) For control applications, choosing the algorithm to be controlled, typically through an M/A Station. 2) Highlighting an item on the screen, such as an item on a menu or in a scrolling list, as a means of choosing an option. SERVER A computer, or software program that provides a specific kind of service to a client software running on other computers. SETPOINT The desired value of a process variable. In modulating control, other variables are continuously modified to maintain the value of the controlled variable at the setpoint. SGML Standard Generalized Markup Language, a text-based language for describing the content and structure of digital documents. SID See System ID. SIMULATOR Software package that runs on an actual Ovation Controller. Can use either simulated or actual I/O hardware to test control logic. SMARTPROCESS Emerson’s plant optimization software used to improve plant processes. SNMP Simple Network Management Protocol. An Ovation program designed to monitor and report the activity in various devices on the network. SOE Sequence of Events. SOE messages are transferred from Controllers to certain drops on the network. SOFTWARESERVER A drop on a network that provides storage and control of system software files.

74

CON_015

Glossary of Terms

SOURCE 1) A location, in memory, that is the srcin of the data to be moved or converted. This may be a register or, at times, an input group used as a register. 2) An ASCII input file containing commands or statements in a programming language. STATIC DATA Portion of the Ovation point record that is stored in volatile memory by the srcinating drop and broadcast to receiving drops on an as-needed basis. The receiving drop stores it in its volatile memory. STATION Addressable node on FDDI or Fast Ethernet network; can transmit, repeat, and receive data. SVGA Super Video Graphics Array, an extension of the VGA video standard. SVGA enables video adapters to support up to 16.7 million colors, known as true colors in a 1024-by-768 pixel display. SWITCH Fast Ethernet device used to connect multiple Ovation Stations to the network. SYNCHRONOUS High speed data communication that is time critical. Must be guaranteed service for nodes transmitting synchronous data. Typically provided periodically. SYSTEM FOLDER The parent folder to all files, objects, and folders that pertain to that System in the Ovation Developer Studio. SYSTEM ID System Identification number (SID). The Data Highway reference number for each point which may be transmitted. SYSTEM TREE The system file structure in the Ovation Developer Studio.

T TCP/IP Transmission Control Protocol / Internet Protocol, a set of communication protocols that allows dissimilar computers to share information over a network. TERMINAL 1) Solaris window where commands are entered. 2) A device that allows the user to send commands to a remote computer.

CON_015

75

Glossary of Terms

TIFF Tagged Image File Format, a file format for bit-mapped graphics that stores the information in discrete blocks called tags. TND Remote Node transition panel. TOKEN A field in the Drop Status Record (DSR) that identifies the drop that broadcast a message. TOOLBAR A row of icons that activate commands or functions when clicked. TREND A display that plots point values over a selected time interval. Trend displays may be generated based on data from the MMI trend history, from a Historian, or from an eDB. TUNING Manually changing the value of point record fields or algorithm record fields.

U UNIT FOLDER The subfolder of a Network in the Ovation Developer Studio. The Unit folder is a parent folder to all files, objects, and folders that pertain to that particular unit. UNIX An operating system used in Ovation drops. Ovation uses the Solaris version of UNIX.

V VGA Video Graphics Array, a standard graphics adapter that enables video adapters to support 16 colors in a 640-by-480 pixel display. VIRTUAL CONTROLLER Software representation of an actual Ovation Controller, but no Controller hardware is required. Virtual Controllers have the same functionality as real Controllers, but do not actually connect to plant I/O.

W WINDOW A screen display using only part of the CRT, often movable and resizable.

76

CON_015

Glossary of Terms

WINDOWS Microsoft 32-bit multitasking Operating System (such as NT or XP). WYSIWYG What You See Is What You Get, when the appearance of the screen output matches exactly (or very closely) the printed output.

Z ZOOM A way of enlarging or reducing a specific area in a graphic.

CON_015

77

INDEX A A Port • 57 Admin Tool • 57 Alarm • 57 Algorithm • 57 Analog • 57 Aperiodic API • 57 Points • 57 Application program • 57 Apply • 57 ASCII • 58 Asynchronous • 58 AUI Cable • 58

B B Port • 58 Backup Mode Action • 36 Balancing Communication Priorities with the interval parameter • 37 Bandwidth • 58 Base Alarm System • 58 Base Unit • 58 Baud Rate • 58 BG • 58 Bit • 58 Bitmap file• •59 58 Bootstrap Branch • 59 Bridge • 59 Broadcast • 59 Bumpless Transfer • 35 Byte • 59

C Cable Choices • 10 Cabling Schemes • 8 Cancel • 59 CDDI • 59 CDE • 59 Characteristics • 59 Client • 59 Coil • 59 Collision • 60 Collision Detection • 60 Compact I/O Modules • 60 Concentrator • 60 Conducting • 60 Configuration • 60 Configuration File • 60

CON_015

Configuration File Example 1 • 50 Configuration File Example 2 • 52 Configuration File Example 3 • 53 Configuration File Example 4 • 54 Configuration File Example 5 • 55 Configuration File Examples • 49 Configuration File Examples Included in This Section • 49 Configuration File Guidelines • 12 Configuring Redundant Hardware • 34 Contact • 60 Control Builder • 60 Control Sheet • 60 Control Task • 60 Controller • 60 Copyright Notice • 2 CPU • 61 Creating a Configuration File • 12 Creating an AUTOEXEC.BAT File • 27 CRT • 61 Cursor • 61

D DAC/DAS • 61 Data Conversion • 27 Data Highway • 61 Data Structures • 61 Database • 61 DCS • 61 Deadband • 61 Default Points • 61 Default Value • 61 Deluxe record type • 62 Destination • 62 Developer Studio • 62 Device • 62 DHC • 62 Diagnostics • 62 Diagram • 62 Dialog Box • 62 Digital • 62 DIN • 62 DIP • 62 Discrete I/O • 63 Displaying Error Messages • 30 Distributed Database • 63 Distributed I/O • 63 Domain • 63 Download • 63 Drop • 63 Drop Loader • 63

79

Index

Drop Point (DU) • 63 Dynamic Data • 63

E eDB Historian • 63 Electronics Module • 64 EMS • 64 Engineering Station • 64 Ethernet • 64

F Fast Ethernet • 64 FDDI • 64 Firewall • 64 Flash Data • 64 Force value • 64 FOUNDATION Fieldbus • 64 FTP • 65 Fully qualified point name • 65

G Gateway • 65 GP • 65 Graphics Builder • 65 Group Operation Parameters • 17 GUI • 65

H Hardware Configuration • 3 Historian • 65 HMI • 65 Host • 65 How Modbus Protocol Represents 32-bit Quantities • 24 Hypertext • 65

I I/O • 65 I/O Builder • 66 I/O Controller • 66 I/O Module • 66 I/O Nodes • 66 Icon • 66 Iconic Alarming • 66 Init Tool • 66 Initializing the Link Controller Modbus Interface • 29 Interface Timing • 37 Interface Timing Considerations • 37 Interpreting the Ovation Link Controller Module LEDs • 32 Introduction to Ovation Link Controller Modbus Interface • 1 IOIC Card • 66 IP Address • 66

80

ISA • 66

K KB • 66

L Ladder • 67 LAN • 67 LC Modbus Interface Redundancy Operation • 35 License • 67 Log Server • 67 Login • 67 Long record type • 67 Loop • 67 Loop Interface Module (LIM) • 67

M M Port • 67 M/A Station • 67 Man pages • 68 Master Database • 68 MAU • 68 MB • 68 Menu • 68 Migration • 68 MMI • 68 MMI Data • 68 Modbus Address and Point Mapping Parameters • 18 Modbus Addresses • 21 Modbus Command Mnemonic Keywords • 20 Modbus Data Type Specifiers • 22 Modbus Protocol • 43 Modbus Protocol Messages • 43 Modem • 68 Module Point (RM) • 68 Monitor • 68 Multi-Drop Interface Configuration • 41 Multiple Networks • 68

N Network • 69 Network Folder • 69 NIC • 69 Node • 69 Node Point (RN) • 69

O OpenWindows • 69 Operation of LC Modbus Interface • 29 Operator Station • 69 Originated Points • 69 Ovation I/O • 69

CON_015

Index

Ovation Keyboard • 69 Ovation Link Controller Module Redundancy • 33 Ovation Network • 69 Ovation System • 70 Overall Parameters • 15

P Packed Digital Point (PD) • 70 Packed Point • 70 Password • 70 PC • 70 PCI PCL••70 70 PCQL Card • 70 PCRL Card • 70 PCRR Card • 70 PDS • 70 Periodic Points • 71 Personality Module • 71 PID • 71 Pin Assignments • 6 Plant Mode • 71 Point • 71 Point Builder • 71 Poke Field • 71 Port • 71 Power Tools • 71 Process Diagrams • 71 Processing time • 71

Q Q-Line • 72 Quality • 72

R

S S Port • 73 SAC/SAS • 73 Sample Configuration File • 14 Sample Debugging Session • 32 Scan • 73 SCSI • 73 Security Builder • 74 Select • 74 Sending Data from the Controller to Field Devices • 36 Sending Data• 36 from the Field Devices to the Controller Server • 74 Setpoint • 74 Setting MessageTimeout • 38 SGML • 74 SID • 74 Significance of watchdog_time • 39 Simulator • 74 SmartProcess • 74 SNMP • 74 SOE • 74 Software Configuration • 11 Software Configuration Overview • 11 SoftwareServer • 74 Source • 75 Static Data • 75 Station • 75 SVGA • 75 Switch • 75 Synchronous • 75 System Folder • 75 System ID • 75 System Tree • 75

Radio Button • 72 RAM • 72 Received Points • 72 Record • 72 Refresh • 72 Register • 72 Relational Database • 72 Remote I/O • 72 Remote Node • 72 Review • 73 Ring • 73 RISC • 73 RNC • 73 ROM • 73

T

ROP • 73 Router • 73 Runtime Diagnostics • 31

U

CON_015

TCP/IP • 75 Terminal • 75 Terminal Block Connections • 5 TIFF • 76 TND • 76 To Create a Configuration File • 13 To Create the AUTOEXEC.bat File • 28 Token • 76 Toolbar • 76 Trend • 76 Troubleshooting LC Modbus Operation • 29 Tuning • 76

Unit Folder • 76 UNIX • 76

81

Index

Using InterMsgDelay to Throttle Communication • 38 Using Multi-Drop Networks • 41

V VGA • 76 Virtual Controller • 76

W What Algorithms are Used for Redundancy? • 34 What are the Interface Connections? • 4 What Configuration File Parameters are Used for Redundancy? • 33 What is a Multi-Drop Network? • 41 What is Redundancy? • 33 What is the Ovation LC Modbus Interface? • 1 What is the Ovation LC Module? • 3 What Software is Required for the LC Modbus Interface? • 11 Window • 76 Windows • 77 WYSIWYG • 77

Z Zoom • 77

82

CON_015

CON_015 Ovation Link Controller (LC) Modbus Interface User Guide

Recommend Documents