DCS EVOLUTION-CENTRALISED CONTROL
DCS EVOLUTION-DISTRIBUTED CONTROL
DCS EVOLUTION-FIELDBUS CONTROL
DCS EVOLUTION- WEB CONTROL
DCS EVOLUTION-WEB CONTROL APPLICATION
ABB DCS ARCITECTURE
ABB DCS HARDWARE
CONTROL SYSTEMS TREND 1) PLC 2) DCS 3) PC - Based Control. • PLC : Introduced in the late 1960 to replace Relays and Hard-wired Programming.
DCS : Introduced in the Mid-1970 to replace pneumatic controls by using computers. • PC-Based Control : Introduced by the early 1980s to avoid the proprietary PLC & DCS systems.
DCS EVOLUTION •
LOCAL CONTROL : Initially control was performed local to the equipment control. The ADVANTAGE was low wiring costs .DISADVANTAGES were - not much control, monitoring, alarming & history.
•
CENTRALISED CONTROL: With the advent of minicomputer, sensors and actuators were into the Central Control (Computer). DISTRIBUTED CONTROL: With the advent of microcomputer, Distributed control systems were installed in the plants near to the control room via proprietary digital communications lines called as Data Hiway. First DCS was developed by Honeywell,U.S in 1975. The ADVANTAGES were greatly reduced wiring costs, much more limited failure and less cost to add more points. The DISADVANTAGES were that wiring costs were that wiring costs were still significant and there was lack of interoperability among controllers of various manufacturers due to the proprietary protocols. Hence the user was locked into a single vendor.
•
DCS System Installations in RCF 1. Yokogawa - CS 3000 : Ammonia II 2. Yokogawa - CS 3000 : ANP 3. Yokogawa - CS 3000 : NNAP 4. Moore - APACS : Methyl amine 5. Fisher - Rosemant - Delta V field Bus : S T P 6. Honeywell - GUS : Ammonia I Synthesis 7. Yokogawa - Centum Excel : Steam Generation Plant 8. Moore - APACS : Suphala 9. Yokogawa - Micro Excel : Methanol 10. Yokogawa - Micro Excel : S A P/C N A 11. ABB - Freelance 2000 : ABC 12. Honeywell - TDC 3000 : Ammonia I 13. Honeywell - GUS : Ammonia/Urea - Thal 14. Fox boro - I/A series : D M A C - Thal 15. Fisher - Rosemant RS3 : PGR 16. Fisher - Rosemant RS3 : Steam Generation - Thal 17. Moore - APACS : Water Treatment Plant - Thal
DCS • • •
The importance of DCS systems to increase as global competitive dynamics in food and beverage, specialty metals, pulp and paper, pharmaceutical and fire chemical processing. The DCS has networking capabilities which are useful for business management. The DCS has capacity for processing large number of I/O points.
TYPES OF DCS : 1) Conventional DCS . 2) PLC based DCS. 3) Hybrid DCS. 4) Open DCS System
CONVENTIONAL DCS This is a pure “Process only” control system. Usually purchased from one vendor. This DCS arranged into three categories: • Small - Less than $ 100,000. • Medium - Greater than $100,000 & Less than $500,000. • Large - Greater than $500,000. PLC Based DCS. This is a network of PLC’s used to perform the task of conventional DCS and programmable functionality when required. Hybrid DCS. Performs both process and sequential control. Open DCS System. This is Field-Bus Control. Advantages are lower wiring cost and less failure, smaller expansion costs and multi vendor interoperability DCS and PLC can be more closely and efficiently interconnected.
Honeywell TDC 3000 DCS Architecture
US#1
US#2
HM LCN A B
HG AMC
Field
EC Link
AMC Data Hiway
A
B
Field
Hiway Gateway (HG) • • • • • • •
LCN Module. Provides a two way communication link between the Local Control Network and data hiway. 68020 based high performance intelligence module. Converts data and protocol between Local Control Network and data hiway. Scans the hiway for alarm conditions. Synchronize time keeping for hiway-based process connected boxes. One HG is required for each data hiway that is connected to the LCN. Up to 20 data hiway pairs can be connected to an LCN. Connects following hiway resident boxes to LCN 1. AMCs 2. CPC ( critical process controller ). 3. DHP. 4. Hiway traffic director etc… HG Functions : 1. Data access :- gets box data requested from LCN modules. 2. Event processing :- sends process and box alarm to LCN modules 3. Database configuration :- 3000 points per hg can be configured.
Data Hiway
Data hiway provides communication link between hiway gateway, preferred access devices and process connecting box. Data hiway operates at 250 kbps. It is redundant pair of 75 ohm coax cable connected to box. It may be 20,000 feet long. There are 3 kinds of devices on the data hiway, 1. Respond only devices Ex:- A-MC (Advanced Multifunction controller) 2. Polled devices Ex:- PIU’s (Process interface unit) 3. Preferred access devices
History Module
• • • • •
LCN Module. Stores process and system information that can be displayed. Based on microprocessors 68020. Winchester disk for data storage. Communicates with all Modules on the LCN. Stores history and general information.
Universal Station Universal station (US) communicates with all modules on the LCN, process connected devices on the hiway via hiway gateway and UCN via network interface module (NIM). The following are the features of US, • Intelligent man/machine interface in the TDC 3000 system. • Stands on the LCN. Communicates with all Modules on LCN, process connected devices on the Hiway via Hiway Gateway. • Provides comprehensive facilities to the process operator, process engineer and maintenance technician on the Universal Window. US provides comprehensive facilities to the following people, • Process engineer • Process operator • Maintenance technician.
AMC •
TDC 3000 controller 1. 2.
• • •
Multifunction – Modulating, sequence, logic, I/O monitoring communication and diagnostic. Faster peer to peer communication over EC link ( 500 kbits/sec ). Proven control techniques 1. 2.
•
Based on Motorola 68000 Microprocessor. Faster execution and control with 500 ms processing rate.
Full function algorithms. Process oriented programming.
Configured as a box on TDC 3000 Data Hiway. Supported by 1.
LCN devices – US, AM, HM.
HONEYWELL - GUS Printer
Drive’s
Printer
Universal Station
US#1
US#2
US#3
US#4
HM History Module A Local Control Network
Universal Control Network
Network Interface Module
NIM HPM HPM HPM
High Performance Manager
B
Honeywell System Description
• • • • •
Global User Station History Modules Network Interface Modules Communication Subsystem - Local Control Network & Universal Control Network High Performance Process Manager
Global User Station Overview
• • • • • • • • •
The TPS system provides an integrated interface between the process and the end user. This interface is named as the Global User Station (GUS). GUS is an important part in the Honeywell Total plant Solutions offerings. It provides access to plant wide process network, plant or organization wide intranet or even Internet. The following hardware is available to enhance the functionality of the GUS: Integrated Keyboard for Operators as well as Engineer. Matrix printer supported by Windows NT. 8 * CD-ROM 100MB ZIP Drive 3.5” Floppy Drive GUS has following functionality's : The “Human ” interface allows effective interaction of the Operator through the use of operating displays Engineering functions such as data point building, display building and report building are available. Communication with other LCN modules is accomplished. Communication on Ethernet.
Honey well GUS Hardware: • • • • • • • • •
Processor Memory Cache Storage Video Colours Keyboard PIN Connection Cursor Control
: : : : : : : : :
Pentium Pro / 200MHZ 64MB RAM ECC 256KB ECC 2 GB hard disk drive, CD ROM, Cartridge Drive 21” high resolution screen 1280 * 1024 Pixels 256 color palette Integrated keyboard with mouse Built in Ethernet QWERTY & Mouse/Touch Screen
Peripherals supported • Printer • 8 * CD-ROM • 1/4” Steamer Tape • 3.5” Floppy Drive • 100 Mb ZIP Drive • Annunciator relay on the console-based keyboard
Honeywell GUS software
• •
Operating System Base System network and all GUS
: :
Windows NT version 4.0 Provides real time data exchange between the functions.
History Modules The History Modules is the bulk module that can be utilized by all module connected to the Local Control Network. It is as the name implies the mass memory of the TPS System. The memory components of this module are one 1.8 gigabyte Winchester discs. It is controlled by an M68040 microprocessor. This provides the module with significant computing power that this used to structure much of the incoming data and format it into a form for easy retrieval. The history in the model is provided by the History Module. Process variables are available for hourly, shift, daily and monthly average calculation and recording. All system event history such as process alarms, system status changes, and error messages are stored into the History Modules. Other modules have access to data in the History Modules for their functions. The History Module provides two functions, storage only and data structuring and storage. The data structuring and storage function provides much of the historical data of the process to which the system is connected.
HM functions and Historization parameter HM functions : It can automatically backup the control databases in the HG, AM, CG. HM can store, • Continuous process history. • Event journal (history). • Active system files. • Static system files. • On process analysis program (maintenance aid) HM Historization parameters : There can be up to 10 HM’s on the LCN. There can be maximum of 150 groups per HM. Each group can have up to 20 points. All points in the group must be in the same unit.
Network Interface Module (NIM)
The Network Interface Module (NIM) provides the link between the local Control Network and the Universal Control Network. As such it make the transition from the transmission technique and protocol or the Local Control Network to the transmission technique and the protocol of the Universal Control Network. The NIM provides access by LCN modules data from UCN resident devices. The NIM is available in the redundant configuration to provide continued operation in the event of the primary failure. It can also do event processing. There can be up to 10 redundant NIM pairs per LCN. A NIM can host upto 8000 tag names and supports a data transfer rate of 2400 parameters per second.
Communication Subsystem Local Control Network (LCN)
The backbone of every TPS system is a communication network, known as Local Control Network. The LCN is a LAN through which TDC 3000 modules communicate with each other. The LCN is a broadcast type of LAN. It is high speed redundant communication bus that connect all the control room equipment. All information is transferred on the network at 5 million bits per sec.,serially. It is based on the IEEE 802.4 Token passing and Bus Standard. Each LCN device that is connected to the Local Control Network is called a module. Up to 64 modules may be connected to the Local Control Network in a TPS system. The Local Control Network is designated as the primary and the other as the back up. Local Control Network provides time synchronization for all modules.
Communication Subsystem
Universal Control Network (UCN) The Universal Control Network is a high speed, high security process control network based on open system interconnection standards. It features a 5 megabit/second, carrier band, token bus network compatible with IEEE and ISO standards. It is used as the real time redundant Communications backbone for process connected devices such as the High Performance Process Manager (HPM), Advanced Process Manager . The UCN supports peer-to-peer communication for sharing data and allowing greater co-ordination of control strategies among network devices. The UCN uses redundant co-axial cables and can support up to 32 redundant devices UCN supports 2 types of devices - Process manager. - Logic manager.
High Performance Process Manager (HPM)
The High Performance Process Manager is the latest in the Progression of High Performance control products offered by Honeywell for the application to Improve controlling of existing and new industrial processes. High Performance Process Manager is a fully integrated member of the TPS family. It is capable of : • performing data acquisition and control functions • fully communicating with operators and engineers at the GUSs and universal Work stations. • Supporting higher-level strategies available on the Local Control Network through the Application Module and Host Computers.
High Performance Process Manager Overview The High Performance Process Manager uses a powerful multi-processor architecture with separate microprocessors dedicated to perform specific tasks. The HPM consists of two modules Communication and Control Module (CCM) and the I/O subsystem the I/O subsystem consist of up to 40 Smart I/O Modules (SIOM). All control operation are performed within the communication and control module. The process engineer has complete flexibility of choice within the maximum HPM design limits. These selections are implemented using the interactive tools provided by both the GUS and Universal Work Station. The I/O processors, for example, provide such functions as engineering unit conversion and alarm limit checking independent of the communication and control modules. The communication process is optimized to provide high performance network communications. The control processor is HPM resource dedicated to executing regulatory,logic and sequence functions, including a powerful user programming facility. Since communication and I/O processing are provided by separate dedicated hardware.
YOKOGAWA CENTUM EXCEL ARCHITECTURE EOPS /1
EOPS /2
ENGG. STATION
Micro-XL
A B HF BUS (1 Mbps) EFCD
EFMS
EFGW
I/O #1 ncst Closed loop control signal Through I/O NEST
I/O #2 ncst
Monitoring signals Through I/O NEST
Third party system with PLC, Gas Analyser etc. thr RS 232C port At the rate of 9600 bps
I/O #3 I/O #5 ncst I/O #4 A B NIO Bus
HF BUS : High frequency Bus: no. of station on HF Bus are 32 EOPS : Extended Operator station: Hard disk capacity of EOPS is 80 MB EFCD : Extended field control station : 80 laps per controller EFMS : Extended field mauture station Max 255 inputs EFGN : Extended field gateway unit ENGS : Engineering station NIO : Nest I/O bus.
Windows NT Based Centum CS Configuration
INTERPLANT NETWORK PC (OPTIONAL)
Ethernet Connectivity (optional)
OPERATOR/ENGINEERING STATION
OPERATOR STATION SUB-SYSTEM
HIS
DM Printer
PRT
HIS
HIS
PRT
Inkjet Printer
DUAL “V NET” 10 Mbps
FCS
RIO BUS NIU
NIU
HIS – Human Interface Station. FCS – Field Control Station. NIU – Node Interface Unit. RIO Bus – Remote I/O Bus.
Centum CS 3000 System Overview Centum CS 3000 is an integrated production control system for medium and large control applications. This system is a synthesis of the latest technology with Yokogawa’s experience and specialist know-how. Centum CS 3000 system features : • Synthesis of DCS with Personal computers. • Online Documentation. • Powerful Operation and Monitoring Functions. • Two Types of Control Station. • Compact I/O Modules. • Powerful Control and Communication Functions. • Efficient Engineering. • Virtual Test functions don’t require Control Station hardware. • Full-Featured Batch Package. • CENTUM CS micro-XL Integration ( to be released ).
Centum CS 3000 System Overview Centum CS 3000 is an integrated production control system for medium and large control applications. This system is a synthesis of the latest technology with Yokogawa’s experience and specialist know-how. Centum CS 3000 system features : •Synthesis of DCS with Personal computers. •Truly open system for integrating multi-vendor solutions. •High Reliability of computed process data by the unique fault tolerant control processor. •Powerful built in “RISC PROCESSOR” with high speed and dynamic error correcting code. •Remote I/O concept enables geographically distribution of I/O Modules thereby reducing cabling cost. •1:1 Redundancy at almost all the system levels except for control processor which employs a special Redundancy with 4 identical CPU’s. •Powerful Control Tools and Communication Functions. •Virtual Test functions don’t require Control Station hardware. •Full-Featured Batch Package. •Built in security features to prevent mal-operations. •CENTUM CS micro-XL Integration ( to be released ).
CS3000 – System Configuration
INTERPLANT NETWORK PC (OPTIONAL)
Ethernet Connectivity (optional)
OPERATOR/ENGINEERING STATION
OPERATOR STATION SUB-SYSTEM
Remote Domain System
HIS
DM Printer
PRT
HIS
HIS
PRT
CGW
Inkjet Printer
V NET 10 Mbps FCS
BCV RIO BUS
NIU
NIU
CS, CS 1000 Centum – XL, -V, -MXL HIS – Human Interface Station. FCS – Field Control Station. NIU – Node Interface Unit. RIO Bus – Remote I/O Bus. CGW – Communication gateway unit BCV – Bus Converter
CENTUM CS 3000 NETWORK
HIS
HIS
HIS
V net
FCS
FCS
FCS
CENTUM CS3000 SYSTEM SPECIFICATION • • • • •
NO. OF TAGS MONITORED TOTAL NO. OF STATION NO. OF DOMAINS NO. OF STATIONS IN A DOMAIN NO. OF HIS / DOMAIN
1,00,000 256 16 64 16 NOS
CENTUM CS3000 SYSTEM SPECIFICATION • • • • • • • • • • • • •
Max. no. of stations Max. no. of Domains Numbering of Domains Domain No. CS3000 Domain (V net Domain) Max. no. of stations/Domain Domain No.Virtual Domain (Non V net Domain) Station NO. HIS Station NO. FCS Max. No. of ICS / Domain Max. No. of NIU / FCS Max. No. of IOU / FCS Max. length of Vnet Max. length of RIO bus
: : :
256 / system 16 / system 1 to 64
: :
1 to 16 64
: : : : : : : :
17 to 64 1 to 64 in descending order 1 to 64 in ascending order 16 8 40 ( Max. 5/ IOU) 20 Km 20 Km (750m ~ 20Km)
Centum CS-3000 Communication V net V net is 10 mbps real time control bus which links station such as FCS , HIS , BCV and CGW. It can be dual redundant. It can be up to 500m using coaxial cable alone, or up to 20 Km when repeater are used or optical fiber is used. • •
10BASE2 cable used by HIS, maximum segment length = 185 m 10BASE5 cable used by stations other than HIS(FCS,CGW etc.) maximum segment length = 500 m
V net Communication
HIS
HIS
V net Protocol : IEEE802.4 Access Control : Token Passing Trans. Speed : 10 Mbps Trans. Distance: 500m to 20Km Media : Coaxial/optical fiber FCS
FCS
V net specification ITEM
SPECIFICATION
Transmission route
Coaxial or fiber optical cable
Type
Bus type or Multi-drop type
Communication rate
10 Mbps
Transmission Distance
500M –20Km Max
Redundancy
Dual-redundant
Proto type
Token passing
V- net Features • • • •
Real time control bus. ( Dual redundant possible ) Cable : 50 ohm coax. cable with BNC connector ( 10Base2 comp. ) Communication speed : 10 Mbps. High reliable token passing communication ( performance guaranteed ) • Std. max. length : 185 m. BNC Connector • Max. length : 20 Km ( with optical fiber ) 1.6 Km ( with coax. Repeater ) VL net cable
VL net I/F card ( PCI )
Ethernet HIS and ENG, HIS and supervisory systems can be connected by an Ethernet LAN; supervisory computers and personal computers on the Ethernet LAN can access messages and trend data in the CS 3000 system. The Ethernet can also be used for sending trend data files from the HIS to supervisory computers, or for equalizing the data in the two HIS station ( rather than using the V net control bus to do this ). A system with only one HIS with engineering functions installed, does not need Ethernet – but in general Ethernet ( and corresponding network engineering ) is required.
Ethernet Specification ITEM
SPECIFICATION
Transmission Route
Coaxial or Fiber optical cable
Type
Bus type or Multi–drop type
Communication Rate
10 Mbps
Transmission Distance
500m – 2.5 Km max.
Redundancy
Not available
Proto type
CSMA/CD Type
TYPES OF HIS • Console type HIS • Desk top type HIS • PHIS Yokogawa brand OPS
HIS Hardware • • • •
CPU Main memory Hard disk Display
• • • •
Serial port Parallel port OS Operator stations
Pentium 166 96MB or larger(for op & monitoring only) 1 GB or larger 256Colors min. resolution 800*600 1024*768 recommend(1280*1024 best) RS232C*1 or more (for operation keyboard) 1 port for printer or more Windows NT 4.0 Workstation Max. 8 stations
Field Control Station Configuration Ethernet
HIS
HIS
HIS V net
I/O Unit RIO Bus
Sub system
Node
Node Interface Unit I/O Unit
Sub system
Compact FCS
Standard FCS
Connection to Centum CS 3000 System
Exapilot client (engineering, operation)
Ethernet Exapilot client (engineering, operation)
HIS
ENG
Exaopc Exapilot server (engineering, operation)
V-net
Exapilot communication data Process data read/write FCS
FCS
Features of Exapilot • • •
Standardize and Automate Manual Procedures Improve Plant Operating Efficiency Improve safety of Plant Operation
Features of Event Analysis Package • • •
Analysis DCS Event History to Help You Enhance Efficiency. Enhance Process Stability: Balance Process Events and Operator Actions. When, Where, What (3W) Filters Help You Narrow Focus of Analysis.
OPEN DCS SYSTEM Ethernet Field Bus Power Supply
Flow Trans. Terminator
HMI
Control Valve
Safety Barrier
Pressure TX.
Field bus It is a standardized digital communication protocol between a process Control field devices and the Control room. It is a simple pair of wires to power and carry the communication signal between the field devices and the Control room. FEATURES : • Drastic reduction in cable, conduits cable trays, marshallive racks, and connectors etc. • Drastic reduction in installation cost. • Fewer non field devices. • More reliability due to the smaller number of devices. • More efficient operation due to better accuracy (no A/D and D/A conversion). • Easy integration into plant management system. • Flexibility for different suppliers are interoperable and interchangeable. • Major reduction in maintenance cost.
Field-bus Benefits Wiring
Wire (pair)
Screw Terms
I/O Cards
IS Barriers
Traditional
3500’
168
2
2
Field bus
640’
64
1
1
Savings
2860’
104
1
1
Savings %
82%
63%
$ 3000 Material $ 2000 Labor $ 5000 Total Typically comments from a plant personal :
Savings $
•Easy to identify what’s out there. •Consistent calibration procedure. •Two days versus four days to commission system. •Familiar with twisted pair wiring – comfortable.
50%
50%
FOUNDATION™ fieldbus Vocabulary Blocks Basic Components Valve
Resource Resource Block Block
Transducer (Servo) Block
Function Function Block(s) Block(s)
FOUNDATION™ fieldbus
FOUNDATION™ fieldbus Vocabulary Blocks Basic Components Resource Resource Block Block
Transducer Block
Temperature Transmitter
Function Function Block(s) Block(s)
FOUNDATION™ fieldbus
FOUNDATION™ fieldbus Vocabulary H1 and H2 • H1 Segment – – – –
Moderate speed Use existing wiring Bus powered Can be intrinsically safe – Low power 2 wire devices – 4 wire devices – Replace analog & proprietary digital
• H2 Segment – High speed – Link multiple H1 Segments – I/O subsystem bus – Replace proprietary networks – New wiring
FOUNDATION™ fieldbus Vocabulary New Approach for H2 • 100 Meg Ethernet technology with extensions – – – – – – – – – –
Improve time to market High speed Mandatory redundancy Widely available technology and silicon Widely available tools Limited incremental development Many suppliers High volume for low cost Works with installed equipment Evergreen technology
• Better than ANY other solution!
FOUNDATION™ fieldbus Vocabulary H1/H2 Bridges Server
H1/H2 Bridge
H2 Segment 100 Meg Ethernet Control Module
PLC
H1 Segment
H1/H2 H1/H2Bridge Bridge Replaces Replaces Traditional TraditionalI/O I/O
H1 Segment
H1 Segment
FOUNDATION™ fieldbus Standards Organizations • IEC – International Electro-technical Commission
• ISA – International Society for Measurement and Control (formerly: Instrument Society of America) • SP50
• CENELEC – European standards body • Parallel (competitive?) Working Groups to IEC
FOUNDATION™ fieldbus Topography H1 Fieldbus Installations Controller Similar SimilarI/O I/OCards Cards
Reduced H1 I/O ReducedWiring Wiring Interface
Junction Box
H1 I/O Terminations
FewerTerminations FewerTerminations
H1 Fieldbus all-digital Marshaling
Fewer FewerTerminations Terminations Fewer FewerIS ISbarriers barriers
IS (Ex i) Barriers
Cost Costsavings: savings: •• wiring wiring •• I/O I/Ocards cards&& cables cables •• terminations terminations •• IS ISbarriers barriers •• marshaling marshaling
H1 Fieldbus all-digital
FOUNDATION™ fieldbus Topography Intrinsic Safety
Barriers
DeltaV System Architecture Engineering station
Operator station
Printer
Printer
8 port Hub primary
8 port Hub Redundant 1
Serial
P S
Contr.
S
Contr.
2 wide carrier for Power/Controller P
A AA DDD I I O I I O
Power supply Controller
8 wide carrier for I/O subsystem
H1 Connector
I/O extension cable RS232 Modbus D O
Blank Blank Blank Blank Blank Blank
PLC For 8 DI & 8 DO
H I
Fieldbus Power
Fieldbus Transmitter 3244MVF1NAB4
Pressure Transmitter 3051TG2A2B21AB4M5FF Smart valve positioner FSDVC0400-201
DCS communication system Hierarchy Level 5 Management Low data rates Superior responsibility
MIS High
Level 4 Scheduling
SCHED. Low
Level 3 Supervisory control
Level 2 Direct digital Control (DDC) Level 1 Sensors (S) & Actuators (A) High data rates Low responsibility
SUP.
SUP.
DDC
S
A
DDC
A
S
DDC
A
PLANT
S
S
S
DDC
A
S
S
A
History of Process Control Signal Around 50 years ago, most plant used 3-15psi pneumatic signal to control their process. The last change change in signal standard was the open protocol HART digital communications format. The HART protocol provides simultaneous digital communications with the 4-20 mA output. The next protocol change will be fieldbus. Fieldbus is entirely digital-there is no analog Signal. Fieldbus also allows migration of control functions to field devices. Process control Timeline – The Evolution of Signal Standard Signal standards have evolved over the years, starting with the 3-15 psi standard. There are also other communication methods, but they have not gained widespread acceptance. With many standard there is typically a slow transition period as plant engineers and managers test period does gain widespread acceptance. However, once the benefits of the Digital: Fieldbus Fieldbus become tested and proven, more plant will install Fieldbus because of its benefit and Digital plus Analog: HART with 4-20mA economic cost. Analog: 4-20mA Pneumatic: 3-15 psi 1940
1950
1960
1970
1980
1990
2000
2010
I/O Bus Network Protocol I/O Bus Network Device bus network
Discrete
Byte-wide Data
Process bus network
Analog
Bit-wide data
Several Hundred Data Bytes
Protocol Standard Field Bus Foundation (Field Bus std.)
Process bus network
Profibus Trade Organization (Profibus std.)
Byte-Wide Data
CAN Bus
Device net SDS
Inter Bus-S
Device bus network
Bit-Wide Data
Seriplex ASI Inter Bus Loop
Fieldbus Architecture Fieldbus is more than just a new signal communications protocol, but a whole new way to control the process. With the release of the low fieldbus (H1), the entire fieldbus will be defined. Most of the recent published literature has focused on the intricate details of the fieldbus architecture, especially those layers that have not been released. However, except physical layer and the user layer, these layer are transparent to the engineers and the manager. Maintenance information system
Workstation
Application Layer
Data Layer
Multivariable Valve Transmitter
a Mkr o wt e N
Physical Layer
Level Pump Transmitter
stack
System management
User Layer
Open System Interconnected Reference Model Application Presentation Session Transport Network Data link Physical
Physical – Provides the standard for transmitting raw electrical signals over the communication channels. Data link – Contains the rule for interpreting electrical signals as data, error checking and physical addressing Network – Describes the rule for routing messages through a complex network and deals with congestion. TCP, SPX, UDP Transport – Establishes a dependable end-to-end IP, IPX, NetBeui connection between two host. HDLC, ETHERNET, ANSI/ISA S50.02 Session – provides Management and Synchronization of complex data transaction. EIA-485, ETHERNET,ANSI/ISA S50.02 Presentation – Establishes protocol for data format conversion, encryption and security. Application – Contains protocol that accomplish task such as e-mail, file transfer or reading a set of registers from a PLC. MBAP, SMB, FTP, SMTP, FMS, IEC 61158, ANSI/ISA S50.2,IEEE 1451
For the purpose of Process control, the top and bottom four layers are used. Layers 5 and 6 are important to large commercial networks.
Field Bus Field Bus is a bi-directional digital communication that interconnects smart field devices to control system or to instrument located in the control room. Field Bus is based on the OSI (Open System Interconnect), which was developed by the ISO (International Standard Organization) to represent the various functions required in any Communication network. Layer
Function
7
Application
Provides formatted data
6
Presentation
Converts data
5
Session
Handles the dialogue
4
Transport
Secures the transport connection
3
Network
Establishes network connections
2
Link
Establishes the data link connection
1
Physical
Connects the equipment
Field Bus
The OSI model consists of seven layers. However for real time application layers 3 to 6 are not considered since they deal with transference of data among networks. For such application following layers are used: • LAYER 1 - PHYSICAL LAYER Defines the type of signal, transmitting medium, data transmission speed, etc. • LAYER 2 – DATALINK LAYER Define the interface between the physical layer and the application layer. It establishes how the messages shall be structured and normalizes the use of multiple masters. • LAYER 3 – APPLICATION LAYER Defines how data is specified, its addresses and its representation.
The Fieldbus was invented by an Indian engineer Mr. Ram Ramchandran ( M.S in Comp. Tech , Texas)
PHYSICAL LAYER The Physical layer defines the medium that transport the messages frames, the signal shape and amplitude limits, data transfer rate, and power distribution. Technical Characteristics: Physical Medium Three types are defined: wires, optic fiber, and radio signals. The specification for wire has been already approved. Bit rate for wire media 31.25 Kbps (H1) 1 megabits and 2.5 megabits (H2). H1 and H2 are classification of the two hanks of Field Bus target applications. H1 has low speed and utilizes existing wires. H2 has high speed and may require independent wires to power up field devices. Number of devices per link (31.25Kbps) 2 to 32 devices, without power and no IS (intrinsic safety). 2 to 6 with power and IS. Maximum distance Up to 1900 meters for 31.25Kbps, without repeaters. Up to 750 meters for 1 megabits. Up to 500 meter for 2.5 megabits.
PHYSICAL LAYER Signal Modulation Manchester bi phase L synchronous. Physical layer preamble on transmissions, the physical layer will add to the data sent by the layer above a preamble and one start delimiter in the beginning of the frame and one end delimiter at the end delimiter at the end of the of the frame.
DATA LINK LAYER The Data Link Layer will assure the integrity of the message by using the frame check sequence: Two bytes added to the frames and a polynomial calculation of all frame data. The Data Link Layer also checks to see that the data reaches the devices correctly. Technical characteristics Medium Access: There are three forms to access the network: • Token passing: Token is the right to initiate a transaction on the bus. A device must have the token to initiate a conversation. As soon it finishes it will return the token to the LAS (Link Active Scheduler). The LAS send the token to the unit that requested in either in a pre-configured way or via scheduling. • Immediate response: A master station will give an opportunity to the station to reply with one frame. • Requested token: a device request a token by using a code in any of the response sent to the bus. The LAS will hear this request and will then send a token to the device when there is time available in the aperiodic traffic scheduling phase.
APPLICATION LAYER AND MANAGEMENT The Application Layer provides a simple interface to the end user’s application. Basically , it defines how to read, write , interpret and execute a message or command. A big part of this job is to define the message syntax. The contents include the requested message, action taken, and the response message. The management defines how to initialize the network : tag assignment, address assignment, clock assignment, clock synchronization, distributed application scheduling across the network or association of the input and output parameters of the function blocks. It also controls the operation of the network with statistic of faults and detection of the addition of the new element or the absence of a station. The system always look for the new stations on the bus by polling the possible station addresses.
Digital Communication Protocol ISO
IEEE SP72 SP50 F.I.P Profibus WorldFIP ISP
- International Standard Organization. Responsible for developing the model that the communication specification are based upon as well as standards for each layer of communication specification. - Institute of Electrical and Electronics Engineers. Formed the IEEE 802 project for defining standards for network media and access methods. - Institute Society of America, Standards and Practice committee Number 72 Developing EIA1393 companion standard for process control messaging. - Institute Society of America, Standards and Practice committee Number 50 Developing standards for digital communication between field devices. - Factory Information Protocol, approved French National Standard. - Process Fieldbus, approved German National Standard. - A U.S./French conglomerate of instrument manufacturers. - Interoperable Systems Project, a multinational group of some 80 manufacturers spanning U.S/Europe and Japan.
HART COMMUNICATION PROTOCOL Why HART protocol ? 4-20 ma is tried, tested and widely used standard but only limited amount of information is sent by a 4-20 ma signal. HART (Hiway Addressable Remote Transducer) protocol enhances these operations by transmitting digital data along with the 4-20 ma signal – without interfering with it ! HART permits two-way communications. It also has all digital mode that allows instrument to be connected to a single cable, cutting installation costs dramatically. Features : 1. Field proven concept that is easy to understand and use. 2. Compatible with existing 4-20 ma systems. 3. Simultaneous point-to-point 4-20 ma and digital communication. 4. Alternative multi-drop mode. 5. Measured variables, tag no. , range and span settings, device information, diagnostics and simple messages transmitted. 6. Digital response time of 500 msec; burst mode response of 300 msec. 7. Open architecture; freely available to any vendor and every user.
HART COMMUNICATION PROTOCOL Method of Operation : The Hart protocol operates using the FSK principal. The digital data is made up from two frequencies –1200 Hz and 2200 Hz representing bits 1 and 0 respectively. Sinusoidal waves of these frequencies are superimposed on the DC analog signal cables to give simultaneous analog and digital communications
HART Protocol Structure : HART follows the basic Open Systems Interconnection (OSI) reference model, developed by the International Organization for Standard (ISO). The HART protocol uses a reduced OSI model, implementing only layers 1,2 and 7
HART COMMUNICATION PROTOCOL OSI reference model Open Systems Interconnections
LAYER
FUNCTIONS
HART
7
Application
Provides formatted data
6
Presentation
Converts data
5
Session
Handles the dialogue
4
Transport
Secures the transport connection
3
Network
Establishes network connections
2
Link
Establishes the data link connection
HART protocol regulations
1
Physical
Connects the equipment
Bell 202
HART instructions
HART PROTOCOL LAYERS Layer 1, the physical layer, operates on the FSK principle Data transfer rate: 1200 bit/s Logic “0” frequency: 2200 Hz Logic “1” frequency: 1200 Hz the vast majority of existing wiring is used for this type of digital communication. Layer 2, the link layer establishes the format for a hart message. HART is a master/slave protocol. the structure of these messages is given below: Preamble SD
AD
CD
BC
Status
Data Parity
SD – start character. AD – display terminal and field addresses. CD – HART instruction. BC – Byte count. Status – Field device and communication status (only from field device to master) The individual characters are : 1 start bit, 8 data bits, 1 bit for odd parity and 1 stop bit.
HART PROTOCOL LAYERS
Layer 7, the application layer, brings the HART instruction into play. The master sends messages with requests for specified values, actual values and any other data or parameters available from the device. The field device interprets these instruction as defined in the HART protocol. The response message provides the master with the status information and data from the slave. For slave devices, logical uniform communication is provided by the following command sets: Universal commands – understood by all field devices. Common practice commands – provide functions which can be carried out by many, though not all, field devices. Drive-specific commands – provide functions which are restricted to an individual device.
HART PROTOCOL – TECHNICAL DATA DATA TRANSMISSION Types of data transmission Transfer rate ‘0’ bit information frequency ‘1’ bit information frequency Signal structure Transfer rate for simple variables
: : : : : :
Frequency shift keying (FSK) 1200 bit/s. 2200 Hz 1200 Hz 1 start bit, 8 data bits, 1 bit for odd parity, 1 stop bit. Approximately 2/s (poll/response)
DATA INTEGRITY Physical layer : Error rate destination circuit : 1/(10^5) Link layer : Recognizes : all groups up to 3 corrupt bits and practically all longer and multiple groups. Application layer : Communication status terminated in a response message.
MODBUS The MODBUS protocol describes an industrial communication and distributed control system developed by Gould-Modicon. MODBUS is a Master/Slave communications protocol, whereby one device (Master), controls all serial activities by selectively polling one or more slave devices. The protocol provides for one master device and up to 247 slave devices on a common line. Each device is assigned an address to distinguish it from all other connected device. Only a master initiates a transaction. Transactions are either a query/response type, or a broadcast/no-response type. A transaction comprises a single query and single response frame or a single broadcast frame. Certain characteristic of a MODBUS protocol are fixed such as frame format, frame sequences, handling of communication errors and exception conditions, and the functions performed. Other characteristics are user selectable. These include a choice of transmission media, baud rate, character parity, no. of stop bits and the transmission modes. The user selected parameter are set at each station. These parameter cannot be changed while the system is running
RS-232 Communication
RS-232 is an asynchronous communication network. Normally, a binary system is used to transmit data in ASCII (American Standard Code for Information Interchange) format. This code translates human readable code (letter/numbers) into “computer readable” code(1’s and 0’s). There are 2 types of RS-232 devices. The first is called a DTE (Data Terminal Equipment) device and a common example is a computer. The other type of device is called DCE (Data Communication Equipment) device and a common example is a modem. In RS-232 the first thing a terminal send is start bit. This start bit is a synchronizing bit added just before each character being send. The last thing send is a stop bit. This stop bit informs to the receiving terminal that the last character has just being send.
RS-232 Communication RS-232 communication is done through Serial port which usually has a 9-pin configuration. The pin and their purposes are shown below.
9-PIN
PURPOSE
1
Frame ground
2
Receive data (RD)
3
Transmit data (TD)
4
Data terminal ready (DTR)
5
Signal ground (GND)
6
Data set ready (DSR)
7
Request to send (RTS)
8
Clear to Send (CTS)
9
Ring indicator (RI) *only for modems*
PC-to-PC Communication through Serial Port
CD 10
01
CD
RXD 20
02
RXD
TXD 30
03
TXD
DTR 40
04
DTR
GND 50
05
GND
DSR 60
06
DSR
RTS 70
07
RTS
CTS 80
08 CTS 09 RI
RI 90
9-Pin D Connector
PC-to-PC Communication through LPT1 Port 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25
Flavours of Internet Telephony PC-to-PC The Internet PC
PC Dial-up or Local ISP Leased Line
Local ISP
PC-to-Phone The Internet PC
Phone Local ISP Voice Gateway
Local ISP
Phone-to-Phone
Access Code The Internet
Phone
Phone Local ISP Voice Gateway
Local ISP Voice Gateway
APACS - Operation Platform Database Ownership
Operator Console
Engineer Console
Operator Console
Controller Level
Controller Module
I/O Level
I/O Modules Transmitter
Interlock
Console Level
I/P Valve
•TAGS •Range •Engineering Unit •Diagnostics
TODAYS INDUSTRIAL SYSTEMS Application
Drivers
-----------------------
HMI 1
2
3
Planning HMI 4
5
Devices PLC
DCS
I/O
6
PC Based Industrial Systems
OPC Client Application OPC Server
HMI
1
2
----------------------------------
Planning HMI
3
Devices PLC
DCS
I/O
Enterprise Automation Schemes
Windows NT
Corporate IT Network Windows NT Server
Control network
Embedded Real System
Windows NT (“New technology”) FEATURES: • A true 32 bit processing. • A very reliable operating system. • Real operating system. TECHNICAL ASPECT: • Multiprocessing, Multithreading and partitioned memory space. • Security - C2 compliance. • In-built networking. • Internationalization . • Human interface as Windows 95. • Object - based : DCOM/OLE - ActiveX. • for special need of the process industries. DCOM and OLE are not robust, deterministic and secure. • Client - Server architecture.
Windows NT Interconnectivity Transparent inter-connectivity to typical business systems in plants: 1) ODBC : It provides access to most SQL databases. 2) ActiveX/OLE : Supports data access between application and embedding of one applications function within another. 3) DDE : Dynamic Data Exchange supports simple data exchange between applications such as plant data populating an Excel spread sheets.
Windows NT features Windows NT is gaining ground in open control because of the following advantages : • User acceptance. • Corporate interoperability • Ease of use. • Connectivity. • Scalability for small and large application.
• • • • • •
However, Windows NT has the following disadvantages : Needs a lot memory and processing power. Optimized for office, not control, requirements. Requires a disk drive which may fail. Depends on single vendor. Reboots at unexpected times Unstable operating system.
Embedded control Operating System - QNX QNX real-time operating system, has evolved from the first-ever micro-kernel operating system for PCs into one of the best selling and most trusted operating systems for mission critical application. Today, QNX is the real time operating system in industrial automation, hand held devices, controllers and soft PLCs QNX is recognized as : • The fastest and most dependable real time operating system. • The most proven high speed, deterministic real time kernel. • Having a hard real time engine that gives PLC-style control. • Enabling data acquisition with milliseconds resolution. • Providing a fault-tolerant architecture on which you can run control, events, alarms in a virtually crash-proof environment.
Windows NT - for Process control Windows NT features : • A true 32 bit processing. • A very reliable operating system. • Real operating system. • Multiprocessing, Multithreading and partitioned memory space. • Security - C2 compliance. • In-built networking. • Internationalization. • Human interface. • Object-based DCOM/OLE : The sending object is shown as client and receiving object is known as server. The MS technology allows any developer to produce small, self contain objects that have “packaged” visual component and specific action. These components are called “ActiveX” objects. NT’s OLE technology is part of Microsoft’s Distributed Component Object Model (DCOM) operating across networks. Anyone can develop ActiveX Object using VC++ or even VB on a PC. For special needs of the process control industries DCOM and OLE are not secure, deterministic and robust enough. OPC is a process industry consortium that is working to make extension to DCOM\OLE
Ethernet Ethernet was originally designed by Digital, Intel and Xerox (DIX) in the early 1970’s and has been designed as a broadcast system. The original format for Ethernet was developed in Xerox Palo Alto Research center (PARC), California in 1972. The two inventors were Robert Metcalf and David Boggs. Ethernet version 1.0 and 2.0 followed until the IEEE 802.3 committee re-jigged the Ethernet II packet to form the Ethernet 802.3 packet. Nowadays you will see either Ethernet II (DIX) format or Ethernet 802.3 format being used. The ‘Ether’ part of Ethernet denotes that the system is not meant to be restricted only to one medium type, copper cables, fiber cables and even radio waves can be used. Briefly, stated Ethernet what is referred to as the Physical layer and the Data-link layers protocols. The physical layer defines the cable types, connectors and electrical characteristics. The Data link layer defines the format an Ethernet frames, the error checking method and the physical addressing method. As Ethernet is only a Physical/Data link layer other protocols need to be added on top of it to address the issues of routing, end-to-end data integrity and house specific network task are carried out.
Ethernet 10Base5 Traditionally, Ethernet is used over ‘thick’ coaxial cable called 10Base5 ( the 10 denotes 10 Mbps, base means that the signal is baseband i.e, takes the whole bandwidth of the cable, 5 denotes 500m maximum length ). The minimum length between stations is 2.5m. The cable is run in one long length forming a ‘Bus Topology’. The segments are terminated by 50 ohm resistor and the shield should be grounded at one end only.
10Base2
Thin Ethernet (Thinnet) uses RG-58 cable and is called 10Base2 (the 2 denotes 200 mtr maximum length cable). Each station connects to the Thinnet by way of Network Interface Card (NIC). At each station the Thinnet terminates at a T-piece and at each end of the Thinnet run a 50 ohm terminator is required to absorb stray signals thereby preventing signal bounce.
Ethernet
10BaseT Nowadays, it is becoming increasingly important to use Ethernet across Unshielded Twisted Pair (UTP) or Shielded Twisted Pair (STP), this being called 10BaseT (the T denotes twisted pair). UTP is installed in star wire format and Ethernet Hubs with UTP ports (RJ45) centrally located. Also there should be no more than a 11.5db signal loss and the minimum distance between devices is 2.5 meters. The advantages of the UTP/STP technology are gained from the flexibility of the system, with respect to moves, changes, fault finding, reliability and security. 10BaseF 10BaseF standard developed by IEEE 802.3 committee defines the use of Fiber for Ethernet. 10BaseFB allows up to 2 Km per segment and is defined for Backbone application such as cascading repeaters. 10BaseFL describes the standards for the Fiber optic links between stations and repeaters allowing up to 2 Km per segment on multimode Fiber.
Ethernet The following table shows the RJ45 pin outs for 10BaseT :
RJ45 Pin
Function
Colour
1
Transmit
White/Orange
2
Transmit
Orange/White
3
Receive
White/Green
4
Blue/White
5
White/Blue
6
Receive
Green/White
7
White/Brown
8
Brown/White
PC-to-PC Communication through Ethernet RJ45
RJ45
1
1
2
2
3
3
4
4
5
5
6
6
7
7
8
8
Ethernet Topology Segmented (star) topology
Workstation
Workstation
Bus topology
Workstation
Workstation
Switched Hub
Controller Controller
Controller
Controller
Wireless LAN Wireless LAN is based on standard IEEE 802.11b which throughput of up to 11Mbps in the 2.4 Ghz band. Similar Wireless Personal Area Network (WPAN) are Bluetooth and Infrared. Ethernet works on the CSMA/CD technology but wireless LAN has difficulty of detecting collision in Radio frequency. Therefore they are using CSMA/CA (Collision Sense Multiple Access / Collision Avoidance) technology to transmit data. Physical Layer is either Photonic or Radio frequency.
Process control Software characteristics The most important feature of process control system is that it needs to be reliable. The process control system used has to be completely crash-proof and any changes in the system need to be made on-line. The process control needs to be made real time, which means that it can update the I/O data table and process the control program in the time required by the process. A process control system that is deterministic refers to whether the operating system allows the highest priority task to work without interruption from task with lower priority. Software offerings in the automation and the process control fields must be versatile and open enough to address the needs of different applications. Finally the chosen solution must deliver tangible, quantifiable values such as : 1. Reducing project implementation time and cost. 2. Improving time-to-market. 3. Achieving higher production and quality. 4. Cutting maintenance and training cost. 5. Increasing profits.
PC-based control system features Unlike the other systems, PCs provide a more open architecture making them ideal for improving, optimizing and integrating the overall automation process, as well as conducting control task. In addition PCs offer the following features : • Lower cost. • Ease of use. • Graphical user interface. • Easy integration of logic, motion and process control. • Simplified application development. • Software portability • Independence from proprietary control system. Using PCs enable the following functions, • Millisecond time stamping which is essential to utilities. • Real time control. • Sequence of events. • Alarming. • Data collection.
PLC conceptual overview Process Graphics
History & Trend
Alarm & Events
SCADA configuration editor
Other Aspect system
SCADA Control Aspect
OP Client
OPC server SCADA server
Real-time database
opc
Modbus
comli
Protocol Protocol xx yy
ABB
Siemens
Allen Bradley
GE Fanuc
….
PLC Programming Standards
The open, manufacturer-independent programming standard for automation is IEC 61131-3. You can thus choose what configuration interface you wish to use when writing your application : • • • • •
Ladder Diagram Instruction List Function Block Diagram Sequential Function Chart Structured Text All users, be they plant electrician or computer scientists, thus have a configuration interface in which they can feel at home.
Industrial IT Trends The availability of information is becoming increasingly crucial in the view of growing global competition. In future, a decisive competitive edge can only be achieved by providing the right information at the right time, in the right place and in the right form for the right person. these leading- edge application are continuously optimized and repositioned. Industrial IT consists of five components: 1. 2. 3. 4. 5.
Engineering IT Operation IT Production IT Optimization IT Evolution / Information
Industrial IT Trend
Business Systems
Sales & Marketing
Operation & Maintenance
ASSET
Y CTIVIT
Plant & Process Eng.
Real-time Automation & Information
U e-PROD
Planning & Scheduling
ION OPTIMIZAT
Distribution
Plant
