Ohaus Corporation 19A Chapin Road P.O. Box 2033 Pine Brook, NJ 07058-2033
ADVENTURER ANALYTICAL AND PRECISION BALANCES SERVICE MANUAL
Ohaus Corporation 19A Chapin Road, P.O. Box 2033, Pine Brook, NJ 07058-2033 (973) 377-9000
SERVICE MANUAL Adventurer Balances
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Ohaus Corporation 19A Chapin Road P.O. Box 2033 Pine Brook, NJ 07058-2033 The information contained in this manual is beli eved to be accurate at the time of publication, but Ohaus Corporation assumes no liability arising from the use or misuse of this material. Reproduction of this material is strictly prohibited. Material in this manual is subject to change. © Copyright 2001 Ohaus Corporation, Corporation, all rights reserved. ® Registered trademark of Ohaus Corporation.
TABLE OF CONTENTS CHAPTER 1 INTRODUCTION Page No. 1.1 Introduc Introduction tion .... ........ ......... ......... ......... .......... .......... .......... .......... ......... ......... .......... .......... .......... ......... ......... .......... .......... ..........1-1 .....1-1 1.2 Service Service Facilitie Facilities s .... ......... ......... ......... ......... ......... ......... ......... ......... ......... .......... .......... ......... ......... ......... ......... ......... ......... ....... .. 1-1 1.3 Tools Tools and Test Equipment Equipment Require Required d ..... ......... ......... .......... .......... .......... .......... ......... ......... .......... .......... ....... 1-2 1.3.1 1.3 .1 Special Special Tools Tools ..... .......... ......... ......... ......... ......... ......... ......... ......... ......... .......... .......... ......... ......... ......... ......... ......... ........ ....1-2 1-2 1.3.2 1.3 .2 Standard Standard Tools Tools and Test Test Equipment Equipment .... ........ ......... .......... .......... .......... .......... ......... ......... ......... ....1-2 1-2 1.4 Test Masses Masses Requ Required ired ..... ......... ......... .......... .......... .......... ......... ......... .......... .......... .......... ......... ......... .......... .......... ......... ....1-2 1-2 1.5 Specific Specification ations s ..... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... ......... ....1-3 1-3 CHAPTER 2 THEORY OF OPERATION 2.1 Balance Balance Operatio Operation n .... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... .......... .......... ......... ......... .....2-1 2-1 2.2 Overview Overview of the Cont Controls rols .... ........ ......... .......... ......... ......... .......... .......... .......... ......... ......... .......... .......... .......... ......... ....... ... 2-1 2.3 Overview Overview of the Display Indicators Indicators .... ........ ......... .......... ......... ......... .......... .......... .......... ......... ......... .......... ....... .. 2-2 2.4 Turning Turning On the Balance Balance ..... ......... ......... .......... .......... .......... ......... ......... .......... .......... .......... ......... ......... .......... .......... ....... .. 2-2 2.5 Menu Setup Setup ..... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... .......... .......... ......... ......... ......... ......... ......... ......... ........ ... 2-3 2.6 Transducer Transducer Description Description ........................... .......................................... ............................. ............................. ................... .... 2-3 2.7 Block Block Diagram Diagram Circuit Description Description .... ........ ......... .......... .......... ......... ......... .......... .......... .......... ......... ......... ....... .. 2-4 2.7.1 2.7 .1 Main PC Board Board .... ......... ......... ......... .......... .......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ...... .. 2-4 2.7.2 2.7 .2 Cell PC Board Board ..... .......... ......... ......... ......... ......... ......... ......... .......... .......... ......... ......... ......... ......... ......... ......... ......... ....... ... 2-4 2.7.3 2.7 .3 RS PC Board Board ..... .......... ......... ......... ......... ......... ......... ......... ......... ......... .......... .......... ......... ......... ......... ......... ......... ........ ....2-4 2-4 CHAPTER 3 TROUBLESHOOTING 3.1 Troubles Troubleshoot hooting ing ..... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... ....... 3-1 3.2 Diagnosti Diagnostic c Guide Guide ..... ......... ......... ......... ......... ......... ......... ......... ......... .......... .......... ......... ......... ......... ......... ......... ......... ......... ...... .. 3-1 3.2.1 3.2 .1 Diagnosis............. Diagnosis................. ......... ......... ......... .......... .......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ....... .. 3-1 3.3 Error Error Code Codes s ..... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... .......... .......... ......... ......... ......... ......... ........ ... 3-2 CHAPTER 4 MAINTENANCE PROCEDURES 4.1 Preventi Preventive ve Maintena Maintenance nce .... ......... .......... .......... .......... ......... ......... .......... .......... .......... ......... ......... .......... .......... .......... ....... 4-1 4.1.1 4.1 .1 Preventi Preventive ve Maintena Maintenance nce Checklis Checklistt .... ........ ......... .......... ......... ......... .......... .......... .......... ......... ........ ....4-1 4-1 4.2 4.2 Test Testin ing g .... ...... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .. 4-1 4-1 4.2.1 4.2 .1 Operatio Operational nal Test ..... .......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... .......... .......... ......... ......... ........ ...4-1 4-1 4.2.1.1 4.2 .1.1 Segmen Segmentt Display Display Test ..... ......... ......... .......... .......... ......... ......... ......... ......... ......... ......... ......... ....4-1 4-1 4.2.2 4.2 .2 Calibrati Calibration on ..... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... ....... 4-2 4.2.2. 4.2 .2.1 1 Calibra Calibratio tion n Masses........ Masses............. .......... ......... ......... ......... ......... .......... .......... ......... ......... ......... ...... 4-2 4.2.2. 4.2 .2.2 2 Span Span Calibr Calibratio ation n ..... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... .......... .......... ........ ...4-2 4-2 4.2.2.3 4.2 .2.3 Lineari Linearity ty Calibra Calibratio tion n ..... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ........ ....4-2 4-2 4.2.3 4.2 .3 Performa Performance nce Tests Tests - Precis Precision ion and and Analyti Analytical cal Balanc Balances es .... ........ ........ ........ ....4-3 4-3 4.2.3.1 4.2. 3.1 Precisi Precision on Test Test - Precis Precision ion and and Analyti Analytical cal Balan Balances ces .... ......... ....... 4-3 4.2.3.2 4.2. 3.2 Off-Cent Off-Center er Load Load Test Test - Preci Precision sion Balance Balances s ..... .......... .......... .......... ........ ... 4-4 4.2.3.3 4.2. 3.3 Off-Cen Off-Center ter Load Load Test Test - Analytica Analyticall balance balances s ..... .......... .......... .......... ........ ... 4-6 4.2.3.4 4.2. 3.4 Cent Centere ered d Load Load Test Test - Precis Precision ion and and Anal Analytic ytical al Balan Balances ces . 4-8 4.2.3.4 Precision/Repe Precision/Repeatabilit atability y Test Test - Precision Precision and and Analytic Analytical al Balances .................................................. ........................................................................... .........................4-9 4-9
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TABLE OF CONTENTS (Cont.) 4.3 Disassembly/Assembly Procedures .....................................................4-10 4.3.1 Disassembling the Balance ..........................................................4-10 4.3.2 Re-assembling the Balance..........................................................4-11 4.4 Replacement of Major Components...................................................... 4-11 4.4.1 Transducer Removal- Precision ...................................................4-11 4.4.2 Transducer Disassembly/Cleaning/Alignment - Precision ............4-12 4.4.2.1 Flexure Removal Replacement - Precision ..................... 4-12 4.4.2.2 Top Flexure Arm Removal/Installation - Precision ..........4-12 4.4.2.3 Bottom Flexure Arm Removal/Replacement - Precision . 4-13 4.4.2.4 Ratio Beam Assembly Removal/Installation - Precision .. 4-13 4.4.2.5 Position Sensor PC Board Removal/Replacement/ Adjustment - Precision ....................................................4-14 4.4.2.6 LED Removal/Replacement - Precision ..........................4-16 4.4.2.7 Transducer Replacement - Precision .............................. 4-16 4.4.3 Transducer Removal- Analytical...................................................4-17 4.4.3.1 Upper Flexure Arm and Lower Flexure Arm Removal/ Installation - Analytical ....................................................4-17 4.4.3.2 Load Flexure Removal/Installation - Analytical ............... 4-18 4.4.3.3 Position Sensor PC Board Removal/Replacement - Analytical......................................................................4-18 4.4.4 Main Printed Circuit Board (PCB) Replacement - Precision and Analytical Balances ......................................................................4-19 4.4.5 RS232 Printed Circuit Board Replacement - Precision and Analytical Balances ......................................................................4-20 4.4.6 Membrane Switch Replacement - Precision and Analytical Balances ......................................................................4-20
CHAPTER 5 DRAWINGS AND PARTS LISTS 5-1 Drawings....... ..........................................................................................5-1 5.1.1 Precision and Analytical Balance Replacement Parts List ............. 5-3 5.1.2 Precision Transducer Parts List ...................................................... 5-5 5.1.3 Analytical Transducer Replacement Parts List ............................... 5-7
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TABLE OF CONTENTS (Cont.) LIST OF TABLES TABLE NO. 1-1 1-2 3-1 3-2 4-1 4-2 4-3 4-4 4-5 5-1 5-2 5-3
TITLE
PAGE NO.
Mass Values ...................................................................................... 1-2 Aventurer Specifications....................................................................1-3 Diagnostic Guide ............................................................................... 3-2 Error Codes .......................................................................................3-2 Calibration Masses............................................................................ 4-2 Tolerances Precision.........................................................................4-3 Tolerances Analytical ........................................................................4-3 Center Load Test Masses - Precision................................................ 4-7 Center Load Test Masses - Analytical .............................................. 4-7 Precision and Analytical Balance Replacement Parts ......................5-3 Precision Transducer Parts List .........................................................5-5 Analytical Transducer Part List .......................................................... 5-7
LIST OF ILLUSTRATIONS FIGURE NO. 2-1 2-2 2-3 4-1 4-2 4-3 4-4 4-5 4-6 4-7 4-8 4-9 5-1 5-2 5-3
TITLE
PAGE NO.
Balance Menus..................................................................................2-3 Transducer Assembly ........................................................................2-4 Adventurer Balance Block Diagram .................................................. 2-5 Segment Display ............................................................................... 4-1 Off-Center Load Test Mass Locations................................................4-4 Mass Placement Location ................................................................. 4-5 Load Adjustments Screw Location .................................................... 4-5 Off-Center Load Adjustments Diagram .............................................. 4-6 Adventurer Balance Opened ...........................................................4-10 Main Board Display Indicator Connector ......................................... 4-14 Sensor Board Adjustment................................................................ 4-15 Shimming the Center Post...............................................................4-17 Overall Exploded View of Precision Balance .................................... 5-2 Exploded View of Precision Transducer ........................................... 5-4 Overall Exploded View of Analytical Balance ................................... 5-6
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TABLE OF CONTENTS (Cont.) LIST OF ILLUSTRATIONS FIGURE NO. TITLE PAGE NO. 5-4 Schematic, Main PC Board (page 1 of 2)...........................................5-8 5-4 Schematic, Main PC Board (page 2 of 2)...........................................5-9 5-5 Main PC Board Assembly ...............................................................5-10 5-6 Cell Board Assembly ....................................................................... 5-11 5-7 RS232 Board Assembly ..................................................................5-11 5-8 Schematic, Cell Board.....................................................................5-12 5-9 Schematic, RS232 Board ................................................................ 5-13
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CHAPTER 1 INTRODUCTION 1.1 INTRODUCTION This service manual contains the information needed to perform routine maintenance and service on the Ohaus Adventurer Analytical and Precision balances. Balances are rated from 65 grams to 4100 grams capacity. The contents of this manual is contained in five chapters.
Chapter 1 Introduction - Contains information regarding service facilities, tools and test equipment, measuring masses, and specifications.
Chapter 2 Theory of Operation - Contains information on the mechanical and electronic functions of t he balance. Chapter 3 Troubleshooting - Contains a diagnosis/diagnostics chart and error code table. Chapter 4 Maintenance Procedures - Contains preventive maintenance procedures, performance tests and adjustments, disassembly/replacement procedures, and calibration procedures.
Chapter 5 Drawings and Parts Lists - Contains exploded views of Adventurer balances and Transducers identifying all serviceable components with parts lists. Before servicing the balance, you should be familiar with the Instruction Manual which is packed with every balance.
1.2 SERVICE FACILITIES To service the Ohaus Adventurer balance, the service area should m eet the following requirements:
DO NOT SERVICE the balance: Next to open windows or doors causing drafts or rapid temperature changes. •
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Near air conditioning or heat vents.
•
Near vibrating, rotating or reciprocating equipment.
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Near magnetic fields or equipment that generates magnetic fields.
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On an unlevel work surface.
•
Allow sufficient space around the instrument for ease of operation and keep away from radiating heat sources.
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CHAPTER 1 INTRODUCTION 1.3 TOOLS AND TEST EQUIPMENT REQUIRED In order to properly service the Ohaus Adventurer balances, certain Ohaus special tools and test items are required in addition to standard electronic tool kits. These items are listed as follows:
1.3.1 Special Tools 1.Test Fixture P/N 923345 for use with Models AR1530, AR2130, AR3130, ARV70. 2.Test Fixture P/N 923389 for use with Models AR5120, ARA520, ARB120, ARC120, ARR W60, ARD110. 3.Test Fixture P/N 476001-02 for use with Models AR0640, AR1140, AR2140.
1.3.2 Standard Tools and Test Equipment 1.Digital Voltmeter (DVM) - Input impedance of at least 10 megohms in the 1 Volt dc position. 2.Nutdriver, 6mm 3.Hex or Allen key wrenches, metric. 4.Other assorted hand tools, tweezers, adjustable open wrenches, etc. 5.Soldering iron (50 watt) and solder (rosin core solder, not acid core). 6.Solder remover.
1.4 TEST MASSES REQUIRED The masses required to test the Ohaus Adventurer balances must meet the requirements of ASTM Class 1 Tolerance. The mass values are listed in Table 1-1.
TABLE 1-1. MASS VALUES CAPACITY 65g 110g 210g 150g 310g 410g/100g 510g 1500g 2100g 3100g 4100g/1000g 4100g
LINEARITY MASSES 20g/50g 50g/100g 100g/200g 100g/150g 100g/300g 200g/400g 300g/500g 500g/1500g 1000g/2000g 1000g/3000g 2000g/4000g 2000g/4000g
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SPAN ONLY MASSES 50g 100g 200g 150g 300g 400g 500g 1500g 2000g 3000g 4000g 4000g
CHAPTER 1 INTRODUCTION 1.5 SPECIFICATIONS Complete specificatons for the Ohaus adventurer balances are listed in Table 1-2. When a balance has been serviced, it must meet the specifications listed in the table. Before servicing the balance, determine what specifications are not met.
TABLE 1-2. AVENTURER SPECIFICATIONS Capacity Readability
65g
(2)
110g
Linearity
210g
(2)
150g
0.1mg
Weighing units/modes Repeatability (Std. Dev.)
(2)
(1)
210g 310g
(1)
410/100g (1)
0.001g
0.01/0.001g
0.1mg ±0.2mg
0.001g
0.01g
±0.3mg
0.01/0.001g
±0.002g
4ppm/°C
±0.02g
0.1/0.01g
0.1g
±0.1/0.01g
±0.1g
10ppm/°C 50° to 86° F/10° to 30° C 8 - 14.5V 50/60Hz 6VA or 9.5 - 20V 6W
Calibration
External Digital
Display (in/cm)
LCD (1.2/3 high) 3.5/9 dia.
3.9/10 dia.
Draft shield clearance height above pan (in/cm)
9.3/23.6
6.8/17.25
Dimensions (WxHxD) (in/cm)
8.5x14.3x13.5/ 36.6x11x34.3
Item No.
0.1g
3 Seconds
Power Requirements
Shipping Wt (lb/kg)
41 00g
Full capacity by subtraction
Operating Temp Range
Net Wt (lb/kg)
4100/1000g 0.1/0.01g
0.01g
±0.01g/0.001 ±0.01g
Stabilization Time (seconds)
Pan Size (in/cm)
3100g
g, kg, mg, ct, N, lb, oz, ozt, gn, dwt, momme, mesghal, 3 taels, ticals, Parts Counting
Tare Range
Sensitivity Drift
510g 1500g 2100g
7.1/18 dia.
8.5x8.3x13.5/ 21.7x21x34.3
8.5x4.3x13.5/21.7x11x34.3
10.5/4.8
10/4.5
8.5/3.9
17/7.8
16/7.3
14/6.4
AR0640 AR1140 AR2140
AR1530 AR2130 AR3130
ARRV70
AR5120 ARA520 ARB120
Note 1. 150 g through 410 g balances include a round draft shield. Note 2. 65 g and 210 g analytical balances include a three door draft shield.
Admissible ambient conditions Use only in closed rooms Temperature range:
50°F to 86°F / 10°C to 30°C
Atmospheric humidity:
80% rh @ to 30°C
Voltage fluctuations:
-15% +10%
Installation category:
II
Pollution degree:
2
Power supply voltage:
8-14V ac, 50/60 Hz, 6VA or 9.5-20V dc, 6W
Power Adapter:
AP3405
120V, 60Hz 10W
AP3405E
230V, 50Hz 80mA
AP3405B
240V, 50Hz 80mA
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ARC120
ARRW60
ARD110
CHAPTER 1 INTRODUCTION
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CHAPTER 2 THEORY OF OPERATION 2.1 BALANCE OPERATION This chapter contains information on the basic operation of the balance, mechanical descriptions of the Transducers and a block diagram description of the circuitry. Exploded view drawings are included in chapter 5 which identifies all mechanical components of the balance. The descriptions in this manual refer to the name of the components identified on the exploded view drawing with t he numbered callout. With power applied, press >O/T<, all segments will appear briefly followed by a software revision number (when plugged in first time) or after a power interruption and then 0.00g. Allow 20 minutes warm-up time. When the balance is first turned on, it can be used to weigh in grams or tare items without setting the menus. *
2.2 OVERVIEW OF THE CONTROLS
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Net BPTG AutoCal
PCSGN# C :
kgm % %
1
2 Off
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On
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No. 1
Designation
Function
>O/T< / On button
Multi-functional, with an intial short press, applies power to balance. With an intial long press, allows entry into the menu. Stores selections. Short press sets balance to zero.
Print button
When pressed, prints data to an external printer or computer.
3
Mode / Off button
Multi-functional, long press turns balance off, permits advancing through menus and selecting measuring units. Enables measuring units ON/OFF.
4
Leveling indicator
Indicates leveling position of the balance (located at rear of balance).
5
Leveling feet
Used to level the balance.
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CHAPTER 2 THEORY OF OPERATION 2.3 OVERVIEW OF THE DISPLAY INDICATORS
+
Not used Net BPTG AutoCal
1
PCSGN# C :
3
kgm % % 2
No.
Function
1
Indicates that the measured value has become stable.
2
Standard (7) segment numeric characters. Eight characters are available and are used for displaying weight values.
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Symbols for weighing modes, include: g - Grams, kg - Kilograms, mg - Milligrams, ct- Carats, N - Newtons, lb - Pounds, oz - Ounces, oz t - Ounces troy, GN - Grain, dwt - Pennyweight, mo - Mommes, m - Mesghal, t - Taels. Taels are available in three types; Hong Kong, Singapore, and Taiwan,cl - Tical, PCS - Parts counting.
2.4 TURNING ON THE BALANCE The Adventure balance is ready to operate. When the balance is first turned on and it completes its checks, it can be used to weigh or tare materials without setting the menus. It is recommended that you calibrate the balance before use. Power ON Press >O/T<, all segments will appear briefly followed by a software revision number (when plugged in first time) or after a power interruption and then 0.00g. Allow 20 minutes warm-up time. When the balance is first turned on, it can be used to weigh in grams or tare items without setting the menus. *
Power OFF To turn the balance OFF, press and hold Mode Off until the display indicates OFF then release.
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CHAPTER 2 THEORY OF OPERATION 2.5 MENU SETUP Programmable features of the Adventurer balances are contained in menus which are accessed through the front panel control switches. Figure 2-1 illustrates how the menus are structured. The Adventurer balances must be properly set in order for test results to be valid. The setup menu permits you to activate available weighing units, parts counting, linearity calibration, keystroke tone and print parameters. To enter the menu the balance must first be turned off. Press and hold the>O/T< until MENU is displayed then release. To advance through the menus, press Mode Off. To enter a selected menu, press >O/T<. After you make selections in any menu, you may continue to make additional changes in other menus before exiting and saving. To exit a menu and return to weigh mode without saving settings, press and hold Mode Off until full display appears, then release. NOTE: Selecting END in the UNITS, SYS and PRINT menus will save the settings for each menu. MENU UNITS - g, kg, mg, ct, N, lb, oz, ozt, GN, dwt, mo, m,Hong Kong taels, Singapore taels, Taiwan taels, cL, and PCS. - Set each to ON or OFF. NOTE: Only one Tael may be on at a time. LIN -
Performs linearity calibration.
SYS -
Permits setting tone ON or OFF, with each keystroke.
PRINT -Permits setting communication and print parameters. MENU - Exit menu and return to weigh mode. END
Figure 2-1. Balance Menus. 2.6 TRANSDUCER DESCRIPTION Figure 2-2 illustrates a typical Transducer used in the Adventurer balances. The Transducer is attached to the case of the balance. The force of a weight placed on the weighing Pan is exerted on the Hanger which is guided by the Upper and Lower Flexure Arms. The Load Flexure transfers the force vertically to the Ratio Beam. The Ratio Flexures form a pivot for the Ratio Beam. Any mass placed on the Pan applies a downward force to the Load Flexure by means of the Center Post. The Load Flexure pulls down on the front end of the Ratio Beam which pivots, pulling the Force Coil up into the air gap of the Magnet. The upward movement of the Vane (which is connected to the Ratio Beam) is detected by the Position Sensor. The Position Sensor contains one light emitting diode (LED) and two photo resistors. When the Vane moves, the amount of light is varied, causing one of the photo resistors to change its resistance value. The resultant signal goes into an amplifier to be amplified and filtered. The signal then goes through a current amplifier, then fed to the force coil which interacts with the Magnet returning the Ratio Beam to the null position. In the null position, light should strike each photo resistor equally. The entire process takes approximately 4 seconds from the time any mass is placed on the Pan to achieve a stable reading. The mechanical zero of the system is moved to the approximate middle of the measuring range by the Counter Weight. Displacement of the Position Sensor Vane from the normal position results in a current change in the Force Coils. The Force Coils are located in the field of the permanent Magnets which are mounted on the Transducer Base. This means that with a 50% load on the Pan, the Ratio Beam is in equilibrium and the sum of the forces from the Force Coils is zero. The temperature sensitivity of the Permanent magnets is compensated in the electronics by a Temperature Sensor which is physically mounted on the magnet assembly.
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CHAPTER 2 THEORY OF OPERATION 2.6 TRANSDUCER DESCRIPTION (Cont.)
FORCE COILS VANE
RATIO COUNTER WEIGHT
WEIGHING PLATFORM
BEAM
UPPER FLEXURE
OVERLOAD PROTECTION
ARM
POSITION SENSOR
PLATFORM HOLDING BRACKET HANGER
TEMPERATURE SENSOR RATIO FLEXURES PRINTED CIRCUIT BOARD
COUPLING LOAD FLEXURE
PERMANENT MAGNETS
BOTTOM FLEXURE ARM
FLEXURE
Figure 2-2. Transducer Assembly 2.7 BLOCK DIAGRAM CIRCUIT DESCRIPTION Figure 2-3 illustrates the Adventurer electronic circuitry as a block diagram.
2.7.1 Main PC Board Power Supply Power is supplied to the balance through an AC/AC adapter which provides 12 Volts ac. The main PC board contains a diode bridge and 3 voltage regulators which provide regulated voltages. The 5 Volts is provided to the digital circuitry and the 14 Volts dc is divided to 10 Volts and 7 Volts for operating the balance.
Weight Measurement The position sensor supplies an electrical current, the magnitude of which depends of the position of the sensor vane, to the PID controller after the current being amplified and converted to voltage. The output signal of the PID controller is compared with a periodic ramp signal. The output signal of the comparator is a pulse signal which is passed to the microprocessing unit as the weighing results.
Temperature Measurement A thermistor is mounted in the transducer as a temperature sensor. The switched temperature dependent current charges and discharges the integrator. The output voltage of the integrator is compared with a dc voltage. The output signal of the comparator is a pulse signal which is passed to the micro controller as the temperature results and it is used to compensate the weighing result in the microprocessing unit.
MELSI2 MELSI2 is a digital integrated circuit that contains the digital circuitry needed to operate a two-channel charge balance deltasigma A/D converter. Microprocessing Unit H8 is an 8 bit single micro controller which is integrated with 60k ROM, 2k RAM, µP, UART for data I/O and LCD-driver. Parameter Storage The EEPROM is a 512 x 8 bit electrically erasable and programmable memory which stores resettable parameters such as the temperature compensations coefficient, unit, scaling factor etc
2-4
CHAPTER 2 THEORY OF OPERATION 2.7 BLOCK DIAGRAM CIRCUIT DESCRIPTION (Cont.) 2.7.2 Cell PC Board The cell PC board contains a reference voltage which is used for producing a constant current source. The two switches are transfer switches for the constant current to the two force coils to compensate the measured weight. The position sensor is also located on the cell PC board.
2.7.3 RS PC Board The data I/O operation is controlled by the UART unit which is integrated in the micro controller. Signals RXD, TXD, DTR and DSR are provided and go to a driver/receiver IC located on the RS232 PC board.
RS BOARD
Cell PC BOARD
WEIGHT INPUT
REFERENCE VOLTAGE
CURRENT SOURCE
POSITION SENSOR
SWITCH
RS-232 DRIVER
COIL EEPROM
AMPLIFIER
PID CONTROLLER
COMPARATOR
AC INPUT
MELSI 2
H8 MICRO CONTROLLER
DISPLAY
POWER SUPPLY 5V, 7V, 10V, 14V, 23V RAMP GENERATOR
TEMPERATURE SENSOR
KEY
TEMPERATURE MEASUREMENT
INTEGRATOR
COMPARATOR BEEPER
DC
MAIN PC BOARD
Figure 2-3. Adventurer Balance Block Diagram.
2-5
I/O CONNECTION
CHAPTER 2 THEORY OF OPERATION
2-6
CHAPTER 3 TROUBLESHOOTING 3.1 TROUBLESHOOTING This section of the manual specifies problem areas of the balance which can occur. Information is contained to isolate specific problems using Table 3-1, Diagnostic Guide, and Table 3-2, Error Codes. Follow all directions step by step. Make certain that the work area is clean and use care when handling components of the balance.
3.2 DIAGNOSTIC GUIDE Table 3-1 is a diagnostic guide designed to help locate the problem area quickly and easily. To use the table, first locate the symptom that you are observing. Follow the symptom column and review the probable cause column and remedy column. The probable causes are listed with the most common cause first. If the first remedy does not fix the problem, proceed on to the next remedy. Before attempting to repair the balance, read all chapters of this manual to familiarize yourself with the balance components and operation. Do not attempt repairs unless you fully understand the operation of the balance.
3.2.1 Diagnosis 1.Isolate and identify the symptom. 2.Refer to Table 3-1 Diagnostic guide and locate the symptom. 3.Follow the suggested remedies in the order that they appear. 4.Perform the indicated checks, or see the appropriate section of the manual. 5.Repair or replace the defective section of the balance. NOTE: If more than one symptom is observed, it is necessary to approach one area at a time, and also remember, that the symptoms may be interrelated. In the event that erratic or fluctuating weight readings are observed, it is necessary to isolate the problem to either the mechanical area or the electronic area of the balance. If a problem arises that is not covered in this manual, contact:
Ohaus Corporation 19A Chapin Road P.O. Box 2033 Pine Brook, NJ 07058-2033 USA Tel: 973-377-9000 Fax: 973-593-0359
In the United States call toll free, 800-526-0659 between 8:00 a.m. and 6:00 p.m. EST.
3-1
CHAPTER 3 TROUBLESHOOTING TABLE 3-1. DIAGNOSTIC GUIDE SYMPTOM
PROBABLE CAUSE
REMEDY
No Display.
Power Adapter not connected.
Connect AC Adapter.
Incorrect weight reading.
Balance out of calibration.
Calibrate the balance.
Balance was not rezeroed before weighing.
Press >O/T< with no weight on the pan, then weigh item.
Calibration procedure does not work. Incorrect calibration masses being used.
Use correct masses.
Unable to display weight in a particu- Weighing unit not activated in menu. lar weighing unit.
Use Units menu to set desired units ON (see menu).
Balance won't store selections made END selection was not used to exit menu. in menu.
You must use END to exit each menu and save selections.
3.3 ERROR CODES This balance is equipped with software which will display an error condition when it occurs. When a problem occurs using the balance, the display will indicate an error code. Review the listed codes and follow instructions to correct the problem.Table 3-2 Error Codes, describes the various error codes which can appear on the display and specifies the probable reason and remedy.
TABLE 3-2. ERROR CODES Error Codes
Problem/Solution
Err 2.0
Stability error - Check if balance is located near vibrating equipment or if air currents are affecting it.
Err 3.0
Calibration error (wrong mass) - Incorrect or no calibration mass used when performing calibration procedure. Error will flash momentarily, then balance will use previous calibration data. Recalibrate correctly.
Err 4
Invalid data checksum in type or adjust data - Return balance for servicing.
Err 6.0
Parts counting error - Average piece weight is less than 1d. Balance shows error then exits parts counting.
Err 8.4
Over or under load - Sample being weighed exceeds the capacity of the balance. If error occurs when the sample is within the balance capacity, balance may be incorrectly calibrated. An underload such as the pan off of the balance could also display Err8.4. Recalibrate the balance.
Err 9
Internal data error - Return balance for servicing.
Err 9.8
Invalid checksum in calibration or setup data - The balance may need recalibration, particularly linearity calibration. If the error persists after recalibration, the balance must be serviced.
3-2
CHAPTER 4 MAINTENANCE PROCEDURES 4.1 PREVENTIVE MAINTENANCE Ohaus balances are precision instruments and should be carefully handled, stored in a clean dry area which is dust f ree, and cleaned periodically. It is recommended that when a balance has had chemicals or liquids spilled on it, the balance should be cleaned as soon as possible. Use warm water on a damp cloth to clean all exterior surfaces. Do not leave a mass on the balance when the balance is not in use. When moving the balance from a storage area which is at a different temperature than the area where the balance is to be operated, allow sufficient time f or the balance mechanism to temperature stabilize. This time can vary quite a bit depending upon the temperature differences. Allow one (1) hour for each 5 degrees Fahrenheit temperature change before using the balance. Also, after turning the balance ON, allow one hour after temperature stabilization for the balance electronics to stabilize.
4.1.1 Preventive Maintenance Checklist On a regular basis, the balance should be inspected and checked as follows: 1. Remove the Platform and Sub Platform (on 4kg balances) and inspect and clean the area beneath the Platform.
2. Clean the outside of the balance using a damp cloth with water. CAUTION DO NOT USE CHEMICAL CLEANERS OR SOLVENTS OF ANY TYPE. SOME CLEANERS ARE ABRASIVE AND MAY AFFECT THE FINISH OF THE BALANCE. 3. Check the Power Cord for broken or damaged insulation. 4. Make a visual inspection for faulty connectors, wiring, and loose hardware.
4.2 TESTING Before servicing the Adventurer balance, an operational test and various performance tests should be made to ascertain whether or not the balance meets specifications. Turn the balance on and allow it warm up for at least one hour before performing these tests. Make sure the test area is free from drafts and the surface that the balance rests on is level and vibration free. The masses used for the performance tests and adjustments must meet or exceed ASTM Class 1 Tolerance.
4.2.1 Operational Test 1. Connect a functioning Power Adapter to the balance power receptacle assembly located at the rear of the balance. 2. Plug the Power Cord into a suitable power source.
4.2.1.1 Segment Display Test 1. Turn the balance on, all segments are enabled and displayed breifly, then the model number of the balance followed by a software revision number. This is a segment display test. Figure 4-1 is a full display test. +
Net BPTG AutoCal
PCSGN# C :
kgm % % Figure 4-1. Segment Display
4-1
CHAPTER 4 MAINTENANCE PROCEDURES 4.2.2 Calibration To verify that the Balance is functioning properly, it must be calibrated prior to testing. At this point , the Balance should have the menus set up if functional. After calibration, proceed to Performance Tests, paragraph 4.2.3 for Precision balances and paragraph 4.2.4 for Analytical balances. Calibration can be affected by changes in location, temperature, or rough handling. AdventurerTM balances can be calibrated in two ways: Span calibration or Linearity calibration. Span calibration resets the balance's weighing range using two weight values: zero and a weight value at or near the balance's capacity. Linearity calibration minimizes deviation between actual and displayed weights within the balance's weighing range. Three weight values are used: zero, a weight value within the balance's weighing range and a weight value at or near the balance's specified capacity. TABLE 4-1. CALIBRATION MASSES
4.2.2.1 Calibration Masses Before beginning calibration, make sure masses are available. If you begin calibration and realize calibration masses are not available, exit the menu. The balance will retain previously stored calibration data. Calibration should be performed as necessary to ensure accurate weighing. Masses required to perform the procedures are listed in Table 4-1.
LINEARITY SPAN ONLY CAPACITY MASSES MASSES 65g 20g/50g 50g 110g 50g/100g 100g 210g 100g/200g 200g 150g 100g/150g 150g 310g 100g/300g 300g 410g/100g 200g/400g 400g 510g 300g/500g 500g 1500g 500g/1500g 1500g 2100g 100g/2000g 2000g 3100g 1000g/3000g 3000g 4100g/1000g 2000g/4000g 4000g 4100g 2000g/4000g 4000g Masses must meet or exceed ASTM Class 1 Tolerance. Calibration masses are available as accessories.
4.2.2.2 Span Calibration 1. With the balance turned ON, press and hold >O/T< until CALis displayed. 2. Release >O/T< , -C- momentarily displayed followed bythe value of the calibrati on mass which is to be placed on the Platform. Do not disturb the balance when -C- is displayed. Incorrect calibration may result. 3. Place the indicated span calibration mass on the pan. 4. Press >O/T<, -C- is momentarily displayed, then the weight of the mass on the Platform is displayed. 5. Remove the calibration mass from the Platform. The balance isnow calibrated and returns to the weighing mode.
4.2.2.3 Linearity Calibration 1. With the balance OFF, press and hold>O/T< until MENU is displayed, then release it and UNITS is displayed. Press Mode Off, LIN is displayed. 2. Press >O/T<, -C- is displayed followed by the value of the first mass which must be placed on the Platform. 3. Place the required mass on the pan and momentarily press >O/T<, -C- is displayed followed by the value of the next mass to be placed on the Platform. Do not disturb the balance while -C- is displayed. 4. Place the second required mass on the Platform and momentarily press >O/T<, -C- is displayed. When the weight on the Platform is displayed with the stability indicator, the balance is calibrated and returns to the weighing mode. 5. Remove the calibration masses from the Platform.
4-2
CHAPTER 4 MAINTENANCE PROCEDURES 4.2.3 Performance Tests - Precision and Analytical Balances Accurate performance of the Adventurer precision balance is determined by a series of four performance tests. The displayed readings are compared with the tolerances listed in Tables 4-2 and 4-3. Tolerance values are expressed in counts. A one count change is equal to the last digit shown on the balance display.
TABLE 4-2. TOLERANCES PRECISION PERFORMANCE TEST 150g
210g
TOLERANCE - COUNTS PRECISION 310g 400/100g 510g 1500g 2100g 3100g 4100g 4100/1000g
Precision (mg)
±1
±1
±1
±10/1
±10
±10
±10
±10
±100
±100/10
Off Center Load (mg)
±5
±5
±3
±3
±30
±30
±30
±30
±100
±100
Centered Load (mg)
±2
±3
±2
±10/1
±20
±20
±20
±20
±100
±100/10
Repeatability (mg)
±1
±1
±1
±10/1
±10
±10
±10
±10
±100
±100/10
TABLE 4-3. TOLERANCES ANALYTICAL PERFORMANCE TEST
TOLERANCE - COUNTS ANALYTICAL 65g 110g 210g
Precision (mg)
±0.1
±0.1
±0.1
Off Center Load (mg)
±0.5
±0.5
±0.5
Centered Load (mg)
±0.2
±0.2
±0.3
Repeatability (mg)
±0.1
±0.1
±0.1
The following performance tests are used to evaluate the balance operation before and after repairs. Each balance tested must meet the requirements specified in each test as well as the specifications listed in Table 1-2 depending upon the model. Before proceeding with the following tests, all the procedures starting with paragraph 4.2 must have been accomplished on the Balance first.
4.2.3.1 Precision Test - Precision and Analytical Balances Precision is a word used in balance specifications meaning the Standard Deviation of a set of similar weight readings. To determine whether a balance meets the calculated Standard Deviation value listed in the Tolerance Tables 4-2 and 4-3, perform the following test:
Test 1. Tare the balance. The reading on the display should be 0g. 2. Select a mass weighing near the maximum capacity of the balance and place the mass on the center of the Platform observe and record the reading. 3. Remove the mass. Reading should return to 0g + 1 count. 4. Repeat this test for three times. Reading should be within + 1 count of the reading recorded. If the reading is less than +1 count, the balance passes the Precision Test. If the deviation for a set of readings is more than +1 count, proceed to the next step. 5. If the deviation for any set of readings (using the same mass placed on the center of the Platform) is greater than the tolerance listed in Table 4-2, the balance does not meet the precision specification. Inspect and correct the following areas:
4-3
CHAPTER 4 MAINTENANCE PROCEDURES 4.2.3.1 Precision Test - Precision and Analytical Balances (Cont.) 5A. Check for mechanical obstructions. Any foreign object touching any part of the moving assemblies will cause a balance to fail the Precision Test. Inspect and correct as necessary. 5B. An error in the Off-Center Load Adjustment can affect the results of the Precision Test. Inspect and correct if necessary. See Off-Center Load Test.
4.2.3.2 Off-Center Load Test - Precision Balances The Off-Center Load Test is used to determine whether displayed wei ght values will be affected by moving the sample to different areas of the Platform. See figure 4-2. Place 1/2 of the balance capacity in the center of the Platform. Press the >O/T< button to return the reading to zero. Move the mass halfway to the rear of the Platform and note the reading. Move the mass halfway between the center and the left edge front of the Platform and note the reading. Repeat this test for the right edge position and note the reading. Move the mass halfway to the front of the Platform and note the reading. Note any differences in the displayed w eight reading at all positions. Maximum allowable change is per Table 4-2 for each of the li sted balances four positions. MASS LOCATIONS
Figure 4-2. Off-Center Load Test Mass Locations. To correct an off-center load error, proceed as follows:
Transducer Adjustment This adjustment requires that the balance Top Cover be removed and the Transducer Shield removed to gain access to the Transducer for adjustments. Refer to Figures 4-4 and 5-1 for location of components called out in this procedure. NOTE: The top cover connector plug may be used to turn the balance on. The pins are numbered from 5 - 1 starting at the left. Shorting pins 5 and 1 turns the unit on and tares. Shorting pins 4 and 1 turns the unit off. See Figure 4-7, page 4-14 for pin connections. 1. Refer to paragraph 4.3.1, page 4-10 and open the balance. 2. Locate the four screws holding the Transducer Shield in place. Remove the screws. 3. Remove the Transducer Shield. The Transducer is now exposed for adjustments. 4. Reinstall the Platform on 1mg balance and Sub Platform and Weighing Platform on 10/100mg balance onto the exposed Transducer shaft. NOTE: Do not attempt these adjustments on the balance unless the balance is free from drafts and is level. The balance is very sensitive and adjustments will be affected.
4-4
CHAPTER 4 MAINTENANCE PROCEDURES 4.2.3.2 Off-Center Load Test - Precision Balances (Cont.) Transducer Adjustment(Cont.) 5. Plug the power cord into the balance and turn the balance on. 6. Place 1/2 of the balance capacity or greater on the rear of the Platform. 7. Tare the balance. Move mass to right front and left front of the Platform as shown in Figure 4-3 and note the readings. Correct the worst error first by turning Adjust ing Screws on the Transducer shown in Figure 4-4. MASS LOCATIONS
A
B
Figure 4-3. Mass Placement Locations. FRONT OF BALANCE ADJUSTMENT SCREW B
ADJUSTMENT SCREW A
Figure 4-4. Load Adjustments Screw Locations. 8.
Repeat the Off-Center Load Test and adjustments until balance is within specifications.
9. Turn the balance OFF and unplug power cord. 10. Remove the Platform and Subflatform if installed. 11. Install the Transducer Shield on the balance and secure with four Screws 12. Refer to paragraph 4.3.2, page 4-11 and re-assemble the balance. NOTE: If the Off-Center Load Adjustment cannot be completed, refer to the Precision Test/Adjustment.
4-5
CHAPTER 4 MAINTENANCE PROCEDURES 4.2.3.3 Off-Center Load Test - Analytical Balances The Off-Center Load Test is used to determine whether displayed weight values will be affected by moving the sample to different areas of the Platform. Place 1/2 of the balance capacity in the center of the Platform. Press the >O/T< button to return the reading to zero. Move the mass halfway (between the center and the edge) to the front of the Platform. Note any differences in the displayed weight reading. Repeat this test for the back, left, and right positions. Maximum allowable change in displayed weight readings is + 5 counts for each of the four positions. If the displayed weight readings change more than 5 counts, proceed to the following adjustment. To correct an off-center load error, proceed as follows:
Adjustment 1. Refer to paragraph 4.3.1, page 4-10 and open the balance. 2. Remove the two adhesive hole plugs on the transducer shield to gain access to the off center load adjustment screws. 3. Reinstall the Platform. NOTE: Do not attempt these adjustments on the balance unless the balance is free from drafts. The Balance is very sensitive and adjustments will be affected. 4. Plug the power cord into the balance and turn the Balance on. 5. Place 1/2 of the Balance capacity on the center of the Platform. 6. Press the >O/T< button to return the displayed weight to 0g. Slide mass front, back, left and right to Platform edge. Note displayed values. Correct any errors by turning Cornerload Adjusting Screws shown in Figure 4-5 (adjust the Hex Nut portion and ensure center screw does not turn).
-
+
A
-
+
B
ADJUSTMENT SCREWS
+
-
-
+
C
D
ADJUSTMENT SCREWS
Figure 4-5. Off-Center Load Adjustments Diagram. 4-6
CHAPTER 4 MAINTENANCE PROCEDURES 4.2.3.3 Off-Center Load Test - Analytical Balances (Cont.) Adjustment (Cont.) 7. Repeat the Off-Center Load Test. 8. Turn the balance OFF. 9. Remove the Platform. 10.Install the 2 adhesive hole pluge on the transducer shield. 11.refer to paragraph 4.3.2, page 4-11 and re-assemble the balance. NOTE: If the Off-Center Load Adjustment cannot be completed, refer to the Precision Test/Adjustment.
4.2.3.4 Centered Load Test - Precision and Analytical Balances The Centered load test is used to determine the span and linearity of the balance throughout its operating range and is in accordance with the tolerances listed in Tables 4-2 and 4-3. The masses used to perform this test must meet or exceed ASTM Class 1 Tolerance. NOTE: The balance must pass the Off-Center Load test and Precision Test before the Centered Load Test is performed. This test is used to determine the linearity of the balance throughout its operating range. Tables 4-4 and 4-5 lists the suggested masses to be used for checking linearity on each Balance model.
TABLE 4-4. CENTER LOAD TEST MASSES - PRECISION C APACITY
210g
310g
410/100g
510g
1500g
1g
1g
1g
1g
1g
1g
1g
1g
Load 1
20g
10g
30g
10g/10g
50g
200g
250g
300g
100g/10g
400g
Load 2
75g
50g
120g
50g/50g
200g
750g
1000g
1200g
1000g/500g 1000g/100g
1600g
Load 3
100g
100g
210g
200g/75g
350g
1000g
1700g
2100g
2000g/750g 2000g/200g
2800g
Load 4
150g
200g
150g
400g/100g
500g
1000g 1500g
2000g 2500g
3100g
4000g/500g 4000g/1000g
4100g
Ref. Wt.
150g
2100g
3100g
4100/1000g 1g
4100g 1g
TABLE 4-5. CENTER LOAD TEST MASSES - ANALYTICAL CAPACITY Ref. Wt.
65g
110g
210g
1g
1g
1g
Load 1
10g
10g
10g
Load 2
20g
25g
100g
Load 3
40g
50g
150g
Load 4
50g
100g
200g
A 1g calibration mass is recommended for the reference mass. All masses are nominal values. HOWEVER, BE CERTAIN TO USE THE SAME REFERENCE MASS THROUGHOUT THE PROCEDURE.
4-7
CHAPTER 4 MAINTENANCE PROCEDURES 4.2.3.4 Centered Load Test - Precision and Analytical Balances (Cont.) Before beginning:
• Perform calibration.
Preliminary Weighings Using the Load 3 and Load 4 weight values (Table 4-3 or 4-4), perform some preliminary weighings and make sure the display returns to zero after weighing. 1. Place Load 3 on the center of the Platform, read the displayed weight, then remove Load 3. If the display does not return to zero, press >O/T< and repeat this. 2. Repeat step 1 using Load 4. After performing preliminary weighings, proceed with checking Linearity. If the balance does not return to zero, it must be repaired. Test 1. Place the reference mass on the center of the Platform and record the exact value (all decimal places) displayed. 2. Remove the reference mass and verify that the display returns to zero. If it does not, disregard the reading, press >O/T< to rezero the display and take that reading again. See note above. 3. Repeat steps 1 and 2 five times and determine the Mean of the weight readings: Mean = Sum of Readings/5 Record the Mean as Mean (0)
4. Place Load 1 on the center of the Platform and press >O/T< . 5. Add the reference mass to the Platform and record the exact value displayed. 6. Remove the reference mass and verify that the display returns to zero. If it does not, disregard the reading, press >O/T< to rezero the display and take that reading again. NOTE: If after several attempts the display fails to return to zero, a repeatability problem is indicated and the balance must be serviced by an Ohaus Product Service Specialist. 7. Repeat steps 5 and 6 five times and determine the Mean of the weight readings as in step 3. Record the Mean as Mean (1). 8. Remove all masses from the Platform and press >O/T<. 9. Repeat steps 4 through 8 except use Load 2, Load 3 or Load 4 as applicable. ings as Mean (2), Mean (3), or Mean (4), respectively. 10. Determine the Mean of ALL weight readings.
4-8
Record the Mean weight read-
CHAPTER 4 MAINTENANCE PROCEDURES 4.2.3.4 Centered Load Test - Precision and Analytical Balances (Cont.) Test (Cont.) Mean (0)+ Mean (1)+ Mean (2)+ Mean (3)+ Mean (4)
= MEAN of ALL Readings
5 11. Determine the deviations from the MEAN:
Determine the deviation of each individual mean (Mean (X)) from the MEAN of ALL Readings as follows: Deviation (X) = Mean (X) - MEAN of ALL Readings Record each deviation as Dev(0), Dev(1), Dev(2), Dev(3), and Dev(4), and identify each as (+) or (-). 12. Determine the Cumulative Deviation: Determine and record the cumulative deviation as follows: Cum. Cum. Cum. Cum. Cum.
Dev (0) = Dev (0) + 0 Dev (1) = Dev (1) + Dev (0) Dev (2) = Dev (2) + Dev (1) + Dev (0) Dev (3) = Dev (3) + Dev (2) + Dev (1) + Dev Dev (4) = Dev (4) + Dev (3) + Dev (2) + Dev
(0) (1)
+ Dev (0)
13. Compare Cumulative Deviation to Linearity Tolerance: Compare the cumulative deviations to the maintenance Linearity tolerance for the particular balance model. For example, if an 210g balance yields the following results it would be within the tolerance. Cumulative Deviation -0.07 mg...........................largest negative value = -0.07 mg +0.01 mg +0.06 mg..........................largest positive value = +0.06 +0.01 mg +0.00 mg Cumulative Deviations are less than 210g balance tolerance of +0.2 If the cumulative deviations are within the tolerance, the balance is linear. If the balance proves to be non-linear, retest the Center Load Test of the balance. If the balance does not meet the specifications of the Center Load Test, the balance must be serviced.
4.2.3.5 Precision/Repeatability Test - Precision and Analytical Balances Precision is a term used in balance specifications which means the standard deviation of a set of similar weight readings. T o
conduct a Repeatability Test, proceed as follows:
1. With the balance calibrated, place a mass on the Platform equal to the capacity of the balance. Record the reading. 2. Remove the mass from the Platform, the balance should return to 0g. Record the reading. 3. Repeat steps 1 and 2 ten more times. Subtract the lowest from the highest reading to determine the difference. Maximum allowable difference is as listed in Table 4-2 or 4-3. 4. If the balance does not meet specifications, refer to Table 3-1 to determine the problem.
4-9
CHAPTER 4 MAINTENANCE PROCEDURES 4.3
DISASSEMBLY/ASSEMBLY PROCEDURES
Depending upon the capacity of the balance, one of two different types of Transducers are used. This section of the manual contains detailed disassembly and assembly procedures.
4.3.1 Disassembling the Balance The Adventure balance can be disassembled with relative ease using common hand tools. Refer to Figures 5-1, 5-2 and 5-3 which are exploded view drawings used in the following procedures. This procedure is used when it is required to replace eit her the front Panel Membrane Switch, RS232 PC Board, Main PC Board, or to gain access to the Transducer for removal and parts replacement and alignment. 1. Turn the balance OFF and unplug the power cord. 2. For an Analytical balance: a) Remove Weighing Pan Assembly and Draft Ring to gain access to the EMC plate. b) Remove the two screws on the EMC plate to gain access to the Draft Shield Bottom. c) Remove the two screws on the Draft Shield Bottom and remove. d) Proceed to Step 5. 3) For a Precision balance with a Draft Shield: a) Remove Draft Shield components from the balance. b) Remove Weighing Pan Assembly to gain access to the Draft Shield Bottom. c) Loosen the two screws on the Draft Shield Bottom and turn slightly to remove. d) Proceed to Step 5. 4) For a precision balance without a Draft Shield: a) Remove Weighing Platform and Sub Platform to gain access to Retaining Ring. b) Loosen the two screws on the Retaining Ring and turn slightly to remove. 5) On the Top Cover, remove the one screw located towards the rear of the balance. This screw secures the Top Cover to the Base. 6) Carefully lift the Top Cover from the rear of the balance and swing towards the front.BE CAREFUL, the cover has membrane switches which are connected to the balance by a very short cable which is part of the membrane switch assembly and is located in the front of the balance. Lay the Top Cover down and disconnect the cable from the main PC Board. You now have access to all components of the balance. See Figure 4-6. LEVELING BUBBLE RS232 PC BOARD
POWER JACK
SHIELD SCREWS
LOAD CELL WIRE LOOM LOAD CELL SHIELD
RS232 BASE
CONNECTOR
POWER
LOAD CELL
CONNECTOR
CONNECTOR MAIN PC BOARD
DISPLAY
MEMBRANE
RETAINING
SWITCH
SCREWS
CABLE
COVER
Figure 4-6. Adventurer Balance Opened. 4-10
CHAPTER 4 MAINTENANCE PROCEDURES 4.3.2 Re-assembling the Balance This procedure is used when the balance has been repaired and all adjustments have been made. 1. Check the interior of the balance and make sure that all connectors are in place and the cables are properly dressed along the left side wall of the Base. Check all PC boards are secured. 2. Position the Top Cover on top of the Base. Make sure the cover front tabs are in position on the Base. 3. Secure the Top Cover to the Base with the one screw previously removed. 4. For an analytical balance: a) Replace the Draft Shield on top of the Top Cover. b) Tighten the two screws holding the Draft Shield Bottom. c) Replace the EMC plate in the Draft Shield. d) Tighten the two screws holding the EMC plate. e) Replace Weighing Pan Assembly. 5. For a precision balance with a Draft Shield: a) Replace the Draft Shield Bottom on top of the Top Cover two exposed screws and turn slightly to lock in place. b) Tighten the two screws holding the Draft Shield Bottom. c) Replace Weighing Pan Assembly and Draft Shield components. 6) For a precision balance without a Draft Shield: a) Replace the Retaining Ring on top of the Top Cover two exposed screws and turn slightly to lock in place. b) Tighten the two screws holding the Retaining Ring. c) Replace the Sub Platform and weighing Platform.
4.4 REPLACEMENT OF MAJOR COMPONENTS When using this section of the Service Manual, you will find it necessary to refer to other sections. References are made to the Exploded Views which are located and identified in Chapter 5, Drawings and Parts Lists. The decision to replace any component or remove for repair should only be made after thoroughly diagnosi ng the problem. If, after the replacement of any component, the balance is still nonfunctional and no other information on the subject is available in the manual, contact: Ohaus Corporation 19A Chapin Road P.O. Box 2033 Pine Brook, NJ 07058-2033 USA Tel: 973-377-9000 Fax: 973-593-0359
4.4.1 Transducer Removal - Precision The removal of the Transducer should only be attempted when it is determined that it requires parts replacement Refer to Figures 4-4 in this Chapter and Figure 5-1 in Chapter 5 for location of components called out in this procedure. To remove the Transducer, proceed as follows: 1. Refer to paragraph 4.3.1, page 4-10 and open the balance. 2. Locate the four screws holding the Transducer Shield in place. Remove the screws. 3. Remove the Transducer Shield. 4. Disconnect the Transducer Cable from the Transducer.
4-11
CHAPTER 4 MAINTENANCE PROCEDURES 4.4.1 Transducer Removal - Precision (Cont.) 5. Locate the three screws in the center of the Transducer which secure the Transducer to the Base. Remove these three screws, and carefully lift the Transducer out of the Base.
CAUTION EXTREME CARE MUST BE EXERCISED SO AS NOT TO DAMAGE THE FLEXURE ARMS FLEXURES, THE RATIO BEAM FLEXURES, THE LOAD FLEXURE, OR ANY OTHER SUPPORT MEMBER. DAMAGE TO ANY ONE OR MORE OF THESE COMPONENTS WILL DESTROY THE ACCURACY OF THE BALANCE. NOTE: Visually inspect the Transducer Assembly for bent, cracked, or distorted Flexures. Each Flexure should be perfectly straight. If it is determined that a Flexure requires replacement, refer to paragraph 4.4.2 for the Upper Flexure Arm and Lower Flexure Arm removal procedure.
4.4.2 Transducer Disassembly/Cleaning/Alignment - Precision The Transducer consists of all the mechanical parts and some electronic components which convert an applied mass into an electronic signal. The Transducer must be very carefully aligned and be free from foreign material. In the event that foreign material has entered the air gap between the Magnet Assembly and the Force Coil , or if any field serviceable component has been damaged, it may become necessary to disassemble the Transducer for cleaning or repair. The Arm Flexure and Ratio Flexures may each be replaced independent of one another and without disassembling the entire Transducer. To clean between the Magnet Assembly and the Force Coil, remove the Top and Bottom Flexure Arms and Center Poast with the Load Flexure still attached (Load Flexure must be disconnected from the Ratio Beam first). To proceed, refer to Ratio Beam Removal/Installation I nstructions 4.4.2.4, starting with step 3. For the following procedures, the Transducer should be removed from the Unit Base as described previously.
4.4.2.1 Flexure Removal/Replacement - Precision To remove components from the Transducer, the use of a Test Fixture is required to hold the components of the Transducer in place. Models AR1530, AR2130, AR3130 and ARRV70 require test Fixture part number 923345. Models AR5120, ARA50, ARB120, ARC120, ARRW60 and ARD110 require test Fixture part number 923389. 1. Install the Test Fixture on the front of the Transducer using the six screws supplied with the fixture. 2. Remove and replace Flexures as required. Ratio Flexures and Load Flexure are accessible.
4.4.2.2 Top Flexure Arm Removal/Installation - Precision 1. Install the Test Fixture on the front of the Transducer using the six screws supplied with the fixture. 2. Remove the four screws on the Top Flexure Arm. See Figure 5-2. 3
Remove the Top Flexure Arm.
4. Replace Top Flexure Arm by placing into position on the Transducer Frame and secure with the four screws previously removed.
4-12
CHAPTER 4 MAINTENANCE PROCEDURES 4.4.2.3 Bottom Flexure Arm Removal/Installation - Precision 1. Install the Test Fixture on the front of the Transducer using the six screws supplied with the fixture. 2. Remove the four screws on the Bottom Flexure Arm. See Figure 5-2. 3
Remove the Bottom Flexure Arm.
4. Replace Bottom Flexure Arm by placing into position on the Transducer Frame and secure with the four screws previously removed.
4.4.2.4 Ratio Beam Assembly Removal/Installation - Precision 1. Install the Test Fixture on the front of the Transducer using the six screws supplied with the fixture. 2. Remove the Top Flexure Arm, see paragraph 4.4.2.2. 3. Remove the Bottom Flexure Arm, see paragraph 4.4.2.3. NOTE: In the next step, be careful as to the color and location of the wires removed. There is one Green wire, one Brown wire and Brown and Green wires twisted together. It is suggested that a diagram be made of the wire positions which you can refer back to when resoldering. 4. Unsolder the four Wires which connect the Ratio Beam to the Terminal Block mounted on the top of the Load Cell Frame. The resistance measurement from the Brown/Green wire to the individual Green wire or the individual Brown wire should be 460 ohms. The resistance reading from any wire to the frame should be open or infinity. 5. Using a piece of tape, tape the position Sensor Board on the top and side to the frame. This is done so that the Sensor Board can be accurately positioned back in place. Using a razor blade, cut the tape between the board and frame. When the board is replaced, you can line up the tape edges for horizontal and vertical positioning. Remove the three screws holding the position Sensor Board from the Transducer Frame. Two of the screws have washers, these are tightened when replaced. NOTE:The one screw on the left side of the position Sensor Board is not to be tightened when replaced, this screw is a guide only. 6. Remove the two small screws holding the Magnet Cover in place. 7. The Ratio Beam can now be removed by lifting straight up. 8. Clean the air gap in the Magnet and also check the Force coil for any signs of debris. Clean if necessary. (Adhesive tape turned back on itself is very helpful when trying to remove debris in the Magnet Assembly.) 9. Reinstall the Ratio Beam in the reverse order. Make sure the position Sensor Board is properly aligned then replace and tighten the two screws on the right side of the board with the washers. DO NOT TIGHTEN the single screw on the left side of the board, this screw is a guide only. 10. Solder the wires back to the Terminal Block removed in step 4. Make sure the wires are properly located. 11. Reinstall the Top and Bottom Flexure Arms removed in steps 2 and 3. 12. Tighten all fasteners and reinstall the Transducer in the Base. 13. Conduct Performance Tests.
4-13
CHAPTER 4 MAINTENANCE PROCEDURES 4.4.2.5
Position Sensor PC Board Removal/Replacement/Adjustment - Precision
When the Position Sensor PC Board (mounted on the Transducer) has been determined that it is defective and requires replacement, proceed as follows: 1. Refer to paragraph 4.3.1, page 4-10 and open the balance. 2. Locate the four screws holding the Transducer Shield in place. Remove the screws. 3. Remove the Transducer Shield. 4. Remove the cable connector coming from the Main PC Board. NOTE: When facing the Sensor Board, you will notice there are three sets of wires connected to the board. The three wires on the left side of the board are connected magnet assembly in the Ratio beam. Make sure these wires are marked to go back in the same position when resoldered. The two white wires at the top of the board are thermistor wires and the polarity is not important. The two wires located at the bottom right hand side of the board must be replaced back in there original position. Mark these wires. Make a little diagram of all wire positions which you can refer back to when resoldering. 5. Unsolder all wires noting there locations. 6. Remove the three screws holding the position Sensor Board from the Transducer Frame. Two of the screws have washers, these are tightened when replaced. NOTE:The one screw on the left side of the position Sensor Board is not to be tightened when replaced, this screw is a guide only. 7. Remove the position Sensor Board. 8. Install the replacement Sensor Board. Replace all screws previously removed. Do not tighten the screw located on the left side of the board. Tighten this screw finger tight. The Sensor Board contains an optical sensor which must be positioned in the center of travel of the Ratio Beam when the balance is operated. If the Sensor Board is postioned to low or to high, the balance will not function properly. 9. Resolder all wires paying attention to their location. 10. Place the Transducer in position and mount with 1 screw. 11. Connect the Transducer cable back to the Sensor Board. 12. Connect the Top Cover membrane switch cable to the Main PC Board. The Top Cover should be lying in front of the Base not on top. If you are unable to connect the cable properly, see Figure 4-7 which is the connector on the main PC board. You can operate the balance directly from the connector by m omentarily shorting out the pins as indicated to turn it on or off. TURN ON & TARE
TURN OFF
5
4
3
2
1
CONNECTOR
Figure 4-7. Main Board Display Indicator Connector. 4-14
CHAPTER 4 MAINTENANCE PROCEDURES 4.4.2.5
Position Sensor PC Board Removal/Replacement/Adjustment - Precision (Cont.)
13. Place the Platform and Subplatform in place on top of the Transducer. Apply power to the balance and turn the balance on. 14. Check the travel of the Shaft Indicator up and down by moving the Sensor Board up and down slightly on the side with the two screws which should be slightly tightned. If the Sensor Board is improperly positioned, the Shaft indicator will stay locked in one position. Adjust the Sensor Board up and down until the display indicates other than 8.4. If the Sensor Board is positioned too high or too low, the display indicates Error 8.4. Position the Sensor Board until the display indicates other than 8.4, then tighten the two screws on the right hand side of the Sensor Board. The Shaft Indicator travel should be equal in it's up and down motion. The amount of travel is about 15 to 20 thousands of an inch. If the Sensor Board repositioning does not allow the Shaft I ndicator to move properly, adjust the Up/Down Stop and try repositioning the sensor Board again. After completing this adjustment, turn the balance off and remove the Platform and Subplatform. Install the remaining screws in the Transducer. SHAFT INDICATOR
UP/DOWN STOP ADJUST
SENSOR BOARD
400G TRANSDUCER
SHAFT INDICATOR
MOUNTING SCREWS
GUIDE SCREW DO NOT TIGHTEN SENSOR BOARD
Figure 4-8. Sensor Board Adjustment. 15. Replace the Transducer Shield over the Transducer and secure with four screws. 16. Refer to paragraph 4.3.2, page 4-11 and re-assemble the balance. 17. Conduct Performance Tests.
4-15
CHAPTER 4 MAINTENANCE PROCEDURES 4.4.2.6
LED Removal/Replacement - Precision
When the LED (mounted on the Transducer) has been determined that it is defective and requires replacement, proceed as follows: 1. Refer to paragraph 4.3.1, page 4-10 and open the balance. 2. Locate the four screws holding the Transducer Shield in place. Remove the screws. 3. Remove the Transducer Shield. 4. Remove the Ratio Beam per paragraph 4.4.2.4. 5. Remove the Position Sensor Board as per paragraph 4.4.2.5. 6. Locate the LED which is positioned in front of the sensor on the Position Sensor Board. 7. Unsolder the LED and replace. 8. Reassemble the balance. perform procedures for the Position Sensor Board paragraph 4.4.2.5 and procedure 4.4.2.4 for the Ratio Beam replacement. 9. Perform procedure 4.4.2.7 and replace the Transducer.
4.4.2.7
Transducer Replacement - Precision
After the Transducer Assembly has been repaired, it is installed as follows: 1. Carefully position the Transducer in the Base. 2. Secure the Transducer to the Base with the three Screws previously removed. Make sure the Transducer is properly aligned before tightening t he screws. 3. Connect the Transducer Cable from the Main PC Board to the Transducer. CAUTION Do not touch any connectors on Main or Position Sensor board. Electrostatic discharge could damage components on the PCB's. 4.Replace the Transducer Shield over the Transducer and secure with four screws. 5.Refer to paragraph 4.3.2, page 4-11 and re-assemble the balance. 6. After assembly, verify that the balance meets all specifications. Perform all tests.
4-16
CHAPTER 4 MAINTENANCE PROCEDURES 4.4.3 Transducer Removal - Analytical 1. Refer to paragraph 4.3.1, page 4-10 and open the balance. 2. Locate the four screws holding the Transducer Shield in place. Remove the screws. 3. Remove the Transducer Shield. 4. Disconnect the Transducer Cable from the Transducer. 5. At the bottom of the Base, remove the two M4 Screws, M4 Ribbed Lock Washers which secure the Transducer Assembly. Hold the Transducer only at the Base, not by Flexure Arms while removing the screws. 6. Lift the Transducer Assembly clear of the Base. NOTE: Visually inspect the Transducer Assembly for bent, cracked, or distorted Flexures. Each Flexure should be perfectly straight. If it is determined that a Flexure requires replacement, refer to paragraph 4.4.3.1 for the Upper Flexure Arm and Lower Flexure Arm removal procedure.
4.4.3.1
Upper Flexure Arm and Lower Flexure Arm Removal/Installation - Analytical CAUTION Before the Upper or Lower Flexure Arms can be removed, the Center Post which contains the Load Flexure must be secured to the base of the Transducer with two screws removed from the Bottom Mounting Plate. This is necessary to prevent further damage from occuring when trying to remove and replace individual Flexures. CENTER POST
SHIM
SHIM
TRANSDUCER BASE
Figure 4-9. Shimming The Center Post. 1. Remove the three screws which secure Bottom Mounting Plate to Transducer Base. 2. At the front of the Transducer Assembly, insert the two Shims between the Center Post and the Transducer Base with the open slotted end in first, see Figure 4-9. The slots should be aligned so that the screw holes in the Center post to the Transducer Base are visible. 3. Take the two Screws removed from the Platform Mounting Assembly and install them in the Center Post through the slots in the Shims. Finger tighten the screws. This will hold the Upper and Lower Flexures Arms in place. 4. Carefully loosen the two Screws located at the rear of the Upper Flexure Arm and the rear of the Lower Flexure Arm. These are the screws which hold the Flexures in place. Do not touch the two rear most screws with the nuts on top as these are the adjustment screws. 5. Fully tighten the two screws which hold the Center Post in place. 6. At the top of the Transducer Assembly, remove the two Screws and Washers which secure the Platform Support to the Center Post.
4-17
CHAPTER 4 MAINTENANCE PROCEDURES 4.4.3.1
Upper Flexure Arm and Lower Arm Flexure Arm Removal/Installation - Analytical (Cont.) NOTE: Do not remove the Upper or Lower Flexure Arms unless there is evidence of damage to one or more of the Flexure Links.
7. To remove the Upper Flexure Arm from the Transducer Assembly, remove the four Screws and Washers, one at each Flexure point. 8. To remove the Lower Flexure Arm from the Transducer Assembly, remove the four Screws and Washers, one at each Flexure point. 9. Examine each Flexure Link. Each one must be perfectly straight. Replace any Flexure Link which is bent, twisted, cracked or deformed in any manner. 10. To replace a defective Flexure Link, remove the Screw and Washer which secures the Flexure Link to the Upper or Lower Flexure Arm. Replace as required. 11. To install Upper and or Lower Flexure Arms, perform steps 1 through 9 in reverse order.
4.4.3.2
Load Flexure Removal/Installation - Analytical
1. To remove the the Load Flexure, procedures in paragraph 4.3.1 must be performed first to gain access to the Load Flexure and to hold the Center Post in position. 2. Remove the two Screws and four Washers holding the Load Flexure in the Center Post using the 3 mm Allen Wrench. 3. Replace Load Flexure and retaining hardware as removed. Ensure that Locking Plate is as far to the right as possible when tightening.
4.4.3.3
Position Sensor PC Board Removal/Replacement Adjustment- Analytical
When the Position Sensor PC Board has been determined that it is defect ive and requires replacement, proceed as follows: 1. Refer to paragraph 4.3.1, page 4-10 and open the balance. 2. Locate the four screws holding the Transducer Shield in place. Remove the screws. 3. Remove the Transducer Shield. 4. Remove the cable connector coming from the Main PC Board. 5. Unsolder coil cable from Position Sensor PC Board. 6. Unsolder thermistor wires from Position Sensor PC Board. 7. Remove the two screws holding the position Sensor Board from the Transducer Frame. 8. Remove the Position Sensor PC Board. Note: The reference resistor of the Position Sensor PC Board must be transferred to the replacement Position Sensor PC Board.
4-18
CHAPTER 4 MAINTENANCE PROCEDURES 4.4.3.3
Position Sensor PC Board Removal/Replacement Adjustment- Analytical (Cont.)
9. Install the replacement Sensor Board. Replace all screws previously removed. The Sensor Board contains an optical sensor which must be positioned in the center of travel of the Ratio Beam when the balance is operated. If the Sensor Board is positioned to low or to high, the balance will not function properly. 10. Resolder all wires previously removed. 11. Re-install the Transducer in the base assembly. 12. Connect the Transducer cable back to the Sensor Board. 13. Connect the Top Cover membrane switch cable to the Main PC Board. The Top Cover should be lying in front of the Base not on top. If you are unable to connect the cable properly, see Figure 4-7 which is the connector on the main PC board. You can operate the balance directly from the connector by moment arily shorting out the pins as indicated to turn it on or off. 14. Place the Platform in place on top of the Transducer. Apply power to the balance and turn the balance on. 15. If the Sensor Board is improperly positioned, too high or too low, the display indicates Error 8.4. Adjust the Sensor Board up and down until the display indicates other than 8.4. Then tight en the two screws. After completing this adjustment, turn the balance off and remove the Platform. 16. Replace the Transducer Shield over the Transducer and secure with four screws. 17. Refer to paragraph 4.3.2, page 4-11 and re-assemble the balance. 18. Conduct Performance Tests.
4.4.4 Main Printed Circuit Board (PCB) Replacement - Precision and Analytical Balances Refer to Figure 4-5 and 5-1 for this procedure. 1. Refer to paragraph 4.3.1, page 4-10 and open the balance. 2. On the Main PC Board, disconnect the Load Cell Cable, RS232 Cable, Power Cable and the cable from the Membrane Switch on the front panel. 3. Remove the four screws on the Main PC Board which secure it to the Base. 4. Install replacement Main PC Board in the reverse order as removed. Check the LCD display on the new board and remove protective plastic covering if in place. 5. Refer to paragraph 4.3.2, page 4-11 and re-assemble the balance. 6. After assembly, verify that the balance meets all specifications. Perform all tests.
4-19
CHAPTER 4 MAINTENANCE PROCEDURES 4.4.5 RS232 Printed Circuit Board Replacement - Precision and Analytical Balances The RS232 PC Board is located at the rear of the balance. Refer to Figure 4-5 and 5-1 for this procedure. 1. Refer to paragraph 4.3.1, page 4-10 and open the balance. 2.
At the rear of the balance, remove the two hex head nuts which secure the RS232 Board to the base.
3.
Remove the small mounting plate and lift out the RS232 board.
4. Disconnect the RS232 Cable from the RS232 PC Board. 5.
Install replacement RS232 Board in the reverse order as removed.
6.
Refer to paragraph 4.3.2, page 4-11 and re-assemble the balance.
7. After assembly, verify that the balance meets all specifications. Perform all tests.
4.4.6 Membrane Switch Replacement - Precision and Analytical Balances The Membrane Switch is mounted on the Top Cover. The replacement Membrane Switch is supplied with a peel off adhesive backing for easy replacement. 1.
Refer to paragraph 4.3.1, page 4-10 and open the balance.
2.
Disconnect the Membrane Switch Cable from the front of the Main PC Board.
3.
Before replacing the Membrane Switch, connect a new Membrane Switch to the Main PC Board connector, apply power to the balance and test the balance. If the balance functions properly with the new Membrane Switch, replace the switch. If the balance fails to operate properly with the new switch, the Main PC Board requires replacement.
3.
Using a small knife or screwdriver, pry up a corner of the Membrane Switch from the front panel. Grasp the edge of the Membrane Switch which is accessible with your fingers and pull carefully across the cover until the membrane switch is free of the cover.
4.
On the Top Cover, remove any adhesive residue from the Top Cover. CAUTION IN THE NEXT STEP,USE CAUTION WHEN APPLYING THE MEMBRANE SWITCH TO THE TOP COVER. IT MUST BE ALIGNED PROPERLY OR IT MAY BECOME DAMAGED IF YOU TRY TO REMOVE AND REPOSITION IT.
5.
Peel off the adhesive backing from the new Membrane Switch, then place the cable from the switch through the hole in the Top Cover. Carefully position the new Membrane Switch on the Top Cover, starting at the bottom edges and roll the Membrane Switch upwards into it's final position. Smooth down the switch until it is completely in position on the Top Cover.
6.
Place the Top Cover into position next to the base and connect the Membrane Switch cable to the connector on the Main PC Board.
7.
Refer to paragraph 4.3.2, page 4-11 and re-assemble the balance.
8. After assembly, verify that the balance meets all specifications. Perform all tests.
4-20
CHAPTER 5 DRAWINGS AND PARTS LISTS 5.1 DRAWINGS This section of the manual contains exploded views for the Aventurer Precision and Analytical balances. The exploded view drawings are designed to identify the parts which can be serviced on the balance in the f ield.
NOTE: In all cases where a part is replaced, the balance must be thoroughly checked after the replacement is made. The balance MUST meet the parameters of all applicable specifications in this manual. If further technical information is needed, please contact: Ohaus Corporation 19A Chapin Road P.O. Box 2033 Pine Brook, NJ 07058-2033 USA Tel: 973-377-9000 Fax: 973-593-0359
In the United States call toll free, 800-526-0659 between 8:00 a.m. and 6:00 p.m. EST.
5-1
CHAPTER 5 DRAWINGS AND PARTS LISTS
20
3
19
4
1
5
1
2
2
22
7
23
6
18 17
24
26
19
27
16
8
12 13 11
9 14 10 9 15
Figure 5-1. Overall Exploded View of Precision Balance.
5-2
25
CHAPTER 5 DRAWINGS AND PARTS LISTS 5.1.1 Precision and Analytical Balance Replacement Parts List TABLE 5-1. PRECISION BALANCE REPLACEMENT PARTS LIST (See Figure 5-1) AR0640, AR1140 AR2140
AR1530, AR2130 AR3130, ARRV70 PART NO.
AR5120, ARA520 ARB120, ARC120 ARRW60, ARD110 PART NO.
KEY NO.
PART NO.
DESCRIPTION
1
12106739
12105372
————
Weighing Pan Assembly
2 2
12106740 ————
———— 12105375
———— ————
Draft Ring Draft Shield Bottom
3
————
————
12105370
Weighing Platform
4
————
————
12105369
Sub Platform
5
————
————
12105371
Retaining Ring
6
12105367
12105367
12105367
Membrane Switch
7
12105340
12105340
12105340
Top Cover, with membrane switch
8
12105336
12105336
12105336
Main PC Board
9
12105376
12105376
12105376
Foot Assembly
10
12106738
12105339
12105339
Base, includes power label, level, hole plug and hole cover
11 12
12105368 12105338
12105368 12105338
12105368 12105338
Level RS232 PC Board
13
12105364
12105364
12105364
Power Cable
14
12105384
12105384
12105384
Hole Plug
15
12105385
12105385
12105385
Hole Cover
16 17
12105365 12106737
12105365 12105363
12105365 12105363
RS232 Cable Load Cell cable
19
————
12105373
————
Draft Shield Glass
20
————
12105374
————
Draft Shield Top
22
12106756
————
————
EMC Plate
23
12106757
————
————
Door, Top with Handle
24 25
12106759 12106758
———— ————
———— ————
Glass, Front Door, Side with Handle
26
12106764
————
————
Handle, Kit of 3
27
12105366
12105366
12105366
LCD
—-
11103740
11103740
11103740
AC Adapter (220-240V EU)
—-
11103741
11103741
11103741
AC Adapter (100-120V US)
— —-
11103742 11103743
11103742 11103743
11103742 11103743
AC Adapter (220-240V UK) AC Adapter (100V JP)
----
400302-010
400302-010
400302-010
In-Use Cover kit
NOTES: 1. In all cases where a part is replaced, the balance shall be thoroughly checked after the replacement is made. The balance must meet the parameters of all applicable specifications in this manual. 2. Ohaus replacement parts warranty only applies to parts purchased from Ohaus Corporation
5-3
CHAPTER 5 DRAWINGS AND PARTS LISTS
3 RATIO BEAM
6 FLEXURE ARM ASSEMBLY
4
5
POSITION SENSOR BOARD
LED UP/DOWN STOP
RATIO FLEXURES
1 6 FLEXURE 1
ARM ASSEMBLY 2 VERTICAL FLEXURE
7 BEAM
Figure 5-2. Exploded View of Precision Transducer. 5-4
CHAPTER 5 DRAWINGS AND PARTS LISTS 5.1.2
Precision Transducer Parts List TABLE 5-2. PRECISION TRANSDUCER PARTS LIST (See Figure 5-2) AR1530, AR2130
AR5120, ARA520
AR3130, ARRV70
ARB120, ARC120
KEY NO.
PART NO.
ARRW60, ARD110 PART NO.
1
12105411
12105412
Ratio Flexures, Kit of 6
2
12105413
12105413
Vertical Flexure, Kit of 6
3
12105331
12105332
Ratio Beam
4
12105337
12105337
Position Sensor Board
5 6
12105335 12105410
12105335 12105410
LED Assembly Flexure Arm Assembly
7
12105333
12105334
Beam
NOTES:
DESCRIPTION
1.
In all cases where a part is replaced, the balance shall be thoroughly checked after the replacement is made. The balance must meet the parameters of all applicable specifications in this manual.
2.
Ohaus replacement parts warranty only applies to parts purchased from Ohaus Corporation.
5-5
CHAPTER 5 DRAWINGS AND PARTS LISTS
1
6 5
3
7 4
2
NOTE: TRANSDUCER ILLUSTRATION MAY VARY SLIGHTLY FROM ACTUAL UNIT.
Figure 5-3. Exploded View of Analytical Transducer. 5-6
8
CHAPTER 5 DRAWINGS AND PARTS LISTS 5.1.3
Analytical Transducer Replacement Parts List TABLE 5-3. ANALYTICAL TRANSDUCER PARTS LIST
KEY NO. 1
PART NO. 12106732
DESCRIPTION Flexure Arm Assembly, Top
2
12106733
Flexure Arm Assembly, Bottom
3
12106750
Flexure, Ratio, Kit of 6
4
12106751
Flexure, Load, Kit of 6
5
12106731
Lever
6
12106728
PCB, Sensor (includes the ref. Resistor)
7
12106749
Contact Strips, Kit of 10
8
12106729
Ref. Resistor 0.5W 0.25% 200Ohm TC5
NOTES: 1. Part numbers are only shown for parts which are field serviceable. 2. In all cases where a part is replaced, the scale shall be thoroughly checked after the replacement is made. The scale must meet the parameters of all applicable specifi cations in this manual. 3. Ohaus replacement parts warranty only applies to parts purchased from Ohaus Corporation.
5-7
CHAPTER 5 DRAWINGS AND PARTS LISTS
Figure 5-4. Schematic, Main PC Board Page 1 of 2. 5-8
CHAPTER 5 DRAWINGS AND PARTS LISTS
Figure 5-4. Schematic, Main PC Board Page 2 of 2. 5-9
CHAPTER 5 DRAWINGS AND PARTS LISTS
TOP OF BOARD
BOTTOM OF BOARD
Figure 5-5. Main PC Board, Assembly. 5-10
CHAPTER 5 DRAWINGS AND PARTS LISTS
Figure 5-6. Cell Board Assembly.
Figure 5-7. RS232 Board Assembly.
5-11
CHAPTER 5 DRAWINGS AND PARTS LISTS
Figure 5-8. Schematic, Cell Board. 5-12
CHAPTER 5 DRAWINGS AND PARTS LISTS
Figure 5-9. Schematic, RS232 Board. 5-13
CHAPTER 5 DRAWINGS AND PARTS LISTS
5-14
