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CHAPTER 1 GETTING STARTED

Ohaus Corporation www.ohaus.com

1-8

Pioneer

™ Balances Service Manual

1.5.7 The Load Cell

Figure 1-4 illustrates a typical Magnetic Force Restoration (MFR) Load Cell.

The force of a weight placed on the Weighing Pan moves 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 Beam Flexures form a pivot for the Ratio Beam. When the Ratio Beam is
moved, the Force Coils mounted on the Ratio Beam are moved. The Force Coils are located in
the magnetic field created by the Permanent Magnets. The magnetic forces are affected by
temperature. A Temperature Sensor is attached near the magnets to measure the temperature
and allow the electronics to compensate for the changes in temperature.

Operation

A mass placed on the Pan applies a downward force to the Load Flexure by means of the
Hanger. The Load Flexure moves one end of the Ratio Beam which pivots, moving the Force
Coil up into the air gap of the Magnet. The Force Coils are located in the field of the Permanent
Magnets. The movement of the Vane (which is connected to the Ratio Beam) is detected by the
Position Sensor. The Position Sensor contains a sender and receiver. When the Vane moves,
the amount of light sent to the receiver also changes. The change in the position of the Sensor
Vane is measured and used along with the Temperature Sensor signal to adjust the current in
the Force Coils. The current in the Force Coils produces a magnetic field which restores the
Ratio Beam to its normal position.

Figure 1-4. Load Cell Assembly.

Ratio Beam
Flexure

Vertical
Flexure

Top Bracket

Hanger

Bottom Flexure Arm

Flexure

Magnet

Printed Circuit

Board

Temperature

Sensor

Position

Sensor

Vane

Force
Coils

Ratio
Beam

Counter
Weight

Upper Flexure Arm

Pan

«
...
16
17
18
19
20
...
»

Summary of Contents for Pioneer PA64

Page 1: ...SERVICE MANUAL Ohaus Corporation 19A Chapin Road P O Box 2033 Pine Brook NJ 07058 2033 973 377 9000 ...

Page 2: ......

Page 3: ...al and Disassembly 3 3 3 3 1 Variations in Pioneer Load Cells 3 3 3 3 2 Disassembly of Precision Balances with Internal Calibration 3 4 3 3 3 Removing Internal Calibration Weights 3 5 3 3 4 Servicing the Internal Calibration Mechanism 3 5 3 3 5 Reassembling the Internal Calibration Mechanism 3 6 3 3 6 Disassembly of Precision Balances with InCal Mechanism 3 6 3 3 7 Removing the Load Cell Precision...

Page 4: ... 4 TESTING 4 1 Testing 4 1 4 1 1 Test Masses Required 4 2 4 2 Operational Test 4 1 4 3 Segment Display Test 4 1 4 4 Performance Tests 4 2 4 4 1 Precision Test 4 2 4 4 2 Off Center Load Test 4 3 4 4 3 Off Center Load Adjustment for Precision Models 4 4 4 4 4 Off Center Load Adjustment for Analytical Models 4 5 4 4 5 Off Center Load Adjustment for Block Style Models 4 6 4 4 6 Repeatability Test 4 7 ...

Page 5: ... Square Pan Block Style Square Pan Balance Housing Internal Parts 5 7 5 4 Precision Draft Shield Balance with Draft Shield Housing Parts 5 9 5 5 Analytical Balance Housing Internal Parts 5 11 5 6 Precision Balance Load Cell Parts 5 13 5 7 Analytical Balance Load Cell Parts 5 15 5 8 Block Style InCal Load Cell Parts 5 17 LIST OF ILLUSTRATIONS FIGURE NO TITLE 1 1 Pioneer Carat and Gold Series Displa...

Page 6: ...Stop Screw 3 15 3 37 Precision Load Cell 150g to 310g top with Service Fixture attached 3 15 3 38 Service Fixture for 510g to 4100g Precision Load Cell attached to Hanger 3 15 3 39 Sideways Motion Stop Plate 3 16 3 40 Two screws secure Magnet Half 3 16 3 41 Contact Board 3 16 3 42 Solder points on Position Sensor Board 3 16 3 43 Precision Load Cell top 3 17 3 44 Precision Load Cell bottom 3 17 3 4...

Page 7: ... Beam Flexures go on the bottom 3 29 3 81 Installing the Magnet Half 3 30 3 82 Four screws on Magnet Half 3 30 3 83 Position Sensor Board 3 30 3 84 3 wire cable soldered to Contact Board 3 30 3 85 Installing the Vane 3 30 3 86 Screws removed from Bottom Mounting Plate inserted into the Hanger 3 31 3 87 Insert shims between the Hanger and the Load Cell on both sides 3 31 3 88 Bottom Flexure Arm 3 3...

Page 8: ... 3 134 Ratio Beam Removed 3 47 3 135 Removing the Ratio Beam 3 47 3 136 Ratio Beam Removed 3 47 3 137 Removing the Aluminum Sleeves 3 47 3 138 Ratio Beam Weight Removal 3 48 3 139 Load Cell Critical Area 3 48 3 140 Magnet Area 3 48 3 141 Ratio Beam Vane Slotted Area 3 49 3 142 Four Ratio Beam sleeves are larger than the four Weight Arm sleeves 3 49 3 143 Replacing the Ratio Beam 3 49 3 144 Positio...

Page 9: ... InCal Balance Housing Internal Parts 5 4 5 3 Square Pan Block Style Square Pan Balance Housing Internal Parts 5 6 5 4 Precision Draft Shield Balance with Draft Shield Housing Parts 5 8 5 5 Analytical Balance Housing Internal Parts 5 10 5 6 Precision Balance Load Cell Parts 5 12 5 7 Analytical Balance Load Cell Parts 5 14 5 8 Block Style InCal Load Cell Parts 5 26 C 1 Com Port Configuration Menu C...

Page 10: ...TABLE OF CONTENTS Pioneer Balances Service Manual viii Ohaus Corporation www ohaus com ...

Page 11: ...play test performance tests and adjustments Chapter 5 Drawings and Parts Lists Contains exploded views of Pioneer balances and Load Cells identifying all serviceable components Before servicing the balance you should be familiar with the Instruction Manual which is packed with every balance 1 2 SERVICE FACILITIES To service a balance the service area should meet the following requirements Should b...

Page 12: ...ns for the Ohaus Pioneer Balances are listed in Tables 1 1 1 5 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 1 SPECIFICATIONS EXTERNAL CALIBRATION MODELS includes M Models MODEL PA64 PA114 PA214 PA153 PA213 PA313 PA413 PA512 PA1502 PA2102 PA4102 PA4101 Capacity g 65 110 210 151 210...

Page 13: ...n Cal Mass g 50 or 60 50 or 100 100 or 200 100 or 200 200 or 400 200 or 500 1000 or 2000 2000 or 4000 Pan Diameter 3 5 in 9 cm 4 7 in 12 cm 7 1 in 18 cm Net Wt 10 lb 4 5 kg TABLE 1 3 SPECIFICATIONS CARAT MODELS MODEL PAJ303 PAJ303C PAJ603 PAJ603C PAJ1003 PAJ1003C PAJ2003 PAJ2003C Capacity g 65 120 210 400 Readability g 0 001 0 01 Repeatability mg 0 1 std dev 1 std dev Linearity 0 003 0 003 0 03 OC...

Page 14: ... 2000 or 4000 1000 or 2000 2000 or 3000 2000 or 3000 Lin Cal Mass g 500 800 1000 2000 2000 3000 2000 4000 1000 2000 2000 3000 2000 4000 Pan Diameter 6 6 x 7 1 in 16 8 x 18 cm Net Wt 10 lb 4 5 kg TABLE 1 5 SPECIFICATIONS GOLD MODELS INTERNAL CALIBRATION MODEL PAJ812C PAJ2102C PAJ3102C PAJ4102C PAJ2101C PAJ3101C PAJ4101C Capacity g 510 2100 3100 4100 2100 3100 4100 Readability g 0 01 0 1 Repeatabili...

Page 15: ... dc 6W Use only in closed rooms 1 5 BALANCE OPERATION This section contains information on the basic operation of the balance and mechanical descriptions of the Load Cell Exploded view drawings are included in Chapter 5 which identifies all replaceable components of the balance Allow one hour for each 5 F or 3 C temperature change before using the balance Following temperature stabilization allow ...

Page 16: ...rt out of menu item Print Cal Short Press Long Press Sends data Initiates Span Calibration 1 5 2 OVERVIEW OF THE DISPLAY INDICATORS Figure 1 2 Pioneer Display Indicators TABLE 1 8 DISPLAY INDICATORS No Function 1 Indicates that the measured value has become stable 2 Negative Indicator 3 Center of Zero Indicator 4 Standard 7 segment numeric characters Eight characters are available and are used for...

Page 17: ...accessed through the Display Panel s control switches See the Instruction Manual for a full description of the menus and how to access them 1 5 6 Menu Structure Figure 1 3 Pioneer Menu Structure ENTER MENU When the balance is on press and hold Unit Menu until mMENU appears Release the button and the Calibrate CAL menu will display MENU NAVIGATION To select menus menu items and settings press Yes o...

Page 18: ... A mass placed on the Pan applies a downward force to the Load Flexure by means of the Hanger The Load Flexure moves one end of the Ratio Beam which pivots moving the Force Coil up into the air gap of the Magnet The Force Coils are located in the field of the Permanent Magnets The movement of the Vane which is connected to the Ratio Beam is detected by the Position Sensor The Position Sensor conta...

Page 19: ...ith CRLF On the rear of the balance the 9 pin female subminiature D connector COM 1 is provided for interfacing to other devices The pin connections are shown in the illustration below TABLE 1 9 COM 1 INTERFACE PIN CONNECTIONS Figure 1 5 COM 1 Connector COM 1 Pin Connections 1 Remote Tare 2 TxD 3 RxD 4 Not used 5 Ground 6 Not used 7 CTS 8 RTS 9 Remote Print External PRINT and or ZERO TARE switches...

Page 20: ...int T Same as pressing Zero Tare key PU Print current weighing unit OFF Turns balance OFF ON Turns balance on PSN Print Serial Number PV Print version name software revision and LFT ON if LFT is set on x Set PC reference weight x in grams Must have been a APW stored P Print PC reference weight x Sent reference weight x in grams Must have reference weight stored P Print percent reference weight 0PF...

Page 21: ... the Load Cell components Be sure they are clean and that no Flexures are bent If they are they must be replaced 2 2 DIAGNOSTIC GUIDE Table 2 1 is a Diagnostic Guide designed to help locate the problem area quickly and easily The probable causes are listed with the most common cause first If the first remedy does not fix the problem proceed to the next remedy Before attempting to repair the balanc...

Page 22: ...s not present replace the input connector If OK proceed Replace the Main PC Board Balance does not respond to front panel controls Main PC Board is defective Replace the Main PCB Poor accuracy Unstable environment Balance out of calibration Balance was not re zeroed before weighing Move balance to suitable location ensure that balance is level Calibrate the balance Press O T with no weight on the ...

Page 23: ...Section 3 3 Calibration Motor is not working Calibration Motor may be defective Load Cell Motor Assembly jammed Main PC board is defective Remove the Calibration Motor check the Calibration Motor with software tool See Section C 5 1 Appendix C replace if defective If motor is OK continue with testing entire assembly With motor removed move the InCal Mechanism by hand If binding is found replace Me...

Page 24: ...s Err 8 3 Weight on Pan exceeds capacity Remove weight from Pan Perform Troubleshooting steps Err 8 4 Pan was removed during weighing Re install Pan Perform Troubleshooting steps Err 9 5 Factory calibration data corrupted Perform Service Calibration See Appendix B Err 9 8 Factory calibration data corrupted Perform Service Calibration See Appendix B Error 53 Cable from Load Cell to Main PCB disconn...

Page 25: ...rature stabilization allow an additional hour after connecting power to the balance for the balance to stabilize 3 1 1 Preventive Maintenance Checklist The balance should be inspected and checked regularly as follows 1 Remove the Pan and Pan Support to inspect and clean the area beneath the Pan 2 Clean the outside of the balance using a damp cloth with warm water CAUTION DO NOT USE CHEMICAL CLEANE...

Page 26: ... Housing See Figure 3 2 Align the groove and lift the panel straight up then out and down to disengage it from the top To remove the front and back panels press on the tab in the middle of the top frame and gently press the panel out Figure 3 1 Top panel lifts up and slides out Figure 3 2 Groove in side panel s door guide aligns with tab on Housing 2 Remove the Weighing Pan For a balance without a...

Page 27: ...include parts being misaligned bent or broken Flexures contamination or debris or in any moving part 3 3 1 Variations in Pioneer Load Cells Pioneer balances have different types of Load Cell Use the illustrations below to identify the type used in the balance being serviced Figure 3 3 Precision Load Cell with InCal Section 3 3 2 p 3 5 Figure 3 4 Analytical Load Cell with InCal Section 3 3 6 page 3...

Page 28: ...28 3 3 2 Disassembly of Precision Balances with Internal Calibration Precision balances that have InCal require additional disassembly procedures See Section 3 3 2 page 3 4 This section explains the additional steps required to disassemble service and reassemble the Precision balances with InCal mechanism Figure 3 9 shows the balance with Top Cover and Load Cell Cover removed Figure 3 9 Precision ...

Page 29: ...t to touch the top or bottom Flexure Arms Figure 3 10 InCal Weight Cover removed If Load Cell is to be disassembled see Section 3 3 2 3 3 4 Servicing the Internal Calibration Mechanism 1 Follow the steps in Section 3 3 3 to remove InCal Weights and Load Cell 2 Remove the two screws that secure the Weight Lifter to the base See Figure 3 11 3 Take out the Weight Lifter 4 Remove the two screws that s...

Page 30: ...Assembly in the Bottom Housing Carefully place the motor s ribbon cable in the groove in the Housing and thread it beside the RS 232 cable along the outside of the Housing Insert its plug in the PCB Then insert and tighten the screws that hold the assembly to the Housing 3 Position the Weight Lifter frame as in Figure 3 11 insert and tighten the screws holding it to the Housing To reassemble Preci...

Page 31: ...verse Figure 3 14 Proper manner to grasp Load Cell when removing Weight Arm assembly 3 3 7 Removing the Load Cell Precision Balances without Internal Calibration 1 Open the balance as explained in Section 3 2 1 2 Carefully unplug the cable that connects the Main PCB to the Position Sensor Board See Figure 3 15 3 Remove the three screws holding the Load Cell in place recessed in the middle of the L...

Page 32: ...923345 Figure 3 18 Service Fixture screws and washers for 510g to 4100g Precision balances Readability 0 01g to 0 1g PN 923389 1 Install the Service Fixture on the front of the Load Cell using the six screws supplied with the Fixture tighten screws finger tight until completing next step See Figures 3 21 and 3 22 Figure 3 21 Service Fixture for 150g to 410g Precision Load Cell attached to Hanger R...

Page 33: ... screws and washers that secure each Ratio Beam Flexure and remove the Flexure 5 Remove the four screws and washers on the Top Flexure Arm and remove it Don t loosen the screws that secure the Flexure to the Flexure Arm 6 Turn the Load Cell over and remove the four screws and washers on the Bottom Flexure Arm Carefully remove it NOTE When handling the Flexure Arms do not bend the Flexures 7 Carefu...

Page 34: ...he Contact Board 13 If the Ratio Beam is to be removed unsolder the 3 wire ribbon cable from the Contact Board See Figure 3 25 Figure 3 25 Contact Board with ribbon cable Figure 3 26 Fine wires connected to the Contact Board and affixed to Ratio Beam 14 Carefully pry the Contact Board off the Load Cell frame and tape it to the Beam Take care not to stress or break the fine wires connected to the C...

Page 35: ...See Figure 3 28 Figure 3 28 Hanger 16 Remove the two screws from the Magnet Half See Figure 3 29 Pull the Magnet Half away from the Ratio Coil Pull hard to overcome magnetic force and any possible corrosion 17 Remove the screws in the Sideways Motion Stop Plate and lift it off See Figure 3 30 Figure 3 29 Two screws secure Magnet Half Figure 3 30 Sideways Motion Stop Plate Hole in vane must be clea...

Page 36: ...f the opening and then turn the black Up Down Stop Screw so the Ratio Beam can clear the stop and gently lift out the Ratio Beam Figure 3 31 Ratio Beam clearing stop on Up Down Stop Screw as it is lifted out Figure 3 32 Magnets must be clean The Load Cell is now completely disassembled To reassemble the Load Cell see Section 3 3 11 Load Cell Reassembly Precision Balances ...

Page 37: ...s finger tight to allow adjustment in Step 9 5 Re solder all wires See Figure 3 33 6 Place the Load Cell in position and mount it with one screw 7 Connect the cable from the Main PCB to the Position Sensor Board 8 Operate the balance with the Weighing Pan in its normal position but with the top cover off Power on using the middle button on the PCB NOTE The Position Sensor Board contains an Optical...

Page 38: ...M 3 3 10 Main Printed Circuit Board PCB Replacement All Balances If the Display persistently shows Error 1 invalid checksum data or 2 overload or underload condition and normal remedies fail to solve the problem the PCB may need to be replaced 1 Disconnect the Load Cell Cable RS232 Cable and Power Cable 2 Remove the screws on the Main PC Board which secure it to the Base 3 Install replacement Main...

Page 39: ... Hanger by hand while inserting the two screws that secure the Fixture to the Hanger Then insert the four screws that secure the Fixture to the Figure 3 36 Installing Ratio Beam clearing the Up Down Stop Screw Load Cell frame and the Ratio Beam See Figures 3 38 and 3 39 Figure 3 37 Service Fixture for 150g to 410g Precision Load Cell attached to Hanger Ratio Beam and Load Cell frame Figure 3 38 Se...

Page 40: ...Contact Board on the Load Cell frame Be extremely careful not to stress or break the fine wires attached to the Contact Board 8 Glue the Contact Board to the frame as in Figure 3 41 Figure 3 41 Contact Board 9 Attach the Position Sensor Board to the Load Cell frame using three screws See Figure 3 35 The left side screw goes in the outside hole It has no washer The two right side screws both have w...

Page 41: ...ole down See Figure 3 45 14 Install the two Ratio Beam Flexures with the elongated holes down 15 Remove the Service Fixture See Figures 3 37 and 3 38 Figure 3 45 Ratio Beam Flexures and Vertical Flexure 16 Position the Load Cell in the balance Housing See Figure 3 46 Insert and tighten the three screws Be sure the Load Cell is squarely mounted in the Housing Connect the cable from the Main PCB to ...

Page 42: ...itioned in the Ratio Beam s center of travel for the balance to function properly 18 Adjust the vertical position of the Position Sensor Board if it is too high or too low the display indicates Error 8 X Move it until the display indicates other than 8 X Then tighten the screws on the board See Figure 3 47 19 When adjustments are complete tighten the screws carefully checking that the display does...

Page 43: ...he balance with the Top Cover and Load Cell Cover removed Figure 3 48 Analytical Balance with InCal Mechanism 3 3 13 Removing Internal Calibration Weights and Components Follow these steps to remove the InCal Weight Covers and Weights 1 Remove the screws that hold Weight Covers on both sides of Load Cell See Figure 3 48 2 Lift off the Weight Covers and then lift out each of the Weights Figure 3 49...

Page 44: ...Cal Figure 3 50 Bottom Housing with Load Cell Weight Arms and Weights removed Motor s ribbon cable from the groove in the base 8 Remove the screws and washers that secure the InCal Motor to the assembly 9 Note the position of the InCal Motor Cam as it is removed Be sure the Cam is in the same position when the mechanism is reassembled See Figure 3 52 Figure 3 52 InCal Motor Cam in correct position...

Page 45: ...ert and tighten the screws holding it to the Housing 6 Install the Load Cell in the Housing carefully place the InCal Weights in the Weight Holders position the Weight covers above them insert and tighten the screws 7 Test the InCal mechanism see Appendix C Section C 5 1 Incal Weight Mechanism Testing 3 3 15 Load Cell Removal Installation Analytical Balances 8 Disassemble the Housing and open the ...

Page 46: ...Figure 3 55 Figure 3 55 Service Fixture screws and shims for Analytical balances 1 Remove the three screws and washers from the Mounting Plate and lift it off Set aside two of the screws to use in the next step See Figure 3 56 Figure 3 56 Bottom Mounting Plate and Flexure Arms Analytical balance s Load Cell Figure 3 57 Top Mounting Plate and Flexure Arms Analytical balance s Load Cell 2 Loosen the...

Page 47: ...er tight into the Hanger Figure 3 59 Shims are inserted between the Hanger and the Load Cell on the left and right of the Hanger 5 Tighten the two screws that stabilize the Hanger 6 Remove the two screws and washers that secure the Top Bracket and lift it off See Figure 3 60 NOTE Do not touch the two rear most screws with nuts on top These are adjustment screws Figure 3 60 Analytical balance Load ...

Page 48: ...ytical balances have two washers each a thicker silver colored one on the bottom and a smaller black one on top Figure 3 62 Top Flexure Arm Analytical Figure 3 63 Bottom Flexure Arm Analytical 9 Turn the Load Cell over and remove the four screws that secure the Bottom Flexure Arm to the Load Cell and remove the Bottom Flexure Arm See Figure 3 63 Place it on a flat surface NOTE When handling the Fl...

Page 49: ... Fixture using the finger screws provided in order to stabilize the moving parts See Figure 3 65 13 Remove the Ratio Beam Flexures 14 Carefully examine each Flexure to see if it is bent If uncertain place the Flexure on a clean flat surface and check that both sides rest evenly on the surface If a Flexure is bent even slightly it must be replaced for the balance to operate properly 15 Remove the t...

Page 50: ...bbon cable that connect to the Contact Board at the rear of the Load Cell See Figure 3 69 18 Use an ohm meter to measure resistance from the middle wire to each side wire The readings should be approximately equal at around 400 460 Ω ohms The resistance from any wire to the frame should be open or infinity If any resistance is measured the Ratio Beam must be replaced 19 Remove the four screws that...

Page 51: ...the Ratio Beam as shown in Figure 3 73 Figure 3 72 A screw connects the Contact Board to the Load Cell Figure 3 73 Use a small screw to fasten the Contact Board to the Ratio Beam 22 Remove the Sideways Motion Stop Plate on the top of the Load Cell which stabilizes the Ratio Beam If necessary turn the black Up Down Stop Screw to allow the Ratio Beam to clear See Figure 3 74 23 Remove the Service Fi...

Page 52: ...nect the cable from the Main PCB to the Position Sensor Board 8 Operate the balance with the Weighing Pan in its normal position but with the Top Housing off Power on using the middle button on the PCB NOTE The Position Sensor Board contains an Optical Sensor which must be positioned in the Ratio Beam s center of travel for the balance to function properly 9 Adjust the vertical position of the Pos...

Page 53: ...ice Fixture is installed prior to installing Ratio Beam Flexures 2 Install the Service Fixture 3 Adjust the Up down Stop Screw so the groove is half way above and below the stop tab Close it completely then open it completely counting turns then close it half way 4 Position the Sideways Motion Stop Plate so the small post in the Ratio Beam is centered in the hole in the Plate Then insert and tight...

Page 54: ...ore installing the board stand the Load Cell on the Service Fixture and lower the PSB into position with an Allen Key holding one screw See Figure 3 83 Figure 3 83 Position Sensor Board 9 Solder the two wires from the Temperature Sensor to the two solder points on the Position Sensor Board See Figure 3 83 It s not critical which wires goes to which solder point 10 Solder the 3 wire Ribbon Cable to...

Page 55: ...8 Bottom Flexure Arm Figure 3 89 Top Flexure Arm 14 Install the Bottom Flexure Arm screw side down Each screw has two washers a silver colored one near the Flexure a black one near the screw See Figure 3 88 15 Install the Top Flexure Arm screw side down See Figure 3 89 16 Install the Vertical Flexure bottom screw last Figure 90 Vertical Flexure Note the order of parts as shown in Figure 3 91 Figur...

Page 56: ...l the Bottom Mounting Plate as shown Note the position of the Weigh Below Hook See Figure 3 94 Figure 3 94 Bottom Mounting Plate on Analytical Load Cell 20 Position the Load Cell in the balance Housing Insert and tighten the three screws from underneath the Bottom Housing Be sure the Load Cell is squarely mounted in the Housing Connect the cable from the Main PCB to the Position Sensor Board See F...

Page 57: ...op Housing off but the Weighing Pan in its normal position The On Off switch is the second button from the right on the main PCB 22 Adjust the vertical position of the Position Sensor Board if it is too high or too low the display indicates Error 8 X Move it until the display indicates other than 8 X Then tighten the screws on the board See Figure 3 96 23 Install the Load Cell Cover Figure 3 96 Wh...

Page 58: ... Load Cell Load Cell Kits are available for replacement purposes for all Block Style model balances Each kit is assembled and consists of metal base plate a Load Cell the InCal Weight Assembly mounted to the base plate and a package of labels Check the label on the balance and verify the capacity and model before ordering a new Load Cell kit Note Analytical and Precision Block Style Load Cells are...

Page 59: ... the instructions in Appendix C for installing the Load Cell 9 Re calibrate the balance following instructions in Appendix B Service Calibration 10 Re calibrate the balance following instructions in Appendix A Standard Calibration 11 Check the performance of the balance using tests in Chapter 4 3 3 21 Progressive Disassembly of Block Style Load Cells Use the following procedures for progressive di...

Page 60: ...he motion of the InCal Weight when you press Raise or Lower If the weight does not move replace the InCal Motor See Section 3 3 21 4 If the operation is not smooth replace the entire InCal Mechanism See Section 3 3 22 3 3 23 InCal Motor Removal Replacement 1 Remove the balance s Housing and Load Cell as described in earlier sections 2 Remove the two screws holding the InCal Motor and InCal Motor S...

Page 61: ...t be in the position shown in Figure 3 102 6 Secure the InCal Motor and InCal Motor Shield to the InCal Mechanism with the screws previously removed 7 Test the InCal Mechanism again as described in Section 3 3 21 8 If the test is successful re install the Load Cell See Section 3 3 19 3 3 24 InCal Mechanism Removal NOTE Replacement InCal Mechanisms are available assembled with the InCal Motor insta...

Page 62: ...et 3 Position the InCal Mechanism so the spacing between the InCal Weight and the InCal Weight Arms is even on both sides See Figure 3 105 Figure 3 105 InCal Mechanism Alignment Figure 3 106 Centering InCal Weight 4 Make sure the InCal Weight is lined up properly on the InCal Weight Arm It must be centered in the slots of the Weight Arm See Figure 3 106 When the Weight Mechanism is properly aligne...

Page 63: ... Cable See Figure 3 107 Figure 3 107 Removing Position Sensor Position Sensor Installation 1 Mount the Position Sensor Assembly Align it centrally on the Ratio Beam Pin and fasten it with the three screws See Figure 3 107 Note The flange of the Position Sensor Assembly is pre bent to ensure its precise positioning after screwing it on Do not attempt to bend it straight Figure 3 108 Ratio Beam Pin ...

Page 64: ...dure is necessary before proceeding with other repairs to the Load Cell Base Plate Removal 1 Remove the Weigh Below Hook and Screw See Figure 3 109 Figure 3 109 Base Plate Removal 2 Hold the Block Style Load Cell and remove the two Load Cell Mounting Screws See Figure 3 109 Note At this point other repairs may be made to the Load Cell Weigh Below Hook Screw Mounting Screws ...

Page 65: ... Figure 3 110 2 Position the Load Cell on the base and install the two mounting screws Do not tighten them fully 3 Looking down at the top of the Load Cell align it with the Base Plate See Figure 3 111 4 Now carefully tighten the two mounting screws and re check alignment Figure 3 111 Load Cell Alignment to Base Plate 5 Install the Weigh Below Hook and screw at the bottom of the Base Plate See Fig...

Page 66: ...e the Load Cell Board Screw and change the Board See Figure 3 112 6 Install new board ensuring the slot in the board is inserted in the slot in the Load Cell Frame See Figure 3 113 CAUTION When screwing in first turn the self tapping Cell Board Screw in a counterclockwise direction until the first screw thread engages and then tighten it See Figure 3 111 7 Re solder the Temperature Sensor Board an...

Page 67: ...e soldered connections to the Load Cell PCB See Figure 3 115 Note Do not adjust the screws around the Temperature Sensor hole It could ruin the Load Cell Figure 3 115 Position Sensor 2 Remove the screw on the bottom edge of magnet that secures the Temperature Sensor It has a very fine thermister extending into the hole between the three screws on the bottom of the Magnet See Figure 3 116 3 Lift ou...

Page 68: ...ng the Ratio Beam on Block Style Load Cells 1 Remove the Position Sensor PCB and Temperature Sensor the three as an assembly prior to removing the Ratio Beam See previous section Figure 3 118 Contact Board Cover is removed by squeezing the plastic post If necessary remove the Contact Board Cover Note If Contact Board has a cover as in Figure 3 118 the cover holder remains after cover is removed Se...

Page 69: ...hole in Ratio Beam directly above it See Figures 3 122 and 3 123 Note The screw changes from the lower to the Figure 3 123 Contact Board with cover holder off upper hole on the Contact Board before inserting it into the hole on the Ratio Beam 5 Carefully loosen and remove the nuts on the Ratio Beam while holding the screw heads to prevent movement This is very important See Figure 3 124 Figure 3 1...

Page 70: ...proceed to Step 9 6 Remove the screws washers and nuts holding the InCal Weight Arm See Figure 3 126 Figure 3 126 Loosening InCal Weight Arm nuts Figure 3 127 Weight Arm Screws and Washers removed 7 Carefully slide the InCal Weight Arm as shown in Figure 3 128 Figure 3 129 illustrates the InCal Weight Arm removed Figure 3 128 InCal Weight Arm Removal Figure 3 129 InCal Weight Arm removed InCal Wei...

Page 71: ...Beam can be removed See Figure 3 131 Figure 3 130 Aluminum Sleeves removed Figure 3 131 Up Down Stop Screw 10 Remove the centering pins See Figure 3 132 Figure 3 132 Centering Pins removed 11 Carefully lift out the Ratio Beam See Figures 3 135 and 3 136 Figure 3 135 Removing the Ratio Beam Figure 3 136 Ratio Beam Removed 12 Remove the Aluminum Sleeves See Figure 3 137 This completes the disassembl...

Page 72: ...e clean and free of debris Hold the Load Cell up to the light to see into the slotted areas If dust or dirt appears in any slotted area use pressurized clean air normally used for cameras and gently blow out any dirt Use extreme care Critical area is shown in Figure 3 139 CAUTION DO NOT USE COMPRESSED OR SHOP AIR AS CONTAMINANTS AND MOISTURE ARE PRESENT WHICH MAY DAMAGE THE LOAD CELL Figure 3 139 ...

Page 73: ...eight Arm sleeves 6 Carefully place the Ratio Beam into position on the Load Cell Do not install the screws yet See Figures 3 143 and 3 144 Figure 3 143 Replacing the Ratio Beam Figure 3 144 Positioning the Ratio Beam over the magnet right 7 Insert a Centering Pin to hold the Ratio Beam in position as shown in Figure 3 145 The Centering Pin also helps to avoid stressing the internal flexures If th...

Page 74: ...inserted in Step 7 on the previous page through the Ratio Beam s screw holes 3 Gently lift the Ratio Beam and insert a second Centering Pin in the InCal Weight Arm near the Magnet See Figure 3 148 Figure 3 148 Weight Arm must be lifted slightly to insert Centering Pin 4 Do not use tools in this step Install the screws washers and nuts for the InCal Weight Arm Work gently to avoid stressing the Loa...

Page 75: ...hold the screw head with a screw driver while tightening the nuts for the Ratio Beam See Figure 3 151 10 Turn the Up Down Stop Screw to its original position See Figure 3 152 11 Remove the Centering Pins They should fall out easily Figure 3 150 Centering pins in Ratio Beam Figure 3 151 Tightening Ratio Beam nuts Figure 3 152 Up Down Stop Screw 12 Move the contact board as shown in Figure 3 153 Be ...

Page 76: ...til the first screw thread engages and then tighten it See Figure 3 111 page 3 42 Figure 3 155 Groove on left of PCB fits tab on Load Cell frame 2 Gently hold PCB in position while inserting and tightening the screw that secures it 3 Carefully position the Temperature Sensor under the Magnet so the Temperature Sensor a very fine thermister that extends from the board goes into the hole between the...

Page 77: ...or on the Magnet It has a cavity allowing it to rest squarely aligned with the screw holes See Figure 3 157 The Ratio Beam pin must be centered in the hole in the back See Figure 3 158 Figure 3 157 Position Sensor on the Magnet Figure 3 158 Pin centered in PSB 6 Install the Ratio Beam Ribbon Cable on the PCB and the Contact Board Ratio Beam Pin centered in PSB hole Cavity under PSB clears Ratio Be...

Page 78: ... Load Cell PCB test connector as shown in Figure 3 159 5 Apply power to the balance Figure 3 159 Load Cell PCB Test Connector Figure 3 160 Test Connector Detail 6 Measure the voltage with the Ratio Beam at the bottom of the Up Down Stop Screw 7 Carefully lift the Ratio Beam with thumb and forefinger until it is at the top of the Up Down Stop Screw Measure the voltage again 8 If the two voltage val...

Page 79: ...M Class 1 or OIML E1 Tolerance The mass values are listed in Table 4 1 TABLE 4 1 TEST MASSES REQUIRED CAPACITY g SPAN MASSES g LINEARITY MASSES g 65 110 210 150 310 410 100 510 1500 2100 3100 4100 1000 4100 50 100 200 150 300 400 500 1500 2000 3000 4000 4000 20 50 50 100 100 200 100 150 150 300 200 400 200 500 1000 1500 1000 2000 1500 3000 2000 4000 2000 4000 4 2 Operational Test 1 Connect a funct...

Page 80: ... mg 0 2 0 2 0 3 Repeatability mg 0 1 0 1 0 1 Linearity mg 0 2 0 2 0 3 NOTE The following performance tests are used to evaluate balance operation before and after repairs The balance must meet the requirements specified in each test as well as the specifications listed in Tables 1 1 1 4 Before proceeding with the following tests the balance should be warmed up for at least five minutes and calibra...

Page 81: ...ecision Test Inspect and correct if necessary See the next section 4 4 2 Off Center Load Test The Off Center Load Test is used to determine whether displayed weight values are affected by moving the sample to different areas of the Pan See Figure 4 2 Figure 4 2 Mass Placement Locations for Off Center Load Test 1 Place a mass weighing half of the balance s capacity in the center of the Pan 2 Press ...

Page 82: ...ght to 0g Move the mass to the front back left and right edges of the Pan Note the displayed values 7 Correct any errors by turning Corner load Adjusting screws as shown in Figures 4 3 and 4 4 Use a nut driver 8 Adjust as shown until the tolerance is 5 counts Figure 4 3 Off Center Load Adjustments on Pioneer Precision Balance 9 Use small adjustments no more than turn at time Repeat Off Center Load...

Page 83: ... 0g Move the mass to the front back left and right edges of the Pan Note the displayed values 7 Correct any errors by turning Corner load Adjusting screws as shown in Figures 4 5 and 4 6 Use a 6mm nut driver 8 Adjust as shown until the tolerance is 5 counts Figure 4 5 Off Center Load Adjustments on Pioneer Analytical Balance 9 Use small adjustments no more than turn at time 10 Repeat the Off Cente...

Page 84: ... Auto Zero to Off in Menu Setup 2 Open the balance See Section 3 1 3 Reinstall the Pan 4 Plug the power cord into the balance and turn it on 5 Place a mass that weighs the balance s full capacity on the center of the Pan 6 Press O T the center button to tare the balance and return the Æ Æ Æ Æ If test weight is unbalanced Æ Æ Æ Æ File in position s marked Figure 4 7 Using a Needle File to adjust Of...

Page 85: ...um or the center of its range B Set the AZT Auto Zero Tracking to 5d or its lowest setting Do not turn it off C Set the instrument to display the same units as the performance specifications Usually kg g or mg Record Settings Filter Level Setting ____________ Auto Zero Tracking Setting ____________ Displayed Units ____________ Mass Used ____________ TEST PROCEDURE 1 Zero the instrument if it does ...

Page 86: ... 4 Reading 5 Reading 6 Reading 7 Reading 8 Reading 9 Reading 10 10 Mean ________ 7 Calculate the Delta for each reading and record in the work sheet Delta Reading Mean 8 Calculate the Delta x Delta for each reading and record in worksheet 9 Add the ten Delta x Delta values and divide by 9 10 Calculate the Standard Deviation by taking the square root of the result from Step 9 Standard Deviation ___...

Page 87: ...es not disregard the reading press ZERO to re zero the display and repeat the process 4 Place a mass equal to of the full scale capacity on the platform and press ZERO 5 Add the Reference Mass to the center of the platform and record the value 6 Remove the Reference Mass and verify that the display returns to zero If it does not disregard the reading press ZERO to re zero the display and repeat th...

Page 88: ...g 4 Reference Weight added at full scale capacity ________________ Calculate Differences Reading 1 Reading 1 Reading 2 2 ________________ Reading 2 Reading 2 Reading 3 2 ________________ Reading 3 Reading 3 Reading 4 2 ________________ Maximum Difference _______________ The difference in the weights of the test mass should be within the tolerance in Table 1 2 If not perform a Standard Calibration ...

Page 89: ...cal Load Cell Parts including InCal Section 5 8 Block Style Load Cell Assembly including InCal Precision Round Pan Precision Round Pan InCal Precision Square Pan InCal Precision Draft Shield Precision Draft Shield InCal Analytical Analytical InCal PA512 PA2102 PA4102 PA4101 PAJ812 PAJ2102 PAJ3102 PAJ4102 PAJ2101 PAJ3101 PAJ4101 PA512C PA2102C PA4102C PA4101C PAJ603C PAJ1003C PAJ2003C PA213 PA413 P...

Page 90: ... Corporation www ohaus com 5 2 Pioneer Balances Service Manual 5 1 PRECISION ROUND PAN BALANCE HOUSING PARTS Precision Round Pan Balance Housing Parts 10 8 6 5 4 2 1 3 15 14 12 13 80 9 Figure 5 1 Precision Round Pan Balance Housing Parts ...

Page 91: ...OUSING PARTS Drawing Item Description 1 Weigh Below Cover 2 Leveling Feet 2 3 Bottom Housing Legal for Trade Lock 4 Cable Set 5 Load Cell 6 Load Cell Cover 8 EMC Plate 9 Pan Support 10 Weighing Pan 12 Function Label 13 Top Housing 14 Liquid Crystal Display LCD 15 Main Printed Circuit Board 80 Power Adapter For all Pioneer Models see specific parts lists through your Ohaus distributor ...

Page 92: ... www ohaus com 5 4 Pioneer Balances Service Manual 5 2 PRECISION ROUND PAN INCAL BALANCE HOUSING PARTS 80 16 10 8 13 6 4 2 1 12 5b 14 15 3 9 Precision Round Pan InCal Balance Housing Parts 5a Figure 5 2 Precision Round Pan InCal Balance Housing Parts ...

Page 93: ...G PARTS Drawing Item Description 1 Weigh Below Cover 2 Leveling Feet 2 3 Bottom Housing Legal for Trade Lock 4 Cable Set 5 Load Cell 5a Traditional MFR 5b Block Style 6 Load Cell Cover 8 EMC Plate 9 Pan Support 10 Weighing Pan 12 Function Label 13 Top Housing 14 Liquid Crystal Display LCD 15 Main Printed Circuit Board 80 Power Adapter For details on Load Cell and InCal Mechanism parts see Section ...

Page 94: ... www ohaus com 5 6 Pioneer Balances Service Manual 5 3 PRECISION SQUARE PAN INCAL BALANCE HOUSING PARTS 13 6 2 1 12 5 14 15 3 Precision Square Pan InCal Balance Housing Parts 80 4 10 8 16 9 Figure 5 3 Precision Square Pan InCal Balance Housing Parts ...

Page 95: ...CAL BALANCE HOUSING PARTS Drawing Item Description 1 Weigh Below Cover 2 Leveling Feet 2 3 Bottom Housing Legal for Trade Lock 4 Cable Set 5 Load Cell 6 Load Cell Cover 8 EMC Plate 9 Pan Support 10 Weighing Pan 12 Function Label 13 Top Housing 14 Main Printed Circuit Board 15 Liquid Crystal Display LCD 80 Power Adapter For details on Load Cell and InCal Mechanism parts see Section 5 6 ...

Page 96: ... www ohaus com 5 8 Pioneer Balances Service Manual 5 4 PRECISION DRAFT SHIELD BALANCE HOUSING PARTS 7 9 11 7 10 8 12 13 6 80 5a 4 2 1 14 15 3 5b Precision Balance with Draft Shield Housing Parts Figure 5 4 Precision Draft Shield Balance Housing Parts ...

Page 97: ...n 1 Weigh Below Cover 2 Leveling Feet 2 3 Bottom Housing Legal for Trade Lock 4 Cable Set 5 Load Cell 5a Traditional MFR 5b Block Style 6 Load Cell Cover 7 Draft Shield Glass 4 sides 8 EMC Plate 9 Draft Shield Posts 10 Weighing Pan 11 Draft Shield Top 12 Function Label 13 Top Housing 14 Liquid Crystal Display LCD 15 Main Printed Circuit Board 80 Power Adapter For details on Load Cell and InCal Mec...

Page 98: ...MS Ohaus Corporation www ohaus com 5 10 Pioneer Balances Service Manual 5 5 ANALYTICAL BALANCE HOUSING PARTS Analytical Balance Housing Parts 7 9 11 7 10 8 12 13 6 5a 4 14 15 3 2 1 80 5b Figure 5 5 Analytical Balance Housing Parts ...

Page 99: ...low Cover 2 Leveling Feet 2 3 Bottom Housing Legal for Trade Lock 4 Cable Set 5 Load Cell 5a Traditional MFR 5b Block Style 6 Load Cell Cover 7 Draft Shield Glass 4 sides 8 EMC Plate 9 Draft Shield Posts 10 Weighing Pan 11 Draft Shield Top 12 Function Label 13 Top Housing 14 Liquid Crystal Display LCD 15 Main Printed Circuit Board 80 Power Adapter For details on Load Cell and InCal Mechanism parts...

Page 100: ...2 Pioneer Balances Service Manual 5 6 PRECISION LOAD CELL PARTS INCLUDING INCAL 1 4 5 6 11 12 13 2 Pioneer Precision Load Cell with InCal Parts InCal Parts InCal Weights for Precision Top Load 12 3 9 7 8 10 14b 14a Figure 5 6 Precision Load Cell Parts including InCal ...

Page 101: ...Item Description 1 Top Flexure Arm Assembly 2 Ratio Beam 3 Position Sensor Board 4 Ratio Beam Flexures 5 Vertical Flexure 6 Bottom Flexure Arm Assembly 7 Ribbon Cable from PSB to Contact Board 8 Hanger 9 LED Assembly 10 InCal Weight Arm Assembly 11 InCal Motor Assembly 12 InCal Weight Covers 13 InCal Weight Lifters 14 InCal Weights 14a InCal Weights for Balance up to 410g 14b InCal Weights for Bal...

Page 102: ...oration www ohaus com 5 14 Pioneer Balances Service Manual 5 7 ANALYTICAL LOAD CELL PARTS INCLUDING INCAL 1 5 6 4 7 Pioneer Analytical Load Cell w InCal Parts 3 2 10 11 12 13 14 InCal Parts Figure 5 7 Analytical Load Cell Parts including InCal ...

Page 103: ...7 ANALYTICAL LOAD CELL PARTS INCLUDING INCAL Drawing Item Description 1 Top Flexure Arm Assembly 2 Ratio Beam 3 Position Sensor Board PSB 4 Ratio Beam Flexures 5 Vertical Flexure Assembly 6 Bottom Flexure Arm Assembly 7 Ribbon Cable from PSB to Contact Board 10 InCal Weight Arm 11 InCal Motor 12 InCal Weight Covers 13 InCal Weight Lifters 14 InCal Weights ...

Page 104: ...LISTS DIAGRAMS Ohaus Corporation www ohaus com 5 16 Pioneer Balances Service Manual 5 8 BLOCK STYLE INCAL LOAD CELL PARTS 2 1 3 Pioneer Block Style Load Cell with InCal 4 5 Figure 5 8 Block Style Incal Load Cell Parts ...

Page 105: ...s Service Manual 5 17 Ohaus Corporation www ohaus com 5 8 BLOCK STYLE INCAL LOAD CELL PARTS TABLE 5 8 BLOCK STYLE INCAL LOAD CELL PARTS Drawing Item Description 1 Position Sensor 2 Ratio Beam 3 Load Cell PCB 4 InCal Mechanism Assembly 5 InCal Motor ...

Page 106: ...CHAPTER 5 PARTS LISTS DIAGRAMS Ohaus Corporation www ohaus com 5 18 Pioneer Balances Service Manual ...

Page 107: ...retain previously stored calibration data See Table 4 1 for specified masses for all Pioneer models Masses must meet or exceed ASTM Class 1 or OIML E1 Tolerance Calibration masses are available as accessories from any Ohaus dealer A 2 Span Calibration With the balance on press and release Unit Menu until CAL appears Press Yes the On Off button CAL SPAN appears Press Yes SPAn The specified mass wei...

Page 108: ...o setting 0 The specified middle weight flashes Place the indicated weight in the center of the Pan 2000 Busy flashes After a few seconds Clear Pan flashes Remove the mass from the Pan BUSY The specified maximum weight flashes Place the indicated weight in the center of the Pan 4000 Busy flashes After a few seconds Clear Pan flashes Remove the mass from the Pan BUSY 0 flashes as the balance re cal...

Page 109: ...2 Ramp The first sub menu in the Service Menu is Ramp The ramp display shows the percentage of use of the A to D circuit The actual value is not as important as how it changes It should increase as the weight on the balance is increased The ramp display should remain constant without fluctuations To view the Ramp value press Yes A number will appear and should be constant Place masses on the balan...

Page 110: ... fail Enter the Service Menu by pressing and holding On Zero Off and Unit together As the balance powers up SERVICE appears followed by RAMP ServICe Press No to advance to Span Calibration ramp SPAN appears Press Yes SPAn The specified maximum mass weight flashes Place the indicated weight in the center of the Pan 4000 Busy flashes After a few seconds Clear Pan flashes Remove the mass from the Pan...

Page 111: ...the diagram below for the correct weight sequence To start from the Service Menu press and hold On Zero Off and Unit together As the balance powers up SERVICE appears followed by RAMP Press No twice to bypass Ramp and Span calibration When 3 Lin appears press Yes If PUSH flashes place maximum weight on the Pan 3 Lin 0 flashes for a few seconds as the balance calibrates a zero setting 0 The specifi...

Page 112: ...eturns to the weighing mode B 5 5 Point Linearity Calibration A five point linearization is also rarely required and is the most difficult to perform accurately under the less than ideal conditions outside the factory This service calibration requires that accurate calibration weights be used Calibration points are done at approximately 0 25 50 75 and 100 of maximum capacity The sequence of loadin...

Page 113: ...cated weight on the center of the Pan Busy flashes 1000 00 The specified maximum weight flashes Place the indicated weight on the center of the Pan Busy flashes 2000 00 The specified maximum weight flashes Place the indicated weight on the center of the Pan Busy flashes 3000 00 The specified maximum weight flashes Place the indicated weight in the center of the Pan Busy flashes 4000 00 The specifi...

Page 114: ...ww ohaus com B 6 Pioneer Balance Service Manual EndServ appears If you have completed Service Calibration press Yes Otherwise press No to cycle through the Service Menu again endServ When calibration is finished the balance returns to the weighing mode ...

Page 115: ......

Page 116: ...rporation all rights reserved Registered trademark of Ohaus Corporation The information contained in this manual is believed 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 ...

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