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KERN & Sohn GmbH Ziegelei 1 Tel: 0049-[0]7433- 9933-0 D-72336 Balingen-Frommern Fax: 0049-[0]7433-9933-149 E-Mail: info@kern-sohn.com Internet: www.kern-sohn.com Service Manual Electronic Analytical Balances KERN ABT Version 1.2 10/2012...
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KERN ABT Version 1.2 Service Manual Electronic Analytical Balances Basic Information Grundlegende Hinweise The device must be repaired only by trained specialist staff or personnel with professional formation (such as a repair-specialist accredited by law concerning verification). The service manual is obligatory for repair work.
CONTENTS Service Menu ......................4 Entering the Service Menu...................4 Service Menu contents..................4 wAd Map......................5 Performance Check ....................6 Repeatability ......................6 Corner Load ......................6 Linearity .......................7 Tilt Error .......................7 Representative Troubles and Error Messages ............9 Representative Troubles and Remedies ..............9 Error Messages....................11 Troubleshooting at Error Message and Interface Failure ........12 3.3.1 “CAL E2”...
1 Service Menu For general operations, please refer to the ABT Series instruction manual. 1.1 Entering the Service Menu Set the balance to display the mass. Press and hold the [ON/OFF] key and [1d/10d] key together for 3 seconds. The mass display remains unchanged. Within 10 seconds, press and hold the [CAL] key and [PRINT] key together for 3 seconds.
(15) -oAd- (* Displayed by average mode selected in the user menu.) Load adjustment value after temperature/linear correction (see 1.3 wAd -Lad- (16) Map) (* Displayed by average mode selected in the user menu.) (17) -wG- Absolute load value (* Displayed by average mode selected in the user menu.) (18) -bAt- Power source voltage AD value...
2 Performance Check • Leave the power on in mass display and let stand for 8 hours or more. • Conduct the performance check in a location without drafts, vibration or sudden changes in room temperature. • Place weights inside the balance weighing chamber in advance to conduct performance check without a temperature difference between the weights and weighing chamber.
2.3 Linearity 1) Conduct “ECAL” (Span Calibration by External Weights) according to the instruction manual procedure. 2) Load weights in order shown in Table 1 and record the readings when the display has stabilized. 3) Calculate the error of each loaded weight. (Error) = (display value of each loaded weight) –...
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Model 120-5DM 220-5DM Weight [g] Minimum display [mg] 0.01 0.01 Repeatability Standard [mg] Weight used [g] 100 Four-corner error Standard ± ± ± ± [mg] Weight used [g] 50 Instrumental error 50g : 5g : 50g : 20g : ±...
3 Representative Troubles and Error Messages 3.1 Representative Troubles and Remedies Symptom Probable cause Remedy (Causes are listed not in the order of probability, but in the order of ease of checking.) Correct power is not supplied. Check the power supply and connect correctly.
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Span calibration has not been Perform span calibration. performed correctly. Damaged EEPROM data. Input the data with the Adjustment S/W. Unit Assy (2) is damaged. If the error is under XXXX, replace Unit assembly. Warm up is insufficient. Warm up sufficiently. Direct sunlight, or air current from Change the balance installation site.
Lever stopper (U7) and/or Clean the Lever stopper and Lever Detector Board assy (U4) are not limit bar and adjust the height of correctly positioned. Lever stopper Detector Board assy (U4). (U7) is contacting Lever limit bar(U52). Dusts exist between them.
3.3 Troubleshooting at Error Message and Interface Failure 3.3.1 “CAL E2” Display Error content: Zero point drift during Span calibration This error message is generated when the zero point drifts ± 20g or more while conducting Span calibration directly after switching the power ON, or when the zero point drifts ±...
3.3.2 “CAL E3” Display Error content: Incorrect external weight value used when calibrating the built-in weights (PCAL) This error is generated when the difference in the actual external weight value and the set weight value is greater than ± 2g. How to cancel the “CAL E3”: press [ON/OFF] key Main cause: The external calibration weight setting (used for calibrating the built-in...
3.3.3 “CAL E4” Display Error content: The weight loading point cannot be measured correctly when conducting span calibration. This error is generated when the built-in calibration weight cannot be correctly loaded/unloaded; when the measurement result differs from the set weight value used for span calibration due to a hardware failure, the set weight value has drifted ±...
3.3.4 “CAL d” Display Error content: Instability/fluctuation occurred when conducting span calibration This error was generated because the balance was shaken or influenced by wind or vibration during span calibration. It is possible to skip this error message and use the balance by pressing the [ON/OFF] key when “CAL d”...
3.3.5 “Err01” Display Error content: Temperature sensor error Main causes: 1) Detector Board Assy (U4) is failed. 2) Temp Sensor Assy (U47) is failed. 3) Detector Board Assy (U4) and Temp Sensor Assy (U47) is not properly connected. 4) Cable (U26) is not properly connected with Detector Board Assy (U4) and Main Board Assy (C42).
3.3.6 External Input / Output Failure Main causes: 1) The cable used to connect the external instrument is incorrect. 2) The communication specifications of the balance and external instrument do not match. 3) Cable (C44), Cable(C45) between Display Board Assy (C40) and Interface Board Assy (C41) are failed.
4 Parts Replacement 4.1 General Precaution and Information when Disassembling and Assembling [Disassembling/Assembling] When disconnecting the cables, pull the connector straight out. Avoid bending the cable/connector when disconnecting. (Fig. 1) Warning! If the connector is not pulled straight out, there is a risk of bending the terminal pins, therefore, the connector may not be reinserted again.
[Check3]: Check the wAd reading. Check the ‘Zero’ and sensitivity are within the below ranges; check the repeatability/deviation. Model Zero Loaded ABT 220-5DM Approx. 6,000,000-7,000,000 Approx. 46,000,000-47,000,000 (200g) ABT 120-5DM Approx. 12,000,000-14,000,000 Approx. 52,000,000-54,000,000 (100g) ABT 320-4M Approx. 8,000,000-9,000,000 Approx. 56,000,000-57,000,000 (300g) ABT 220-4M Approx. 6,000,000-7,000,000 Approx.
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[Procedure of Internal Inspection] Disconnect the AC adapter. Remove the anti-drift ring (6), pan (5), and pan supporter assy (4) from the weighing chamber. Remove the two M2.5 x 6 SEMS screws (9), detach the anti-draft plate (11) (Fig. 5). Remove the four M3 x 5 Truss screws (28) locking the balance rear panel (8), detach the rear panel (8).
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Fig.8 Fig.9 [Check4]: Check the Stopper plate (U6) and Lever pin (U51) do not come into contact with each other and there is no dust between them. (Fig. 10) → If there is contact or dust, loosen the two M3 x 6 screws (U20) and adjust the Stopper plate (U6) position.
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Remove the two M4 x 8 SEMS screws (B29), Remove the Weight stopper (B22) and take out Calibration weight (26) beneath it. (Fig. 11) Warning! Do not damage Unit Assy (2) when removing Calibration weight (26). Warning! Do not scratch or contaminate Calibration weight (26). In Unit Assy (2), insert UniBloc protection pin (J1) of the Jig set into the lever- locking hole down to the scribed line (Fig.
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[Assembling (after internal inspection )] Remove UniBloc protection pin (J1) from the lever-locking hole in Unit Assy (2). Warning! Remove the pin by carefully holding the lever assy (U1) horizontally. Do not touch or press the elastic fulcrum. Gently place the calibration weight (26) around the Unit Assy’s pan supporter shaft (53) and lock the weight stopper (B22) by the two M4 x 8 SEMS screws (B29) (Fig.
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Lock Case Assy (3) by the single M4 x 45 hexagon socket head bolt (17) inside the rear case assembly frame. (Fig. 18) Lock the rear panel (8) to rear frame of Case Assy (3) by the four M3 x 5 Truss screws (28).
4.3 Replacing Components Fig.22 Table.2 Replacement Component Adjustment / Inspection Requirements Coarse-fine Calibration of Linearity Tilt error Calibration ratio built-in weights temperature adjustment characteristics Main Board (C42) Required Required Required Not required Not required Interface Board (C41) Not required Not required Not required Not required Not required...
4.3.2 Replacing Interface Board Assy(C41) Disconnect the AC adapter. Remove the pan (5), anti-draft ring (6), and pan supporter assy (4) from inside the weighing chamber. Remove the four M3 x 5 Truss screws (28) fixing the balance rear panel (8), detach the rear panel (8).
4.3.4 Replacing Weight Loader Assy (B11) Separate the base assembly (B1) and case assembly (3) by following procedures 1) to 8) in ‘4.2 Balance Internal Inspection [Assembling,(after internal inspection )] and remove Calibration weight. Unscrew the four M4 x 8 SEMS screws (B29), take out the weight loader assembly (B11).
4.4 Unit Assy (2) Disassembling/Assembling (Force Coil Assy (L4), Detector Board Assy (U4) Replacement) [Disassembling] Dismount Unit Assy (2) from Base Assy (B1) by the procedure described in ‘4.3.5 Replacing the Unit Assembly (2)’. Disconnect the cable (sensor, 2-pin)(U35) from Detector Board assy (U4), connect the cable (detector, 12-pin)(U26) to Main Board assy (C42).
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Remove the four M2.5 x 6 screws (U30), slide out the four Magnet covers (U29). (Fig. 32) [Check11]: Check if the Force Coil Assy (L4) and Magnet Assy (U4 (beneath U29)) are not in contact with each other and there is no dust between them.
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Inserting the gap setting shim (J3) between Lever limit bar (U52, Compenents2) and Lever stopper (U7), temporarily lock Lever stopper (U7) in position by the two M3 x 8 screws (U19). (Fig.34) Position the hole of Stopper plate (U6) at the center of Lever pin (U51, Components2).
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Gently shake Unit Assy (2) holding the outer die-cast part. If the Lever Assy (U1) makes a clear sound with resonance as it strikes Lever stopper (U7), the assembling of Unit Assy (1) is complete. Warning! If a clear sound cannot be heard, it is possible that Lever pin (U51) and Stopper plate (U6), or Force Coil Assy (L4) and Magnet Assy (U41) are contacting or having dusts.
4.5 Case Assy (3) Components Replacement [Disassembling] Open the Glass door. Take out Knob (C39) of the other Glass door(s) from inside the weighing chamber. Remove the side Glass Door Assy (left)(C4), (right)(C5) and Glass Door Assy (top) (C38) from the rear of Case Assy (3). Remove Door Rail (left)(C9), (right)(C8) from Case Assy (3).
5 Adjustments 5.1 Physical Adjustments of Unit Assy 5.1.1 Adjusting the Height of Detector Board Assy (U4) 1) Remove Unit Assy (2) from Base Assy (B1) by following the procedure described in ‘4.3.5 Replacing the Unit Assembly (2)’. 2) Disconnect Cable (sensor, 2-pin)(U35) from Detector Board Assy (U4), connect Cable (detector,12-pin)(U26) to Main Board Assy (C42).
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6) If the adjustment standard (see ‘2 Performance Check’ ‘Table 1. Inspection Standard List’) is not met, insert UniBloc protection pin (J1) into the lever locking hole in UniBloc of Unit Assy (2), loosen the balance weight (L16) locking the gravity centering counterbalance (L15) (eccentric shaped counterweight) of Lever Assy (U1).
5.1.4 Corner Load Adjustment (1) Follow steps 1) to 8) of ‘4.2 Balance Internal Inspection’ [Disassembling ] to separate Case Assy (3) and Base Assy (B1). Remove Calibration weight (26). (Place Pan (5) back after this.) (2) Connect Cable (detector, 12P) to Main Board (C42), and plug the balance to the power skipping the calibration.
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Adjustment procedure and warnings Warning: Do not grind the areas within 3mm from the side edge of UniBloc, in order to prevent deformation of the edges. Warning: Be careful not to bend the flexures of the block. Warning: Metal dusts generated in this operation must be removed without falling and entering into the gaps of the mechanism.
0.5mg 0.3mg including ABT 120-5DM Warning: After Corner load adjustment: When corner load adjustment has been performed, mechanical balance of Unit Assy changes. Check Tilt error and mechanical balancing (according to 5.1.2 and 5.1.3) after corner load adjustment and perform necessary adjustments.
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<How to perform control parameter adjustment> 1) Enter Service Menu (refer to 1.1) and select “Pun Adj”. 2) Wait It automatically complete adjustments taking about two minutes, and rewrite the new parameters. Never perform this adjustment when not necessary. If it is done, new linearity adjustment would be needed.
5.2 Linearity Adjustment of ABTxx-4M Series Balances 5.2.1 Inputting the Linearity Adjustment Weight Values 1) Prepare the weights shown in Table 3. 2) Remove object(s) from the pan. 3) When “Lin-Set” is displaying in the service menu, press the [TARE] key to display the weight values in the order shown in Table 3.
5.3 Linearity Adjustment of ABTxx-5DM Series Dual-range Balances For the linearity procedure on all ABT 120-5DM and ABT 220-5DM semi micro balances, a special developed adjustment software is necessary. The installation, the configuration and the adjustment itself require extensive service training.
5.6 Using Data Edit Mode (“Edit” in Service Menu) (1) Entering Data Edit Mode When “Edit” is displaying in the service menu, press the [TARE] key to select Edit mode. The Data Edit display shown in the figure below appears. Address segment Data segment The address and a two-byte data segment from the address are displayed.
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