OHAUS CKW-55, Service Manual

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CHAPTER 3 INDICATOR TESTING
3.14 CALIBRATION VERIFICATION USING A LOAD CELL SIMULATOR (Cont.)
5. When connecting a 3 mv/v Simulator: Jumper W1 must be removed or left in place with one
pin uncovered. See Figure 3-15.
6. When connecting 4-wires with no sense wires: Jumpers W2 and W3 must be in place
shorting the two pins.
7. When connecting six wires that includes sense wires: Jumpers W2 and W3 must be removed
or in place with 1 pin uncovered.
8. When connecting a Simulator with an extra ground shield wire: The shield wire may be
connected to the center position of J2.
9. After wiring is completed and jumpers are in place, the Indicator can now be calibrated.
10.After testing, replace switch cover.
3.14.1 Calibration Test Using a Simulator
This test calibrates the Indicator using a Load Cell Simulator and can verify that the Main PC Board is
functioning properly.
1. With the Indicator on, CLr. PAn, ERROR 3 may be displayed, this is normal. Enter the menu
and perform a span calibration.
2. Follow the Indicator prompts. When the Indicator indicates a given mass should be placed
on the base, set the Simulator to an equivalent value to simulate the output for the base.
Alternate values from Table 3-6 can be set if a CKW Base is used. For example, when a span
value of 6 kg for a 6 kg Indicator application is shown, the simulator should be set to 7.2
(1.6 + 5.6) mV/V.
3. Upon completion of calibration, the Main PC Board can be further checked using the Simulator
to simulate various weight values. Review Table 3-6 and adjust the Simulator to simulate 0%
load, 50% load and 100% load for the capacity that the Indicator is rated for. If simulator
settings and weight reading on the Indicator agree, the Main PC Board is functional. If the
Indicator readings vary or are not linear, the Main PC Board is defective and should be
replaced.
Note : The Indicator readings are only as accurate as the Load Cell Simulator.
4. If needed, remove power from the Indicator and proceed with Section 4.3 and replace the Main
PC Board.
5. After Main PC Board replacement and assembly of the Indicator, perform Operational Tests in
Section 3.9.