Service manual

8508A
Service Manual
3-40
Table 3-10. Resistance Verification Points and Sequence (cont)
Tolerance
1
8508A Range Resistance
HiVΩ
2
0 GΩ Perform input zero operation to calibrator range locked zero output 20 MΩ
10 MΩ ± 0.0000202 MΩ
0 GΩ Perform input zero operation to calibrator range locked zero output 200 MΩ
100 MΩ ± 0.0000870 MΩ
0 GΩ Perform input zero operation to calibrator range locked zero output 2 GΩ
1 GΩ ± 0.0003150 GΩ
0 GΩ Perform input zero operation to calibrator range locked zero output 20 GΩ
1 GΩ ± 0.012675 GΩ
[1] Based on 365 day Tcal ±1 °C 99 %CL Absolute specifications. See comments in Applicable Verification Tolerance section above
regarding the impact of calibration uncertainties and use of other specifications.
[2] Ranges require separate input zero operation in each resistance mode.
DC Current Checks
Equipment Configuration
1. Ensure that the calibrator output is set to
STANDBY and configured for Internal
Guard (
EXT GRD is deselected).
2. Connect the equipment as described for Routine Calibration.
3. Press the
DCI key
4. Press the
CONFIG key. Select Filt and RESL7.
5. Confirm that the Multimeter is configured for internal guard (External Guard is
deselected) by checking that the
Ext Grd legend does not appear on the left-hand
display.
Procedure
Repeat the following sequence for each range, starting with the 200μA range and
working up to the 20A range, as listed in Table 3-11. An input zero operation is
performed on each Multimeter range prior to performing the range verification
measurements with the calibrator set to zero by range locking the calibrator in the range
from which the output will be obtained.
1. Select the required Multimeter range.
2. On the calibrator set the output to zero. Select OPERATE.
3. On the Multimeter press the
INPUT key, and select Zero Rng to initiate the zeroing
operation.
The
Busy legend will appear, and then extinguish when the zero operation has
completed.
4. On the calibrator select the value required for verification in the positive polarity.
5. Note the Multimeter’s reading. Compare the result with the allowable tolerance,
taking into account any known error from nominal of the calibrator for this output.
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