1-28 Performance Verification Model 2750 Multimeter/Switch System Service Manual
Verifying dry circuit resistance
Check the dry circuit resistance function by connecting accurate resistance values to the
Model 2750 and verifying that its resistance readings are within the specified limits.
CAUTION Do not apply more than 300V between the 7700 plug-in module INPUT or
SENSE H and L terminal, or between any adjacent channels, or instrument
damage could occur.
Follow these steps to verify dry circuit resistance accuracy:
1. Using shielded Teflon or equivalent cables in a 4-wire configuration, connect the
Model 7700 CH1 H and L INPUT terminals, and CH11 H and L SENSE terminals
to the calibrator as shown in Figure 1-15.
NOTE The 1k¾ range can tolerate 80% of range (0.8¾) lead resistance. Ensure that
relay and cable connections have ð0.8¾ of resistance before verifying the 1¾
range.
Tab le 1- 14
Limits for plug-in module normal resistance verification
Range
Nominal
resistance
Nominal reading limits
(1 year, 18°C to 28°C) Recalculated limits**
1
10
100
1k
10k
100k
1M
10M
100M
1
10
100
1k
10k
100k
1M
10M
100M
0.999820 to 1.000180
9.99880 to 10.00120
99.9880 to 100.0120
0.999894 to 1.000106k
9.99894 to 10.00106k
99.9890 to 100.0110k
0.999890 to 1.000110M
9.99590 to 10.00410M
99.5770 to 100.4230M
__________ to __________
__________ to __________
__________ to __________
__________ to __________ k
__________ to __________ k
__________ to __________ k
__________ to __________ M
__________ to __________ M
__________ to __________ M
* Enable OCOMP for 1, 10, and 100 ranges.
** Calculate limits based on actual calibration resistance values and Model 2750 one-year resistance accuracy
specifications. See “Verification limits.”
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