Two-Wire Compensation Verification - Fluke 5700A Series Service Manual

Table 3-4. Low Value Resistance Calibration Using a Current Source
5720A (UUT) Apply Current
Resistance
1Ω
1.9Ω
10Ω
5700A (UUT) Apply Current
Resistance
1Ω
1.9Ω
10Ω
14. For the remaining tests, no current source is required. Verify that each true UUT
value is within the limits shown in Table 3-16 for 5700A and Table 3-17 for 5720A.
a. Connect the DMM, set for 4-wire resistance, first to the Resistance Standard
equal to the UUT nominal output and then to the UUT itself. In each case, record
the resistance standard DMM reading and the resistance standard certified value.
b. Calculate the DMM correction by subtracting the DMM reading from the
certified value; enter this calculated value on the test record as DMM ERROR.
c. Move the DMM to the UUT terminals; enter the DMM reading on the test record
as DMM UUT RES RDG.
d. Algebraically add the DMM ERROR and the DMM UUT RES RDG; enter the
sum on the test record as UUT TRUE RES VALUE.
e. Adjust the output adjustment knob for a UUT Control Display reading equal to
the true resistance value previously calculated. The error from the displayed
value is also shown on the Control Display. Enter this error (with polarity
reversed) on the test record as the UUT DEVIATION FROM DISPLAYED
VALUE.

3-17. Two-Wire Compensation Verification

Use the following steps to verify that two-wire compensation operates correctly:
1. Connect the UUT (output set to 100Ω, with external sensing) to the DMM (set for 4-
wire resistance measurement). Note the DMM reading.
2. Connect two shorts: DMM SOURCE HI to SENSE HI and DMM SOURCE LO to
SENSE LO.
3. Activate UUT 2-wire compensation.
4. Check that the DMM reading returns to within 4 miliohms of the reading noted in
step 1.
5720A Deviation From
Displayed Value (90-day)
100 mA
100 mA
10 mA
5700A Deviation From
Displayed Value (90-day)
100 mA
100 mA
10 mA
5720A Displayed Value
±95 ppm
±95 ppm
±25.0 ppm
5700A Displayed Value
±95 ppm
±95 ppm
±28.0 ppm
Calibration and Verification
Full Verification
0.9995 to 1.0005
1.89905 to 1.90095
9.997 to 10.003
0.9995 to 1.0005
1.89905 to 1.90095
9.997 to 10.003
3
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