5700A/5720A Series II Calibrator
Service Manual
3-30
3-20. Direct Current Accuracy Verification Test
Equipment required for the Direct Current Accuracy Verification Test is listed in Table
3-6. Proceed as follows to test accuracy of the dc current function:
Table 3-6. Equipment Required for Direct Current Test
Equipment Model
DC DMM, 6-1/2 digit Wavetek 1281 or HP 3458A
High-Current Shunt Fluke Y5020 (for 5725A only)
Resistance Standards L&N 4221B (0.1Ω at 2A)
Fluke 742A-1 (1Ω at 200 mA)
Fluke 742A-10 (10Ω at 20 mA)
Fluke 742A-1k (1 kΩ at 2 mA)
Fluke 742A-10k (10 kΩ at 200 µA)
Use Table 3-20 (5720A) and Table 3-21 (5700A) for the test records.
1. Connect the dc DMM to the Calibrator output and set the Calibrator for outputs of
200 mV, -200 mV, 2V, and -2V, and record the dc DMM reading at each voltage in
Table 3-20 or 3-21.
2. Refer to the resistance standard test report and enter the corrections for all the
certified values in ± ppm in column A on the test record.
Note
The STD RES CORRECTION is the difference between the nominal
standard resistor value and the certified or true resistor value. For
example, if the nominal value is 0.1
Ω
and the certified value is
0.0999963
Ω
, the difference equals 0.0000037
Ω
, or +37 ppm.
3. Connect the equipment as shown in Figure 3-10 using the L&N 0.1Ω resistor.
4. Set the Calibrator for a 2A dc output, and adjust the Calibrator using the output
adjustment knob to obtain the characterized voltage reading on the dc DMM. Wait 3
seconds, and record the Calibrator error display reading in ± ppm (Column B).
LO
OUTPUT SENSE
HIHI
LO
CALIBRATOR (UUT)
HI
LO
SHUNT
USE INTERNAL GUARD
DC DMM
GND
GRD
INPUT
F3-7.EPS
Figure 3-9. Direct Current Accuracy Test Setup
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