9: Low Ohms, Adjusting Low Resistance Measure - Fluke 525A Service Manual

525A
Service Manual

9: Low Ohms, Adjusting Low Resistance Measure

When adjusting the calibration for the 5-400 Ohms Measure range (Low Ohms Measure),
the Calibrator will measure 3 resistances. Refer to Table 20 for a list of equipment used
in this section.
Manufacturer
Fluke
Fluke
Fluke
Wavetek
The method described below uses the 1281 to establish a ratio between the 5520A output
and the 742 to improve the accuracy with which the 5520A's output resistance is known.
1. Connect channel A of the 1281 to the Resistance Standard as follows:
2. Connect channel B of the 1281 to the 5520A as follows:
3. Connect 525A to the 5520A as follows:
4. Type 9 {enter} on the PC. The following will be displayed on the PC.
40
Table 20. List of Equipment for High Ohms Measure Calibration Adjustments
FLUKE-525A/LEADS
742A-100
5520A
1281
a. Connect I+ of the DMM to the high side of the current input of the Resistance
Standard.
b. Connect I- of the DMM to the low side of the current input of the Resistance
Standard.
c. Connect the high side (HI) of the DMM sense input to the high side of the sense
output of the resistance standard.
d. Connect the low side (LO) of the DMM sense input to the low side of the sense
output of the resistance standard.
a. Connect I+ of the DMM to the high side of the current input of the 5520A.
b. Connect I- of the DMM to the low side of the current input of the 5520A.
c. Connect the high side (HI) of the DMM sense input to the high side of the sense
output of the 5520A.
d. Connect the low side (LO) of the DMM sense input to the low side of the sense
output of the 5520A.
a. Connect HI INPUT 4W RTD Ω jack of the 525A to the high side of the current
input of the 5520A.
b. Connect LO INPUT 4W RTD Ω jack of the 525A to the low side of the current
input of the 5520A.
c. Connect the HI SENSE 4W RTD Ω jack of the 525A to the high side of the sense
output of the 5520A.
d. Connect the LO SENSE 4W RTD Ω jack of the 525A sense input to the low side
of the sense output of the 5520A.
Input ~100 Ohms, Enter the actual value when stable:
Model
Test Lead Set
Resistance Standard, 100 Ω
Calibrator
DMM
Equipment