10: Sprt 25, Adjusting Sprt Low Resistance Measure - Fluke 525A Service Manual

The ~100 indicates that the desired resistance is about 100 Ω. The actual resistance
is not as important as the accuracy with which the value is known.
5. Set the 5520A to source 100 Ω.
6. Using the two channels on the DMM, calculate the actual value of the 5520A's
output. This is done by using the ratio of a known standard to the output of the
5520A. You can use the 1281 to calculate the ratio or proceed as follows.
Ratio = A/B
RA = RS/Ratio
Where:
A = The reading taken from channel A on the DMM.
B = The reading taken from channel B on the DMM.
RS = The value of the resistance standard (in this case 100 Ω).
RA = The actual output of the 5520A.
After the actual output value is entered, the PC displays the following:
Input ~200 Ohms, Enter the actual value when stable:
7. Set the 5520A to source 200 Ω (nominal) and enter the actual value calculated as
described above.
Set Input ~400 Ohms, Enter the actual value when stable:
8. Set the 5520A to source 400 Ω (nominal) and enter the actual value calculated as
described above.
After the value is entered, the calibration constants will be saved and the display will
return to the main Calibration Menu.

10: SPRT 25, Adjusting SPRT Low Resistance Measure

The SPRT 25 range is used for measuring SPRTs (typically 25 Ohm R0) and Ohms from
0 to 100 Ohms in the 0-400 Ohms range. The 525A will measure a short, and 2
resistances. Refer to Table 21 for a list of equipment used in this section.
Table 21. List of Equipment for Low Ohms Measure Calibration Adjustments
Manufacturer
Fluke
Fluke
Fluke
Wavetek
1. Insert a good 4-wire short into the 525A 4W RTD Ω jacks.
2. Type 10 and press the Enter key on the PC. The following is displayed on the PC.
Input 0 Ohms, Press Enter When Stable
Model
FLUKE-525A/LEADS
742A-100
5520A
1281
Calibration Adjustment
Equipment
Test lead set
Resistance Standard, 100• •
Calibrator
DMM
525A
41