AMETEK APG-XT - Manual (Page 34)

Section 4. Calibration
Current Mode Calibration
52 Operating Manual for APG for XT/HPD Series Power Supply
Current
Readback
1. Ensure the current shunt has been connected to the power supply as shown in
Figure 4.2 . See also “Current Calibration Setup” on page 51 , step 4. Connecting
a DVM is optional.
2. Program the output to 5% of full scale current by sending the following
command string from the computer:
VSET40;ISET1.25 (for 1kW Model 40-25)
3. Perform a readback operation of the output current from the computer:
IOUT?
4. Adjust the current readback offset potentiometer R38 (IZERO) until the
readback value is within the current readback accuracy specification. Refer to
specification tables in
Section 1 .
Example: ±140mA ± (0.15% (5% of 25A)) (for 1kW Model 40-25)
5. Program the output to full scale current by sending:
VSET40;ISET25 (for 1kW Model 40-25)
6. Perform a readback operation of the output current from the computer:
IOUT?
7. Adjust the current readback full scale potentiometer R45 (IGAIN) until the
readback current value is within specification. Refer to specification tables in
Section 1 .
Example: ±140mA ± (0.15% of 25A) (for 1kW Model 40-25)
8. Repeat steps 2 (IZERO) to 7 (IGAIN) for best linearity.