M9B-HFS INTERFACE
CALIBRATION
Release 1.0 (97/10)
4-3
4.3 Current Mode Calibration
Follow all procedures in the sequence given. Make sure that you are set up as in Section 4.3.1 Current
Calibration Setup before doing current calibration.
4.3.1
Current Calibration Setup
1. Disconnect any load from the power supply to be calibrated.
2. Connect a current shunt across the supply's output terminals.
3. Connect a voltmeter across the current shunt.
Figure 4.3-1 Current Calibration Setup
4.3.2
Current Program Calibration Procedure
1. Connect the current shunt to the power supply as shown in Section
4.3.1 Current Calibration Setup.
2. Activate calibration mode by sending command CMODE ON to the power supply.
3. Send commands ILO; VLO to the power supply. Measure and record the output voltage shown on the
external voltmeter.
4. Send commands IHI; VHI to the supply, then measure and record the output voltage shown on the
external voltmeter.
5. Calculate ILO and IHI from the voltages measured and the shunt resistance. I =V/R.
6. Send the command IDATA <ilo>,<ihi> to the power supply. <ilo> and <ihi> are the current values
obtained from sending the ILO and IHI commands to the supply. When the power supply is calibrated,
the low to high current program calibration values are stored as constants.
7. Program the supply at various levels using the ISET command to confirm that the calibration was
successful and that linearity is observed. Refer to the current program accuracy specification in
Appendix A.
8. Turn off calibration mode by sending the command CMODE
OFF to the supply.
