Keithley 2520, Service Manual, Page: 62 / 137

2-32 Calibration Model 2520 Pulsed Laser Diode Test System Service Manual
7. Send this command to turn on the outputs:
:OUTP1 ON
8. Send the following command to output -20V:
:SOUR2:VOLT -20
9. Note the DMM voltage reading, then calculate the current from the characterized
resistance value and DMM voltage reading: I = V/R
10. Send the following command to calibrate the negative full-range current point:
:CAL:PROT:SENS2 <Calculated_current>
11. Send the following command to output 0V:
:SOUR2:VOLT 0
12. Note the DMM voltage reading, then calculate the current from the characterized
resistance value and DMM voltage reading: I = V/R
13. Send the following command to calibrate the zero range current point:
:CAL:PROT:SENS2 <Calculated_current>
14. Switch current measurement polarity to negative:
:SENSE2:CURR:POL NEG
15. Calibrate the negative zero range current point:
:CAL:PROT:SENS2 <Calculated_current>
16. Send the following command to 20V:
:SOUR1:VOLT 20
17. Note the DMM voltage reading, then calculate the current from the characterized
resistance value and DMM voltage reading: I = V/R
18. Send the following command to calibrate the positive full-range current point:
:CAL:PROT:SENS2 <Calculated_current>
Note that if the measured voltage is negative, the current will be negative.
19. Repeat steps 4 through 18 for the 20mA, 50mA, and 100mA ranges using
Table 2-13 as a guide. Be sure to:
• Select the appropriate range using the :SENS2:CURR:RANG <Range>
command.
• Send the appropriate calibration current values with the :CAL:PROT:SENS2
<Current> command.
20. Turn off the outputs by sending:
:OUTP1 OFF
21. Repeat steps 3 through 20 for the other photodiode current measurement channel.
Be sure to:
• Connect the DMM and resistor to the testhead DETECTOR 2 jack
( Figure 2-8 ).
• Use the :SOUR3:CURR:RANG command to select the correct range.
• Use the :CAL:PROT:SOUR3 command for each calibration point.