Keithley 2520 Service Manual page 56

2-26 Calibration
Step 3: Current source calibration
Follow these steps to calibrate the current source.
calibration resistances and commands.
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
Send the following command to select the pulse mode:
:SOUR1:FUNC:SHAP PULS
Send the following commands to set source and measure polarities:
:SENS1:VOLT:POL POS
:SOUR1:CURR:POL POS
Connect the 10 to 15Ω resistor to the Model 2520 testhead VOLTAGE SENSE and
CURRENT OUTPUT jacks, as shown in
Set the pulse transition to fast:
:SOUR1:PULS:TRAN:STAT OFF
Set ranges with these commands:
:SENS1:VOLT:RANG 10
:SOUR1:CURR:RANG 0.5
Send this command to turn on the source output:
:OUTP1 ON
Set the compliance DAC to full scale so that it does not affect the measurement:
:DIAG:KEIT:BITS:VDAC1 4095
Source 10% of full scale:
:SOUR1:CURR 0.05
Trigger a pulse:
:INIT
Send the following query to request the Model 2520 voltage measurement:
:SENS1:DATA?
Note the voltage reading returned by the Model 2520 in step 10, then calculate the
actual sourced current as follows: I = V/R. Here, I is the actual sourced current, V
is the returned Model 2520 voltage reading, and R is the actual resistance value.
Send the following calibration command using the current calculated in step 11:
:CAL:PROT:SOUR1 <Calculated_Current>
For example, if the resistance value is 14.02Ω, and the returned voltage reading
from step 10 is 0.6732V, the actual current is: I = 0.6732V/14.02Ω = 0.048017A.
In this example, the calibration command is:
:CAL:PROT:SOUR1 0.048017
Send this command to source 90% of full scale current:
:SOUR1:CURR 0.45
Repeat steps 9 through 12.
Send this command to select the slow transition pulse:
:SOUR1:PULS:TRAN:STAT ON
Model 2520 Pulsed Laser Diode Test System Service Manual
Table 2-10
Figure 2-3.
summarizes current source