Keithley 2520, Service Manual, Page: 18 / 137

1-6 Performance Verification Model 2520 Pulsed Laser Diode Test System Service Manual
Verification limits
The verification limits listed in this section have been calculated using only the
Model 2520 one-year accuracy specifications; they do not include test equipment
uncertainty. If a particular measurement falls outside the allowable range, recalculate new
limits based on Model 2520 specifications and corresponding test equipment
specifications.
Example limits calculation
As an example of how verification limits are calculated, assume you are testing the 10mA
measurement range with a 10mA input current. Using the Model 2520 one-year accuracy
specification of ±(0.3% of r 20
μ
A offset), the calculated reading limits are:
Limits = 10mA ± [(10mA
×
0.3%) + 20
μ
A]
Limits = 10mA ± (30
μ
A + 20
μ
A)
Limits = 10mA ± 50
μ
A
Limits = 9.95mA to 10.05mA
Restoring factory defaults
Before performing the verification procedures, restore the instrument to its factory front
panel (BENCH) defaults as follows:
1. Press the SETUP key. The instrument will display the following prompt:
SAVESETUP MENU
SAVE RESTORE POWERON RESET
2. Select RESET, then press ENTER. The unit displays:
RESET ORIGINAL DFLTS
BENCH GPIB
3. Select BENCH, then press ENTER to restore BENCH defaults.
Performing the verification test procedures
Test summary
• Detector current measurement accuracy
• Laser diode voltage measurement accuracy
• Laser diode current source accuracy
• Detector voltage bias source accuracy
If the Model 2520 is not within specifications and not under warranty, see the calibration
procedures in Section 2, Calibration, for information on calibrating the unit.