Current Measurement Accuracy - Keithley 2520 Service Manual

1-14 Performance Verification

Current measurement accuracy

Follow the steps below to verify that Model 2520 detector current measurement accuracy
is within specified limits. This test involves applying currents and verifying that
Model 2520 current readings are within required limits.
1.
2.
3.
Figure 1-7
Connections for DETECTOR 1 current measurement verification tests
Model 2001 DMM
Ω2 Ω4
DCV ACV DCI ACI
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4.
5.
6.
7.
8.
9.
10.
11.
With the power off, connect the 2kΩ resistor and DMM to the testhead
DETECTOR 1 jack, as shown in
parallel resistor construction.)
Turn on the Model 2520 and DMM, and allow them to warm up for a minimum of
one hour.
Select the DMM DC volts function, and enable auto-range.
Input HI
SENSE
Ω 4 WIRE INPUT
HI
350V 1100V
!
PEAK PEAK
2001 MULTIMETER
LO
500V
PEAK
INPUTS
FREQ TEMP
RANGE
F R
AUTO
FRONT/REAR
2A 250V
AMPS
RANGE
CAL
EXIT ENTER
Resistor
Input LO
(See Text)
Restore front panel (BENCH) defaults as outlined previously in
defaults" on page 1-6.
Press the DETECTOR 1 I
RANGE key.
Press the DETECTOR 1 VB key, then press the EDIT key, and set the voltage bias
source value to +20.000V.
Turn on the Model 2520 outputs by pressing the ON/OFF OUTPUT key.
Press the TRIG key. Note the DMM voltage reading, then turn off the outputs by
pressing the ON/OFF OUTPUT key.
Calculate the current from the DMM voltage reading and characterized resistance
value: I = V/R.
Calculate reading limits based on the current and Model 2520 specifications, then
verify that the Model 2520 DETECTOR 1 current reading is within the limits.
Repeat steps 5 through 10 for the 20mA, 50mA, and 100mA ranges. Be sure to use
the correct test resistor for each range.
Model 2520 Pulsed Laser Diode Test System Service Manual
Figure 1-7. (See
Center
Conductor
Model 2520 Testhead
BIAS
Inner DETECTOR 1
Shield !
ISOLATION FROM EARTH: 10V MAX.
DETECTOR 1
key, then select the Model 2520 10mA range with the
PD
Figure 1-4 and Figure 1-5
HI LO
CURRENT
OUTPUT
CURRENT
INPUT
!
CAT I
DETECTOR 2
VOLTAGE
SENSE
HI LO
"Restoring factory
for