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2 – Verification and Performance Tests
Low Range Current Readback Accuracy
This test verifies the readback accuracy of the 20 milliampere current range.
a.
Turn off the supply and connect the output as shown in Figure 2-1b. Set the DMM to operate in current
mode.
b.
Turn on the supply under test, set the current to low range and program the output voltage to zero and
full scale output current. The current on the UUT display should be approximately 0 mA.
c.
Record the current reading on the DMM and the reading on the front panel display. The difference
between the two readings should be within the limits specified in the performance test record chart
under 20mA RANGE CURRENT READBACK ACCURACY @ 0A.
d.
Program the output voltage to 8 V and record the current reading on the DMM and the reading on the
front panel display. The difference between the readings should be within the limits specified in the
performance test record chart for the appropriate model under 20mA RANGE CURRENT
READBACK ACCURACY @ 20mA
e.
Turn off the supply and connect the output and an external supply as shown in Figure 2-1c. Set the
DMM to operate in current mode.
f.
Turn on the external supply and program it to 8 V and 1 A. Then program the supply under test to zero
volts and 1 amp. The UUT display should read approximately −20 mA.
c.
Record the current reading on the DMM and the reading on the front panel display. The difference
between the two readings should be within the limits specified in the performance test record chart
under 20mA RANGE CURRENT READBACK ACCURACY @ −20 mA.
CC Load and Line Regulation
These tests (CC Load Effect and CC Source Effect given below) are tests of the dc regulation of the power
supply's output current. To insure that the values read are not the instantaneous measurement of the ac peaks
of the output current ripple, several dc measurements should be made and the average of these readings
calculated. An example of how to do this is given below using an Agilent 3458A System Voltmeter
programmed from the front panel. Set up the voltmeter and execute the "Average Reading" program
follows:
a.
Program 10 power line cycles per sample by pressing
b.
Program 100 samples per trigger by pressing (N Rdgs/Trig) 1 0 0 ENTER .
c.
Set up voltmeter to take measurements in the statistical mode as follows:
Press Shift key, f0, Shift key, N
Press ^ (up arrow) until MATH function is selected, then press >.
Press ^ (up arrow until STAT function is selected then press (ENTER).
d.
Set up voltmeter to read the average of the measurements as follows:
Press Shift key, f1, Shift key, N.
Press down arrow until RMATH function is selected, then press >.
Press ^ (up arrow) until MEAN function is selected, then press ENTER.
e.
Execute the program by pressing f0, ENTER, TRIG, ENTER
f.
Wait for 100 readings and then read the average measurement by pressing f1, ENTER.
To repeat the measurement, perform steps (e) and (f).
18
NPLC 1 0 ENTER .
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