Performance, Calibration, and Configuration - B
149
1A Range Current Readback Accuracy (performance, calibration)
This test verifies the readback accuracy of the 1 ampere current range.
a. Turn on the dc source and set the current range readback to 1 A. Program the output voltage to 5 V
and the current to 0 A. The dc source’s current detector must be set to DC.
b. Divide the voltage drop (DVM reading) across the current monitoring resistor by its resistance to
convert to amps and record this value (Iout). Also, record the current reading on the front panel
display. The difference between the two readings should be within the limits specified in the
performance test record card for the appropriate model under 1A Range Current Readback @ 0 A.
c. Program the output current to 1 A.
d. Divide the voltage drop (DVM reading) across the current monitoring resistor by its resistance to
convert to amps and record this value (Iout). Also, record the current reading on the front panel
display. The difference between the two readings should be within the limits specified in the
performance test record card for the appropriate model under 1A Range Current Readback @ 1A.
0.02A Range Current Readback Accuracy (performance, calibration)
This test verifies the readback accuracy of the 20 milliampere current range.
a. Turn off the dc source and connect the output as shown in Figure B-1c using the 400 ohm load
resistor. Set the DMM to operate in current mode.
b. Turn on the dc source and set the current range readback to 0.02A. Program the output voltage to
zero and the current to the full scale value in Table B-2. 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 card
under 20mA Range Current Readback @ 0 A.
d. Program the output voltage to 8V and record the current reading on the DMM and the reading on the
front panel display. If the meter indicates overrange, lower the 8 volts slightly. The difference
between the readings should be within the limits specified in the performance test record card for the
appropriate model under 20mA Range Current Readback @ +20 mA
Current Sink (-CC) Operation (performance, calibration)
This test verifies current sink operation and readback.
a. Turn off the dc source and connect the output and an external power supply as shown in Figure B-1d
using the 400 ohm load resistor. Set the DMM to operate in current mode.
b. Turn on the dc source and set the current range readback to 0.02A
c. Turn on the external power supply and program it to 8V and 5A. Then program the dc source to 0V
and 1A. If the meter indicates overrange, lower the voltage of the external supply slightly. The UUT
display should read approximately −20 mA.
d. 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 card
under 20mA Range Current Readback Accuracy @ −20 mA.
e. Turn off the dc source and short out the 400 ohm load resistor by connecting a jumper across it.
Connect the current monitoring resistor across the input of the DMM as previously shown in figure
B-1b. Set the DMM to operate in voltage mode.