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Performance and Calibration Procedures
91
Current Priority Constant Current Test
This test measures the change in output current resulting from a change in output voltage from about zero
volts to the maximum output voltage.
NOTE: The voltage limits in Current Priority Mode are not programmable.
Action Program Commands
1. Turn off the dc source and connect the output as shown in Figure B-1c
with an ammeter in series with a 16k ohm load resistor across the Hi
and Lo output terminals. Also connect a shorting switch across the
resistor.
“*RST”
2. Start with a short across the output (switch closed). Turn on the dc
source and program the Current Priority mode. Program the current to
the maximum value (0.5mA).
“OUTP ON,(@1)”
“SOUR:FUNC:MODE CURR,(@1)”
“CURR 0.0005,(@1)”
3. Set the ammeter to the 1A range, and record the output current
reading on the ammeter (shorted-output value).
5. Remove the short from the output (open the switch).
6.
Read back the N3280A status to be sure that it’s in the
CC mode. This
query should return a Bit value of “
8” for CC mode.
“STAT:OPER:COND? (@1)”
7. Record the output current reading on the ammeter (full-load current
value).
The difference between the two current readings is the Load Effect
current and should be within the limits listed in the performance test
record card for the appropriate model under Current Priority Load
Effect Current.
Source Effect Tests
These tests measure the change in output voltage or current that results from a change in ac line voltage
from the minimum to maximum value within the line voltage specifications. The tests should all be done
at 60Hz line frequency.
Voltage Priority, Constant Voltage Source Effect
Action Program Commands
1. Connect the ac input of the dc source to a variable voltage transformer
(or ac source). Set the transformer to nominal line voltage.
Connect the output as shown in Figure B-1b with a 20 ohm resistor or an
electronic load across the output terminals and a DVM across the Hi
and Lo sense terminals.
2. Turn on the dc source, program the output voltage to the full-scale value
(10.0V), and the current limit to the maximum value (0.5125A).
“OUTP ON,(@1)”
“VOLT 10,(@1)”
“CURR:LIM 0.5125,(@1)”
3. If you are using an electronic load, adjust it for the full-scale output
current, 0.5A.