with the ac input grounded. The internal residual noise of the ac
section is measured and checked against a limit of -10mV to 70mV at
the output of the rms-to-dc converter.
621 AC rms full scale failed
This test configures for the 100mV ac
range. The 1mA ohms current source is switched on to charge the ac
input capacitor C614. This produces a pulse on the output of the rms-
to-dc converter which is sampled 100ms after the current is applied. A
20ms A/D measurement is performed and checked against a limit of
2V to 13V into the ADC.
622 DC 10V reference failed
This test configures to the 10V dc
range with 5V input applied. A 20ms ADC measurement is
performed and the result is checked against a limit of 4.55V
± 0.15mV.
624 Unable to sense line frequency
The supplied voltage AC2 is
routed through a comparator U4 to generate a logic input signal. This
test checks that the logic input from U4 to panel MCU U3 is toggling. If
no logic input is detected, the instrument will assume 50Hz line
operation for all future measurements.
650 Front-End MCUs Firmware Version Error (System Error)
660 Firmware Version Error
661 External Memory Verion Error
662 Calibration Version Error
663 Scanner card Version Error
664 Temperature Version Error
665 GPIB Version Error
666 RS-232 Version Error
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