Keithley 2100 User Manual page 92

Section 4: Front Panel Operations
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
668 Manual Calibration Version Error
669 Self-Test Version Error
670 Command Version Error
4-44
Model 2100 6 1/2-Digit Resolution Digital Multimeter User's Manual
Return to Section Topics 2100-900-01 Rev. D / September 2011