Abstract: For calibration of a microprocessor-based electrical metering device, the scaled values of current and voltage inputs are presented on a display along side of the associated scaling factors. Soft keys on the display are used to increment or decrement the scaling factors to adjust the scaled values of the associated current or voltage to the value indicated by a precision reference meter which measures test values of current and voltage provided by a stable source. For analog inputs, both a zero scaling factor (offset) and a full scale factor (slope) are presented on the display adjacent the scaled analog value and can be separately adjusted by the soft keys.

Abstract: A monitor/analyzer for an ac electrical system can be programmed through a display on the front panel to respond to selected events by generating triggers signals when selected monitored electrical parameters including neutral current exceed programmed thresholds. The trigger signals initiate simultaneous waveform capture of multiple waveforms in the ac system. Multiple trigger signals result in sequential waveform capture so that if a plurality of triggers are programmed for the same event, extended waveform data is captured for the event. Alarm screens are generated in response to the events, as well as for hardware failure, an excessive neutral-to-ground voltage or reverse sequence.

Abstract: Apparatus for monitoring electrical parameters in an electrical system includes a display on which values of the various monitored electrical parameters are displayed, several at a time. The apparatus can be programmed to generate a custom display presenting selected ones of the many parameters, such as the ones most often referenced by the operator, so that it is not necessary to scroll through the large number of parameters to find those of frequent interest.