in the instrument,
and any of these can be selected by the user.
To select the desired current transformer ratio, the "F" key-switch is kept
pressed when the instrument is switched on. Keeping it pressed further causes
the transformers ratios to be displayed, one after another. When the desired
ratio is displayed, de-energisation of the M610 will cause that value
of ratio to be set. This setting is stored in non-volatile memory, protected
against power interruption. The phase currents are displayed as instantaneous
and 15-minute averaged values, the latter being equivalent to the bimetallic
function of analog meters.
The peak values of measurements are also stored and displayed, similar in
function to drag-pointer type peak value registration in analog meters.
The M610 derives its operating power from the voltage measuring inputs,
thereby keeping instrument wiring to a minimum. For medium voltage systems,
100 V versions of the instrument are available, which display the primary
side voltage, with appropriate scaling.