Frequency measurement

The EL34x3 can measure the frequency of the input signals at a voltage circuit (L1, L2 or L3).

Held frequency

The last frequency is displayed via indexes 46, 47 and 48, "Held Frequency", before one or more channels report an "Undervoltage" or "Missing Zero Crossing" error.
The values may not represent the actual mains frequency (see also last note in chapter "PM Inputs Channel 1/2/3").