4.3 Measuring ranges
Device description
5191 / 07/2021 en
BENNING CM 2-1
22
4.3
Measuring ranges
The device is provided with an automatic switch-over of the measuring range. For this reason, a
default setting is not required.
If a measuring range is exceeded, this is indicated by “0L” or “-0L” and, depending on the
measuring function, additionally by an acoustic warning. Please note that there will be no
indication and warning in case of overload. In case of dangerous contact voltages (from
60 V‑DC or 30 V‑AC RMS on), the flashing symbol " “ is additionally displayed.
Measuring accuracy
The measuring accuracy is specified as the sum of the following:
• Relative part of the measured value
• Number of digits (counting steps of the last digit)
The stated measuring accuracy is specified for 1 % to 100 % of the final measuring range value
and applies at a temperature of 23 °C ±5 °C and a relative air humidity lower than 80 %. In case
of deviating temperatures, observe the temperature coefficient by adding the following value to
the specified measuring accuracy:
0.2 [1/°C] x specified measuring accuracy x difference to reference temperature range [°C]
Additional specifications for AC functions
The measured value is obtained and displayed as real r.m.s. value (TRUE RMS). For non-
sinusoidal curves, the accuracy of the displayed value decreases. Thus, an additional error
results for the following crest factors:
• Crest factor from 1.0 to 2.0: +1.0 %
• Crest factor from 2.0 to 2.5: +2.5 %
• Crest factor from 2.5 to 3.0: +4.0 %
Maximum crest factor of the measuring signal:
• 3.0 @ 2 000 digits
• 1.5 @ 4 000 digits
Note the following additional features:
• Measured values <10 digits are set to 0 on the digital display.
• Square-wave signals are not specified.
• Positioning error of the conductor within the measuring clamp: ± 1 % of the measured value
“HFR (AC)” function (low-pass filter)
Please observe the following features for the “HFR (AC)” function (low-pass filter):
• Additional error for AC current or voltage measurements:
– Frequency range 15 ... 60 Hz: ±4 % with regard to the specified measuring accuracy
– Frequency range >60 Hz: Not specified
• Limiting frequency fg (-3 dB): 800 Hz
