Benning CM 7 Bedienungsanleitung Seite 15

7.4­ Alternating­current­ranges
Measuring
Resolution
range
0 - 200 A
200 - 400 A
400 - 1000 A
* The measuring value is gained and indicated as effective value (True RMS,
1
AC coupling). The measuring accuracy is specified for sinusoidal curves
and applies to the final value of the measuring range as well as for non-
sinusoidal curves up to 50 % of the final value of the measuring range.
In case of non-sinusoidal curves, the indicating value becomes inaccurate.
Thus, an additional error occurs for the following crest factors:
crest factor from 1.4 to 2.0 additional error + 1 %
crest factor from 2.0 to 2.5 additional error + 2.5 %
crest factor from 2.5 to 3.0 additional error + 4 %
* additionally ± 4 digits for measuring values < 15 % of the final value of the
2
measuring range
The stated precision is specified for conductors that are centrally clamped by
the current probe  (see Fig. 4 Direct/ alternating current measurement). For
conductors that are not centrally clamped, an additional error of 1 % of the
display value needs to be taken into account.
7.5­ Resistance­measuring­range­and­acoustic­continuity­testing
Overload protection: 600 V
Meas. range Resolution
400 Ω
The built-in buzzer sounds in the case of a resistance R less than 30 Ω.
7.6­ Frequency­ranges
Overload protection: 1000 A
Meas. range
400 Hz
Minimum input frequency: 20 Hz
Minimum input sensitivity: 3 A
7.7­ PEAK­HOLD
Measuring ranges: V AC, A AC
In the PEAK-HOLD function (storage of the peak value), an additional error has
to be considered for the specified accuracy:
+ (± 3 % + 20 digits)
Measuring values > 750 Vpeak or 800 Apeak are not specified.
The PEAK-HOLD function automatically selects the measuring range with the
lowest resolution.
7.8­ MIN/MAX
In the MIN/MAX function (storage of the minimum/ maximum value), an
additional error has to be considered for the specified accuracy:
+ (± 15 digits)
The MIN/MAX function automatically selects the measuring range with the
lowest resolution.
8.­ Making­measurements­with­the­BENNING­CM­7
8.­ Preparations­for­making­measurements
Operate and store the BENNING CM 7 only at the specified storage and
operating temperatures conditions. Avoid continuous insulation.
- Check rated voltage and rated current details specified on the safety measuring
lines. The nominal voltage and current ratings of the safety measuring
cables included in the scope of delivery correspond to the ratings of the
BENNING CM 7.
11/ 2006
Meas. precision *
frequency range 50 Hz - 400 Hz
0,1 A ± (2.9 % of the measuring value + 3 A)
0,1 A ± (1.9 % of the measuring value + 2 A)
1 A ± (2.9 % of the measuring value + 5 A)
eff
0,1 Ω ± (1 % of the measuring value + 3 digits)
eff
Resolution
1 Hz
eff
B ENNING CM 7
within the
1*2
within the frequency
range 50 Hz - 200 Hz
Meas. precision
Meas. precision
± (1 % of the measuring value + 2 digits)

Overload
protection
1000 A
eff
1000 A
eff
1000 A
eff
Max. idling voltage
3 V
3