Frequency Ranges; Making Measurements With The Benning Cm - Benning CM 7 Instrucciones De Servicio

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 Resistance measuring range and acoustic continuity testing
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 Frequency ranges

Overload protection: 1000 A
Meas. range
400 Hz
Minimum input frequency: 20 Hz
Minimum input sensitivity: 3 A
7.7 PEAK HOLD
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 addi-
tional 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.

Making measurements with the BENNING CM 7

8.1 Preparations for making measurements
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 meas-
uring 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.
- Check the insulation of the safety measuring cables. Discard the safety
measuring cables immediately if the insulation is damaged.
- Check safety measuring lines for continuity. If the conductor in the safety
measuring line is interrupted, the safety measuring line must be quaran-
tined immediately.
- Before - at the rotary switch  a different function is selected, the safety
measuring lines must be disconnected from the measuring point.
- Strong sources of interference in the vicinity of the BENNING CM 7 can
lead to unstable readings and measuring errors.
02/ 2011
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
BENNING CM 7
within the frequency
range 50 Hz - 200 Hz
Meas. precision
Meas. precision
± (1 % of the measuring value + 2 digits)

1000 A
eff
1000 A
eff
Max. idling voltage
3 V
13