BENNING CM 12 Digital Power Clamp Meter Instruction Manual

Operating manual

Fig. 1: Front tester panel

Fig. 2: Direct voltage measurement

Fig. 3: Alternating voltage measurement (frequency measurement)

Fig. 4: DC/ AC current measurement (frequency measurement)

Fig. 5: Resistance measurement/ diode test/ continuity test with buzzer

Fig. 6: Capacity testing

Fig. 7a: Single-phase load

Fig. 7b: Three-phase load without neutral conductor (N)

Fig. 7c: Three-phase load with a neutral conductor (N)

Fig. 8: Phase sequence indication

Fig. 9: Current measurement with the flexible AC current transformer BENNING CFlex 1

Fig. 10: Voltage indicator

Fig. 11: Battery replacement

Operating manual
BENNING CM 12

TRUE RMS digital current clamp multimeter for

• DC/ AC voltage measurements
• DC/ AC current measurements
• resistance measurements
• diode/ continuity tests
• capacity measurements
• frequency measurements
• effective power measurements
• power factor measurements (cos phi)
• phase sequence indication

User instructions

This operating manual is intended for

• skilled electricians and
• electrotechnical trained personnel.

The BENNING CM 12 is intended for measurements under dry ambient conditions. It must not be used in electrical circuits with a nominal voltage higher than 1000 V AC/ DC (see section 6 „Ambient conditions“ for details).
The following symbols are used in this operating manual and on the  BENNING CM 12:

| Application around and removal from HAZARDOUS LIVE conductors is permitted.
---|---
| Warning of electrical danger!
Indicates instructions that must be followed to avoid danger to persons.
| Attention! Must comply with documentation!
This symbol indicates that the information provided in the operating manual must be complied with in order to avoid risks.
| This symbol on the BENNING CM 12 indicates that the BENNING CM 12 is equipped with protective insulation (protection class II).
| This symbol on the BENNING CM 12 means that the BENNING CM 12 complies with the EU directives.
| This symbol appears on the display to indicate a discharged battery.
| This symbol designates the „diode test“ field.
| This symbol designates the „continuity test“ field.
The buzzer is intended for acoustic result output.
| This symbol marks the range „capacity testing”.
| (DC) A direct voltage or current
| (AC) An alternating voltage or current
| Ground (voltage against the ground)

Safety instructions

The instrument is built and tested in accordance with
DIN VDE 0411 Part 1/ EN 61010-1
DIN VDE 0411 Part 2-032/ EN 61010-2-032
DIN VDE 0411 Part 2-033/ EN 61010-2-033
DIN VDE 0411 Part 031/ EN 61010-031
and has left the factory in perfectly safe technical condition.
To preserve this condition and to ensure the safe operation of the device, the user must observe the notes and warnings given in these instructions at all times.
Improper handling and non-observance of the warnings might involve severe injuries or danger to life.

WARNING! Be extremely careful when working with bare conductors or mainline carriers!
Contact with live conductors will cause an electric shock!

The unit may be used only in electrical circuits of overvoltage category III with a maximum voltage of 1000 V to earth, or of overvoltage category IV with a maximum voltage of 600 V to earth.
Only use suitable measuring leads for this. With measurements within measurement category III, the projecting conductive part of a contact tip of the measuring leads must not be longer than 4 mm.
Prior to carrying out measurements within measurement category III, the push-on caps provided with the set and marked with CAT III and CAT IV must be pushed onto the contact tips.
The purpose of this measure is user protection.
Remember that work on electrical components of all kinds is dangerous.
Even low voltages of 30 V AC and 60 V DC may be dangerous to human life.

In order to prevent any danger, always measure a present voltage first without a low-pass filter (without high-frequency suppression) to detect a dangerous voltage.
Before starting the multimeter, always check it as well as all measuring leads and wires for signs of damage.

Should it appear that safe operation of the multimeter is no longer possible, it should be shut down immediately and secured to prevent that it is switched on accidentally.
It may be assumed that safe operation is no longer possible:

• if the instrument or the measuring leads show visible signs of damage, or
• if the multimeter no longer works, or
• after long periods of storage under unfavorable conditions, or
• after being subjected to rough transport, or
• if the device or the measuring leads are exposed to moisture.

In order to avoid danger,

• do not touch the bare probe tips of the measuring leads,
• insert the measurement leads in the appropriately designated measuring sockets on the digital current clamp multimeter

Cleaning:
Regularly wipe the housing by means of a dry cloth and cleaning agent. Do not use any polishing agents or solvents!

Scope of delivery

The scope of delivery for the BENNING CM 12 comprises:

1. One BENNING CM 12
2. One safety measuring lead, red (L = 1.4 m)
3. One safety measuring lead, black (L = 1.4 m)
4. One compact protection carrying case
5. Six 1.5 V micro batteries (IEC LR03/ type AAA) (integrated into the device)
6. One operating manual

Note on optional accessory:

• Flexible AC current transformer BENNING CFlex 1 (part no. 044068) Alternating current ranges: 30 A/ 300A/ 3000 A

Note on replaceable parts:

• The BENNING CM 12 is supplied by means of six integrated 1.5 V micro batteries (IEC LR03/ type AAA).
• The above-mentioned safety measuring leads (tested accessories, part no. 044145) are approved in accordance with CAT III 1000 V/ CAT IV 600 V and are approved for a current of 10 A.

Description of unit

See figure 1: Front panel

The display and operating elements are shown in Fig. 1 are as follows:

1. Measuring clamp, for clamping on the single-wire live conductor,
2. The bulge for the current clamp protects against contact with the conductor,
3. LED (red) for voltage indicator and continuity test
4. Opening lever, for opening and closing the current clamp, for activation of the measuring point illumination and LC display illumination
5. Rotary switch, for selecting the measuring function,
6. Bluetooth® keys, for activation of the Bluetooth® interface
7. RANGE key, switchover between automatic and manual measuring range
8. MODE key, for selecting the measuring function/secondary function
9. HOLD/ZERO key, measured value storage respectively ZERO for null balance (ADC)
10. Digital display, for the measurement value, bar graph, and display for over range  indication
11. Polarity indication,
12. Battery condition indicator,
13. Cursor key, menu control (up/ down/ , right/ ►, left/ ◄)
14. OK/ENTER key, selection of the function
15. COM jack, common jack for voltage/ resistance/ frequency/ capacity measurements, diode tests and continuity tests,
16. Jack (positive 1 ), for V, Ω, Hz, µF 1) This is what the automatic polarity indication for DC current and DC voltage refers to

General information of the digital current clamp multimeter

General information

1. The digital display 10 is designed as a 4-digit liquid crystal indicator with 14 mm digit height and decimal point. The highest value displayed is 9999. The display illumination switches on automatically for 15 seconds as soon as the rotary switch 5, the opening lever 4 , or any key is actuated.

2. The bar graph display consists of 60 segments.

3. The polarity indication 11 functions automatically. Only a polarity contrary to the socket definition is indicated as “-“.

4. The range overload will be displayed with “OL” or “- OL” and sometimes with an acoustic signal.
   Attention: No indication and prior warning in the event of an overload condition! An exceeding dangerous contact voltage (> 60 V DC/ 30 V AC RMS) is indicated by an additional flashing symbol „( )“.

5. The BENNING MM CM 12 confirms each button press with a signal sound. Invalid button presses are confirmed by a double signal sound.

6. The nominal measurement rate of the BENNING CM 12 is 3 measurements per second (sec) for the digital display.

7. The BENNING CM 12 is switched on and off by the rotating switch 5.
   Switch-off position “OFF”.

8. The BENNING CM 12 switches off automatically after approx. 15 minutes (APO, Auto-Power-Off).
   It switches on again if the rotary switch  5 is switched on again from switch position „OFF“.
   The switch-off can be adjusted individually in the setup menu (see section 5.1.9).

9. The BENNING CM 12 offers individual setting possibilities. To change a setting, press one of the following keys and simultaneously switch on the BENNING CM 12 from the “OFF” position.
   Cursor key 13 up/down :| Querying the software version.
   ---|---
   OK/ENTER key 14:| Switching off the APO function. “AoFF” indication.
   Cursor key 13 left ◄:| Switching off the display illumination. “LoFF” indication.
   HOLD key 9 :| Displaying all display symbols.

10. Temperature coefficient of measurement value: 0.2 x (stated measurement accuracy)/ °C < 18 °C or > 28 °C, relative to the value at the reference temperature of 23° C.

11. The BENNING CM 12 is powered by six 1.5 V micro batteries (IEC LR03/ type AAA).

12. The battery indication L continuously shows the remaining battery capacity via a maximum of three segments. When switched on, the device additionally displays the battery status “Full” (full), “HALF” (half) or “Lo” (low).
    As soon as all segments of the battery symbol have disappeared and the battery symbol is flashing, the batteries must be replaced by new ones immediately in order to prevent danger for persons due to incorrect measurements.

13. The life span of a battery is approx. 50 hours (alkali battery) (without display illumination and Bluetooth ® )

14. Appliance dimensions: (L x W x H) = 243 x 103 x 55 mm Appliance weight: 540 g with batteries

15. Largest clamp opening: 33 mm

16. The safety measuring leads supplied are expressly suited for the rated voltage and the rated current of the BENNING CM 12.

17. The BENNING CM 12 supports wireless data transmission via the Blue- tooth ® 4.0 standard to an Android or IOS device (smartphone/tablet).

AUTO SENSE mode

In the rotary switch position,  and  the AUTO SENSE mode auto- the AUTO SENSE mode auto- matically selects the correct measuring range and the coupling mode (AC or DC). Depending on which part is larger, the measured value is displayed as AC or DC value. Press the MODE key 8 to additionally select the coupling mode (AC, DC, AC+DC) and further functions directly. Press the key for approx. 2 seconds to switch the device back to the AUTO SENSE mode.

Key functions

The BENNING CM 12 confirms each button press with a signal sound. Invalid button presses are confirmed by a double signal sound.

1. Press the Bluetooth ® key 6 to activate the Bluetooth ® interface with the symbol „ “ shown on the LC display J at the same time.
2. The RANGE key 7 can be used to change over to the manual measuring ranges and to hide “AUTO” on the display at the same time. Press the key for approx. 2 seconds to activate the automatic range selection (“AUTO” on the display).
3. Press the MODE key 8 to select the secondary, third, fourth, or fifth function of the rotary switch position:
   Rotary switch position:| Secondary/ third function:| Fourth/ fifth function:
   ---|---|---
   V (AUTO SENSE)| AC/DC| AC+DC
   A (AUTO SENSE)| AC/DC| AC+DC
   W (AUTO SENSE)| AC/DC| PF/RST
   Ω| |

Press the MODE key 8 for approx. 2 seconds to select the AUTO SENSE function.

4. The HOLD/ZERO key 9 has two functions: HOLD key functions: Press the HOLD/ZERO key 9 to store the measuring result. The „HOLD“ symbol simultaneously appears on the display J. If the measured value exceeds the stored value, the change of the measured value is indicated by the display flashing and an acoustic signal. (functions ,  , , and   ). Press the key again to switch the device back to measuring mode. ZERO key  functions: For null balance in case of current measurements (function with AUTO SENSE, DC, and AC+DC). For this, remove the BENNING CM 12 from all live conductors and press the HOLD/ZERO key 9 for 2 seconds until the “ZERO” symbol is displayed briefly.
5. Press the Cursor keys M (up/ down/ , right/►, left/◄) to select the menu function on the LC display J.
6. Press the OK/ENTER key N to confirm the selected function.

Menu functions

Press the Cursor keys 13 to select the functions shown on the LC display 10. The selected function is indicated by a flashing symbol. To start a function, press the OK/ENTER key 14 and the symbol will be shown with an underscore. To exit a function, press the OK/ENTER key 14 for approx.. 2 seconds.

1. MMA function (“MAX”, “MIN” and “AVG” (average) value storage) Use the Cursor keys M to select the “MMA” function and start the measurement by pressing the OK/ENTER key 13. The function MMA automatically records and stores the highest measured value (MAX), the lowest measured value (MIN) and the average value (AVG) of a series of measurements. Press the OK/ENTER key 14 to display the corresponding value on the LC display 10. Pressing the OK/ENTER key 14 for approx. 2 seconds switches the instrument back to normal  operating mode.

2. Hz function (frequency measurements)
   Use the rotary switch 5 and the MODE key 8 to select the measuring function V AC or A AC. Use the Cursor keys M to  select the “Hz” function and start the measurement by pressing the OK/ENTER key 13. Pressing the OK/ENTER key 14 switches the instrument back to normal operating mode.

3. HFR function (high-frequency suppression)
   Use the rotary switch 5 and the MODE key 8 to select the measuring function V AC or A AC. Use the Cursor keys 13 to select the “HFR” function and start the measurement by pressing the OK/ENTER key 14. The function HFR is intended for connecting a low-pass filter (high-frequency suppression) in the V AC and A AC functions in order to filter out high-frequency pulses e. g. at pulsed motor drives. “HFR” symbol on the LC display 10. The limiting frequency (- 3 dB) of the filter is fg = 1000 Hz. When reaching the limiting frequency fg, the displayed value is lower by a factor of 0.707 than the actual value without filter. Pressing the OK/ENTER key 14 switches the nstrument back to normal operating mode.without HFR (without low-pass filter) with HFR (with low-pass filter)

   ---

In order to prevent any danger, always measure a present voltage first without low-pass filter (high-frequency suppression) to detect a dangerous voltage.

4. Function -PEAK-HOLD (peak value storage)
   Use the rotary switch 5 and the MODE key 8 to select the measuring function V AC or A AC. Use the Cursor keys 13 to select the “ “ function. Measurement function V AC:
   Start the measurement by pressing the OK/ENTER key 14.
   Measurement function A AC:
   Start the measurement by pressing the OK/ENTER key 14 for approx. 2 seconds.
   The PEAK HOLD function (peak value storage) detects and stores the “PEAK MAX”/“PEAK MIN” value on the display 10. The “Peak MAX” / “Peak MIN” value is called via the OK/ENTER key 14. Pressing the OK/ ENTER key 14 for approx. 2 seconds switches the instrument back to normal operating mode.

5. Function INRUSH (inrush current measurement)
   Use the rotary switch 5 and the MODE key 8 to select the measuring function A AC. Use the Cursor keys 13 to select the “ ” function. Start the measurement by pressing the OK/ENTER key 14. With the INRUSH function (inrush current measurement), the measuring process is initiated for 100 milliseconds after a trigger current has occurred. The determined r.m.s. value of this time period is displayed. Pressing the OK/ENTER key 14 for approx. 2 seconds switches the instrument back to normal operating mode. Trigger current: (> 1 A in the 100 A measuring range, > 10 A in the 600 A measuring range)

6. Function THD (total harmonic distortion)
   Use the rotary switch 5 and the MODE key 8 to select the measuring function V AC or A AC. Use the Cursor keys M to select the “ ” function. Start the measurement by pressing the OK/ENTER key N (display „THD“ and „rdy“). In order to assess the mains quality, it is possible to determine the total harmonic distortion (THD value in %) and the distortion of an individual harmonic h01 to h25 (%):

• up to the 25th harmonic

Data logger function “LOG”

The data logger function “LOG” allows the automatic storage of series of measurements with a predefined measuring interval and up to 9,999 measured values. The measuring interval can be set from 1 s to 600 s. For further processing, the measured values can be read out later by means of the display 10 or via Bluetooth ®
Use the Cursor key 13 to select the “LOG” function and press the OK/ENTER key 14 to open the “LOG” menu.
Use the Cursor keys 13 to select the following submenus:

SAVE+C17:D19| Press the OK/ENTER key 14 to start the data logger function “LOG”. Press the OK/ENTER key 14 again to stop the storage.
Note: Any restart will delete all measured values stored in the data logger (LOG).
---|---
LOAD| Press the OK/ENTER key 14 to open the measured values stored in the data logger. Press the Cursor keys 13 (right/►, left/◄) to call the storage location number on the display 10. Press the RANGE key 7 to toggle between the storage location number and the stored measured value. Press the OK/ ENTER key 14 to cancel the function.
RATE| Press the OK/ENTER key 14 to set the sampling rate defining the time interval between two measuring points. Use the  Cursor keys 13 (right/ ►, left/ ◄) to adjust the sampling from
1 s to 600 s. Press the OK/ENTER key 14 to confirm. The deviation of the timer is less than 3 s  er hour.

Use the Cursor key M to select the “LOG” function and press the OK/ENTER key N to leave the “LOG” menu.

Memory function “MEM”

The memory function “MEM” allows the automatic and manual storage of series of measurements with up to 1,000 measured values. For further processing, the measured values can be read out later by means of the display 10  or via Bluetooth ® .
Use the Cursor key 13 to select the “MEM” function and press the OK/ENTER key 14 to open the “MEM” menu. Use the Cursor key 13 to select the following submenus:

A-SAVE| Press the OK/ENTER key 14 to start the automatic storage of measured values “A-SAVE” for voltage and resistance measurement. As soon as a stable measured value is detected by the measuring probes of the safety measuring leads, an  acoustic signal will be emitted and the measured value will be stored in the memory
automatically. Connect the safety measuring leads to the next measuring point in order to store another measured to the memory. Press the RANGE key 7 to call the number of the stored measured values. Press the
OK/ ENTER key 14 to cancel the function. Measured values below  5 % of the final measuring range value will not be recorded. Note: Any restart will delete all measured values stored in the memory (MEM).
---|---
SAVE| Each time the OK/ENTER key N is pressed, a measured value will be stored in the memory. Press the RANGE key 7 to display the number of stored measured values and press it again to go back to the storage mode. To cancel, press the OK/ ENTER key N for approx. 2 seconds.
LOAD| Press the OK/ENTER key 14 to open the measured values stored in the memory. Press the Cursor key M  right/►, left/◄) to call the storage location number on the display J. Press the RANGE key 7 to toggle between the storage location number and the stored measured value. Press the OK/ ENTER key 14 to cancel the function.
CLR| Press the OK/ENTER key 14 to open the “CLR” mode. Press the OK/ENTER key 7 to delete all measured values stored in the memory (MEM). To cancel, press the OK/ENTER key N for approx. 2 seconds.
MMA (MAX/MIN)| The MMA function can only be called after having finished the A-SAVE function. Press the OK/ENTER key N to open the maximum value (MAX) and the minimum value (MIN) of a series of measurements. To cancel, press the OK/ENTER key 14 for approx. 2 seconds.

Use the Cursor key 13 to select the “MEM” function and press the OK/ENTER key 14 to leave the “MEM” menu.

Data transmission to the smartphone/ tablet

The BENNING CM 12 is provided with a Bluetooth® Low Energy 4.0 interface for real-time wireless transmission of measured values to an Android or IOS device. The “BENNING MM-CM Link” app required for this is available in the Google Play Store and in the Apple App Store.
The “BENNING MM-CM Link” app offers i.a. the following functions:

• Displaying of the measured values in real time and storage as csv file.
• Download of the data logger LOG (up to 9,999 measured values) and of the memory MEM (up to 1,000 measured values) from the BENNING CM 12.

To activate the Bluetooth® interface, press the Bluetooth®  key 6 at the BENNING CM 12 (symbol “ ” flashes). As soon as a Bluetooth® connection is established, the symbol “ ” is displayed permanently. Range in open space: approx. 10 m

Ambient conditions

• The BENNING CM 12 is designed only for measuring in dry surroundings,

• Maximum barometric height during measurement: 2222 m.

• Overvoltage category / setting category: IEC 60664/ IEC 61010-1 → 600 V category IV; 1000 V category III.

• Degree of contamination: 2

• Protection class: IP 30 (DIN VDE 0470-1 IEC/ EN 60529).
  IP 30 means: Protection against access to dangerous parts and protection against solid impurities of a diameter > 2.5 mm, (3 – first index). No protection against water, (0 – second index).

• Operating temperature and relative humidity:
  At operating temperatures of 0 °C to 30 °C: relative humidity under 80 %.
  At operating temperatures of 31 °C to 40 °C: relative humidity under 75 %.
  At operating temperatures of 41 °C to 50 °C: relative humidity under 45 %.

• Storage temperature: The BENNING CM 12 can be stored at temperatures from – 10 °C to + 50 °C (humidity 0 up to 80 %). The batteries must be removed from the unit.

Electrical data

Note: The measurement accuracy is stated as the sum of

• a relative proportion of the measurement value and
• a number of digits (i.e. numerical steps of the last place).

This measurement accuracy applies for a temperature of 18 °C to 28 °C and a maximum relative humidity of max. 80 %.

Voltage ranges

Overload protection: 1000 V AC/DC

Function| Measuring range| Resolution| Measurement accuracy [1]
---|---|---|---
V AC| 99.99 V
999.9 V| 10 mV
0.1 V| ± (5.0 % of measured value + 5 digits), 15 Hz – 50 Hz
± (1.0 % of measured value + 5 digits), 50 Hz – 500 Hz
V AC (HFR)| 99.99 V
999.9 V| 10 mV
0.1 V| ± (5.0 % of measured value + 5 digits), 15 Hz – 50 Hz
± (1.0 % of measured value + 5 digits), 50 Hz – 60 Hz
± (5.0 % of measured value + 5 digits), > 60 Hz – 400 Hz
V DC| 99.99 V
999.9 V| 10 mV
0.1 V| ± (0.7 % of measured value + 2 digits)
[1] V AC range below 1,000 digits plus 3 digits
V DC range below 1,000 digits plus 6 digits
Input resistance: 3.5 MΩ, < 100 pF

Additional specifications:
The measured value is obtained and displayed as a true effective value (TRUE RMS). Selectable coupling type: AC or AC+DC. For AC+DC coupling, the accuracy specifications for VAC +VDC have to be added. In the case of non-sinusshaped curves (50 Hz/ 60 Hz) the display value becomes less precise. Thus an additional error results for the following crest factors:
Crest factor from 1.4 to 2.0 additional errors + 1.0 %
Crest factor from 2.0 to 2.5 additional errors + 2.5 %
Crest factor from 2.5 to 3.0 additional errors + 4.0 %
Crest-Faktor 3 @ 460 V, 280 A
Crest-Faktor 2 @ 690 V, 420 A
HFR high-frequency suppression (low-pass filter):
Limiting frequency (- 3 dB): 1000 Hz
Attenuation: approx. – 18 dB

 PEAK-HOLD function (memory of peak value)

Measuring accuracy specified for sinusoidal curves > 5 A eff with repetitive events. Rectangular shapes of the curve are unspecified.

Current ranges

Function| Measuring range| Resolution| Measurement accuracy| Overload protection
---|---|---|---|---
A AC| 0.10 A – 99.99 A
599.9 A| 10 mA 0.1 A| ± 5.0 % + 5 digits (15 Hz – 50 Hz)
[1] ± 1.9 % + 5 digits (50 Hz – 60 Hz) [1] ± 2.4 % + 5 digits (> 60 Hz – 400 Hz) [1]| 600 Aeff
A AC (HFR)| 0.10 A – 99.99 A 599.9 A| 10 mA 0.1 A| ± 5.0 % + 5 digits (15 Hz – 50 Hz)
[1] ± 1.9 % + 5 digits (50 Hz – 60 Hz) [1]  ± 5.4 % + 5 digits (> 60 Hz – 400 Hz) [1]
A DC| 99.99 A 599.9 A| 10 mA 0.1 A| ± 1.9 % + 0.2 A ± 1.9 % + 5 digits
[1]

Measuring range below 1,000 digits: plus 5 digits Positioning error: ± 1 % of the displayed value A DC: The influence of the temperature and of the residual magnetism can be compensated by pressing the HOLD/ZERO key 9 (2 seconds). “ZERO” symbol is displayed. Additional specifications:
The measured value is obtained and displayed as a true effective value (TRUE RMS). Selectable coupling type: AC or AC+DC. For AC+DC coupling, the accuracy specifications for A AC + A DC have to be added. In the case of non- sinusshaped curves (50 Hz/ 60 Hz) the display value becomes
less precise. Thus an additional error results for the following crest factors:
Crest factor from 1.4 to 2.0 additional errors + 1.0 %
Crest factor from 2.0 to 2.5 additional errors + 2.5 %
Crest factor from 2.5 to 3.0 additional errors + 4.0 %
Crest-Faktor 3 @ 460 V, 280 A Crest-Faktor 2 @ 690 V, 420 A

PEAK-HOLD function (memory of peak value)

Measuring accuracy specified for sinusoidal curves > 5 Aeff with repetitive events. Rectangular shapes of the curve are unspecified.

 INRUSH function (inrush current measurement)

Measuring accuracy specified for sinusoidal curves (50 Hz – 60 Hz).
Average time: 100 ms
Trigger current: > 1 A eff in the 100 A measuring range, > 10 A eff in the 600 A measuring range

Resistance measuring ranges, continuity and diode testing

Overload protection: 1000 V AC/DC

Max. no-load voltage for resistance and continuity: approx. 3.0 V
Max. no-load voltage for diode: approx. 1.8 V
Max. short-circuit current: approx. 0.5 mA
The integrated buzzer sounds at a resistance R lower than 30 Ω – 100 Ω.
Buzzer response time: <100 ms

Capacity ranges

Overload protection: 1000 V AC/DC
Conditions: Capacitors discharged and connected in accordance with the polarity stated.

Frequency ranges

Overload protection: 1000 VAC/DC

Function| Measuring range| Resolution| Measurement accuracy
---|---|---|---
W AC/ W DC| 9.999 kW¹| 1 W| measuring error current x measuring value voltage

• measuring error voltage x measuring value current
  99.99 kW| 10 W
  599.9 kW| 0.1 kW
  PF| 1.00| 0.01| ± 5 digits

¹ Measuring range below 1,000 kW plus 10 digits Specified measuring accuracy for: W AC: Sinusoidal curve, V AC > 10 Veff , A AC > 5 Aeff , 50 Hz – 60 Hz, PF = 1.00

THD function (total harmonic distortion)

Function| Measuring range| Resolution| Measurement accuracy
---|---|---|---
A AC/ V AC| 99.90%| 0.10%| ± 3 % + 10 digits

Distortion of an individual harmonic

Harmonic| Measuring range| Resolution| Measurement accuracy
---|---|---|---
H01 – H12| 99.90%| 0.10%| ± 5 % + 10 digits
H13 – H25| 99.90%| 0.10%| ± 10 % + 10 digits

Indication below the minimum sensitivity (< 10 Veff , < 10 Aeff ): „rdy“ Indication outside the frequency range of the fundamental frequency (45 Hz –
65 Hz): „out.F“

Measuring input of flexible AC current transformer

digits (61 Hz – 400 Hz) [2]
PEAK-HOLD| 420.0 A/ 4200 A| ± 3 % + 80 digits (50 Hz – 500 Hz)
INRUSH| 300.0 A/ 3000 A| ± 2 % + 10 digits (50 Hz – 60 Hz)  [3]
Frequency| 99.99 Hz/ 999.9 Hz| ± 0.5 % + 3 digits (< 500 Hz)
THD| 99.90%| ± 5 % + 10 digits  [4]
H01 – H12| 99.90%| ± 5 % + 10 digits [4]

1. The measuring accuracy of the flexible current transformer BENNING CFlex 1 (item no. 044068) has not been taken into consideration.
2. Measuring range below 300 digits plus 3 digits
3. Trigger current: > 1 % of the measuring range
4. Indication below the minimum sensitivity (< 30 Aeff ): „rdy“

Measuring with the BENNING CM 12

Preparation for measuring

Store and use the BENNING CM 12 only under the correct temperature conditions stated. Always avoid longer exposure to sunlight.

• Check the rated voltage and rated current stated on the safety measuring leads. The safety measuring leads supplied with the unit are suitable for the rated voltage and current of the BENNING CM 12.
• Check the insulation of the safety measuring leads. If the insulation is damaged in any way, do not use the leads.
• Check the continuity of the safety measuring leads. If the conductor in the safety measuring lead is interrupted, do not use the leads.
• Before selecting another function with the rotating switch 5, always disconnect the safety measuring leads from the measuring point.
• Sources of strong current in the vicinity of the BENNING CM 12 may cause unstable or incorrect readings.

Voltage and current measurement

Always observe the maximum voltage to earth potential! Electrical hazard!
The maximum voltage which may be applied to the sockets,

• COM socket 15
• socket + 16

of the BENNING CM 12 to earth is 600 V CAT IV/ 1000 V CAT III.

Voltage measurement

• Use the rotary switch 5 to select the desired function and press the
  MODE key 8 to select the coupling mode at the BENNING CM 12.

• Connect the black safety measuring lead to the COM socket 15 on the BENNING CM 12.

• Connect the red safety measuring lead to the socket + 16 on the BENNING CM 12.

• Connect the safety measuring leads to the measuring points. Read the measurement value displayed in the digital display 10
  See figure 2: Direct voltage measurement
  See figure 3: Alternating voltage (frequency measurement)

Current measurement

• Use the rotary switch 5 to select the desired function and press the
  MODE key 8 to select the coupling mode at the BENNING CM 12.

• Press the null balance key ZERO 9 (2 seconds) to switch the BENNING CM 12 to the initial mode (coupling mode: DC, AC+DC).

• Operate the opening lever 4 and clamp the single-wire live conductor centrally by means of the clamp 1

• Read the measurement value displayed in the digital display 10 of the BENNING CM 12.
  See figure 4: Direct current/ Alternating current measurement (frequency measurement)

Resistance measurements

• Select the desired function  by means of the rotary switch 5 of the BENNING CM 12.
• Connect the black safety measuring lead to the COM socket 15 on the BENNING CM 12.
• Connect the red safety measuring lead to the socket + 16 on the BENNING CM 12.
• Connect the safety measuring leads to the measuring points. Read the measurement value displayed in the digital display 10.
  See figure 5: Resistance measurement/ diode test/ continuity test with buzzer

Diode tests

• Select the desired function by means of the rotary switch 5 of the  BENNING CM 12.
• Connect the black safety measuring lead to the COM socket 15 on the BENNING CM 12.
• Connect the red safety measuring lead to the socket + 16 on the BENNING CM 12.
• Connect the safety measuring leads to the measuring points. Read the measurement value displayed in the digital display 10. The display behaviour of the BENNING CM 12 has changed and depends on the serial number:

As of serial no. 91000277:

• For a typical silicone diode tested in the forward-biased direction a voltage flow between 0.400 V and 0.800 V is displayed. A display showing “000” indicates a short circuit in the diode, whereas a display showing “OL” indicates an open circuit in the diode.
• For a diode tested in the reverse-biased direction the display reads “OL”. If the diode is damaged, the display will show “000” or other values.

Up to serial no. 91000277:

• For a normal silicone diode located in flow direction, the flow voltage between 0.400 V and 0.800 V is displayed. “OL” indicates a short-circuit or an interruption inside the diode.
• For a diode applied in reverse direction, a negative forward voltage between -0.400 V and -0.800 V is indicated.

See figure 5: Resistance measurement/ diode test/ continuity test with buzzer

Continuity test with buzzer

• Select the desired function by means of the rotary switch 5 of the BENNING CM 12.
• Connect the black safety measuring lead to the COM socket 15 on the BENNING CM 12.
• Connect the red safety measuring lead to the socket + 16 on the BENNING CM 12.
• Connect the safety measuring leads to the measuring points. If the line resistance between the COM jack 15 and the jack + 16 falls below the adjustable limiting value (30 Ω to 100 Ω), the integrated buzzer of the BENNING CM 12 sounds and the red LED 3 lights up.

See figure 5: Resistance measurement/ diode test/ continuity test with buzzer

Capacity measurement

Discharge capacitors fully before measurement! Never apply voltage to the sockets for capacitance measurement as this may cause irreparable damage to the unit. A damaged unit may represent an electrical hazard!

• Select the desired function by means of the rotary switch 5 of the BENNING CM 12.
• Determine the polarity of the capacitor and discharge capacitor completely.
• Connect the black safety measuring lead to the COM socket 15 on the BENNING CM 12.
• Connect the red safety measuring lead to the socket + 16 on the BENNING CM 12.
• Contact the discharged capacitor with the safety measuring leads observing correct polarity. Read the measurement value on the digital display 10 of the BENNING CM 12. See figure 6: Capacity measurement

Frequency measurement

Select the desired function or by means of the rotary switch 5 of the BENNING CM 12.

Frequency measurement in the function:

• Connect the black safety measuring lead to the COM socket 15 on the BENNING CM 12.
• Connect the red safety measuring lead to the socket + 16 on the BENNING CM 12.
• Use the MODE key 8 to select the coupling mode “V AC”. Use the Cursor keys 13 to select the “Hz” function and confirm it by pressing the OK/ENTER key 14.
• Read the measurement value displayed in the digital display 10.

Frequency measurement in the function:

• Use the MODE key 8 to select the coupling mode “A AC”.
• Use the Cursor keys 13 to select the “Hz” function and confirm it by pressing the OK/ENTER key 14.
• Operate the opening lever 4 and clamp the single-wire conductor centrally by means of the clamp 1.
• Read the measurement value displayed in the digital display 10.
• Remember the minimum sensitivity for frequency measurements using the BENNING CM 12 according to chapter 7.5!
  See figure 3: Alternating voltage (frequency measurement)
  See figure 4: Direct current/ Alternating current measurement (frequency measurement)

Effective power measurements/ power factor measurements

• Select the desired function by means of the rotary switch 5 of the BENNING CM 12.
• Connect the black safety measuring lead to the COM socket 15 on the BENNING CM 12.
• Connect the red safety measuring lead to the socket + 16 on the BENNING CM 12.
• Connect the black safety measuring lead to the neutral conductor (N) of the supplying mains.
• Connect the red safety measuring lead to the phase (L1) of the supplying mains.
• Operate the opening lever 4 and clamp the single-wire live conductor centrally by means of the clamp 1 of the BENNING CM 12. The „+“ symbol on the clamp 1 must be directed towards the energy source.
• By means of the MODE key 8 , it is possible to switch over from effective power (W AC, W DC) to power factor (PF).
• Read the measurement value displayed in the digital display 10.

Note on effective power:
If the energy flow changes its direction (from the load in direction of the energy source), the „minus“ symbol is displayed in the digital display 10.

Note on power factor:
In case of correct polarity and if no sign is displayed, there is an inductive load. If the „minus“ sign is dislayed in the digital display 10, there is a capacitive load.

General note:
For voltages below 10 V AC/DC or currents below 5 A AC/DC, nothing is displayed. Overflow indication: “OL.U” at overflow voltage, “OL.A” at overflow current and “OL.W” at overflow effective power. Please observe figures 7b and 7c for measurements in the threephase supply network.
See figure 7a: single-phase load
See figure 7b: three-phase load without neutral conductor (N)
See figure 7c: three-phase load with neutral conductor (N)

Phase sequence indication

• Use the rotary switch 5 to select the desired function and press the MODE key 8 to select the phase sequence test (RST) at the BENNING CM 12. “RST” and “LoU” are shown on the display.

• Connect the black safety measuring lead to the COM socket 15 on the BENNING CM 12.

• Connect the red safety measuring lead to the socket + 16 on the BENNING CM 12.

• Connect the black safety measuring lead to the assumed phase L3.

• Connect the red safety measuring lead to the assumed phase L1. With normal function, „L1“ is displayed for approx. 3 seconds. [1]

• If „L2“ is displayed, the buzzer sounds twice. In this case, immediately
  bring the red safety measuring lead into contact with the assumed phase L2 while „L2“ still is indicated.

• When the „L2“ indication disappears, the test result is displayed as follows: a) „1,2,3“ indication = clockwise phase sequence, L1 in front of L2

b) „3,2,1“ indication = anti-clockwise phase sequence, L2 in front of L1
c) „—-“ indication = measurement cannot be evaluated
d) „LoU“ indication = One of the safety measuring leads has not been contacted during measurement.

Press the OK/ENTER key 14 to repeat the measurement. [1] Note:
If the voltage is < 30 V, „Lou“ is displayed, and if the voltage is > 1050 V, „OL.U“ is displayed. If the frequency is not within the range from 45 Hz
or 65 Hz, „out. F“ is displayed. The three-phase network system does not have to be earthed! See figure 8: Phase sequence indication

Current measurement with the flexible AC current transformer BENNING

CFlex 1

• Select the desired function by means of the rotary switch 5 of the BENNING CM 12.
• Connect the black safety measuring line of the BENNING CFlex 1 to the COM jack 15 at the BENNING CM 12.
• Connect the red safety measuring line of the BENNING CFlex 1 to the + jack 16 at the BENNING CM 12.
• Select the 3,000 A (1 mV/A) measuring range at the AC current transformer BENNING CFlex 1.
• Clamp the single-wire live conductor centrally by means of the flexible measuring loop 1.
• Read the measurement value displayed in the digital display 10.

See figure 9: Current measurement with the flexible AC current transformer BENNING CFlex 1

Voltage indicator (NCV)

The voltage indicator function is not intended for testing the absence of voltage. Even without an indication signal, a dangerous contact voltage might be applied. Electrical danger!

The voltage indicator function is intended for non-contact detection of an alternating field. The detector is located in the measuring clamp 1 and is active as soon as the function, or has been selected. If a phase voltage is localized, the red LED 3 lights. An indication is made in earthed AC current networks only!
Note: In the function or INRUSH, phase sequence test (RST), the voltage indicator (NCV) is not active! Practical hint: Interruptions (cable breaks) in cables lying around openly such as e.g. cable reels, fairy lights, etc. can be traced from the feeding point (phase) to the point of interruption. Functional range: ≥ 230 V See figure 10: Voltage indicator with buzzer

Maintenance

Before opening the BENNING CM 12, make sure that the device is free of voltage! Electrical danger!

Working on the opened BENNING CM 12 under voltage must be carried out by skilled electricians with special precautions for the prevention of accidents only!
Before opening the BENNING CM 12, remove it from all sources of voltage as follows:

• First remove the both safety measuring leads from the measurement points.
• Remove both safety measuring leads from the BENNING CM 12.
• Turn the rotating switch 5 to ”OFF”.

Securing the unit

Under certain circumstances, the safety of the BENNING CM 12 can no longer be guaranteed. This may be the case if:

• there are visible signs of damage on the unit,
• errors occur in measurements,
• the unit has been stored for a long period of time under the wrong conditions, and
• if the unit has been subjected to rough handling during transport.

In these cases, the BENNING CM 12 must be switched off immediately, removed from the measuring points and secured to prevent it from being used again.

Cleaning

Clean the outside of the unit with a clean dry cloth. (Exception: any type of special cleaning cloth). Never use solvents or abrasives to clean the testing unit. Ensure that the battery compartment and the battery contacts have not been contaminated by electrolyte leakage. If any electrolyte or white deposits are seen near to the battery or in the battery compartment, remove them with a dry cloth, too.

Battery replacement

Before opening the BENNING CM 12, make sure that the device is free of voltage! Electrical danger!

The BENNING CM 12 is powered by six 1.5 V micro batteries (IEC LR03/ type AAA). Battery replacement (see figure 11) is required as soon as all segments of the battery symbol 12 have disappeared and the battery symbol is flashing. Proceed as follows to replace the batteries:

• First remove the safety measuring leads from the measurement circuit.
• Remove the safety measuring leads from the BENNING CM 12.
• Turn the rotating switch 5 to “OFF”.
• Put the BENNING CM 12 face down and unscrew the four screws of the battery compartment cover.
• Lift the battery compartment cover off the bottom part.
• Remove the discharged batteries from the battery compartment.
• Insert the new batteries into the battery compartment at the provided places (please observe correct polarity of the batteries).
• Lock the battery compartment cover into place on the bottom part and tighten the screws.

See figure 11: Battery replacement

Remember the environment! Do not dispose of used batteries with domestic waste. Dispose of them at a battery-collection point or as toxic waste. Your local authority will give you the information you need.

Calibration

Benning guarantees compliance with the technical and accuracy specifications stated in the operating manual for the first 12 months after the delivery date. To maintain the specified accuracy of the measurement results, the instrument must be recalibrated at regular intervals by our factory service. We recommend a recalibration interval of one year. Send the multimeter to the following address: Benning Elektrotechnik & Elektronik GmbH & CO. KG Service Centre Robert-Bosch-Str. 20 D – 46397 Bocholt

Technical data of the measuring accessories

• Standard: EN 61010-031,
• Maximum rated voltage to earth ( ) and measuring category: With push-on caps: 1000 V CAT III, 600 V CAT IV, Without push-on caps: 1000 V CAT II,
• Maximum rated current: 10 A,
• Protective class II ( ), continuous double or reinforced insulation,
• Contamination class: 2,
• Length: 1.4 m, AWG 18,
• Environmental conditions: Maximum barometric elevation for making measurements: 2000 m, Temperatures: 0 °C to + 50 °C, humidity 50 % to 80 %
• Only use the measuring leads if in perfect and clean condition as well as according to this manual, since the protection provided could otherwise be impaired.
• Throw the measuring lead out if the insulation is damaged or if there is a break in the lead/ plug.
• Do not touch the bare contact tips of the measuring lead. Only grab the area appropriate for hands!
• Insert the angled terminals in the testing or measuring device.

Environmental notice

At the end of the product’s useful life, please dispose of it at appropriate collection points provided in your country.

Benning Elektrotechnik & Elektronik GmbH & Co. KG
D – 46397 Bocholt
Phone: +49 (0) 2871 – 93 – 0
Fax: +49 (0) 2871 – 93 – 429
www.benning.de
E-Mail: duspol@benning.de

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