Benning CM 7 Operating and installation instructions

BENNING
CM7 Electrical Tester
Service Information

i
TABLE OF CONTENTS Page
Introduction 1
Precautions and Safety Information 1
Symbols 1
Safety 2
Specifications 3
General Specification 3
Voltage Specification 4
Resistance & Continuity Specification 4
Current Specification 5
Frequency Specification 5
Physical and environment characteristics 7
Certification and compliance 7
Required Equipment 8
Basic Maintenance 9
Opening the Meter Case 9
Replacing the Battery 9
Performance Tests 10
Testing the Voltage Function 10
Testing the Resistance Function 11
Testing the AC Current Function 12
Testing the DC Current Function 12
Testing the Hz Function 13
Calibration 14
Calibrating DCV, ACV, ACA Functions 14

1
Introduction
Warning
To avoid shock or injury, do not perform the verification tests or calibration procedures
described in the manual unless you are qualified to do so.
The information provided in this document is for the use of qualified personnel only.
Caution
The CM7 contain parts that can be damaged by static discharge.
Follow the standard practices for handling static sensitive devices.
For additional information about BENNING GMBH & CO. KG. and its products, and
services, visit BENNING GMBH & CO. KG. web site at:
www.benning.de
Precautions and Safety Information
Use the Meter only as described in the Service Manual. If you do not do so, the protection provided
by the Meter may be impaired. Read the “Safety Information” page before servicing this product.
In this manual, a Warning identifies conditions and actions that pose hazard (s) to the user; a
Caution identifies conditions and actions that may damage the Meter or the test instruments.
The Symbols
The symbols used on the Meter and in this manual are explained in Table 1.
Table A. The Symbols
Risk of electric shock
See instruction card
DC measurement
Equipment protected by double or reinforced
insulation
Battery
Earth
AC measurement
Conforms to EU directives

2
SAFETY
Review the following safety precautions to avoid injury and prevent damage to this product or
products connected to it. To avoid potential hazards, use the product only as specified.
CAUTION: These statements identify conditions or practices that could result in damage to
the equipment or other property.
WARNING: These statements identify conditions or practices that could result in personal
injury or loss of life.
Specific precautions
Do not operate without covers. To avoid personal injury, do not apply any voltage or current to
the product without covers in place.
Electric overload. Never apply a voltage to a connector on the product that is outside the range
specified for that connector.
Avoid electric shock. To avoid injury or loss of life, do not connect or disconnect probes or test
leads while they are connected to a voltage source.
Do not operate in wet/damp conditions. To avoid electric shock, do not operate this product in
wet or damp conditions.

3
SPECIFICATIONS
All specifications are warranted unless noted typical and apply to the CM7.
Stated accuracies are at 23°C±5°C at than 80% relative humidity and without the battery
indicator displayed.
General specifications
Characteristics Description
Display count 3 3/4
Numeric update rate 1.5 times / sec
Polarity display Automatic
Overrange display “OL” is display
Low voltage indicator is indicated
Automatic power-off time Automatic backslit off = 30 minutes
Power source One 9V battery
Maximum input voltage 600V CAT Ⅳbetween V and COM
Maximum floating voltage 600V CAT Ⅳbetween any terminal and earth
V connector V, V, , 
Temperature Coefficient 0.2×(Spec. Accuracy) / °C, <18°C or >28°C
Battery Life 100 hours typical (Alkaline)

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3
Measurement Characteristics
Accuracy is ±(% reading + number of digits) at 23°C ± 5°C, less than 80% R.H.
Temperature coefficient: 0.2 × (Specified accuracy) /°C, <18°C, >28°C
Operating temperature: 0°C ～30°C (≦80% RH)
30°C ～40°C (≦75% RH)
40°C ～50°C (≦45% RH)
(1) AC Volts: Auto-ranging
Range Resolution Accuracy Over voltage
protection
400.0V 100mV
750V 1V
±(1.0% reading + 5 digits) 50Hz ～500Hz 750V rms
Input Impedance：≧1M// less than 100pF.
AC Conversion Type: Reading less Full Scale 15% add 4 dgt.
AC Conversions are ac-coupled, true rms responding, calibrated to the rms
value of a sine wave input. Accuracies are given for sine wave at full scale and
non-sine wave below half scale. For non-sine wave add the following Crest
Factor corrections:
For Crest Factor of 1.4 to 2.0, add 1.0% to accuracy.
For Crest Factor of 2.0 to 2.5, add 2.5% to accuracy.
For Crest Factor of 2.5 to 3.0, add 4.0% to accuracy.
CF 2 @ 600V
1.5 @ 750V
(2) DC Volts: Auto-ranging
Range Resolution Accuracy Over voltage
protection
400.0V 100mV
1000V 1V ±(0.7% reading + 2 digits) 1000V rms
Input Impedance：≧1M
(3) Resistance Auto-ranging
Range Resolution Accuracy Over voltage
protection
400.0100m±(1.0% reading + 3 digits) 600V rms
Continuity: Built-in buzzer sound when resistance is less than 30approximately.

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(4) Frequency: Hz
Range Resolution Accuracy Over voltage
protection
20Hz ～400Hz 1Hz ±(0.1% reading + 2 digits) AC/DC 1000A
for 1 min.
Min. Input Frequency：20Hz
Sensitivity: 3A rms for ACA (A～)(>400Hz Unspecified)
(5) ACA: Auto-ranging
Range Resolution Accuracy Frequency
Response
Overload
protection
0A ～200.0A 0.1A ±(1.9% reading + 3 Amp)
200.0A ～400.0A 0.1A ±(1.9% reading + 2 Amp) 50Hz ～400Hz
400A ～1000A 1A ±(2.9% reading + 5 Amp) 50Hz ～200Hz
1000A rms
Operating Temperature: 0℃to 30℃(≦80%RH), 30℃to 50℃(≦75%RH)
AC Conversion Type: Reading less Full Scale 15% add 4 dgt.
AC Conversions are ac-coupled, true rms responding, calibrated to the rms
value of a sine wave input. Accuracies are given for sine wave at full scale and
non-sine wave below half scale. For non-sine wave add the following Crest
Factor corrections:
For Crest Factor of 1.4 to 2.0, add 1.0% to accuracy.
For Crest Factor of 2.0 to 2.5, add 2.5% to accuracy.
For Crest Factor of 2.5 to 3.0, add 4.0% to accuracy.
CF 2 @ 600V
1.5 @ 750V
(6) DCA:
Range Resolution Accuracy Over voltage
protection
0A ～200.0A ±(2.9% reading + 3 Amp)
200A ～400.0A 0.1A ±(1.9% reading + 2 Amp)
400A ～1000A 1A ±(2.9% reading + 5 Amp)
AC 1000A
for 1 min.
Additional error according to remanence: 1% max. of current crest.

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(7) Auto Power Off (APO)
The meter will automatically shut itself off after approximately 30 minutes after power on.
(8) Peak Hold: ±(3% reading +20 digits)
* >750V Unspecified.
* >800A Unspecified.
(9) Min/Max Hold: Add ± 15 dgt to accuracy for ACA.
Add ± 15 dgt and add remanence to accuracy for DCA.
*Automatically switch to the low resolution range at Peak Hold and Min/Max Hold.

7
Physical and Environmental Characteristics
Characteristics Description
Dimensions (H×W×D) 51mm×90mm×275mm
Weight (with battery) 420g
Environmental characteristics Description
Temperature operating 0 to +50°C
Non-Operating -20 to +60°C
Humidity (operating) <80% R.H.
Altitude Operating 2,000M (6560 ft.)
Non-Operating 12,300M (40354 ft.)
Vibration & shock Operating
MIL-T-28800E TYPE II Class 5
3gRMS, 5 to 55 Hz, 3axes
(10 minutes each)
Indoor Use Indoor Use
Certifications and compliances
Safety IEC 61010-1 600V CAT Ⅳ
Input rating V / : Category Ⅳ600 Volts
CAT Ⅳ: Equipment of OVERVOLTAGE CATRGORY Ⅳis for
use at the origin of the installations. Note examples
include electricity meters and primary over-current
protection equipment.
CAT Ⅲ: Distribution level mains, fixed installation.
CAT Ⅱ: Local level mains, appliances, portable equipment
Over voltage category
CAT Ⅰ: Signal level, special equipment or parts of equipment,
telecommunication, electronics.
Pollution Degree 2 Do not operate in environments where conductive
Pollutants may be present.
EC Declaration
of Conformity
Meets the intent of Directive 89/336/EEC for Electromagnetic
Compatibility and Low Voltage Directive 73/23/EEC for specifica -
tions as listed in the official Journal of the European Communites:
En 55011 Class A: Radiated and Conducted
Emissions.
En 50082-1 Immunity: IEC 801-2 Electrostatic Discharge
IEC 801-3 RF Radiated
En 61010-1 Safety requirements for electrical equipment for
measurement, control, and laboratory use.

8
Required Equipment
Required equipment is listed in Table B. If the recommended models are not available, equipment
with equivalent specifications may be used.
Repairs or servicing should be performed only by qualified personnel.
Table B. Required Equipment
Equipment Required Characteristics Recommended Model
Calibrator AC Voltage Range: 0 ～750V AC
Accuracy: ±0.07% (Basic)
Frequency Range: 40 ～1KHz
Accuracy: ±2%
DC Voltage Range: 0 ～1000V DC
Accuracy: ±0.006% (Basic)
Current Range: 0 ～10A
Accuracy: AC (40Hz to 1KHz): ±0.08% (Basic)
DC: ±0.02% (Basic)
Frequency Source: 5.00Hz ～100MHz
Accuracy: ±0.001%
Amplitude: 0.5V p-p ～1.0V p-p (square wave)
Accuracy: ±5%
Resistance Range: 1～100M
Accuracy: ±0.03% (Basic)
Fluke 5500 or Wavetek
9100 Calibrator or
equipment

9
Basic Maintenance
Warning
To avoid shock, remove the test leads and any input signals before opening the case or
replacing the battery.
Opening the Meter Case
Caution
To avoid unintentional shock circuit, always place the uncovered Meter assembly on a protective
surface. When the case of the Meter is open, circuit connections are exposed.
To open the Meter case, and do the following:
1. Disconnect test leads from any live source, push the bottom the rotary to OFF.
2. Remove the battery door by using a flat-blade screwdriver to turn the battery door screws turn
counter-clockwise.
3. The case bottom is secured to the case top by two screws. Using a Phillips-had screwdriver,
remove the two screws.
Replacing the Battery
The Meter powered by 9V battery for CM7.
To replace the battery refer to figure.

10
Performance Tests
The following performance tests verify the complete operability of the Meter and check the
accuracy of each Meter function against the Meter’s specifications.
Accuracy specifications are valid for a period of one year after calibration, when measured at an
operating temperature of 18°C to 28°C and a maximum of 80% relative humidity.
To perform the following tests, it is not necessary to open the case, no Adjustments are
necessary, merely make the required connections, apply the designated inputs, determine if the
reading on the Meter display falls within the acceptable range indicated.
If the Meter fails any of these tests, it needs calibration adjustment or repair.
Testing the voltage Function
To verify accuracy in the AC and DC voltage ranges, do the following:
1. Turn the rotary switch to “V” position.
2. Connect the Calibrator to the VΩand COM inputs on the Meter.
3. Set the Calibrator for the voltage and frequency from step 1 to 4 in Table 1.
4. Compare the reading on the Meter display with the display reading shown in Table 1.
5. If the display reading falls outside of the range shown in Table 1, the Meter does not meet
specification.
Table 1 AC Voltage Test:
Step Input Frequency Reading
1 390.0V 50Hz 385.6 to 394.4
2 390.0V 500Hz 385.6 to 394.4
3 750V 50Hz 737 to 763
4 750V 500Hz 737 to 763

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6. Turn the rotary switch to “V” position.
7. Set the calibration for the voltage from step 1 to 4 in Table 2.
8. Compare the reading on the Meter display with the display reading shown in Table 2.
9. If the display reading falls outside of the range shown in Table 2, the meter does not meet
specification.
Table 2 DC Voltage Test:
Step Input Reading
1 390.0V 387.1 to 392.9
2 -390.0V -387.1 to –392.9
3 1000V 991 to 1009
4 -1000V -991 to –1009
Testing the Resistance Function
To verify the accuracy of the resistance function, do the following:
1. Connect the calibrator to VΩand COM on the Meter.
2. Turn the rotary switch to .
3. Apply the inputs for step 1 in Table 3.
4. Compare the Meter display readings to the display readings in Table 3.
5. If the display reading falls outside of the range shown in Table 3, the Meter does not meet
specification.
Table 3 Resistance Test:
Step Source Reading
1 380.0375.9 to 384.1
Continuity check: Internal sounds activates if the resistance of the circuit under test is less the
30.

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Testing the AC Current Function
To verify the accuracy of AC current measurement functions, do the following:
1. Using jaw of the meter around the suitable wire or conductor.
2. Turn the rotary switch to A.
3. Apply the inputs for steps 1-2 in Table 4.
4. For each input, compare the readings on the Meter display to the reading in Table 4.
5. If the display reading falls outside of the range shown in the Table 4, the meter does meet
specification.
Table 4 AC Current Test:
Step Source Frequency Reading
1 380.0A 50Hz to 400Hz 370.8 to 389.2
3 1000A 50Hz to 200Hz 966 to 1034
Testing the DC Current Function
To verify the accuracy of DC current measurement functions, do the following:
1. Using jaw of the meter around the suitable wire or conductor.
2. Turn the rotary switch to A.
3. Apply the inputs for steps 1-2 in Table 5.
4. For each input, compare the readings on the Meter display to the reading in Table 5.
5. If the display reading falls outside of the range shown in the Table 5, the meter does meet
specification.
Table 5 DC Current Test:
Step Source Reading
1 380.0A 370.8 to 389.2
2 1000A 966 to 1034

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Testing the Hz Function
To verify the accuracy of Hz current measurement functions, do the following:
1. Using jaw of the meter around the suitable wire or conductor.
2. Turn the rotary switch to Hz.
3. Apply the inputs for steps 1-2 in Table 6.
4. For each input, compare the readings on the Meter display to the reading in Table 6.
5. If the display reading falls outside of the range shown in the Table 6, the meter does meet
specification.
Table 6 Hz Current Test:
Step Source Reading
1 0.020KHz 0.018 to 0.022
2 0.400KHz 0.398 to 0.402

14
Calibration Procedure
Recalibrate your meter:
It is recommended that the meter may be calibrated once year. Use the following procedure to
calibrate the clamp meter.
1. Perform calibration at an ambient temperature and a relative humidity (23ºC±2ºC and RH≦
80% ). Allow instrument to sit at this temperature for at least thirty minutes.
2. Disconnect the test leads and turn the meter off. Remove the test leads from the front
terminals.
3. Position the meter face down. Remove the front screw and back screw from the case
bottom.
4. Lift the case bottom from the circuit board. Do not remove the screw from the circuit board.
(A) DCV Calibration (Adjust VR1)
1. Set the clamp meter at DCV function.
2. Set the output of DC calibrator for 300V±0.02% and connect to V-and COM input terminals
on clamp meter.
3. Using a small flat-tipped screwdriver adjust the potentiometer VR1 until the display reads
300.0 or 300.1.
4. Disconnect the DC calibrator for from the clamp meter.
(B) ACV Calibration (Adjust VR2)
1. Set the clamp meter at ACV function.
2. Set the output of AC calibrator for 300V±0.02% 50Hz and connect to V-and COM input
terminals on clamp meter.
3. Using a small flat-tipped screwdriver adjust the potentiometer VR2 until the display reads
299.9 or 300.1.
4. Disconnect the DC calibrator for from the clamp meter.
(C) Position Error Calibration (Adjust VR101)
1. Set the clamp meter at DCA function.
2. Flow the current of AC 100A/50Hz around the suitable wire or conductor.
3. Open spring-loaded clamp pressing trigger on the right side of instrument.
4. Position clamp around wire or conductor and release trigger to make sure the clamp is
entirely closed.
5. Using a small flat-tipped screwdriver adjust the VR101 until the error is limited under 0.2%
while position the.
6. Disconnect the clamp from the wire on conductor.
(D) DCA Zero Calibration (Adjust VR102, VR105)
1. Set the clamp meter at DCA function.
2. Using a small flat-tipped screwdriver adjust the VR102 until the display shows 0.0±20 digits.
3. Using a small flat-tipped screwdriver adjust the VR105 until the display shows 0.0±2 digits.

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(E) AC 400A Range Calibration (Adjust VR104)
1. Set the clamp meter at ACA function.
2. Flow the current of AC 360A±0.02%/50Hz around the suitable wire or conductor.
3. Position clamp around wire or conductor and release trigger to make sure the clamp is
entirely closed.
4. Reposition the clamp to make the wire or conductor is in the center of the clamp.
5. Using a small flat-tipped screwdriver adjust the potentiometer VR104 until the display reads
367.0 or 367.2.
6. Disconnect the clamp from the wire on conductor.
(F) AC 1000A Range Calibration (Adjust VR103)
1. Set the clamp meter at ACA function.
2. Flow the current of AC 700A±0.02%/50Hz around the suitable wire or conductor.
3. Position clamp around wire or conductor and release trigger to make sure the clamp is
entirely closed.
4. Reposition the clamp to make the wire or conductor is in the center of the clamp.
5. Using a small flat-tipped screwdriver adjust the potentiometer VR103 until the display reads
699 or 701.
6. Disconnect the clamp from the wire on conductor.