BENNING CM 9 (01) PDF Document

These operating instructions are intended for skilled electricians and trained electronics personnel.

The BENNING CM 9 is intended for making measurements in a dry environment. It must not be used in power circuits with a nominal voltage higher than 300 V AC.

This symbol indicates that application around and removal from hazardous live conductors is permitted.

This is a warning of electrical danger. It indicates instructions that must be followed to avoid danger to persons.

This symbol means that the BENNING CM 9 is totally insulated, belonging to protection class II.

This symbol appears in the display to indicate a discharged battery that needs replacement.

The ground symbol indicates voltage against ground.

The BENNING CM 9 may be used only in power circuits within the overvoltage category III with a conductor for 300 V AC maximum to earth.

Before starting the appliance tester up, always check it for signs of damage. If safe operation is no longer possible, it should be shut down immediately and secured to prevent it from being switched on accidentally.

Safe operation is no longer possible if:

1. The instrument shows visible signs of damage.

2. The appliance tester no longer functions.

3. It has been stored for long periods under unfavourable conditions.

4. It has been subjected to rough transport.

5. The device is exposed to moisture.

No. Do not open the tester because it contains no components which can be repaired by the user. Repair and service must be carried out by qualified personnel only.

The scope of delivery comprises:

1. One BENNING CM 9 unit.

2. One compact protective pouch.

3. Two 1.5 V micro-batteries (type AAA/IEC LR 03) fitted in the unit.

4. One operating instructions manual.

The primary components include:

1. Measuring pliers: For clamping on current-carrying conductors.

2. Opening lever: For opening and closing the current probe.

3. Digital display: Shows measurements and status icons.

4. Range key: For selecting measuring ranges.

5. HOLD/PEAK key: For power and hold functions.

6. Wide/50-60Hz, Compare key: For filter and comparator activation.

7. Bulge of current probe: Protects against contact with the conductor.

The BENNING CM 9 features a 3 5/6-digit liquid crystal display with 12 mm high numerals and a decimal point. The largest numerical value that can be displayed is 6000.

Over-ranging is indicated by the display showing “0L”. Note that there is no other warning in the event of an overload condition.

To switch the unit on, press the HOLD/PEAK key. To switch it off, press and hold the same key for approximately 5 seconds.

The RANGE key is used to change between individual measuring ranges: 6 mA, 60 mA, 600 mA, 6 A, 60 A, and 100 A. To activate AutoRange, press and hold the RANGE key for approximately 2 seconds until “AutoRange” is shown on the display.

The Hold function stores the current measured value. Briefly press the HOLD/PEAK key to store the value. If the measured value subsequently changes by more than 50 measuring steps, the display will flash and an acoustic signal will be emitted.

PeakHold continuously stores the maximum measured value determined. Press and hold the HOLD/PEAK key for approximately 2 seconds to activate this. When PeakHold is active, the BENNING CM 9 changes to manual range mode.

If the measured value does not change within 10 measuring cycles, it is stored and “AutoHold” appears on the display. If the measured value then changes, the indicator disappears and an acoustic signal sounds.

Step 1. Ensure the BENNING CM 9 is switched off.

Step 2. Press the HOLD/PEAK key and hold it for approximately 5 seconds.

Step 3. The display will flash “AutoHold” three times and two acoustic signals will sound.

Step 4. To fully activate, switch the unit off and then back on by briefly pressing the HOLD/PEAK key.

The low-pass filter attenuates interfering signals starting at a limit frequency of 100 Hz with -24 dB/octave. It can only be activated during manual measuring range selection.

Step 1. Press and hold the Wide/50-60Hz, Compare key for approximately 3 seconds to activate the comparator. “Compare” will appear on the display.

Step 2. Use the RANGE key to scroll through the stored limiting values: 0.25 mA, 0.5 mA, and 3.5 mA.

Step 3. Confirm the selection by pressing the Wide/50-60Hz, Compare key again.

If the measured value exceeds the selected limit, the internal buzzer sounds and the display flashes.

APO stands for Auto-Power-Off. The BENNING CM 9 switches off automatically after approximately 20 minutes of inactivity. A buzzer tone signals the automatic shutdown.

When switching on the unit, press and hold the HOLD/PEAK key for more than 3 seconds to deactivate the automatic switch off.

A brightness sensor is located behind the AUTO BACKLIT window. As soon as the ambient light decreases, the background lighting switches on automatically.

The unit is designed for the following conditions:

1. Maximum barometric elevation: 2000 m.

2. Contamination class: 2.

3. Protection Class: IP 40 (protected against objects > 1 mm, no protection against water).

4. Operating Temperature: 0 °C to 30 °C (humidity < 80%), 31 °C to 40 °C (humidity < 75%), or 41 °C to 50 °C (humidity < 45%).

Overload protection for all ranges is 300 Veff.

Dimensions: 205 mm (L) x 75 mm (W) x 40 mm (H).

Weight: 270 g.

Largest opening of pliers: 43 mm.

Largest cable diameter: 40 mm.

Clean the casing externally with a clean dry cloth. Avoid using solvents or scouring agents. Ensure the battery compartment and contacts are not contaminated by leaking electrolyte.

Step 1. Switch the BENNING CM 9 off.

Step 2. Place the unit face down and unscrew the screw on the battery compartment cover.

Step 3. Lift off the battery compartment cover from the bottom part.

Step 4. Remove the discharged batteries.

Step 5. Insert two new 1.5 V micro batteries (type AAA) observing correct polarity.

Step 6. Lock the cover back into place and tighten the screw.

To maintain specified precision, it is recommended that the instrument be recalibrated by the factory service at regular intervals of one year.

The BENNING CM 9 can perform:

1. Leakage current measurement at the ground conductor.

2. Differential current measurement at single-phase systems.

3. Leakage current measurement via ground conductor for three-phase supply.

4. Differential current measurement for loads supplied in three-phase (with or without N-type conductor).

The stated precision is specified for conductors that are centrally clamped by the measuring pliers. If a conductor is not centrally clamped, an additional error of 1% of the display value must be taken into account.

The nominal measuring rate is 5 measurements per second.

Enclose both the phase conductor (L) and the neutral conductor (N) within the measuring pliers. The display will show the differential (leakage) current.

The influence of a magnetic field from parallel lines is typically 0.002%.

Before opening the BENNING CM 9, you must make quite sure that the device is voltage-free to avoid electrical danger.

For temperatures below 18 °C or above 28 °C, the coefficient is 0.2 x (stated measuring precision) per °C, related to the value at the reference temperature of 23 °C.

If the device is exposed to moisture, it may be assumed that safe operation is no longer possible. It should be shut down and secured against accidental use.

Measuring precision is specified as the sum of a relative fraction of the measured value and a number of digits (counting steps of the least significant digit).

This key has two functions: it activates/deactivates the low-pass filter (short press) and activates the comparator function (press for 3 seconds).

The active filter covers the 50 Hz to 100 Hz range and attenuates signals above 100 Hz.

Yes, a battery test is performed automatically every time the BENNING CM 9 is switched on.

Enclose a single current-carrying conductor with the measuring pliers. Ensure it is centrally positioned for maximum precision.

The filter damping characteristic is -24 dB/octave.

The filter limit frequency is 100 Hz.

Yes, but you must be extremely careful. Contact with live bare conductors will cause an electric shock.

If the battery voltage drops below 2 V, a battery symbol appears in the display and the batteries must be replaced immediately to prevent wrong measured values.

The unit requires two 1.5 V micro batteries, type AAA (IEC LR 03).

For storage, the batteries should be taken out of the instrument. It can be stored in temperatures ranging from -20 °C to +60 °C with relative humidity from 0 to 80%.

The storage temperature range is -20 °C to +60 °C.

The measuring accuracy is specified for a sinusoidal curve only. The measured value is obtained by mean value rectification and displayed as an r.m.s. value.