Clarke CDM90 Installation and operation manual

OPERATING & MAINTENANCE
INSTRUCTIONS
GC0111
PROFESSIONAL DIGITAL CLAMPMETER
- 6 FUNCTION
MODEL No: CDM90
Part No: 4500097

2
INTRODUCTION
Thank you for purchasing this CLARKE CDM90 Digital Clampmeter.
Please read this manual thoroughly and follow the instructions carefully, in
doing so you will ensure that operations are carried out in complete safety
and you can look forward to the product giving you long and satisfactory
service.
GUARANTEE
This CLARKE product is guaranteed against faulty manufacture for a period
of 12 months from the date of purchase. Please keep your receipt as proof
of purchase. This guarantee is invalid if the product is found to have been
abused or tampered with in any way, or not used for its intended purpose.
Faulty goods should be returned to their place of purchase, no product can
be returned to us without prior permission.
This guarantee does not effect your statutory rights.
Specification
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3
CONTENTS
SAFETY INFORMATION ................................................ 4
Preliminary ........................................................................................................ 4
During Use ......................................................................................................... 4
Symbols .............................................................................................................. 5
DESCRIPTION .............................................................. 6
Components of the Meter ........................................................................ 7
The LCD (Liquid Crystal Display) .............................................................. 8
OPERATION INSTRUCTIONS ........................................... 9
Holding Readings ........................................................................................... 9
Backlight ............................................................................................................ 9
Measuring AC Current ................................................................................. 10
Measuring AC Voltage ............................................................................ ... 10
Measuring DC Voltage ................................................................................ 11
Measuring Resistance ................................................................................... 12
Testing Diodes .................................................................................................. 12
Continuity Testing ........................................................................................... 13
MAINTENANCE ............................................................ 14
General Care ................................................................................................... 14
Replacing the Battery .................................................................................. 14
Replacing Test Leads ...................................................................................... 14
Calibration ......................................................................................................... 14
DECLARATION OF CONFORMITY ..................................... 15

4
SAFETY INFORMATION
WARNING
Take care when using this meter. Improper use can result in electric shock
or damage to the meter. Take all normal safety precautions and follow the
safeguards suggested in this manual.
PRELIMINARY
1. When using the meter, the user must observe all normal safety rules
concerning:
General protection against electric shock
Protection of the meter against misuse.
2. When the meter is delivered, confirm it has not been damaged in
transit.
3. Before using, check that the insulation on the test leads has not been
damaged or any wire exposed.
4. Use only the test leads supplied to ensure operational safety. If
necessary, they must be replaced with test leads of the same model or
class.
DURING USE
1. Do not take measurements that exceed the maximum values for this
meter.
2 . Do not touch the metal probes of the test leads when the meter is
connected to the circuit being measured.
3. Keep your fingers behind the probe barriers when taking
measurements.
4. Do not take voltage measurements if you suspect the value exceeds
1000V.
5. If the appropriate value range is unknown select the highest range on
the scale.
6. Disconnect the test leads from the circuit under test before turning the
rotary function selector.
7. Do not measure the resistance, diode or continuity of live circuits.
8. Never touch exposed wiring, connections or any live circuit while
taking any measurements.
9. Do not use the meter near explosive gases or steam.

5
10. Stop using the meter if any abnormalities or faults are observed.
11. Do not use the meter unless its rear case and battery cover are
correctly and securely fastened.
12. Do not store or use the meter in areas exposed to direct sunlight, at
high temperature or with high relative humidity.
13. To avoid false readings, replace the battery as soon as the Low
Battery indicator appears.
14. Before use, verify the meter operation by measuring a known voltage.
15. Keep your body isolated from ground by using dry clothing, rubber
shoes, rubber mats or any approved insulating material.
SYMBOLS
Caution, risk of danger.
Beware electrical hazards.
Double insulation ( Protection class II).
Conforms to the European Union Directive
Earth (ground) terminal

6
DESCRIPTION
This meter is a portable, professional, measuring instrument with a Liquid
Crystal Display (LCD) and back light for easily reading.
The meter can perform measurements of AC current, AC/DC voltage, as
well as resistance, continuity and diode testing.

7
COMPONENTS OF THE METER
1. Moving Jaw Measures AC current flowing through the
conductor
2. HOLD Button When this button is pressed, the display will keep
the last reading and “H” symbol will appear on
the LCD until the button is pressed again.
3. Rotary Selector Used to select functions and ranges.
4. Light Button Press this and the backlight display will come on.
After approx 4-6 seconds the light will
automatically turn off.
5. (LCD) Liquid Crystal Display.
6. ‘V’ Jack This is the positive input terminal for measuring
Voltage. Connection is made using the red lead.
7. COM Jack This is the negative (ground) input terminal for all
measurement modes except current.
Connection is made to it using the black lead.
8. Ω Jack This is the positive input terminal for ohms and
diode measurement. Connection is made using
the red lead.
9. On/Off Button Used to turn the meter on/off.
10. Trigger Used to open the jaws.

8
THE LCD (Liquid Crystal Display)
AC Alternating current
DC Direct current
Diode test
Continuity buzzer
Battery low
HThis indicates that the display data is being held.
VVoltage
AAmperes (Current)
Ω, kΩ, MΩOhms, Kilo-ohms, Mega-ohms (Resistance)
O
C Outside recommended working temperature range
Voltage or current should not exceed the specified value
kHz Kilohertz (Frequency)

9
OPERATION INSTRUCTIONS
1. Switch on the power by pressing the ON/OFF button.
2. Turn the rotary selector to the required function and range to be
measured. Choose the highest range when the value of the voltage or
current to be measured is unknown.
3. Connect the black earth test lead before the red positive test lead
when making the connection. Remove the positive test lead first when
disconnecting.
HOLDING READINGS
1. Press the HOLD button while taking measurements.
• The value on the display will be held.
2. Press the HOLD button again to release the function.
THE BACK LIGHT
1. Press the LIGHT button to switch on the back light if the natural light in
the environment is too dim for taking readings.
• The backlight will turn off automatically after 6 seconds.
NOTE:
•Frequent use of the back light will shorten the life of the battery
and therefore should not be used unnecessarily.
Low Battery Indicator
When the battery voltage falls too low, the Low Battery symbol, will
appear on the LCD. The accuracy of measurement cannot be assured
when the symbol appears.
NOTE:
•When the back light is on, the low battery symbol may appear
due to the greater working current causing the voltage to drop. In
this case, there is no need to replace the battery until the Low
Battery symbol appears when the back light is not being used.

10
MEASURING AC CURRENT
Ensure the test leads are disconnected from the meter before making
current clamp measurements.
1. Set the rotary selector to the A range position.
2. Squeeze the trigger to open the jaw. Fully enclose only one
conductor.
3. Take the reading showing on the LCD.
NOTE:
•If the figure “1” is displayed, this indicates the current has
exceeded the maximum value allowed in the range, and a higher
range should be selected.
• For accurate results, only enclose one conductor in the jaws.
• For optimum results, centre the conductor in the jaws.
• Overload protection: 1200A for 60 seconds maximum
• Frequency range: 50 to 60Hz
MEASURING AC VOLTAGE
Pay special attention to avoid electric shock if measuring high voltages.
Do not connect to a voltage of more than 750V rms AC.
1. Plug the black test lead into the COM jack and red test lead into the
V~ jack.
2. Set the rotary selector to the 750V~ position.
3. Connect the test leads to the voltage source being measured.
4. Note the reading on the LCD.
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