CEM DT-337 User manual

OPERATING INSTRUCTION
DC/AC CLAMP METER

1
Safety
International Safety Symbols
This symbol, adjacent to another symbol or
terminal, indicates the user must refer to the
manual for further information.
This symbol, adjacent to a terminal, indicates that,
under normal use, hazardous voltages may be
present
Double insulation
SAFETY NOTES
•Do not exceed the maximum allowable input range of
any function
•Do not apply voltage to meter when resistance function
is selected.
•Set the function switch OFF when the meter is not in
use.
WARNINGS
•Set function switch to the appropriate position before
measuring.
•When measuring volts do not switch to
current/resistance modes.
•Do not measure current on a circuit whose voltage
exceeds 240V.
•When changing ranges using the selector switch always
disconnect the test leads from the circuit under test.
•Do not exceed the maximum rated input limits.

2
CAUTIONS
Improper use of this meter can cause damage, shock, injury
or death. Read and understand this user manual before
operating the meter.
Always remove the test leads before replacing the battery.
Inspect the condition of the test leads and the meter itself for
any damage before operating the meter. Repair or replace
any damage before use.
Use great care when making measurements if the voltages
are greater than 25VAC rms or 35VDC. These voltages are
considered a shock hazard.
Remove the battery if the meter is to be stored for long
periods.
Always discharge capacitors and remove power from the
device under test before performing Diode, Resistance or
Continuity tests.
•Voltage checks on electrical outlets can be difficult and
misleading because of the uncertainty of connection to the
recessed electrical contacts. Other means should be used
to ensure that the terminals are not "live".
•If the equipment is used in a manner not specified by the
manufacturer, the protection provided by the equipment may
be impaired.
Input Limits
Function
Maximum Input
A AC, A DC
80A
V DC, V AC
600V DC/AC
Resistance, Diode, Continuity,
Frequency, Duty Cycle,
Capacitance Test,
250V DC/AC

3
n
u
Meter Description
1. Current clamp
2. Clamp trigger
3. Safety protection ring
4. ZERO button
5. Data Hold and Backlight button
6. Mode select button
7. Range select button
8. Hz/%duty button
9. Rotary Function swith
10. LCD display
11. COM input jack
12. V ΩHz/% jack
13. Battery Cover
1. AC DC AC (alternating current)
and DC (direct currrent)
2. Minus sign
3. 8.8.8.8 4000 count (0 to 3999)
measurement reading
4. AUTO AutoRange mode
5. ZERO ZERO mode
6. Diode test mode
7. •))) Audible Continuity
8. HOLD Data Hold mode
9.
℃
,
℉
,m,V,A,K,M,
Ω
,Units of measure list

4
Specifications
Function
Range &
Resolution
Accuracy (% of reading)
DC Current
4.000 A DC
± (2.8% + 10 digits)
80.0 A DC
± (3% + 8 digits)
AC Current
(50/60Hz)
4.000 A AC
± (3.0% +10digits)
80.0A AC
± (3.0% + 8 digits)
DC Voltage
400.0 mV DC
± (1.0% + 15 digits)
4.000 V DC
± (
1.0
% + 3 digits)
40.00 V DC
± (1.5% + 3 digits)
400.0 V DC
600 V DC
± (2.0% + 3 digits)
AC Voltage
(50/60Hz)
400.0 mV AC
± (1.0% + 30 digits)
4.000 V AC
± (2.0% + 5 digits)
40.00 V AC
400.0 V AC
600 V AC
± (2.0% + 5 digits)
Resistance
400.0 Ω
± (1.0% + 4 digits)
4.000KΩ
± (1.5% + 2 digits)
40.00KΩ
400.0KΩ
4.000MΩ
± (2.5% + 3 digits)
40.00MΩ
± (3.5% + 5 digits)
Capacitance
40.00nF
±(5.0% reading + 30digits)
400.0nF
±(3.0% reading + 5 digits)
4.000μF
±(3.5% reading + 5 digits)
40.00μF
100.0μF
±(5.0% reading + 5 digits)
Frequency
5.000Hz
±
(1.5% reading + 5 digits)
50.00Hz
±(1.2% reading + 2 digits)

5
500.0Hz
Sensitivity: 10Vrms min.
@ 20% to 80% duty cycle
5.000kHz
50.00kHz
500.0kHz
5.000MHz
10.00MHz
Duty Cycle
0.5 to 99.0%
±(1.2% reading + 2
digits)
Pulse width: 100µs - 100ms, Frequency: 5Hz
to 150kHz;
Sensitivity: 10Vrms min.
Analog output: (for ACA & DCA range), 10mV/Amp (20KHz
at ±3dB)
Accuracy: ±( 4.5% reading + 1mV )
Output impedance: approx 3KΩ

6
Clamp size Opening 0.9" (23mm) approx
Diode Test Test current of 0.3mA typical;
Open circuit voltage 1.5V DC
typical.
Continuity Check Threshold <150Ω; Test
current< 1mA
Low Battery Indication “ ” is displayed
Overrange Indication “OL” is displayed
Measurements Rate 2 per second, nominal
Input Impedance 7.8MΩ(VDC and VAC)
Display 4000 counts LCD
Operating Temperature 14 to 122oF (-10 to 50oC)
Storage Temperature -22 to 140oF (-30 to 60oC)
Relative Humidity 90%(0oC to 30oC); 75%(30oC
to 40oC); 45%(40oC to 50oC)
Altitude Operating: 3000m; Storage 10,000m
Over voltage Category III 600V
Battery Two 1.5V “AAA” Batteries
Auto OFF approx. 25 minutes
Dimensions/Weight 200x50x35mm/200g
Safety For indoor use and in
accordance with Overvoltage
Category II, Pollution Degree
2. Category II includes local
level, appliance, portable
equipment, etc., with transient
overvoltages less than
Overvoltage Cat. III

7
600V
V
%Hz/
600V
Hz/%
V
80A
AC
4A
V
4A
80A
OFF
AC
4A
VOFF
4A
80A
80A
Operation
NOTICES: Read and understand all warning and
precaution statements listed in the safety
section of this operation manual prior to using
this meter. Set the function select switch to the
OFF position when the meter is not in use.
AC/DC Current Measurements
WARNING: Ensure that the test
leads are disconnected from the
meter before making current clamp
measurements.
1. Set the Function switch to the
80ADC, 4ADC, 80AAC or 4AAC
range. If the range of the
measured is not known, select
the higher range first then move
to the lower range if necessary.
2. Press the trigger to open jaw. Fully enclose one
conductor
to be measured.
3. If is DCA measurement need press ZERO button to
enter the zero reading.
3. The clamp meter LCD will display the reading.

8
DC/AC Voltage Measurements
1. Insert the black test lead into the negative COM terminal
and the
red test lead into the positive Vterminal.
2. Set the function switch to the V position.
3. Select AC or DC with the MODE button.
4. Connect the test leads in parallel to the circuit under test.
5. Read the voltage measurement on the LCD display.
Resistance and Continuity Measurements
1. Insert the black test lead into the negative COM terminal
and the
red test lead into the positive terminal.
2. Set the function switch to the •))) Ω
position.
3. Use the multifunction MODE button to select resistance.
4. Touch the test probe tips across the circuit or component
under
test. It is best to disconnect one side of the device under
test so
the rest of the circuit will not interfere with the resistance
reading.
5. For Resistance tests, read the resistance on the LCD
display.
6. For Continuity tests, if the resistance is < 150Ω, a tone
will sound.
Diode Measurements
1. Insert the black test lead banana plug into the negative
COM jack and the red test lead banana plug into the
positive diode jack.
2. Turn the rotary switch to the •))) position.

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3. Press the MODE button until “ “ appears in the
display.
4. Touch the test probes to the diode under test. Forward
voltage will indicate 0.4V to 0.7V. Reverse voltage will
indicate “OL”. Shorted devices will indicate near 0mV
and an open device will indicate “OL” in both polarities.
Capacitance Measurements
WARNING: To avoid electric shock, disconnect power to
the unit under test and discharge all capacitors before
taking any capacitance measurements. Remove the
batteries and unplug the line cords.
1. Set the rotary function switch to the cap position.
2. Insert the black test lead banana plug into the negative
(COM) jack.
Insert the red test lead banana plug into the positive (V)
jack.
3. Touch the test leads to the capacitor to be tested.
4. Read the capacitance value in the display
Frequency or % duty cycle measurements
1. Set the rotary function switch to the “Hz/%”
position.
2. Insert the black lead banana plug into the negative
COM jack and the red test lead banana plug into
the positive V jack.
3. Select Hz or % duty with the Hz/% button.
4. Touch the test probe tips to the circuit under test.
5. Read the frequency on the display.
Red Black Black Red
Probe Probe Probe Probe
Forward test Reverse test

10
12V
AC
80A
4A
80A
4A
OFF
V
600V
Hz/%
V
V
mV
Analog Signal Output
1. Switch the function selector to DCAor ACArange.
2. Connect red test lead to “V
Ω
” terminal and black one to
the “ COM ” terminal.
3. Connect tip of the test leads to the meter or
oscilloscope input terminal.
4. Open the clamp by pressing the jaw-opening handle
and insert the cable to be measured into the jaw.
5. Close the clamp and get the analog voltage signal from
the meter.
Note:
If measuring DC via clamp, signal output will be DC voltage.
If measuring AC via clamp, signal output will be DC voltage.
If measuring AC via clamp, signal output will be AC voltage.

11
Data Hold
To freeze the LCD meter reading, press the data hold
button. The data hold button is located on the left side of the
meter (top button). While data hold is active, the HOLD
display icon appears on the LCD. Press the data hold button
again to return to normal operation.
Note: The HOLD feature will activate when the Backlight is
turned on. Press the HOLD key again to exit Hold.
Backlight
Press and hold the HOLD key for >1 second to turn
on or off the display backlight function.
Note: The HOLD feature will activate when the Backlight is
turned on. Press the HOLD key again to exit Hold.
ZERO BUTTON
For ACA and Capacitance Zero & Offset adjustment.
Manual Ranging
The meter turns on in the autoranging mode. Press the
Range button to go to manual ranging. Each press of the
range button will step to the next range as indicated by the
units and decimal point location. Press and hold the Range
button for two seconds to return to autoranging. Manual
ranging does not function in the AC Current , Diode and
Continuity check functions
Battery Replacement
1. Remove the one rear Phillips head screw
2. Open the battery compartment
3. Replace the Requires two “AAA” batteries (UM4 R03)

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4. Re-assemble the meter