DCL31DR
01-1507 2040 6011
DIGITAL CLAMP METER
INSTRUCTION MANUAL
Dempa Bldg
.
, 4-4 Sotokanda 2-Chome
Chiyoda-ku, Tokyo, Japan
This manual emplys soy ink.
[1] SAFETY PRECAUTIONS
Before use, read the following safety precautions
This instruction manual explains how to safely use your new DCL31DR digital
clamp meter. Before use, please read this manual thoroughly. After reading it,
keep it together with the product so you can refer to it when necessary. If this
product is not used as specified in this manual, its protection function may be
compromised.
To avoid accidental burns or electric shock, always follow any instructions with
“ WARNING” or “ CAUTION” headings.
1-1 Explanation of Warning Symbols
The meanings of the symbols used in this manual and on the product are
explained below.
: Very important instructions for safe use.
•Warning messages are intended to prevent accidents to operating
personnel such as burn and electric shock.
•Caution messages are intended to prevent damage to the instrument.
The meanings of the symbols used exclusively on the product are explained below.
: Symbol requesting reference to the instruction manual before use
: Potential of connection to a power line in live status
: Double in sulation or reinforced insulation
: Power switch
: Backlight
1-2 Warning Instructions for Safe Use
To avoid physical injury such as burns or electric shock, be sure to
observe the following instructions when using this instrument.
1. This instrument is a digital clamp meter for low voltages. It should be
used on power lines with a voltage to ground of 300 Vrms or less.
2. Pay special attention when measuring voltages of AC 33 Vrms (46.7 V
peak) or DC 70 V or more to avoid injury. Also use insulating protective
equipment as required.
3. Never use the instrument on power lines that exceed the maximum
rated input current (see 1-3).
4. Do not use the instrument if the main unit is damaged or broken.
5. Do not use the instrument with the case or battery compartment cover
removed.
6. Do not hold the measurement clip at any point beyond the barrier.
7. Before performing measurement, make sure that the function is properly set.
8. Do not use the instrument when it or your hand is wet.
9. Do not attempt to repair or modify the instrument except to replace the
batteries.
10. Be sure to check the instrument before each use and inspect it at least
once a year.
11. Always use the instrument indoors.
12. To avoid compromising the protection function of this instrument, do
not use it in any way other than instructed in this manual.
* Voltage to ground of 300 Vrms or less: When the Y-connection voltage is 415 V,
the voltage to ground is equal to 415 /
3
≒
240 V.
1-3 Overload Protection Input Values
Input
Max. rated input current
Max. overload protection input
Clamp sensor
AC
/
DC 420 A
AC
/
DC 450 A
[2] APPLICATIONS AND FEATURES
2-1 Applications
This instrument is an AC/DC clamp meter with RMS response that allows you
to measure the current range specified in IEC 61010-1 CAT. III 300 V. It is
suitable for measuring the current of low-voltage power lines and electrical
appliances, etc.
WARNING
2-2 Features
• Safety design that complies with IEC61010-1 CAT. III 300 V
• Compact pocket size
• AC/DC compatible clamp meter
• DC+AC (True RMS) function
• Auto power OFF (approx. 15 min.) (Disabling also possible)
• Backlight
Measurement Category (Overvoltage Category)
Equipment of CAT II :
Primary cable runs of power-consuming equipment from a wall socket.
Equipment of CAT III :
Primary cable runs of equipment directly connected to a distribution board
and cable runs from a distribution board to wall sockets.
Equipment of CAT IV :
Cable runs from an incoming line to a distribution board.
[3] NAME OF COMPONENT UNITS
3-1 Main unit
3-2 Display
[4] DESCRIPTION OF FUNCTIONS
4-1 Power button:
button
Press the button to switch the power ON and OFF.
4-2 Auto power OFF function
The instrument incorporates the auto power OFF function that turns the
instrument OFF in about 15 minutes after the last operation. This function can
be disabled by switching the instrument ON while holding the button. The
indicator on the display panel is extinguished when the auto power OFF
functions is disabled.
4-3 Low battery indication
The
indicator lights on the display when the batteries have discharged
down to a supply voltage of about 2.3 V or less. Replace the batteries when
this indicator lights up.
4-4 Data hold: HOLD/PEAK button
Press the
button shortly. The
indicator lights on the display and
the value displayed at that time is held and will not change even if the
measurement data varies. Pressing the button shortly again extinguishes the
indicator and the measurement data is no longer held.
* The held data is cleared when the function is switched by pressing the
SELECT
button.
4-5 Function switching: SELECT button
Each press of this button switches the measurement function in sequence of
AC
→
DC
→
DC AC
→
AC
→
…
4-6
Zero setting: ZERO button
When the
ZERO
button is pressed while the
DC
or
DC
+
AC
function is
selected, the
indicator lights on the display and the current input value is
displayed as zero. Pressing the ZERO button again cancels the zero setting.
* This button is disabled while the AC function is selected.
4-7 Backlight function: button
Press this button to light the backlight of the display. Pressing the button again
extinguishes the backlight. The backlight is also extinguished automatically in
about 10 seconds after it is lit.
4-8 Peak hold: HOLD/PEAK button
When the
HOLD/PEAK
button is held depressed (for more than 1 sec.) during the
voltage or current measurement, the
PEAK
indicator lights on the display and the
Peak Hold mode fixed at the 400.0 A range is started. Holding the button
depressed again cancels the Peak Hold mode. In the Peak Hold mode, the peak
value of input waveform is held at intervals of 1 msec. The held value is updated
whenever a higher value is input but not updated at lower values. For instance,
when the input is a 100 A sine wave AC, the peak value is about 141 A ( 2 times
the rated value).
• Almost the same values are displayed with both the AC and DC functions.
• Peak Hold does not work with the negative (-) input with both the AC and DC
functions.
• When the
HOLD/PEAK
button is pressed in the Peak Hold mode, the
PEAK
and
indicators light and the value displayed at that moment is held. Even
when the displayed value is held, the peak value continues to be updated
internally so, when the
HOLD/PEAK
button is pressed again to release the held
value, the latest updated peak value is displayed.
• The Peak Hold mode is canceled when the function switch is switched.
Examples of peak hold measurement:
* The peak value of the negative (-) current is not held.
DC current peak
AC current peak
DC+AC current peak
Measurement impossible
Measurement impossible
Measurement impossible
Measurement possible
Measurement possible
Measurement possible
DC current peak
AC current peak
DC+AC current peak
Measurement impossible
Measurement impossible
Measurement impossible
Measurement possible
Measurement possible
Measurement possible
4-9 AC Detection method
This meter employs the root-mean-square value method and indicates the
magnitude of AC as the same amount of work as DC. Root-mean-square
values of sinusoidal waves and such non-sinusoidal waves as square waves
and chopping waves can be measured by the true RMS (Root Mean Square)
circuit. (The input signal measurement value is used as the scale of the actual
input signal power. It is therefore measured as a more effective value than the
value obtained by average detection.)
4-10 Crest factor
The CF (crest factor) indicates the peak value of a signal by dividing it by its
root-mean-square value. With most common waveforms such as sinusoidal
wave and chopping wave, the crest factor is low. With low duty cycle pulse
waveforms, the crest factor is high. For the voltages and crest factors for
typical waveforms, see the table below.
Input Waveform 0 to PEAK
Vrms
Average
Value
Crest
Factor
Form
Factor
Root Mean
Square Value
Vavg
Vp/Vrms Vrms/Vavg
Sinusoidal
wave
Square
wave
Chopping
wave
Pulse
=1.414 =1.111
Vp
Vp
Vp
1
0
0
p p
Vp
Vp
0
Vp
－
Vp
2
√
=0.707 Vp
－
2
Vp
π
=0.637 Vp
2
√
Vp
－
2
√
2
π
2π
π
π
Vp
Vp
1
π
2π
2π
－
Vp
3
√
=0.577 Vp
－
Vp
2
=0.5 Vp
－
2
3
√
=1.155
3
√
=1.732
2π
τ
0
Vp
－
τ
2π
・
Vp
－
τ
2π
・
Vp
－
2π
τ
－
2π
τ
Vp
Voltages of Various Waveforms
[5] MEASURING PROCEDURE
1. Do not apply an input voltage exceeding the maximum rated current.
2. During measurement, do not hold the measurement clip at any point
beyond the barrier.
5-1 Start-up inspection
Perform the following pre-operational check for safety.
• Check the external appearance. Check that the main unit is free of abnormality
or damage due to dropping, etc.
• Check that the test leads are free of irregularity such as wire disconnection or
crack.
• Check that the
indicator is not lit. If it is lit, replace the batteries with new ones.
• Make sure your hands and the instrument are not wet.
*If nothing is displayed on the LCD, the batteries might have been totally discharged.
5-2 Current measurements
1. To improve the measuring accuracy, position the conductor at the center
of the clamp sensor.
2. Always clamp only one wire at a time. Accurate measurement is impossible
if two or more wires, a cable with multiple conductors or a parallel cord is
clamped.
3. Accurate measurement is impossible if the clamp sensor is not closed
completely.
4. Accurate measurement is sometimes impossible near a source of strong
magnetic field such as a transformer or high-current line, near a source of
electromagnetic waves such as radio equipment or near a charged object.
5. The CT may generate an oscillating sound when a high current is applied.
This is not malfunction.
6.
During measurement with the DC current (DCA) function, the reading may
vary by a few counts when the orientation (effect of the terrestrial magnetism)
or the ambient temperature of this instrument is changed significantly.
* Perform measurements using the clamp sensor. Each press of the button
switches the measurement function in sequence of
AC
→
DC
→
DC AC
→
AC
→
…
→
→
→
Clamping single conductor on the center of clamp sensor.
Clamping multiple conductors.
Force applied to the tip of
clamp sensor.
Correct
○
Incorrect
×
Load
Load
WARNING
CAUTION
Clamping current sensor
(CT)
Center position indication
Polarity
indicators
Barrier
HOLD/PEAK button
ZERO button
SELECT button
Data HOLD
Auto power OFF enabled
DC (Direct current)
Zero setting indicator
Polarity (-)
Trigger
Power button
Backlight button
LCD
PEAK measurement
mode
Low battery indication
Unit (ampere)
Numeric value & decimal point
AC (Alternate current)
− 2 −
− 4 −
− 1 −
− 3 −