GW Instek GCM-407 User manual

GCM-407 User Manual
I. Overview - - - - - - - - - - - - - - - - - - - - - - - - - - 1
II. Open-case Inspection - - - - - - - - - - - - - - - - - 1
III. Safety Operation Guidelines - - - - - - - - - - - - 2
IV. Electrical Symbols - - - - - - - - - - - - - - - - - - - 4
V. External Construction - - - - - - - - - - - - - - - - - 5
VI. Display Symbols - - - - - - - - - - - - - - - - - - - - 6
VII. Key Functions - - - - - - - - - - - - - - - - - - - - - 7
VIII. Technical Indicators - - - - - - - - - - - - - - - - - 8
1. General Specifications - - - - - - - - - - - - - - - 8
2. Environmental Restraints - - - - - - - - - - - - - 9
3. Electrical Specifications - - - - - - - - - - - - - 10
IX. Measurement Operating Instructions- - - - - 13
1. AC Current Measurement - - - - - - - - - - - - 13
2. AC voltage Measurement - - - - - - - - - - - - 15
3. DC voltage Measurement - - - - - - - - - - - - 17
4. Resistance Measurement - - - - - - - - - - - - 18
5. Continuity Test- - - - - - - - - - - - - - - - - - - - 19
6. Diode Measurement- - - - - - - - - - - - - - - - 21
7. Capacitance Measurement - - - - - - - - - - - 22
8. Non-contact AC Voltage Sensing NCV- - - 24
9. Power- - - - - - - - - - - - - - - - - - - - - - - - - - 25
10. Automatic Shutdown Function - - - - - - - - 25
X. Maintenance and Upkeep - - - - - - - - - - - - - 25
1. General Maintenance- - - - - - - - - - - - - - - 25
2. Installation or Replacement of the Batteries 25

GCM-407 User Manual GCM-407 User Manual
I. Overview
GCM-407 is a portable, true 6000 count, auto range
clamp ammeter with a simulation bar. Featuring a
large scale integrated circuit, Σ/∆ analog-digital
converter, full-function on-screen display, full-range
overload protection and a unique design has given
this specific clamp ammeter superior performance.
The clamp ammeter is applicable to the following
measurements: AC/DC voltage, AC current,
resistance, diode, continuity, capacitance,
data-hold, maximum/minimum value measurement,
relative value measurement, flashlight function,
VFC function, NCV function, under-voltage display
and an automatic shutdown function.
The instruction manual includes relevant safety
information and warning indicators. Please read
them carefully and strictly observe all warnings and
notes.
Warning:
Prior to using the clamp meter, please read the
relevant "Safety operation guidelines" carefully.
II. Open-case Inspection
Unpack and take out the instrument. Carefully
check that the following accessories are not
damaged or missing.
1.An operating instruction manual
2.Test leads
3.Carrying case
If anything is missing or damaged, please contact
your GW Instek distributor. If the instrument is not
used in an appropriate manner the safety protec-
tions could be impaired. The unit can be used for
MAINS measurements up to CATII 1000V or CATIII
600V according to IEC 61010-031.
III. Safety Operation Guidelines
Please note the “warning signs” and notes.
Warnings indicate a condition or action that may
cause a threat to the user or may damage the
instrument or the equipment under test.
This meter complies with EN61010-1, 61010-2-032,
61010-2-033, Pollution Degree 2, Overvoltage
Category (CATII 1000V, CATIII 600V) and double
insulation standards.
Conforms to UL STD 61010-1 and IEC STD
61010-2-032
Certified to CSA STD C22.2 No.61010-1 and
61010-2-032.
This product has been tested to the requirements
of CAN/CSA-C22.2 No. 61010-1, second edition,
including Amendment 1.
CAT II: Applicable to test and measurement circuits
connected directly to utilization points (socket
outlets and similar points) of the low-voltage MAINS
installation.
CAT III: Applicable to the test and measurement
circuits connected to the distribution part of the
building’s low-voltage MAINS installation.
1. Check the clamp ammeter and test leads before
use. Refrain from using the clamp if the clamp is
damaged in anyway.
1 2

8. When the LCD display shows the icon, “ ”, it
indicates that the battery should be replaced to
ensure the measurement accuracy. Take out the
battery from the clamp meter when the meter
has not been used for a long time.
9. Refrain from altering the internal wiring of the
clamp meter to prevent damage to the meter or
harm to the operator.
10.Refrain from storing or using the clamp meter in
the environments with explosive elements,
flammables, high temperatures, high humidity or
strong electromagnetic fields.
11.Clean the clamp meter case with a soft cloth and
neutral detergents. Do not use abrasive
materials or solvents to prevent corroding the
case, damage to the instrument and to prevent
danger to the operator.
GCM-407 User Manual GCM-407 User Manual
IV. Electrical Symbols
This symbol signifies the product complies with
both USA and Canadian requirements
Complies with EU standards
Danger! High voltage!
AC or DC (Alternating current or direct current)
Diode
Buzzer on-off
DC (Direct current)
AC (Alternating current)
Warning prompt
Ground
Dual insulation
Capacitance
Do not use the clamp meter if the test lead
insulation is damaged, if the case insulation is
damaged, if the LCD is not functioning or if the
clamp meter is not functioning properly.
2. Do not use the clamp meter if the rear cover or
battery cover is not in place. Failure to do so
may cause electric shock.
3. Keep fingers behind the finger guard. Do not
touch any bare wires, conductors, unused input
terminals, or circuits that are being measured
when the clamp meter is in operation.
4. Make sure the function switch is in the correct
position prior to measurement. Do not change
ranges when using the clamp meter to prevent
damaging the meter.
5. Refrain from applying more than DC1000V/
AC750V to the clamp meter to prevent electric
shock to the user and damage to the clamp
meter.
6. Be careful when measuring RMS voltages
greater than 30DCV or 30ACV as electric shock
can occur.
7. Do not measure voltages or current higher than
the allowable input values. Set the function
range switch to the highest range possible if the
magnitude of the measured value is not known.
Before measuring resistors, diodes or continuity
in a circuit, the circuit should be powered down
and all capacitors in the circuit should be
completely discharged or the measurement
results could be inaccurate.
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GCM-407 User Manual GCM-407 User Manual
Open/Short or Continuity prompt
V. External Construction (See Figure
1)
1. Clamp head: A device used to measure AC
current and convert current into voltage.
2. Clamp body: Designed to safely protect the
operator from touching dangerous areas.
3. Trigger. Press the trigger to open the clamp
head. When the trigger is released the clamp head
closes.
4. Function dial: Selects the measurement function
or range.
5. Function keys: HOLD, MAX/MIN, REL.
6. LCD display area: Displays the measured data
and the function icons.
7. Input Terminals: Input terminals for measure-
ments other than AC current measurement.
VI. LCD Display (See Figure 2)
Max./Min measurement prompt
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GCM-407 User Manual GCM-407 User Manual
VII. Key Functions
1. SELECT
Tap the SELECT key to select measurement
modes.
2. HOLD
Press the HOLD key to enter the data hold
measurement mode. Press the key again to exit
this mode.
Long-press the HOLD key to turn the backlight
on. If the HOLD key is long-pressed again within
15 seconds, the backlight will be turned back off.
The backlight will automatically turn off after 15
seconds.
3. MAX/MIN
Pressing the MAX/MIN key will toggle the
measurement between the maximum and
minimum measurement mode. “MAX” or “MIN”
will be displayed on the LCD when in the
maximum or minimum measurement mode. This
measurement mode is applicable for AC voltage,
AC current and resistance measurements.
Long-press the MAX/MIN key to exit from
maximum/minimum measurement.
4. REL
Pressing the REL key enters the relative
measurement mode. In the relative measure-
ment mode the main display will show the
measured value minus the reference value. The
reference value is obtained from the current
measurement when the REL key is pressed. This
function is only applicable for AC voltage, AC
current, resistance and capacitance measure-
ment. Press the REL key again to exit the
relative measurement mode. The LCD will
display “∆” when in this mode.
5. FLASHLIGHT
Long-press this key to turn the flashlight function
on.
Press the this key to turn the flashlight function
off.
VIII Technical Indicators
1. General Specifications
Liquid crystal display: Displays 6000 counts
maximum.
Polarity display: Automatic positive and negative
polarity display.
Overload display: “OL”, “-OL”.
Low voltage display: “Figure 2” indicates that the
battery voltage is lower than the working voltage,
indicating that the battery should be replaced.
Sampling rate: Approximately 3 samples/sec.
Sensor type: Coil induction.
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GCM-407 User Manual GCM-407 User Manual
Test Position Error:
An additional reading error of ±1.0% may occur
when the measured wired is not clamped into the
center of the clamp head.
Impact Resistance Strength:
1m fall impact.
Maximum Clamp Head Diameter:
30mm
Maximum Diameter of Conductor Allowed:
30mm
Electromagnetic Field Impact:
Using this meter near electromagnetic fields may
result in an unstable display or inaccurate readings.
Power:
3 AAA 1.5V zinc manganese batteries.
Dimensions:
228mmx77mmx41mm;
Weight:
About 265g (inclusive of the battery).
2. Environment Constraints:
Working environment: Indoor
Altitude: 2000m
Safety codes: IEC61010-1; IEC61010-2-032;
CAT II 1000V, CAT III 600V;
Pollution grade: 2;
Operating humidity and temperature: 0ºC ~ 30ºC
(not greater than 80%RH), 30ºC ~ 40ºC (not
greater than 75%RH), 40ºC ~ 50ºC (not greater
than 45%RH).
Storage humidity and temperature: -20ºC ~ 60ºC
(not greater than 80% RH).
3. Electrical Specifications
Accuracy: ±(% of reading + digits)
Calibration interval: 1 year.
Ambient temperature: 23ºC±5ºC.
Ambient humidity: ≤80% RH
Temperature coefficient: 0.1x(accuracy)/ºC
1. AC Current ( )
Display: True RMS AC current: applicable for
ranges from 10% to 100%.
Frequency response: 50Hz ~ 60Hz;
The measurement accuracy of non-sinusoidal
current waveforms should be 5% higher.
2. AC Voltage ( )
10
9

6. Diode Test ( )
7. Capacitance ( )
Display: True RMS AC voltage; applicable for
ranges from 10% to 100%.
Voltage: Input impedance ≥ 10MΩ;
Frequency response: 40~400Hz
3. DC Voltage ( )
Input impedance ≥10MΩ
4. Resistance ( Ω )
5. Continuity Test ( )
GCM-407 User Manual GCM-407 User Manual
Open-circuit
voltage is
approx. 3.3V,
measurable PN
forward bias ≤
3V. Silicon PN
typical forward
bias is approx.
0.5~0.8V.
11 12

8. NCV
IX. Measurement Operation Instructions
1. AC Current Measurement (see Figure 3)
1) Set the switch to AC current mode and press the
trigger to open the clamp head. Position the
conductor in the clamp head and slowly release
the trigger until the clamp head is completely
closed. Be sure the conductor is clamped to the
center of the clamp head, otherwise additional
errors may be introducted. Only one current
conductor should be measured at a time.
Measuring two or more current conductors may
result in erroneous measurement readings.
2) Read the AC value directly from the display.
Note:
• Be sure the conductor to be measured is
clamped at the center of the clamp head, if not,
an additional reading error of ±1.0% may result.
GCM-407 User Manual GCM-407 User Manual
3
13 14
• The true RMS AC current meaurement accuracy
is based on sinusoidual waveforms. For
non-sinusoidal waveforms, adjust the accuracy
as follows:
Crest factor 1.4 ~ 2.0: additional ±1.0%
Crest factor 2.0 ~ 2.5: additional ±2.5%
Crest factor 2.5 ~ 3.0: additional ±4.0%

2. AC Voltage Measurement (see Figure 4)
1) Insert the red test lead in the “V” input jack and
the black test lead in the “COM” input jack.
2) Rotate the function dial to the AC voltage
measurement function and connect the test leads in
parallel to the load to be measured.
3) Read the AC voltage from the display.
Note:
• Do not input voltages greater than AC 750V.
Higher voltages may damage the meter.
• Be aware that higher voltages can cause electric
shock.
• After all measurement operations are completed,
disconnect the test leads from the EUT.
• When the measured voltage is greater than the
safety voltage of 30VAC, the LCD will display a
high voltage warning prompt, “ ”. When
voltages greater than the AC 750V range are
input, the meter warning prompt, “ ”, will flash
and the meter will automatically buzz intermit-
tently.
4
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15 16
• The true RMS AC voltage meaurement accuracy
is based on sinusoidual waveforms. For
non-sinusoidal waveforms, adjust the accuracy
as follows:
Crest factor 1.4 ~ 2.0: additional ±1.0%
Crest factor 2.0 ~ 2.5: additional ±2.5%
Crest factor 2.5 ~ 3.0: additional ±4.0%

3. DC Voltage Measurement (See Figure 5)
1) Insert the red test lead into the “V” input jack and
the black test lead into the “COM” jack.
2) Rotate the function dial to the DC voltage
measurement mode and connect the test leads in
parallel to the load to be measured.
3) Directly read the measured voltage from the
display.
Note:
• Do not input voltages greater than 1000V DC.
Measuring voltage greater than 1000V DC may
damage the meter.
• Be aware that higher voltages can cause electric
shock.
• After all measurement operations are completed,
disconnect the test leads from the EUT.
• When the measured voltage is greater than the
safety voltage of 30VDC, the LCD will display a
high voltage warning prompt, “ ”. When voltages
greater than DC 1000V range are input, the
meter warning prompt, “ ”, will flash and the
meter will automatically buzz intermittently.
4. Resistance Measurement (See Figure 6)
1) Insert the red test lead into the “Ω” input jack and
the black test lead into the “COM” jack.
2) Rotate the function dial to the “Ω” measurement
mode. Press the SELECT key to select resistance
measurement, “Ω”, and connect the test leads in
parallel to the resistance to be measured.
3) Directly read the measured resistance from the
display.
GCM-407 User Manual GCM-407 User Manual
17 18
5
Note:
• If the open circuit resistance or the resistance
being measured exceeds the maximum range of
the meter, the display will show “OL”.
• When measuring at the 600mV range, the REL
function (relative measurement function) must
be used to obtain a precise measurement
reading; To use the REL function, short the test
leads and press the REL key to obtain a
reference value. The displayed resistance value
will now be equal to the measured resistance
minus the reference value.

Note:
• When checking in-circuit open/short conditions
make sure power is turned off and all capacitors
are discharged before measurement.
• With respect to the circuit continuity measure-
ment, the open circuit voltage is approximately
-3.5V with a 600Ω range.
• Do not input voltages higher than 30VDC or
30VAC or personal injury may occur.
• After completing all measurement operations,
disconnect the test leads from the measured
circuit.
• Before measuring in-circuit resistors, turn off the
power from the circuit and discharge any
capacitors for best measurement results.
5. Continuity Test (see Figure 7)
1) Insert the red test lead into the “Ω” input jack and
the black test lead in the “COM” input jack.
2) Rotate the function selection switch to the “ ”
measurement mode. Press the SELECT key to
select “ ” continuity measurement. Connect
the test leads in parallel with the EUT. When the
measured resistance is <30Ω, the circuit is
judged as conductive and the buzzer will sound.
3) Read the resistance value from the display.
6
7
19 20
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6. Diode Measurement (See Figure 8)
1) Insert the red test lead into the “Ω” input jack
and the black test lead into the “COM” input
jack. The polarity of the red and black test lead
is “+” and “-’, respectively.
2) Rotate the function dial to the ” “ measure-
ment mode. Press SELECT to select the diode
measurement ” “. Read the approximate
forward bias voltage drop accross the PN
junction. For silicon PN junction diodes, the
voltage drop is typically 500~800mV.
Note:
• ”OL” will be displayed when the measured diode
is open-circuited or the polarity of the diode is
inverted (reverse biased).
• Before measuring diodes, the power to the
circuits should be turned off and all capacitors
should be discharged to ensure measurement
accuracy.
• The open circuit test voltage for the diode
measurement is approximately 3.5V.
• Do not input voltages higher than 30VDC or
30VAC or personal injury may result.
• After completing all measurement operations,
disconnect the test leads from the measured
circuit.
7. Capacitance Measurement (See Figure 9)
1) Insert the red test lead into the “ ” input jack
and the black test lead into the “COM” input
jack. Capacitance should be measured using
the REL function mode.
2) Rotate the function dial to the ” “ measure-
ment mode to select capacitance. Connect the
test leads in parallel with the two terminals of the
capacitor.
3) Read the measured capacitance from the
display. Use the shortest test leads possible to
reduce the impact caused by distributed
capacitance.
GCM-407 User Manual
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GCM-407 User Manual
21 22

Note:
• If the measured capacitance is shorted or the
capacitance exceeds the maximum range of the
meter, the display will show “OL”. It takes a
longer time to correctly measure capacitances
over 600uF.
• To ensure measurement accuracy, discharge all
residual charge from the capacitor under test
before connecting the capacitor to the meter.
This is particulary important for capactors with
high voltages to prevent damage to the meter or
to prevent personal injury.
• After completing measurement operations,
disconnect the test leads from the EUT.
910
23 24
GCM-407 User Manual GCM-407 User Manual
8. Non-contact AC Voltage Sensing NCV (See
Figure 10)
In order to sense whether there is AC voltage or
an electromagnetic field present, place the front
-end of the clamp meter near the conductor to be
tested (distance <10mm). When the electric field
voltage is ≥100VAC, the display will indicate up
to four levels, “-”, “--”, “---”, “----”, based on the
sensed voltage.
The buzzer will beep continuosly and the NCV
LED will flash red.

c. Only install batteries of the correct type and
rating.
d. After installing the new batteries, re-install the
battery cover.
This manual contains proprietary information, which is
protected by copyright. All rights are reserved. No part of
this manual may be photocopied, reproduced or translated
to another language without prior written consent of Good
Will company. The information in this manual was correct at
the time of printing. However, Good Will continues to
improve products and reserves the rights to change
specification, equipment, and maintenance procedures at
any time without notice.
Good Will Instrument Co., Ltd.
No. 7-1, Jhongsing Rd., Tucheng Dist.,
New Taipei City 236, Taiwan.
GCM-407 User Manual GCM-407 User Manual
11
25 26
9. Power (OFF)
Turns the instrument off.
10. Automatic Shutdown Function
If the function dial is not turned or a key is not
pressed on the clamp within a 15 minute window,
the display will turn off and the clamp will enter a
low power state. To wake the meter up, press
any key.
Press the SELECT key to turn on the unit with
the automatic shutdown disabled.
X. Maintenance and Upkeep (See
Figure 11)
Warning: To prevent electric shock, keep the
protective caps on the test leads when not in
use.
1. General Maintenance
a. The clamp meter should be maintained by
qualified personnel or return the unit to the GW
Instek service center.
b. Clean the outer case with a soft cloth. Do not use
cleaning agents containing abrasive materials or
solvents.
2. Installation or Replacement of Batteries
3 AAA 1.5V batteries power the product. Please
install or replace batteries as follows:
a. Shut down the clamp meter and remove the test
leads.
b. Place the unit face down and unscrew the screw
from the battery cover. Remove battery cover
and replace the batteries. Take note of the
polarity indicated in the battery compartment.