GW Instek GDM-350A User Manual

Model GDM-350A: OPERATING MANUAL

Table of Contents (1)

Title

Overview
Unpacking Inspection
Safety Information
Rules For Safe Operation
International Electrical Symbols
The Meter structure
Functional Buttons
Measurement Operation

A. DC Voltage Measurement
B. AC Voltage Measurement
C. DC Current Measurement
D. Measuring Resistance
E. Diodes and Continuity

Measurement

F. Temperature Measurement

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Model GDM-350A: OPERATING MANUAL

Table of Contents (2)

General Specifications
Accuracy Specifications

A. DC Voltage
B. AC Current
C. DC Current
D. Resistance
E. Diodes and Continuity

Measurement

F. Temperature

Maintenance
A. General Service
B. Replacing the Battery
C. Replacing the Fuses

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Model GDM-350A: OPERATING MANUAL

Overview

This Operating Manual covers information on safety and cautions. Please read
the relevant information carefully and observe all the Warnings and Notes strictly .

Warning
To avoid electric shock or personal injury, read the “Safety Information” and
“Rules for Safety Operation” carefully before using the Meter.

The Model GDM-350A Multimeters (hereafter referred as “the Meter”) are 3
1/2 digits with steady operations, fashionable design and highly reliable
hand-held measuring instrument. The Meter can measure AC/DC voltage,
AC/DC Current, Resistance, Temperature, Diode and Continuity. It is an ideal
tool for maintenance.
Except where noted, the descriptions and instructions in this Operating Manual
apply to all Model GDM-350A.

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Model GDM-350A: OPERATING MANUAL

Unpacking Inspection

Open the package case and take out the Meter. Check the following items carefully
to see any missing or damaged part:

Item

English Operating Manual

1
2

Test Lead

3

Point Contact Temperature Probe

4

Holster

Description

Qty

1 piece

1 pair
1 piece
1 piece

In the event you find any missing or damage, please contact your dealer immediately.

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Model GDM-350A: OPERATING MANUAL

Safety Information(1)

Safety Information

This Meter complies with the standards IEC61010: in pollution degree 2, overvoltage
category (CAT I 600V, CAT II 300V) and double insulation.

CAT. I: Signal level, special equipment or parts of equipment, telecommunication,
electronic, etc., with smaller transient overvoltages than overvoltages CAT. II.

CAT. II: Local level, appliance, PORTABLE EQUIPMENT etc., with smaller transient
overvoltages than CAT. III

Use the Meter only as specified in this operating manual, otherwise the protection
provided by the Meter may be impaired.

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Model GDM-350A: OPERATING MANUAL

Safety Information(2)

In this manual, a Warning identifies conditions and actions that pose hazards to the
user, or may damage the Meter or the equipment under test.A Note identifies the
information that user should pay attention on.

International electrical symbols used on the Meter and in this Operating Manual are
explained on page 10.

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Model GDM-350A: OPERATING MANUAL

Rules For Safe Operation (1)

Warning
To avoid possible electric shock or personal injury, and to avoid possible
damage to the Meter or to the equipment under test, adhere to the following
rules:

l Before using the Meter inspect the case. Do not use the Meter if it is
damaged or the case (or part of the case) is removed. Look for cracks or
missing plastic. Pay attention to the insulation around the connectors.
l Inspect the test leads for damaged insulation or exposed metal. Check
the test leads for continuity. Replace damaged test leads with identical
model number or electrical specifications before using the Meter.
l Do not apply more than the rated voltage, as marked on the Meter, between
the terminals or between any terminal and grounding.
l The rotary switch should be placed in the right position and no any
changeover of range shall be made during measurement is conducted to

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Model GDM-350A: OPERATING MANUAL

Rules For Safe Operation (2)

prevent damage of the Meter.
l When the Meter working at an effective voltage over 60V in DC or 42V rms
in AC, special care should be taken for there is danger of electric shock.

l Use the proper terminals, function, and range for your measurements.
l Do not use or store the Meter in an environment of high temperature, humidity,

explosive, inflammable and strong magnetic field. The performance of the
Meter may deteriorate after dampened.

l When using the test leads, keep your fingers behind the finger guards.
l Disconnect circuit power and discharge all high-voltage capacitors before

testing resistance, continuity, diodes and current.
l Before measuring current, check the Meter’s fuses and turn off power to
the circuit before connecting the Meter to the circuit.
l Replace the battery as soon as the battery indicator appears. With a low
battery, the Meter might produce false readings that can lead to electric
shock and personal injury.

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Model GDM-350A: OPERATING MANUAL

Rules For Safe Operation (3)

l Remove test leads and temperature probe from the Meter and turn the
Meter power off before opening the Meter case.
l When servicing the Meter, use only the same model number or identical
electrical specifications replacement parts.
l The internal circuit of the Meter shall not be altered at will to avoid damage
of the Meter and any accident.
l Soft cloth and mild detergent should be used to clean the surface of the
Meter when servicing. No abrasive and solvent should be used to prevent
the surface of the Meter from corrosion, damage and accident.

l The Meter is suitable for indoor use.
l Turn the Meter off when it is not in use and take out the battery when not

using for a long time.
l Constantly check the battery as it may leak when it has been using for some
time, replace the battery as soon as leaking appears. A leaking battery
will damage the Meter,

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Model GDM-350A: OPERATING MANUAL

International Electrical Symbols

AC or DC

AC Current
DC Current
Earth Ground

Double Insulated.

Low Battery.
Diode.
Fuse.
Continuity Test
Safety Rules
Conforms to Standards of European Union.

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Model GDM-350A: OPERATING MANUAL

The Meter Structure

The Meter Structure (figure 1)

1) LCD Display

2) HOLD Button

3) Display Backlight Button

4) Rotary Switch

5) COM Input Terminal

6) 10A Input Terminal

7) Other Input Terminals

(figure 1)

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Model GDM-350A: OPERATING MANUAL

Functional Buttons

Below table indicated for information about the functional button operations.

Button Operation Performed

HOLD button

BLUE button

l Press HOLD once to enter hold mode.
l Press HOLD again to exit hold mode.
l In Hold mode, H is displayed and the present value is shown.

l Press BLUE button once to turn the display backlight on.
l Press BLUE button again to turn the display backlight off.
l Display backlight will NOT be automatically off unless pressing

the BLUE button

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