Good Will GDM-360 User manual

Handheld Digital Multimeter
GDM-360, GDM-397, GDM-398, GDM-461
USER MANUAL
GW INSTEK PART NO. 82DM-46100MA1
ISO-9001 CERTIFIED MANUFACTURER

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.
The information in this manual was correct at the time of printing. However, we
continue to improve our products and therefore reserve the right to change the
specifications, 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.

Table of Contents
1
Table of Contents
OVERVIEW............................................................................................................................. 4
Unpacking Inspection.......................................................................................................................5
Safety Information ............................................................................................................................6
Rules for Safe Operation...................................................................................................................7
International Electrical Symbols .......................................................................................................9
The Meter Structure ........................................................................................................................10
Rotary Switch...................................................................................................................................11
Functional Buttons..........................................................................................................................12
Display Symbols..............................................................................................................................13
MEASUREMENT OPERATION........................................................................................... 16
A. DC/AC Voltage Measurement....................................................................................................16
B. DC/AC Current Measurement....................................................................................................19
C. Resistance Measurement ...........................................................................................................22
D. Testing for Continuity ................................................................................................................25
E. Testing Diodes ............................................................................................................................27
F. Capacitance Measurement .........................................................................................................30
G. Frequency Measurement ...........................................................................................................33
H. Temperature Measurement (GDM-397 only) ...........................................................................35
I. Transistor hFE Measurement (GDM-398 only) ..........................................................................37
J. EF Function (GDM-398 only) ......................................................................................................39
Hold Mode ......................................................................................................................................41
RANGE button ................................................................................................................................42

GDM-360/397/398/461 User Manual
2
MAX MIN button (GDM-360/397/398 only) .................................................................................42
Peak Hold (GDM-461 only) ............................................................................................................42
Outputting Data (Except GDM-398) ..............................................................................................43
The Use of Relative Value Mode.....................................................................................................44
The BLUE button.............................................................................................................................45
Turning on the Display Backlight (GDM-360/397/398 only).........................................................45
Sleep Mode (GDM-360/397/398 only)...........................................................................................45
GENERAL SPECIFICATIONS .............................................................................................. 46
Accuracy Specifications...................................................................................................................48
DC Voltage ......................................................................................................................................48
AC Voltage.......................................................................................................................................50
DC Current ......................................................................................................................................53
AC Current.......................................................................................................................................56
Resistance .......................................................................................................................................59
Capacitance.....................................................................................................................................62
Frequency ........................................................................................................................................65
Diode Test .......................................................................................................................................66
Continuity Test................................................................................................................................66
Temperature Measurement (GDM-397 only) ................................................................................67
Transistor hFE (GDM-398 only) .....................................................................................................67
MAINTENANCE .................................................................................................................. 68
General Service ...............................................................................................................................68
Replacing the Battery ......................................................................................................................69

Table of Contents
3
Replacing the Fuses ........................................................................................................................71
USB and RS232C Serial Port...........................................................................................................73

OVERVIEW
4
OVERVIEW
This User Manual covers information on safety and cautions. Please read the
relevant information carefully and observe all the Warnings and Notes.
Warning
To avoid electric shock or personal injury, read the “Safety Information” and
“Rules for Safe Operation” carefully before using the Meter.
Digital Multimeter Model GDM-360 (True RMS), GDM-397, GDM-398 and GDM-
461 (True RMS) (hereafter referred to as “the Meter”) are auto ranging multimeters.
The Meter can measure AC/DC Voltage and Current, Resistance, Diode,
Continuity Buzzer, Capacitance, Frequency and Temperature (˚C or ˚F), hFE and
EF function. In addition to the conventional measuring functions, there is an
RS232C or USB serial port (optional), data hold, relative mode, peak measurement
(GDM-461), low battery display, display backlight (GDM-360/397/398) and sleep
mode (GDM-398/397/360). Except where noted, the descriptions and instructions
in this User Manual apply to all models.

GDM-360/397/398/461 User Manual
5
Unpacking Inspection
Open the package case and take out the Meter. Check the following items carefully
to see if there are any missing or damaged parts:
Item
Description
Qty
1
User Manual
1 piece
2
Test Lead
1 pair
3
K-type Temperature Probe (thermocouple) (GDM-397 only)
1 piece
4
Multi-Purpose Socket
1 piece
5
9V Battery (NEDA1604, 6F22 or 006P)(built-in)
1 piece
6
RS232C Interface Cable (Except GDM-398)
1 piece
7
USB Interface Cable (Optional at extra cost)(Except GDM-398)
1 piece
8
Installation Guide & Computer Interface Software (CD-ROM)
(Comes with the RS232C or USB Interface Cable, except GDM-398)
1 piece
In the event you find anything missing or damaged, please contact your dealer
immediately.

OVERVIEW
6
Safety Information
This Meter complies with the EN61010-1 and EN61010-2-030 standards: in
pollution degree 2, overvoltage category (CAT. III 1000V, CAT. IV 600V) and
double insulation.
CAT III: Distribution level, fixed installation, with smaller transient overvoltages
than CAT. IV.
CAT IV: Primary supply level, overhead lines, cable systems etc.
Use the Meter only as specified in this User Manual, otherwise the protection
provided by the Meter may be impaired.
In this manual, a Warning identifies conditions and actions that pose as hazards to
the user, or may damage the Meter or the equipment under test.
A Note identifies the information that a user should pay attention to.
International electrical symbols used on the Meter and in this User Manual are
explained on page 9.

GDM-360/397/398/461 User Manual
7
Rules for Safe Operation
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:
Before using the Meter inspect the case. Do not use the Meter if it is damaged or
if the case (or part of the case) is removed. Look for cracks or missing plastic.
Pay attention to the insulation around the connectors.
Inspect the test leads for damaged insulation or exposed metal. Check the test
leads for continuity. Replace damaged test leads with those of the same type
before using the Meter again.
Do not apply more than the rated voltage, as marked on the Meter, between the
terminals or between any terminal and ground.
To prevent damage of the Meter, the rotary switch should be placed in the right
position and the measurement range should not be changed during
measurement.
When measuring voltages over 60V in DC or 30V rms in AC, special care should
be taken to avoid electric shock.

OVERVIEW
8
Use the proper terminals, function, and range for your measurements.
Do not use or store the Meter in an environment with high temperature,
humidity, explosives, inflammable materials or strong magnetic fields. The
performance of the Meter may deteriorate when dampened.
When using the test leads, keep your fingers behind the finger guards.
Disconnect circuit power and discharge all high-voltage capacitors before testing
resistance, continuity and diodes.
Before measuring current, check the Meter’s fuses and turn off the current that is
to be tested before connecting the Meter to the circuit. After connecting the
circuit reliably, turn the current that is to be tested on.
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.
When servicing the Meter, use only the same model number or identical
electrical specifications for replacement parts.
The internal circuit of the Meter shall not be altered to avoid damaging the
Meter and to prevent accidents.