GW Instek GDM-8245 User manual

Digital Multimeter
GDM-8245
USER MANUAL
GW INSTEK PART NO. 82DM-82450E01
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 of the 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 right to change specifications, equipment, and maintenance
procedures at any time without notice.
Good Will Instrument Co., Ltd.
No. 7-1, Jhongsing Rd., Tucheng City, Taipei County 236, Taiwan.

Table of Contents
3
Table of Contents
SAFETY INSTRUCTIONS ....................................................5
Safety Symbols....................................................5
Safety Guidelines ................................................6
GETTING STARTED..........................................................10
GDM-8245 Characteristics ................................ 11
Front Panel Overview ........................................ 12
Rear Panel Overview ......................................... 16
Set Up ............................................................... 17
BASIC MEASUREMENT....................................................20
Basic Measurement Overview........................... 21
AC/ AC mV/DC/ DC mV/AC+DC Voltage
Measurement .................................................... 22
DC/ DC 20A / AC/AC 20A/AC+DC Current
Measurement .................................................... 28
Resistance Measurement .................................. 31
Diode Test ......................................................... 33
Continuity Test .................................................. 34
Capacitance Measurement................................ 35
Calibration button ............................................. 36
ADVANCED MEASUREMENT ...........................................37
Advanced Measurement Overview .................... 38
dBm Measurement............................................ 39
Max/Min Measurement..................................... 40
Relative Value Measurement............................. 41
Hold Measurement ........................................... 42
AC+Hz Measurement........................................ 43
FAQ ..................................................................................44
APPENDIX........................................................................45
Fuse Replacement ............................................. 46

GDM-8245 User Manual
4
Specifications....................................................49
Declaration of Conformity.................................55
INDEX ............................................................................. 56

SAFETY INSTRUCTIONS
5
SAFETY INSTRUCTIONS
This chapter contains important safety instructions that
you must follow when operating the GDM-8245 or
when keeping it in storage. Read the following before
any operation to insure your safety and to keep the
GDM-8245 in the best possible condition.
Safety Symbols
These safety symbols may appear in this manual or on the GDM-8245.
WARNING
W
arning: Identifies conditions or practices that could
result in injury or loss of life.
CAUTION
Caution: Identifies conditions or practices that could
result in damage to the GDM-8245 or to other
properties.
DANGER High Voltage
A
ttention Refer to the Manual
Protective Conductor Terminal
Earth (ground) Terminal
Do not dispose electronic equipment as unsorted
municipal waste. Please use a separate collection facility
or contact the supplier from which this instrument was
purchased.

GDM-8245 User Manual
6
Safety Guidelines
General Guideline
CAUTION
Make sure that the voltage input level does not exceed
DC1200V/AC1000V. (Limitations apply, please see the
specifications)
Make sure the current input level does not exceed 20A.
Do not place any heavy objects on the GDM-8245.
Avoid severe impact or rough handling that leads to
damaging the GDM-8245.
Do not discharge static electricity to the GDM-8245.
Use only mating connectors, not bare wires, for the
terminals.
Do not perform measurement at the source of a
low-voltage installation or at building installations
(Note below).
Do not disassemble the GDM-8245 unless you are
qualified as service personnel.
(Note) EN 61010-1:2001 specifies the measurement categories and
their requirements as follows. The GDM-8245 falls under category
II(1200V) and III(600V).
Measurement category IV is for measurement performed at the
source of low-voltage installation.
Measurement category III is for measurement performed in the
building installation.
Measurement category II is for measurement performed on the
circuits directly connected to the low voltage installation.
Measurement category I is for measurements performed on circuits
not directly connected to Mains.
Power Supply
WARNING
AC Input voltage: 100V/ 120V/ 230 V AC, 50/60Hz
The power supply voltage should not fluctuate more
than 15%.
Connect the protective grounding conductor of the
AC power cord to an earth ground, to avoid electrical
shock.

SAFETY INSTRUCTIONS
7
Fuse
WARNING
Fuse type:
100V/120V T0.1A 250V
230V T0.08A 250V
Make sure the correct type of fuse is installed before
power up.
To avoid fire, only replace the fuse with the specified
type and rating.
Disconnect the power cord before fuse replacement.
Make sure the cause of a fuse blowout is fixed before
fuse replacement.
Cleaning the
GDM-8245
Disconnect the power cord before cleaning.
Use a soft cloth dampened in a solution of mild
detergent and water. Do not spray any liquid into the
GDM-8245.
Do not use chemicals or cleaners containing harsh
material such as benzene, toluene, xylene, and acetone.
Operation
Environment
Location: Indoor, no direct sunlight, dust free, almost
non-conductive pollution (Note below)
Relative Humidity: < 75%
Altitude: < 2000m
Temperature: 0°C to 50°C (operation)
(Note) EN 61010-1:2001 specifies the pollution degrees and their
requirements as follows. The GDM-8245 falls under degree 2.
Pollution refers to “addition of foreign matter, solid, liquid, or
gaseous (ionized gases), that may produce a reduction of dielectric
strength or surface resistivity”.
Pollution degree 1: No pollution or only dry, non-conductive pollution
occurs. The pollution has no influence.
Pollution degree 2: Normally only non-conductive pollution occurs.
Occasionally, however, a temporary conductivity caused by
condensation must be expected.
Pollution degree 3: Conductive pollution occurs, or dry,
non-conductive pollution occurs which becomes conductive due to
condensation which is expected. In such conditions, equipment is
normally protected against exposure to direct sunlight, precipitation,
and full wind pressure, but neither temperature nor humidity is
controlled.
Storage
Environment
Location: Indoor
Relative Humidity: < 75% (0~35°C),<50% (35~50°C)*
Temperature: 40°C to 70°C
*Excluding 2M/20Mranges

GDM-8245 User Manual
8
Disposal
Do not dispose this instrument as unsorted municipal
waste. Please use a separate collection facility or
contact the supplier from which this instrument was
purchased. Please make sure discarded electrical waste
is properly recycled to reduce environmental impact.

SAFETY INSTRUCTIONS
9
Power cord for the United Kingdom
When using the GDM-8245 in the United Kingdom, make sure the power
cord meets the following safety instructions.
NOTE: This lead / appliance must only be wired by competent persons
WARNING: THIS APPLIANCE MUST BE EARTHED
IMPORTANT: The wires in this lead are coloured in accordance with the
following code:
Green/ Yellow: Earth
Blue: Neutral
Brown: Live (Phase)
As the colours of the wires in main leads may not correspond with the
coloured marking identified in your plug/appliance, proceed as follows:
The wire which is coloured Green & Yellow must be connected to the Earth
terminal marked with either the letter E, the earth symbol or coloured
Green/Green & Yellow.
The wire which is coloured Blue must be connected to the terminal which is
marked with the letter N or coloured Blue or Black.
The wire which is coloured Brown must be connected to the terminal
marked with the letter L or P or coloured Brown or Red.
If in doubt, consult the instructions provided with the equipment or contact
the supplier.
This cable/appliance should be protected by a suitably rated and approved
HBC mains fuse: refer to the rating information on the equipment and/or
user instructions for details. As a guide, a cable of 0.75mm2should be
protected by a 3A or 5A fuse. Larger conductors would normally require 13A
types, depending on the connection method used.
Any exposed wiring from a cable, plug or connection that is engaged in a live
socket is extremely hazardous. If a cable or plug is deemed hazardous, turn
off the mains power and remove the cable, any fuses and fuse assemblies. All
hazardous wiring must be immediately destroyed and replaced in accordance
to the above standard.

GDM-8245 User Manual
10
GETTING STARTED
This chapter describes the GDM-8245 in a nutshell,
including its main features as well as its front and rear
panels. After going through the panel overview, follow
the Power-up sequence before attempting to use the
DMM.
Please note the information in this manual was correct
at the time of printing. However as GW Instek
continues to improve its products, changes can occur at
any time without notice. Please see the GW Instek
website for the latest information and content.
Characteristics GDM-8245 Characteristics..................................... 11
Panel Overview Front Panel Overview............................................. 12
Measurement keys (Upper row)............................. 13
Measurement keys (Lower row) ............................. 14
Rear Panel Overview .............................................. 16
Setup Tilt Stand ............................................................... 17
Power Up ............................................................... 18

GETTING STARTED
11
GDM-8245 Characteristics
The GDM-8245 is a portable, dual-display digital
multimeter suitable for a wide range of applications,
such as production testing, research, and field
verification.
Performance High DCV accuracy: 0.03%+4
High current range: 20A
High Voltage range: 1000V
High ACV frequency response: 50kHz
Features 50000 count display
Multiple functions: ACV, DCV, ACA, DCA, R, C, Hz,
Continuity Beeper, Diode test, MAX/MIN, REL, dBm
and HOLD.
Manual or Auto ranging
AC true RMS or AC + DC true RMS

GDM-8245 User Manual
12
Front Panel Overview
Power Switch
Turns On or Off the main
power. For details about the power
up sequence, see page 18.
Primary Display Shows the primary measurement results and parameters.
Secondary
Display
Shows the secondary measurement results and
parameters.
Fuse
Fuse protection for the instrument
from over-current. Rating: T2A,
250V.
For the fuse replacement procedure,
see page 48.
COM Terminal
A
ccepts ground (COM) line in all
measurements.
Voltage/
Resistance/Diode
/Capacitance
Terminal
A
ccepts input in all measurements
except for DC/AC Current.

GETTING STARTED
13
DC/ AC Current
Input
A
ccepts DC/AC Current input of up
to 20A.
For DCA/ACA details, see page 28.
DC/ AC Current
Input
(less than 2 A)
A
ccepts DC/AC current input less
than 2A. For details, see page 28.
Measurement keys (Upper row)
DCV
Measures DC Voltage (page 22).
SHIFT →DCV
(DC mV) DCV
DC mV
Measures DC Voltage (mV)(page 22).
ACV
Measures AC Voltage (page 22).
SHIFT →ACV
(AC mV) ACV
AC mV
Measures AC Voltage (mV)(page 22).

Measures resistance (page 31).
Continuity
Tests continuity (page 34 ).
SHIFT→ 
Diode test (page 33 ).
MAX/ MIN
Measures the maximum or the
minimum value (page 40).
UP
Used to increase a parameter or for
menu navigation.
AUTO/MAN
Selects Automatic (AUTO) or
Manual (MAN) Ranging.

GDM-8245 User Manual
14
SHIFT→
AUTO/MAN
(CAL)
AUTO/MAN
CAL
Calibration (page Error! Bookmark
not defined.)
Measurement keys (Lower row)
DCA
Measures DC Current (page 28).
SHIFT →
DCA(DC 20A)
Measures DC Current (20A)(page
28).
ACA
Measures AC Current (page 28).
SHIFT →ACA(AC
20A)
Measures AC Current (20A)(page
28).
AC+DC AC+DC
Measures AC+DC Voltage (page 22)
or AC+DC Current (page 28).
SHIFT→AC+DC(A
C+Hz)
Measures AC+Frequency and
(page 43).
(Capacitance)
Measures capacitance (page 35).
SHIFT→(dBm)
Measures dBm (page 39).
HOLD
A
ctivates the Hold function
(page 42).
SHIFT→HOLD(R
EL)
A
ctivates the REL function (page
41).
DOWN
Used to decrease a parameter or for
menu navigation.

GETTING STARTED
15
SHIFT
The Shift key selects the second
function assigned to each panel key.
W
hen pressed, the indicator
appears in the display.

GDM-8245 User Manual
16
Rear Panel Overview
120
Power Cord
Socket
A
ccepts the power cord. AC
100/120V or 230V; 50/60Hz.
For the power on sequence, see page
18.
Fuse Socket
100
230
120
Holds the main fuse:
100/120V: T0.1A 250V;
230V: T0.08A 250V;
For the fuse replacement details, see
page 46.

GETTING STARTED
17
Set Up
Tilt Stand
Steps 1. Pull handle base away from the casing.
2. Turn handle into any of the preset positions.
Stand Position Carry Position

GDM-8245 User Manual
18
Power Up
1. Ensure that the correct voltage is lined up with
the arrow on the fuse cover on the rear panel.
100V 120V 230V
100
230
120
100
230
120
100
230
120
Steps 2. Connect the power cord to the AC Voltage input.
230
100
120
Note Ensure the ground connector of the power cord is
connected to a safety ground. This will affect the
measurement accuracy.
3. Press the main power switch on the front panel.
POW
ER

GETTING STARTED
19
4. The display will light up and show the default
range of DC 1000V, and auto range.
Example: ACV, Auto
A
V
k
M
Hz
F
n


m
SHIFT
REL
ACDC
MAX
mV
kHz
MIN
AUTO AC ERROR dBm
RMT
HOLD
A
V
k
M
Hz
F
n


m
SHIFT RELACDCMAX
mV
kHz
MIN AUTO AC ERROR dBmRMT HOLD

GDM-8245 User Manual
20
BASIC MEASUREMENT
Overview Basic Measurement Overview................................ 21
Voltage AC/ AC mV/DC/ DC mV/AC+DC Voltage
Measurement......................................................... 22
Select Voltage range .............................................. 24
Voltage conversion table........................................ 25
Crest factor table ................................................... 27
Current DC/ DC 20A / AC/AC 20A/AC+DC Current
Measurement......................................................... 28
Select Current range .............................................. 30
Resistance Resistance Measurement....................................... 31
Select Resistance range ......................................... 32
Diode Diode Test.............................................................. 33
Continuity Continuity Test....................................................... 34
Capacitance Capacitance Measurement..................................... 35
Calibration Calibration Button ................................................. 36