Amprobe BDM40-UA User Manual

BDM40-UA

Bench Digital Multimeter

User Manual

BDM40-UA

Bench Digital Multimeter

User Manual

PN 1675449
March 2007
©2007 Amprobe Test Tools.
All rights reserved. Printed in Taiwan

1

Limited Warranty and Limitation of Liability

Your Amprobe product will be free from defects in material and workmanship for 1 year from the date of
purchase. This warranty does not cover fuses, disposable batteries or damage from accident, neglect, misuse,
alteration, contamination, or abnormal conditions of operation or handling. Resellers are not authorized to extend
any other warranty on Amprobe’s behalf. To obtain service during the warranty period, return the product with
proof of purchase to an authorized Amprobe Test Tools Service Center or to an Amprobe dealer or distributor. See
Repair Section for details. THIS WARRANTY IS YOUR ONLY REMEDY. ALL OTHER WARRANTIES - WHETHER
EXPRESS, IMPLIED OR STAUTORY - INCLUDING IMPLIED WARRANTIES OF FITNESS FOR A PARTICULAR
PURPOSE OR MERCHANTABILITY, ARE HEREBY DISCLAIMED. MANUFACTURER SHALL NOT BE LIABLE FOR
ANY SPECIAL, INDIRECT, INCIDENTAL OR CONSEQUENTIAL DAMAGES OR LOSSES, ARISING FROM ANY
CAUSE OR THEORY. Since some states or countries do not allow the exclusion or limitation of an implied
warranty or of incidental or consequential damages, this limitation of liability may not apply to you.

2

CONTENTS

CERTIFICATIONS AND PRECAUTIONS............................................................. 3

SYMBOLS USED IN THIS MANUAL .................................................................... 3

FOR UNITED KINGDOM ONLY............................................................................ 4

INTRODUCTION ................................................................................................... 4

UNPACKING YOUR INSTRUMENT ..................................................................... 5

GETTING ACQUAINTED ...................................................................................... 5

USING YOUR METER .......................................................................................... 5

OPERATING GUIDELINES................................................................................... 7

MEASUREMENT TECHNIQUES.......................................................................... 8

VOLTAGE MEASUREMENTS ............................................................................ 10

CURRENT MEASUREMENTS............................................................................ 14

RESISTANCE MEASUREMENTS ...................................................................... 15

DIODE MEASUREMENT .................................................................................... 16

MAINTENANCE AND REPAIR ........................................................................... 22

SPECIFICATIONS............................................................................................... 24

OPTIONAL ACCESSORIES ............................................................................... 27

CERTIFICATIONS AND PRECAUTIONS

This instrument is EN61010-1 certified for Installation Category I -1200V; Pollution Degree II, Class 2. It may only
be used to make measurements on energy limited circuits within equipment. All inputs are protected against
continuous overload conditions up to the limits of each function's stated input protection (see specifications).
Never exceed these limits or the ratings marked on the instrument itself. Always inspect your Multimeter, test
leads and accessories for signs of damage or abnormality before every use. If an abnormal condition exists
(broken or damaged test leads, cracked case, display not reading, etc.), do not use. Never ground yourself when
taking measurements. Do not touch exposed metal pipes, outlets, fixtures, etc., which might be at ground
potential. Keep your body isolated from ground and never touch exposed wiring, connections, test probe tips, or
any live circuit conductors. Do not operate instrument in an explosive atmosphere (flammable gases, fumes,
vapor, dust.) Do not use this or any piece of test equipment without proper training.

SYMBOLS USED IN THIS MANUAL

Refer to the manual

W

Dangerous voltage

X

Double Insulation

T

Earth Ground

J

B

Alternating Current

F

Direct Current

Complies with EU

P

directives

G

Diode

3

This meter is shipped with two power cords. The 117/230 volts
power switch on the rear panel has been set to 230 volts and the

0.08A fuse installed.

Please verify the switch and fuse for your location before
installing the power cord
To change to 117 V operation, install proper fuse at back panel
(see manual) and set switch to 117V.

This instrument is shipped configured for 230 volt operation. Operation at 117 VAC requires that the fuse be
changed and the proper power cord used.

FOR UNITED KINGDOM ONLY

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 colours 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 the letter E or by the earth symbol
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, cable of 0.75 mm should be
protected by a 3A or 5A fuse. Larger conductors would normally require 13A types, depending on the connection
method used. Any moulded mains connector that requires removal / replacement must be destroyed by removal
of any fuse & fuse carrier and disposed of immediately, as a plug with bared wires is hazardous if engaged in live
socket. Any re-wiring must be carried out in accordance with the information detailed on this instruction.

E

L

N

or coloured Green or Green & Yellow. The wire

INTRODUCTION

This instrument is a line powered, bench-type digital multimeter with a 4-1/2 digit LED display. The DMM can
measure AC/DC volts, AC/DC current, and resistance. Among other features:

• True RMS Measurements of AC or AC+DC Signals : True RMS measurement is the only accurate way to

directly measure AC or AC+DC signals that are not noise-free pure sine waves. This instrument measures AC
voltage frequencies up to 50 kHz.

• Five measurement functions :

• AC and DC VOLTS: Standard linear voltage measurements from 10 µV to 1200 VDC and 10 mV to

1000 VAC or AC+DC true rms.

4

• AC and DC Current: Standard current measurements from 10 nA to 20 ADC and 10 µA to 20 AAC or
AC+DC true rms.

• Resistance: Standard resistance measurements from 10 mΩ to 20 MΩ.

• Each measurement range has: Autopolarity operation. Overrange indication. Effective protection from

overloads and transients. Dual slope integration measurement technique to insure fast, accurate,
noise-free measurements.

• Diode test: Ranges of the resistance function that will turn on PN junctions allowing testing of diodes
and transistors. These ranges are marked with a diode symbol on the front panel of your DMM. The
preferred 2kΩ range is marked with the largest diode symbol.

• Improved test leads: Finger guards on the probes and shrouded contacts on the input terminals decrease

the possibility of accidental contact with circuit voltage.

• Long-term calibration accuracy: 1-year.

UNPACKING YOUR INSTRUMENT

The shipping box should contain this manual, your multimeter, test leads (one red and one black), two spare
fuses (2A); two spare fuses 0.08A (230V) and 0.125A (117V), and 2 power cords (1 - 115V and 1- 230V ). Check
the shipment for damage.

W CAUTION

This meter has dual operating voltages. It can be operated from 117VAC or 230VAC
source. The unit is shipped in the 230VAC configuration with an 0.08A / 250 V fuse
installed. If you plan to use the BDM40-UA on a 117 V source, unplug the power cord,
switch to the 0.125A / 250V fuse (supplied with instrument), and set the rear panel
switch to 117V.

If the meter maybe damaged if is not setup properly for the source voltage being used.

The label on the top side of your instrument is marked with the line voltage and
frequency required for proper operation. Refer to Maintenance section if a change in the
input power configuration is desired.

GETTING ACQUAINTED

Your meter is light-weight with a low profile, and requires little space on the work bench. The black case is made
of rugged, high-impact plastic. The handle can be rotated to eight positions. The right side of your DMM contains
two rows of switches and LED display. The power cord receptacle is located on the rear panel of your DMM. The
meter inputs are the 4 inputs on the front panel and are marked for the functions.

USING YOUR METER

The following paragraphs describe each of the controls on your DMM and how these controls can be used for
each instrument function. Exercises are included to help you familiarize yourself with your DMM and to verify that
your instrument is functional.

The LED Display

The high-contrast 4-1/2 digit LED display is easily read from across the room. It can register from 0000 to 19999
counts. For ease of discussion, the 19999 will be rounded to 20000 in the remainder of this text. For example, we
will refer to the 2V range, not the 1.9999V range. In all linear functions, the decimal point position is determined
by the range selected. Polarity of the input signal is indicated by a ‘ – ‘ sign at the center of the left side of the LED.
The + sign is disabled in the AC V, AC mA, and kΩ measurement functions. The ‘ – ‘ sign may appear in any
measurement function, but is normally not meaningful when making AC V, AC mA, and kΩ measurements. You

5

will only get this indication of an energized circuit if the power in the circuit is negative with respect to the
COMMON input terminal. If the power in the circuit is positive with respect to the COMMON input terminal, an
erroneous resistance will be displayed. If there is any doubt about whether there is energy remaining in the circuit
you are reading, read the resistance, then reverse the test lead positions. If the minus sign is displayed in either
case, the remaining energy must be removed from the circuit before correct resistance readings can be made. If
you apply an input signal that exceeds the limits of the range selected, the LED display will flash. All decimal point
positions appear in the display to indicate certain illegal combinations of front panel switch settings. For example,
if you select the DCV function and the 20M range, all four decimal points will appear on the display.

POWER Switch

The green POWER switch is located in the right corner of the DMM front panel. To turn the meter ON, push the
POWER button in. To turn the meter OFF, push the POWER button in.

CAT I
1200V

DC 1200V
AC 1000V

500V
MAX

20 A

20A MA X

TRUE

BDM40-UA

RMS

AC

DC

200mV 2 20 200

200u A 2mA 20mA 200m A 2A 20A

200 2k

1000VAC
1200VDC

20k 2 00k 2M 2 0M

POWER

mA-2A

2A MA X

V

COM

A

B

C

D

E

F

G

H

I

AC MAINS SELECTOR

117 V 230 V

MAINS SUPPL Y FUSE

117 VAC F 0.125 A / 250V
230 VAC F 0.08 A / 250 V

15 VA MAX 50 Hz / 60 Hz

117 VAC 105 VA C - 128 VA C
230 VAC 210 VA C - 257 VA C

WARNING

TO AVOID ELECTRICAL SHOCK
DISCONNECT TEST LEADS AND
POWER CORD BEFORE REMOVING
COVER.
DO NOT OPERATE INSTRUMENT
WITH COVER REMOVED.
TO PREVENT FIRE, REPLACE FUSE
WITH SA ME AND RA TING

MADE IN TAIWAN

SERIAL NO.

Voltage, Ohms, Diode and COM inputs.

Current (mA to 2A) and 20A inputs.

Reading display 0000 to 19999.

Power button (green).

Range selection switches. The pushbuttons are interlocked with the other ranges.

Function selection switches. The pushbuttons are interlocked with the other two white
function selection switches A and Ω.

Line Power connector.

Line Voltage selector switch.

Line Power Fuse.

Figure 1: BDM40-UA Controls

6

OPERATING GUIDELINES

To use your multimeter fully, there are some additional factors to be considered, such as measurement
techniques, the maximum signal input levels that will not damage your instrument, and common applications.

Operating Notes

The operating notes present the capabilities and limitations of this instrument and routine operator maintenance
instructions. Everyone using an DMM should be familiar with the operating notes.

Input Overload Protection

Exceeding the maximum input overload limits can damage your instrument. The
transient overload protection circuit is intended to protect against short duration high
energy pulses. The components used limit the protection to approximately five pulses
per second for 6kV - 10 microsecond pulses, and about 0.6 watts average for lower
amplitude pulses .

Each measurement function is equipped with input overload protection. Table 1 lists the overload limits for each
function.

Input Connections to Common

TO AVOID ELECTRICAL SHOCK AND/OR INSTRUMENT DAMAGE, DO NOT CONNECT THE
COMMON INPUT TERMINAL TO ANY SOURCE OF MORE THAN 500 VOLTS DC OR PEAK
AC ABOVE EARTH GROUND

This instrument may be operated with the common input terminal at a potential of up to 500V dc or ac peak with
respect to earth ground. If this limit is exceeded, instrument damage or an operator safety hazard may Occur.

W CAUTION

WX WARNING

Operating Power

This instrument is available in a universal version that uses 117V or 230V AC at 47 to 440Hz

Table 1. Maximum Input Signal Limits

FUNCTION
SELECTED

DC ALL RANGES 1200VDC or Peak AC

V

AC

2A Fuse protected: F 2A / 250V

DC or
AC

20A

kΩ ALL RANGES

RANGE SELECTED

20V, 200V, 1000V 1000VDC or Peak AC

200mV, 2V

ALL RANGES

INPUT

TERMINALS

V / Ω and

COMMON

mA / 20A and

COMMON

V / Ω and

COMMON

MAXIMUM INPUT OVERLOAD

1000Vrms for no longer than 15 sec.

Not fused

250VDC or VAC rms

7

MEASUREMENT TECHNIQUES

The information provided here describes techniques in measurement and interpretation of measurements that
may extend the usefulness of your DMM. These techniques, common throughout the electronics industry, have
been tailored specifically for this instrument.

AC Measurement Techniques

When making precise measurements of AC signals, there are special parameters that must be considered such as
the type of AC converter the meter uses (average, rms, etc.), crest factor, bandwidth, noise, etc.

True RMS

In order to compare dissimilar waveforms, calculate Ohm's law statements or power relationships, you must
know the effective value of a signal. If it is a DC signal, the effective value equals the DC level. If the signal is AC,
however, we have to use the root mean square or rms value. The rms value of an AC current or AC voltage is
defined as being numerically equal to the DC current or voltage that produces the same heating effect in a given
resistance that the ac current or voltage produces.

In the past, average responding converters were the type of converter most widely used. Theoretically, the rms

value of a pure sine wave is

meters converted to the average value, the rms value was

2 / 1 of the peak value and the average value is 2 / pi of the peak value. Since the

pi / 22 / 1 ÷ = )2 (2 / pi = 1.11 of the average

value when measuring a sine wave. Most meters used an average responding converter and multiplied by 1.11 to
present true rms measurements of sine waves. As the signal being measured deviated from a pure sine wave, the
errors in measurement rose sharply. Signals such as square waves, mixed frequencies, white noise, modulated
signals, etc., could not be accurately measured. Rough correction factors could be calculated for ideal waveforms
if the signal being measured was distortion free, noise-free, and a standard waveform. The true rms converter in
your meter provides direct, accurate measurement of these and other signals. Since this DMM is AC and DC
coupled, refer to the section on Voltage Measurement Techniques for combined AC and DC signal measurements.

Crest Factor

Crest factor range is one of the parameters used to describe the dynamic range of a voltmeter's amplifiers. The
crest factor of a waveform is the ratio of the peak to the rms voltage. In waveforms where the positive and
negative half cycles have different peak voltages, the higher voltage is used in computing crest factor. Crest
factors start at 1.0 for a square wave (peak voltage equals rms voltage).

FREQENCIES

SQUARE

WAVE

SINE WAVE

TRIANGLE

SAWTOOTH

MIXED

CREST FACTORWAVE FORM

1.0

1.414

1.732

1.414 to 2.0

Figure 2 Crest Factors

SCR OUTPUT

WHITE NOISE

AC COUPLED
PULSE TRAIN

8

SPIKE

CREST FACTORWAVE FORM

1.414 to 3.0

3.0 to 4.0

3.0

> 9.0