Megger TDR1000/3 User manual

TDR1000/3
TDR1000/3P
CFL510G
TDR500/3
Time Domain Reflectometers
User Manual

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CONTENTS
Introduction 6
Overview 8
Instrument layout and display 8
Controls 10
Rotary switch 10
Range and cursor control 11
Backlight and hold 12
Setup 13
Operation 14
General testing procedure 14
Operating modes 14
Connection to cable under test 15
Velocity factor 17
Pulse widths 18
Techniques 19
Test the cable from both ends 19
Care and maintenance 19
Battery 20
Battery replacement 20
Battery indicator 21
Specifications 22
Waste electrical and electronic equipment 24
Test Lead selection 26
Repair and warranty 27
Megger contact information 29

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GSAFETY WARNINGS
 Safety warnings and precautions must be read and understood before the instrument is used. All Safety warnings and
precautions must be observed during use.
 The circuit under test must be switched off, de-energised, securely isolated and proved safe before test connections are
 made.
 Use the correct lead set. On power systems the Megger fused lead set must be used. Refer to the Test Lead selection page in
this user guide to identify the correct lead set.
 The operator must verify that the circuit is safe before testing and take the appropriate precautions.
 Ensure that hands remain behind guards of probes/clips when testing.
 The instrument should not be used if any part of it is damaged. Also all test leads, probes and crocodile clips must be in good
order, clean and with no broken or cracked insulation.
 Disconnect the test leads before removing the battery cover. The battery cover must be in place whilst conducting tests.
 This product contains no user service parts.
 All relevant safety procedures must be followed.
THE INSTRUMENT MUST ONLY BE USED BY SUITABLY
TRAINED AND COMPETENT PERSONS

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Symbols
The following symbols are used on this instrument
GCAUTION: RISK OF DANGER
tEQUIPMENT PROTECTED THROUGHOUT BY DOUBLE INSULATION OR REINFORCED INSULATION
cEQUIPMENT COMPLIES WITH RELEVANT EU DIRECTIVES
EQUIPMENT COMPLIES WITH AUSTRALIAN EMC REQUIREMENTS (C-tick) (NOT FOR SAFETY)
THIS EQUIPMENT SHOULD BE RECYCLED AS ELECTRONIC WASTE

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Introduction
Thank you for purchasing this cable fault locator. Before attempting use of your new instrument please take the time to read this user guide,
ultimately this will save you time, advise you of any precautions you need to take and could prevent damage to yourself and the instrument.
This is an advanced instrument capable of identifying a wide range of cable faults. The instrument uses a technique called Pulse Echo (also
known as Time Domain Reflectometry or TDR). A pulse is launched into a cable from one end. This can be on either a pair of conductors, or
a conductor and the screen. The cable’s construction will determine its characteristic impedance and the velocity a pulse travels down the
cable.
The pulse velocity is normally described as a fraction of the speed of light and is called the Velocity Factor. By measuring the time between
the transmitted pulse and the reception of the reflected pulse, and multiplying this by the speed of light and the velocity factor, the actual
distance to the reflection point can be established.
Reflections are caused by changes in the cable’s characteristic impedance, such as poor joints or discontinuities. Faults showing impedance
higher than that of the cables normal impedance will cause a reflection of the same polarity, i.e. positive, while faults with impedance lower
than that of the cable will cause a negative going reflection. Matched cable terminations absorb all the pulse hence no “end of cable”
reflection will occur, the cable appearing endless. Open or short circuits will reflect all the pulse and a large reflection will be displayed. At an
open or short circuit all the transmitted energy is reflected and the TDR will not ‘see’ the cable beyond that fault.
As a pulse travels down a cable, the size and shape of that pulse is gradually attenuated by the cable. The pulse reduces in amplitude and
becomes more elongated or stretched. The level of attenuation (or loss) is determined by the cable type, the condition of the cable and
any connections along its length. The limit of how far you can see is determined by the point beyond which you will not be able to see or
distinguish a reflection. To help identify small reflections, especially at greater distance the instrument has an adjustable gain setting. By
increasing the gain small reflections become visible.
The velocity factor of the TDR must be adjusted to match that of the cable under test, allowing an accurate distance measurement to be
read directly from the instrument. Where the VF of a cable is not known, but the length is, the cursor can be set to the end of the cable and
the VF on the TDR adjusted until the correct cable length is displayed.

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The instrument can be used on any cable consisting of at least two separate conductive elements, one of which may be the armouring or
screen of the cable. It has internal matching networks to allow testing of 25 Ω, 50 Ω, 75 Ω and 100 Ω cables. (These typically correspond to
power, coaxial data and data/telecoms cable). By selecting the TDR impedance closest to that of the cable under test, maximum power can
be transmitted into the cable allowing long cables to be tested. If the impedance of the cable under test is unknown, the auto-impedance
function may be used to determine the cable impedance and set-up the TDR automatically.
The distance units can be changed between metres and feet. Display contrast is automatically adjusted for temperature, but can be adjusted
further for optimum display. A backlight aids viewing in low ambient light conditions.
The instrument can be powered by manganese alkali, or nickel-metal-hydride battery. All cells must be of the same type.

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Overview
Instrument Layout and Display
Backlit
256 x 128
dot matrix display
There is an audible tone on key
presses. A low tone means the key
is invalid
Left & Right Arrows
used in setup
Backlight
Hold key
Four Way Joy Switch
Mainly controls range and cursor
Rotary Switch
Turn to OFF to switch the instrument off. Turn to
any other position to turn the instrument on

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Display
Battery State Indication
Cursor 1
Cursor 1
Position
Distance Between Cursor 1 and 2
Cursor 2
Position
Hold Indicator
Cursor 2
Range
Impedance
Velocity Factor

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Controls
Rotary Switch
Turn the switch from OFF to another position to turn the instrument on. The instrument may be turned off, by switching to OFF, or the
instrument may switch itself off if it has not been used for 5 minutes or the battery is exhausted.
The other selections are:
*where fitted
Auto
*Cursor 2
*Cursor 1
Setup

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Range & Cursor Control
The range is set using the four way switch; press up to increase the
range and down to reduce the range.
Moving the four-way switch left or right will move the active cursor.