Radiodetection T631 TDR Operating Manual

T631 TDR

High Specification Coaxial
Cable Fault Locator

Operating Manual

Issue 6

Refer to Preface and Safety Instructions before operating

Radiodetection Ltd.

Western Drive

Bristol

BS14 0AF

United Kingdom

Tel: [phone]

Fax: [phone]

E-mail: [e-mail]

00901209-6

© Radiodetection Ltd 2007. All rights reserved.
This document is copyright and may not be copied or reproduced or transmitted or modified or used, in whole or in part, in any

way whatsoever, without the specific prior wr

itten consent of Radiodetection Ltd.

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T631 OPERATING MANUAL 2

CONTENTS

Page

1. Preface & Safety 5

2. Introduction 7

3. Front Panel - Controls & Indicators 11

4. Power Sources 16

5. Display 19

6. Operating Modes 20

7. Operating Instructions 21

7.1 General 21

7.2 Switch On 21

7.3 Programming from the Help Menu 22

7.4 Setting Dielectric (PVF) 23

7.5 Connecting to cable under test 27

7.6 Locating a cable fault 27

7.7 Use of left hand cursor 28

7.7.1 Eliminating the length of the test lead 29

7.7.2 Measuring between two features 29

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CONTENTS

Page

7.7.3 Resetting the LH cursor 30

7.8 Auto Fault Find 30

7.9 Return Loss Measurements 32

7.10 Filter 38

8. Use of the Memory 39

8.1 Storing a trace 39

8.2 Recalling a trace 39

8.3 Comparing a live and stored trace 39

8.4 Difference between a live and stored trace 40

9. RS232 Printing and PC Interface 41

10. Help Menu 43

11. Error Messages 44

12. Specification 45

13. Product Safety Data 53
Appendix – Bicotest Product Range 57

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T631 OPERATING MANUAL 4

1. PREFACE & SAFETY

1.1 HEALTH AND SAFETY AT WORK ACT 1974 SECTION 6.1 (C)

Thisproductistestedandsuppliedinaccordancewithpublishedspecificationsand,whenused
in normal or prescribed applications and within the parameters specified, it will not cause
danger or hazard to health or safety.

All usage of the product must be in accordance with the Operating Manual for this equipment
and any workonthe electricalcomponentshoused within the machine must be undertaken by
qualified personnel.

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1.2 SAFETY PRECAUTIONS

Forconnectiontolivecablesupto600 VRMSusethe Bicotest T631F Blocking Filter.

Only fit 2 Ah ‘C’size NiCad cells.
Do not charge the batteries when the ambient temperature is below 0°C.

AC adaptor and its carry pouch are not waterproof.

AC adaptor is for indoor use only.

The main unit is safe and conforms to IEC 1010. The AC adaptor conforms to the
manufacturers safety standards.

1.3 BATTERIES

The T631 is provided with a set of 2 Ah rechargeable NiCad cells. These are supplied in the
discharged state and must be charged for 24 hours before use. Charge the batteries as
describedin section 4.Note that full rated capacity maynotbeachievedforthefirstthreecycles
of use.

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T631 OPERATING MANUAL 6

2. INTRODUCTION

The Model T631 is a pulse reflection (TDR) Cable Test Set, for locating cable faults and
evaluating changes in impedance caused by connectors, taps, terminations etc. Pulses
transmitted into a cable are reflected by cable imperfections. The transmitted pulse and the
reflectedpulse(s) are shown on thedisplay.Thetimetaken by the pulse totraveltothe faultand
return is ameasure of the distance to the fault.Distance to fault is displayedon the screen after
the cursor is positioned to coincide with the start of the fault pulse. The type of fault can be
determined by analysis of the displayed waveform.

Althoughdesignedprincipallyfor50,75and93 Ω coaxial cables it is equally effectiveonothercable
types as a fault locator.

Impedance mismatches can be measured in terms of Return Loss (dBRL) with the location
displayed in feet, metres or time.

Principle features include a 15 location memory for trace storage with ability to transfer to a
printer or PC, and dual cursors for point to point measurements.

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2.1 SAMPLE TRACES

1.

Open circuit/high impedance series faults

Note: Positive (upward) reflection

2.

Short circuit/low impedance shunt faults
Note: Negative (downward) reflection

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T631 OPERATING MANUAL 8

Transmit Pulse Reflected Pulse

Transmit Pulse Reflected Pulse

The T631 will display:

a) A “live” trace.
b) A stored trace recalled from the memory.
c) A live and stored trace together for comparison.
d) The difference between a live and stored trace.

2.2 POWER SOURCE

The T631 is powered by 8 rechargeable cells in a compartmentaccessiblefrom the rear of the
T631, or from an external DC power source via the DC jack.

When operated from batteries, the T631 will automatically switch off before the batteries are
completely discharged.

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2.3 MAIN FEATURES

Figure 1 shows the front panel of T631.

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T631 OPERATING MANUAL 10

3. FRONT PANEL

3.1 CONTROLS

Switches the unit ON. To conserve battery life the unit will switch off 5 mins
after the last key operation. If automatically switched off all measurement
parameters will be restored when switched on again.

Switches the unit OFF. This will reset the instrument to the 6 m range, (or
equivalentinfeetortime),GainA1,2 nspulseandLINEmode.PVF,unitsand
impedance will remain as they were before switch off.

Rotary control to adjust the contrast of the screen display.It is recommended
that it is set to the mid position on switch on to obtain a display.

CURSORS – two independent cursors

Adjusts the position of the appropriate cursor. Cursors move left or right as
indicated.Ifhelddownthecursorinitiallymovesslowlyandwillthenaccelerate.
The cursor being moved is displayed as a solid line, the passive cursor is a
broken line.

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PULSE WIDTHS

Enablesthevarious pulse widths availableoneachrange to be selected.The
pulse widths are either automatically selected (AUTO) or set to a specific
value (MANUAL) via the HELP menu.

HORIZONTAL EXPANSION (ZOOM)

Enablesthetraceaboutthesolidcursortobeexpandedbyfactorsof2,4and8,
dependingonrangeselected(seeSection7.7andSection12,Specificationfor
further details).

OPERATION

Selects the operating mode (see Section 6 for further details).

DIELECTRIC

Used to set the appropriate velocity factor for the cable dielectric. The value
willincrementordecrement.Ifhelddownthevaluechangesslowlyatfirstand
then quickens.Also act as numbers 6 and 11.

RANGE

Selects the displayed range.The range will increase or decrease and if held
down will step through the available ranges. Also act as numbers 7 and 12.

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T631 OPERATING MANUAL 12

SHIFT

Adjusts the vertical position of the live trace. If held down the trace shifts

– slowly at first and then quickens.Also act as numbers 8 and 13.

AMPLITUDE

Adjusts the vertical amplitude of the trace. If held down the unit will step
through the available gain stages.Also act as numbers 9 and 14.

MEMORY

Enablesalivetracetobestored into any of 15 memorylocations.Also acts as
number 10.

Enables any of 15 stored traces to be recalled.Also acts as number 15.

BACKLIGHT

Switches the display backlight ON and OFF. The backlight will switch off
automatically after 5 minutes.Also acts as number 5.

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INTERFACE

Calls up a menu from which the displayed trace and data may be transferred
toaprinter,or memorised waveformsmaybetransferredtoa PC,or reloaded
from a PC.Also acts as number 4.

AUTO FAULT FIND

Causes the unit to search for the next significant reflection, startingfrom the
right hand cursor position (see Section 7.8). Also acts as number 3.

HELP MENU

Accesses a “Help” menu for setting machine parameters (see Section 10).
Also acts as number 2.

RETURN LOSS

Enables the return loss between the transmitted pulse and a selected
reflected pulse to be determined. Also acts as number 1.

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T631 OPERATING MANUAL 14

3.2 CONNECTORS
Input/Output

BNC socket to connect to the cable under test.

9 way D connector to interface with a printer or PC.

DC jack to supply 12 – 20 V external DC.
Note centre is positive.

3.3 CHARGE INDICATOR
Battery Charging

Charge Indicator illuminates when the internal battery is being charged.

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4. POWER SOURCES

4.1 INTERNAL BATTERY

4.1.1 RECHARGING

Thecellsmaybe recharged by connecting the ACadaptortothe DC power jack and leaving the
equipment switched off. The charge indicator will illuminate while the batteries are being
charged.Full charge is achieved in 14 hours. A fully charged battery will give approximately 8
hours operation if the backlight is not used. (see Section 12 ‘Power Source’ for details of
charging voltages).

Note:Whenfittingnewcells the initial charge period should be 24 hoursand14hoursthereafter.

4.1.2 MAXIMISING BATTERY LIFE

Do not recharge until the Battery Low warning is displayed.
Do not charge for more than 24 hours.
Stay within the RECOMMENDED temperature limits shown in the specification (Section 12).

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T631 OPERATING MANUAL 16

4.1.3 REPLACEMENT

Figure 2 shows the rear view of the unit.
Cells are accessed by removing the back

cover which is secured by 2 fasteners.
See specification (Section 12) for cell type.
Itis recommended that cellsare replaced as

a set of 8.

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Figure 2 – Battery Access

4.2 EXTERNAL DC

Theunitwillrunfromanexternal12 – 20 VDCpowersourceviatheDCjack.This maybeeither
the AC adaptor or any other DC supply that meets the specification.Centre is positive.

Notethat the batter ies arecharged when external 15 – 20VDCpoweris applied and the
unit is switched off – DO NOT FIT NON-RECHARGEABLE BATTERIES.

4.3 MEMORY BACK UP BATTERY

The memory back up battery is a lithium manganese cell which is part of the main PCB
assembly.

The life expectancy is typically four years and replacement is recommended every two years
during a routine service to avoid possible loss of stored traces.

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T631 OPERATING MANUAL 18

5. DISPLAY

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Figure 3 – T631 Display

6. OPERATING MODES

The unit has 4 display modes.

1. Line (L) thetraceobtainedfromthecableconnectedtotheBNCsocketisdisplayed.

2. Memory (M) the trace from a selected memory is displayed.

3. Dual (L & M) the trace obtained from the cable connected to the BNC socket and a

selected trace recalled from the memory are displayed simultaneously.

4. DIFF (L – M) the trace displayedisthedifferencebetweenthetraceof the cable connected

to the BNC socket and a selected trace from the memory.

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T631 OPERATING MANUAL 20

7. OPERATING INSTRUCTIONS

7.1 GENERAL

For correct operation the cable under test should be taken out of service with all sources of
supply removed.If this is not possibleand the cable is energised or likely to become energised
then the blocking filter accessory should be used.

RF signals present on telecommunications cables may corrupt the display.

7.2 SWITCH-ON

Powertheunitfrompreviouslycharged internal batteries or fromtheACadaptor,orexternal DC
source.

Press the on button and the display should appear.
Rotate the contrast control if necessary to obtain a well defined trace.
On receipt from the factory the unit will powerup in the LIVE cable mode, on the 6 m range, with

thedistancereadoutinmetres,apropagationv elocityfactor (PVF)of0.667andimpedance75 Ω.
The left hand cursor,(dotted), will be at the startof the transmitted pulse (0 m). The right hand

cursor, (solid), will be approximately one third of the way across the display.

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Thedistanceunits,impedanceandthePropagation VelocityFactorMode (i.e.PVF,V,or

V
2

)

can be re-programmed via the HELP menu and once programmed will be set automatically
on switch on thereafter.

Should the unit switch off automatically, the last established machine settings are restored
when the unit is switched on.

7.3 PROGRAMMING FROM THE HELP MENU

7.3.1 DISTANCEUNITS

Press HELP key to obtain the Menu.
Selects UNITS by pressing the key indicated.
Select Feet, Metres or Time by pressing the appropriate key.

7.3.2 DIELECTRIC PARAMETERS

Press HELP key to obtain the Menu.
Select DIELECTRIC by pressing the key indicated.
Select PVF, V, or

V
2

by pressing the appropriate key.

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T631 OPERATING MANUAL 22

7.3.3 IMPEDANCE

Press HELP key to obtain the Menu.
Select IMPEDANCE by pressing the key indicated.

Select 50, 75 or 93 Ω by pressing the appropriate key.

7.3.4 PULSE SELECTION

A fixed pulse width may be selected by pressing HELP,PULSE WIDTH and then choosing the
required pulse.This pulse width will then apply to all ranges and the pulse width control will not
function until auto is restored, or the unit is switched off.

Auto pulse selection allows the instrument to select a pulse appropriate to the selected range.
This mode is selected by pressing HELP and then selecting PULSE WIDTH and AUTO.

7.4 SETTING DIELECTRIC (PVF)

7.4.1 FROM CABLE TYPE

Theunitcanbedirectlyprogrammedfromthelist of cable types containedintheHELPMenu.
To access the Menu, press HELP, press the key appropriate to CABLE TYPE. From the list of

options select the appropriatecategory and then the particularcabletype.The available cable
types are shown in the following table.

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On returning to normal operation the display will confirm the selected PVF value.

Note:The PVF values are nominal values and variations may be encountered. The DIEL keys
are then used to set the specific value.

The PVF (DIEL) can also be set using the DIEL controls to the value appropriateto the cable
under test.

OPTION MAIN TYPE SUB TYPE DIELECTRIC SETTING

M/µs

(PVF) V V/2

1 TELEPHONE POLY PE

JELLY FILLED
PAPER (0.83 uF)
PAPER (0.72 uF)

0.667

0.64

0.72

0.88

200
192
216
264

100

96
108
132

2 POWER PILC 25 kV

XLPE
MIC

0.54

0.52

0.41

162
156
123

81

78

62

3 CATV QR PARA III

PARA I
T, TR
TX, TX10
RG6, RG11, RG59

0.88

0.82

0.87

0.89

0.82

264
246
261
267
246

132
123
131
134
123

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T631 OPERATING MANUAL 24

OPTION MAIN TYPE SUB TYPE DIELECTRIC SETTING

M/µs

PVF V V/2

4 IBM TYPE 1

TYPE 2
TYPE 3
TYPE 6
TYPE 9

0.78

0.78

0.62

0.78

0.69

234
234
186
234
207

117
117

93
117
104

5 DATA RG58

RG58U
THICK ETHERNET
THIN ETHERNET
RG11, RG6

0.78

0.66

0.78

0.67

0.82

234
198
234
201
246

117

99
117
101
123

For conversion 1 metre = 3.28 feet.

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IfthevalueofthePVForthecable type is not knownthenthePVFcanbedeterminedasfollows.

7.4.2 DIELECTRIC CONSTANT(PERMITTIVITY) KNOWN

PVF =

1

ε

Example: For polyethylene ε = 2.25

PVF ==

1

225

0667..

7.4.3 SHORT LENGTH OF SAME TYPE OF CABLE

1. Measure physical length of the sample.

2. Obtain a reading for the apparent length of the cable using any PVF value.

3. Adjust the PVF value until the distance reading indicated is the same as the measured

length.

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T631 OPERATING MANUAL 26

7.5 CONNECTING TO CABLE UNDER TEST

Connect the cable under test directly to the BNC socket or via the test lead supplied.
UnlesstheLHcursorismovedtocoincidewiththeendofthetestlead,thedistanceread out will

include the length of the test lead which must be subtracted from the reading obtained.

7.6 LOCATING A CABLE FAULT

Set the DIEL appropriate to the cable type (see Section 7.4).Select a RANGE to coverthe full
cable length.Use “AUTO”Pulse Width selection unless a specific pulse width is preferred.

Adjust the AMP controls until the fault reflection is observed.
If the fault reflection is less than halfway across the screen select a shorter range and a

narrower pulse width for optimum results.
If there is no fault reflection there are two possibilities.

1. Thecablelength is longer thanits recorded length. In this case increase the rangeuntil a
reflection is seen.

2. The fault is very close to the position at which the instrument is connected. In this case
reduce the range until a reflection is seen. In both cases, use may be made of the auto
fault find facility (see Section 7.8).

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AdjusttheRight Hand cursor controls to bringthe RH cursor to the pointatwhich the startofthe
reflected pulse just leaves the horizontal as shown.

The distance to the fault is as indicated on the LCD.
For closer examination, press ZOOM to expand the trace and reposition the cursor more

precisely .
Remember to subtract the length of the test lead if used.

7.7 USE OF THE LEFT HAND CURSOR

The left hand cursor can be moved to:

1. Eliminate the length of the test lead.

2. Measure between any two features on the trace.

3. Whenmovedthe LH cursorbecomes the livecursor and changes to a solid line, with the

RH cursor becoming a broken line.

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7.7.1 ELIMINATINGTHE LENGTH OF THE TEST LEAD

Connect the test lead to the unit. Select 3 m or 6 m range.
Adjust the controls so that the reflection from the end of the test lead is obtained.
Using the LH cursor controls move the LH cursor to the start of the reflection.
Connect the test lead to the cable under test and locate the fault as described in Section 7.6.

NB: The distance to fault is now that from the end of the test lead.

7.7.2 MEASURING BETWEEN TWO FEATURES

Using the LH cursor controls set the LH cursor to the start of the feature on the LH side.
Using the RH cursor controls set the RH cursor to the start of the feature on the RH side.
The RH cursor is then live and becomes a solid line with the LH cursor a broken line.
Thedistance read out is the distance between the

two cursors as shown.
IntheZOOMmode,ifacursorisnotonthescreen

it cannot be moved.Therefore if a measurement

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between two features is to be made in ZOOM mode, position cursors at the relevant positions,
then ZOOM and make any fine adjustments as necessary. The readout is always the distance
between the cursors, even if one is not on the screen. Since expansion takes place around the
live(solid) cursor, the ZOOM facility can be activated by either the left orright cursor by moving
the relevant cursor and thereby making it solid.

7.7.3 RESETTING THE LH CURSOR

The LH cursor may be reset to `0' for normal measurements by switching the unit off and on.
Note that the instrument is calibrated such that cable lengths are measured from the co-ax

socket.Dueto the internalwiring of the instrument, this may result in the left hand cursor being
set a short distance into the displayed transmit pulse, especially on the short pulses. This is
correct and ensures accurate cable length measurements.

7.8 FIND FAULT – ENSURE RANGE SETTING IS FULL AND NOT EXPANDED (ZOOM)

The “FIND FAULT” function is a means whereby the unit will automatically scan a cable and
locate the nearest significant feature and configure the parameters of the unit to optimally
display the feature.

Pressing the key a second or subsequent time locates the next significant feature along the
cable.

Itis essential that the PVF is set to the valueappropriate to thecable type in orderthat distance
measurements are accurate (see Section 7.4).

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T631 OPERATING MANUAL 30

Having obtained the display the parameters may then be altered if required.
This feature is intended for use on coaxial cableswhere the reflection from a fault may be quite

small, so the sensitivity used is quite high. On a power cable or twisted pair telephone cable,
mismatches due to joints, or change of cable type may give rise to many reflections which the
instrument will detect even though they are not faults.

7.8.1 OPERATION

The FIND FAULT function starts at the location of the RH cursor and searches to the right.
Therefore for a full search the RH cursor should first be placed just to the rightof the transmit
pulse.

Pressing the FIND FAULT key will start the search. This may take several seconds. While
searching, “AFF” is displayed in place of the usual mode display.

Searching is carried out on all ranges from the one appropriate to the starting cursor position
(6 m range if the cursor starts on zero) to 12 Km. Gain and Pulse Widths appropriate to the
range are used.

When a fault is found,the unit will beep twice and place the RH cursor just before the fault.Ifno
fault is found the unit will beep 4 times, and return to the original conditions.

Pressing FIND FAULTagain will cause the next fault to be found.Note that “FIND FAULT” may
change the machine settings.

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7.9 RETURN LOSS (dBRL) MEASUREMENTS

The T631 has two principles of operation.

1. Simple fault location.

2. Qualitative measurement and location.

In the Simple Fault Location mode the pulse width is automatically selected with each range to
onebest suited to provide a strong reflection from the fault, in orderto easily identify and locate
it.Nosignificant conclusion can be drawn from the amplitude of the reflected pulse although its
polarity is indicative of the type of fault.

i.e. Upwards – positive – high series impedance

Downwards – negative – low shunt impedance

In order to gain a measure of the significance of the reflection it is necessary to compare the
amplitude of the reflected pulse with that of the transmitted pulse.

The amplitude of the reflection resulting from an impedance change, relative to that of the
transmittedpulseis a measure of theimpedancemismatch at that point andthe ratio is referred
to as the reflection coefficient.

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T631 OPERATING MANUAL 32

Reflection coefficient

ρ=

Ar
At

where

Ar = amplitude of reflected pulse
At = amplitude of transmitted pulse

The amplitude of the reflected pulse cannot normally exceed that of the transmitted pulse and
therefore the reflection co-efficient cannot exceed unity. It is usual therefore to express the
reflection in percentage termsor millirhos (mρ) where:

1000 mρ = 1 rho = 100 % reflection
ImpedancemismatchescanalsobeexpressedlogarithmicallyintermsofReturnLosswhere:

Return Loss = 20 log

10

At
Ar

dB

or Return Loss = 20 log

10

1

ρ

dB

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At

Ar

A conversion chart is given below:

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Reflection Coefficient/Return Loss Conversion Chart

The foregoing assumes an ideal “lossless" cable.In practice, measurements obtained include
the effect of pulse attenuation due to cable loss and requires correction in order to obtain true
return loss.

i.e.True Return Loss = Measured Return Loss – Pulse Attenuation
Sincethe amplitude of the reflection varies with the pulsewidth it is essentialwhen determining

Return Loss to use the SAME PULSE WIDTH for all measurements.
This is facilitated by the HELP Menu. Press HELP and then the appropriate key for

PULSE WIDTH. From the list of options select the pulse appropriate to the measurement. On
returning to the trace the selected pulse width will be confirmed on the display,and the PULSE
key will be inoperative.

TheoutputimpedanceoftheT631mustbesettomatch the impedance of the cableundertest.

7.9.1 MEASUREMENT OF RETURN LOSS (dBRL)

Through the HELP Menu select the IMPEDANCE to match the cable under test.
Similarly select the PULSE WIDTH appropriate to the measurement.
To minimise any possible mismatches the cable under test should be connected directly to the

unit using matched connectors.

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Select the appropriate RANGE & PVF.
Set the AMP to A1 (0 db) on the LCD.
Ensure that the LH cursor is set to the start of the transmitted pulse or a particular pulse if an

interfeature measurement is required.
Increase the AMP control until the desired reflection is obtained.
Move the RH cursor to coincide with the start of the reflected pulse.
Check the distance reading to confirm the location - note the distance.
Press dBRL and the Return Loss in dB will be calculated and displayedon the LCD together

with the corresponding reflection co-efficient.
The result is “Measured Return Loss” which requires correction for Pulse Attenuation.
Press RS232 key to print results.Note: this option is not displayed on screen but is available.

Ensure printer lead is plugged into the instrument and printer and that the printer is ready to
print (see section 9).

Press key 8 to return to normal operation.

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T631 OPERATING MANUAL 36

Notes
a) Note that a positive dB value (or mrho value <1000) indicates a return loss (i.e. the

reflectionissmallerthanthetransmitpulse).Undercertainconditionsitispossibleforthe
reflectionto have a greatervoltageamplitude than the transmit pulse.In this case the dB
value will be shown as negative and the mrho figure will be greater than 1000.

b)

If the return loss is outside the range of the instrumentthenXXX dB and XXX mρ will be
displayed.

c) The position of the cursor prior to pressing dBRL is important as the signal level at that

point is used as the zero reference.Be sure to place the cursor on the flat section of the
trace just before the pulse.

d) Whenmeasuring very smallreflections switching the filter incan improve the performance

of the return loss function.

7.9.2 MEASUREMENT OF PULSE ATTENUATION

This should be determined using a sample length of the same type of cable as that under test.
Connect the cable directly to the T631 with the end shorted or open.
Measure the Return Loss and the length. Since the cable ends provides a 100% (0dB)

reflection, the loss measured is entirely due to the pulse attenuation.

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Divide the loss obtained by the cable length and obtain the pulse attenuation loss in dB per
metre or per foot.

Multiply by the distance reading for the cable length noted in the Return Loss measurement to
obtain the appropriate pulse attenuation.

Obtain the TRUE RETURN LOSS from:
True Return Loss = Measured Return Loss – Pulse Attenuation.

Note: Pulse Attenuation (Cable Loss) is frequency dependent and will be higher for narrow
pulse widths than wider pulse widths. The pulse width used for measuring pulse attenuation
MUST be the same as that used to measure the Return Loss.

AlibraryofPulseAttenuation(CableLoss)fordifferentcabletypesfordifferentpulsewidthscan
be compiled using the procedure detailed in “Measurement of Pulse Attenuation”.

7.10 FILTER

A low pass filter is available from the Help menu. It is used to reduce noise, especially on high
gain settings.It should not be used with the 2 ns and 10 ns pulses.

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T631 OPERATING MANUAL 38

8. USE OF THE MEMORY

8.1 STORING A TRACE

Obtain the desired LIVE trace using the method previously described in Section 7.
Press the SAVE key and then select the desired Memorylocation by pressing the appropriate

key.
The live trace is now stored in the selected memory location, together with the associated

machine settings.
Any trace present in the memory will be overwritten and lost.

8.2 RECALLING A STORED TRACE

Press the RECALL key and then select the desired memory location.
The stored trace will then be displayed on the LCD and memory location confirmed.
The machine parameters are set in accordance with the stored trace, and cannot be altered.

8.3 COMPARING A LIVE AND STORED TRACE

Press the MODE key and select L & M. The displayed memory waveform will be the last one
that was accessed by either SAVE or RECALL.

T631 OPERATINGMANUAL 39

Radiodetection Ltd. 00901209-6

Recall the appropriate stored trace from memory as described earlier.
The machine parameters are set in accordance with the stored trace.
If not already connected to thecable under test, connect to the cable and observe that boththe

live trace and the recalled trace are overlaid.
TheSHIFT control may be used toseparate the traces for easier identification and comparison.

The live trace moves relative to the stored trace.

8.4 DIFFERENCE BETWEEN A LIVE AND STORED TRACE

Press the MODE key and then select L – M.
Recalltheappropriatestoredtracefrommemoryasdescribedearlier.The machine parameters

are set in accordance with the stored trace.
If not already connected to the cable under test, connect to the cable and observe the trace

which is the difference between the live and recalled trace.
ToviewtheLIVEtraceandrecalledtraceseparatelyuse the MODE keyandthenselectLIVE(L)

OR MEMORY (M) as required.

Radiodetection Ltd. 00901209-6

T631 OPERATING MANUAL 40

8.5 HELP MENU

When in the MEMORY mode, if the HELP menu is accessed, those keys that affect set
parameters are disabled.

9. RS232 – PRINTING AND PC INTERFACE

Screen information and Memory contents can be transferred to a printer or PC via the RS232
interface.

9.1 PRINTING

AsuitableprinteristheSeikoDPU411 – 21Bavailablein220 V50 Hzor120 V60 Hzversions.
Otherprintersmayrequireadifferentinterfacecableandprinterset-upanddetailsoftheRS232
interface is given in the specification Section 12.

T631 OPERATINGMANUAL 41

Radiodetection Ltd. 00901209-6

9.2 PRINTER SET-UP SEIKO DPU 411-21B

The DIP switch on the printer must be set as shown below.

Connecttheinterfacecablesuppliedwith the printerbetween the printer and the RS232 port.
Obtain the required display on the screen, either a live trace, a recalled memory trace, or an

L & M or L – M trace.
Depress the RS232 key and select menu option 1 “PRINTER”. The display will then display

“PRINTING” as the data is transferred to the printer.

9.3 PC TRANSFER

A PC software kit, X600 TRACEability™ is available. This enables a cable database to be
established.Data from all memories can be transmitted to, and received from, a PC.See the
manual supplied with the software for full instructions.

Radiodetection Ltd. 00901209-6

T631 OPERATING MANUAL 42

10. HELP MENU MACHINE SET UP

1. Impedance 4. Dielectric 6. Pulse Width
93Ω

1 PVF 1 2 ns 1

75Ω

2 V 2 10 ns 2

50Ω

3 V/2 3 30 ns 3
Help Menu 7 Help Menu 7 100 ns 4
Operation 8 Operation 8 300 ns 5

1200 ns 6

2. Filter 5. Cable Type Auto 7
Filter ON/OFF Telephone 1 Operation 8

Power 2

3. Units CATV 4 7. Help Text
Feet 1 IBM 4 Explanation 1
Metres 2 Data 5 2
Time 3 Help Menu 7 3
Help Menu 7 Operation 8 4
Operation 8 6

7
8

8. Operation

T631 OPERATINGMANUAL 43

Radiodetection Ltd. 00901209-6

11. ERROR MESSAGES

WhenswitchedontheT631performs a selftest.Ifitfailsthe followingmessageisdisplayed:

INTERNAL MALFUNCTION ERROR XX

PLEASE REFER TO MANUAL

Please contact your supplier and report the error number.

.

Radiodetection Ltd. 00901209-6

T631 OPERATING MANUAL 44

12. SPECIFICATION

All specifications in this section assume a PVF of 0.667.
1 metre is equivalent to 3.28 feet or 10 nanoseconds.

RANGES AND RESOLUTION:

Maximum
Displayed

Range Nominal

Horizontal

Expansion (Zoom)

Resolution at

Max Zoom

3 m x1 13 mm

6 m x1 26 mm
12 m x1, x2 26 mm
25 m x1, x2, x4 26 mm
50 m x1, x2, x4, x8 26 mm

100 m x1, x2, x4, x8 52 mm
200 m x1, x2, x4, x8 0.1 m
400 m x1, x2, x4, x8 0.2 m

800 m x1, x2, x4, x8 0.4 m
1600 m x1, x2, x4, x8 0.8 m
3200 m x1, x2, x4, x8 1.6 m
6400 m x1, x2, x4, x8 3.2 m

12800 m x1, x2, x4, x8 6.4 m

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Radiodetection Ltd. 00901209-6

Accuracy Typically <0.5%

(48 m range and above)

Dielectric PVF 0.300 - 0.999

V 90 - 300 m/µs
V/2 45 - 150 m/µs

Cursors

2

Pulse Characteristics:

Waveform

Amplitude

Pulse Widths

Source Impedance

Connector
Protection

Mode Selection

Filter

Sine Squared
Nominally 2.5 V into selected

impedance
2, 10, 30, 100, 300, 1200 ns half

height nominal
50, 75 or 93 Ω
BNC Female
250 V RMS, 0-60 Hz
Auto or Manual
16 Mhz Low Pass Filter

VERTICAL DEFLECTION:

SENSITIVITY

Gain Setting Signal for

Full Scale Deflection

A1
A2
A3
A4
A5
A6
A7
A8
A9
Aa
Ab

16 V

8 V
4 V

2 V
960 mV
480 mV
240 mV
120 mV

60 mV
30 mV
15 mV

Radiodetection Ltd. 00901209-6

T631 OPERATING MANUAL 46

T631 OPERATINGMANUAL 47

Radiodetection Ltd. 00901209-6

AUTO MODE PULSE SELECTION

Nominal Range
(@PVF = 0.667)

Default Pulse

(ns)

Available Pulses

(ns)

3 m

6 m
12 m
24 m
48 m
96 m

192 m
384 m
800 m

1600 m

& above

2

2
10
10
30

100
100
300
300

1200

2, 10
2, 10
2, 10, 30
2, 10, 30
2, 10, 30, 100
2, 10, 30, 100
2, 10, 30, 100, 300
2, 10, 30, 100, 300, 1200
2, 10, 30, 100, 300, 1200
2, 10, 30, 100, 300, 1200

Return Loss Measurement Range: 0 dB to > 30 dB

Display Modes Line (L)

Memory (M)
Comparison (L & M)
Difference (L-M)

Memories 15 - Stores trace displayed in Mode L.

Interface RS232 to printer or PC.

Connector 9 pin D Male.
Configuration 4800 baud, no parity, 8 bits, 1 stop bit.

PIN FUNCTION DIRECTION

2 Received Data (RXD) Input
3 Transmit Data (TXD) Output
5 Ground
6 Data Set Ready (DSR) Input
7 Request To Send (RTS) Output

Display 240 x 128 pixel LCD

240 x 100 pixel waveform area

Radiodetection Ltd. 00901209-6

T631 OPERATING MANUAL 48

Backlight LED with auto switch off (5 mins)

Keyboard Sealed membrane

Power Sources Battery - internal rechargeable NiCad provides 8 hours operation (excluding backlight).

Cells - 8 x R14

External DC:

Operating 12 to 20 V 0.25 A
Charging 15 to 20 V 0.25 A
Connector 2.1 x 5.5 x 9.5 mm plug centre positive (reverse polarity protection).

Dimensions 300 x 183 x 75 mm

Weight 2.5 kg (including batteries & carry bag)

Accessories Carry bag - soft weatherproof bag with shoulder strap and accessory pouch.

AC Adaptors - 120 V or 230 V 50/60 Hz (see separate specification).
Test Lead - 3 metre 75 Ω BNC/BNC + BNC/Crocodile clip + BNC/F Adaptor
Operating Manual

Safety IEC 1010-1

T631 OPERATINGMANUAL 49

Radiodetection Ltd. 00901209-6

AC Adaptors UK

230 V ±10% 50 Hz 90 mA
Output 15 V DC 400 mA

North America
120 V ±10% 60 Hz 180 mA
Output 15 V DC 400 mA

Europe
230 V ±10% 50 Hz 90 mA
Output 15 V DC 400 mA

Environmental & Safety
(Main Unit)

Safety
Maximum permissible voltage

on input connector for safe
operation

BS EN 61010-1 : 1993 and IEC 1010-1 : 1990 and Amendment 1 : 1992
30 V RMS

Radiodetection Ltd. 00901209-6

T631 OPERATING MANUAL 50

Temperature Operating temperature:

Including batteries: 0°C to +50°C
Excluding batteries: -5°C to +50°C

Storage temperature:
Including batteries: -20°C to +50°C
Excluding batteries: -20°C to +65°C

Recommended temperature
limits to maximise battery life
(for Varta RSH2K cells)

Damp Heat, Steady State

Damp Heat, Cyclic

Charging: +10°C to +35°C
Discharging: -5°C to +45°C
Storage: 0°C to +45°C

BS 2011, part 2.1 Ca : 1977 (IEC 68-2-3 : 1969)
40°C, 93% RH, 4 days

BS 2011, part 2.1 Db : 1981 (IEC 68-2-30 : 1980)
25°C, 95% RH, 12 hr
55°C, 93% RH, 12 hr
6 cycles

Low Air Pressure BS 2011 part 2.1 M : 1984 (IEC 68-2-13 : 1983)

Non operational: 150 mb 16 hours
Operational: 533 mb 30 minutes

T631 OPERATINGMANUAL 51

Radiodetection Ltd. 00901209-6

Random Vibration BS 2011 part 2.1 Fdb : 1973

5 to 150 Hz, 0.005g

2

/Hz
2 hours in each of 3 planes
(in soft carry case)

Shock

Bump

BS EN 60068-2-27 : 1993 part 2, test Ea (IEC 68-2-27 : 1987)
50g, 11ms
(in soft carry case)

BS EN 60068-2-29 : 1993 part 2, test Eb (IEC 68-2-29 : 1987)
40g, 6ms, 1000 bumps in each of 3 axes
(in soft carry case)

Free Fall

Water and dust Protection

BS EN 60068-2-32 : 1993 part 2, test Ed (IEC 68-2-32 : 1975)
1m
(in soft carry case)

BS EN 60529 (IEC 529 : 1989)
To IP54

Radiodetection Ltd. 00901209-6

T631 OPERATING MANUAL 52

13. PRODUCT SAFETY DATA

The T631 is a Pulse Echo TestSet that provides visual indication of cable faults. The T631 is
tested and supplied in accordance with our published specifications,and when used in normal
or prescribed applications within the parameters specified for electrical and mechanical
performance, will not present any danger or hazard to health or safety, provided normal
engineering and safety practices are observed.

Doubt relating to any aspect of usage of this instrument must be referred to Bicotest Limited.

13.1 QUALITY

Bicotest Limited is a BS EN ISO 9001 registered company.

13.2 POWER SUPPLY

a) The instrument is fitted with eight rechargeable NiCad batteries type R14 with capacity of

2 Ah. Replacement batteries must be of similar type, preferably Varta type RSH2K. A
quickblowfusethatis not accessible to theoperatorisfittedtoprotectthebatterycircuit.

b) The instrument can also be powered with an external 12 to 20 V DC source 0.25 A as

outlined in specification (section 12). A quick blow fuse that is not accessible to the
operator is fitted to offer protection.

c) The instrument can also be poweredwith an optional AC Adaptor (forfurther details see

specification, section 12).

T631 OPERATINGMANUAL 53

Radiodetection Ltd. 00901209-6

13.3 ROUTINE SERVICING

ItisrecommendedthattheinstrumentisreturnedtoBicotestLimitedeverytwoyearsforservice
and calibration checks. The instrument is fitted with eight rechargeable NiCad batteries type
R14 with capacity of 2 Ah. Replacement batteries must be of a similar type, preferably Varta
type RSH2K.

13.4 COMPOSITION/TOXIC HAZARDS

Under normal conditions of use, storage and handling, the T631 presents no toxic hazards,
however, in certain circumstances the following could apply:

a)

Incineration

Theinstrument houses NiCad batteries andthesemustnot be incinerated.Additionallysome

of the electronic components included in the assembly are constructed with resins and other
chemicals which produce toxic fumes during incineration. It is required that the instrument is
submitted to the correct authority for disposal in accordance with local by-laws.

b)

Acidic or Caustic Compounds

Some of the electronic components included in the assembly, particularly the electrolytic
capacitors contain acidic compounds. In the event of any damaged items coming into contact
with the skin, the affected area should be washed with clean, cold water. In the event of eye
contamination, thoroughly irrigate with recognised eyewash and seek urgent medical
assistance.

Radiodetection Ltd. 00901209-6

T631 OPERATING MANUAL 54

c)

Physical Damage

Some of the components used in the assembly may contain very small quantities of toxic
materials.Thereexistsaremotepossibilitythatphysicallydamagedcomponentsmaypresenta
toxic hazard. As a general precaution avoid unnecessary contact with damaged electronic
components and arrange fordisposal in accordance with local legislation that may currentlybe
in force.

13.5 TRANSPORT AND HANDLING

The instrument is supplied in a soft carry bag which offers adequate protection under normal
working conditions. For transportation over long distances the instrument should be suitably
packed in a box filled with shock absorbing material such as bubblepack or corrugated
cardboard.

13.6 STORAGE

The instrument should be stored in a dry, clean environment. The NiCad batteries will self
discharge within three months and it will be necessarytofully charge the batteries which takes
14 hours using the recommended AC adaptor outlined in specification (section 14).

No hazard is anticipated during storage.

13.7 DISPOSAL

When disposing of electrical and electronic equipment or packaging materials, exercise
precautions that are required by local legislation.If in doubt, contact the local authority.

T631 OPERATINGMANUAL 55

Radiodetection Ltd. 00901209-6

13.8 SAFE USE

The T631 is designed to be used by suitably trained personnel following the procedures and
instructions described in this operating manual. Additionally, the following points should be
noted:

a)

Personal Protection/Protective Clothing

NotnecessaryforoperatingtheT631,providingthatnormalsafeworkingpracticeisobserved.

b)

Working Environment

No special precautions are needed for operating the T631. Appropriate precautions must be
observedforpotentiallyhazardous,working environments such as construction site installations,
electricity substations, explosive atmospheres, etc.

Radiodetection Ltd. 00901209-6

T631 OPERATING MANUAL 56

T631 OPERATINGMANUAL 57

Radiodetection Ltd. 00901209-6

Other products available from Bicotest:

VIXXON™ S3000 Intermittent LV Fault Location System

The unique system solution to intermittent LV Faults

BOXXER™ S4000 Power Cable Fault Location System

The system solution to intermittent, flashing and high resistance HV faults

AXXIS™ S5000 Sheath Fault Location System

The cost-effective, system solution to cable sheath faults

P109 and P122 DC and ACTest Sets

HV test sets for proof testing on cable and equipment

VICTORT120A

For safe, hand-held fault sectioning on medium voltage networks

M225 Cable and Pipe locator

For location and route tracing of cable and pipes

LEXXI™T810

A universal hand-heldTDRforuseonalltypesof metallic cable,includingliveACwhenusedwiththeblockingfilterlead

T600 SeriesTDRs

World class, user-friendly cable fault locators which feature interface with PCs via X600TRACEability software

T631F,T620FS,T620FD Blocking Filters

Single and dual input LV mains blocking filters for use with T600 series TDRs

T272 High Resistance Cable Fault Locator

For location of high resistance insulation faults of up to 200 megohms

Please contact our sales Office for further information on the above systems.

Radiodetection Ltd. 00901209-6

T631 OPERATING MANUAL 58

The Bicotest Comprehensive

HV and LV Fault Location Process

TDR

<300 Ohms

>300 Ohms

Intermittent

Fault

Fault Triggers

DAU

Establish

Cable Length

Prelocate

Fault

Prelocate

Fault

Pinpoint
Fault

Pinpoint
Fault

Locate
Fault

Locate
Fault

Sheath

Fault

Resistance HV

Faults

Intermittent,

Flashing or High

TDR

VIXXON
S3000 SP

TM

VIXXON
S3000 SP

TM

BOXXER

S4000

TM

BOXXER

S4000

TM

AXXIS

S5000

TM

AXXIS

S5000

TM

LV

Fault Diagnosis

HV Fault
Diagnosis

BOXXER S4000

TM

LV & HV
Fault Diagnosis
AXXIS S5000

TM

T272

High Resistance

Fault Locator

LINXX

B110

TM

FIX

FAULT

Locate
Fault