ASL INTERCOM CTR5000 User manual

CTR5000 Operating Instructions
ASL operating instructions, model CTR5000 i
Manual
Precision thermometer CTR5000
Accuracy 0.01 K
Version 1.1, 03/14

CTR5000 Operating Instructions
ii ASL operating instructions, model CTR5000
Contents
CONVENTIONS USED IN THIS MANUAL...................................................................................................... VII
Structure of manual ............................................................................................................................. vii
Terminology.......................................................................................................................................... vii
Warnings and Notices ......................................................................................................................... vii
IMPORTANT SAFETY INFORMATION .......................................................................................................... VIII
IMPORTANT INSTALLATION INFORMATION ..................................................................................................X
IMPORTANT PROBE SAFETY INFORMATION .................................................................................................XI
IMPORTANT DISPOSAL INFORMATION .......................................................................................................XII
European Union.................................................................................................................................... xii
Outside the European Union............................................................................................................... xii
Batteries ................................................................................................................................................ xii
1. INTRODUCTION ..................................................................................................................................... 14
1.1 Overview .................................................................................................................................14
1.2 Definitions and terminology .................................................................................................. 15
1.3 Differences between CTR5000 and F250.............................................................................. 15
1.4 Principles of measurement.................................................................................................... 16
1.5 Temperature measurement .................................................................................................. 16
1.6 Measurement units................................................................................................................. 16
1.7 Security.................................................................................................................................... 17
2. SETTING UP THE CTR5000 ...................................................................................................................... 18
2.1 Safety information .................................................................................................................. 18
2.2 Unpacking the instrument ..................................................................................................... 18
2.3 Getting started........................................................................................................................ 19
3. ABOUT THE CTR5000 PRECISION BRIDGE ............................................................................................ 21
3.1 The front panel........................................................................................................................ 21
3.2 About the LCD display screen .............................................................................................. 22
3.3 LED indicator ........................................................................................................................... 22
3.4 Keypad .................................................................................................................................... 22
3.5 Input connections .................................................................................................................. 24
3.5.1 Passive and Smart Probes................................................................................................. 24
3.5.2 Probe connections ............................................................................................................ 25
3.5.3 2 Wire PRT............................................................................................................................ 26
3.5.4 4 Wire PRT............................................................................................................................ 26
3.5.5 4 Wire PRT with Smart Probe.............................................................................................. 26
3.5.6 Internal 100Ω check resistor............................................................................................. 26
3.6 Rear panel............................................................................................................................... 27
3.6.1 Name plate and serial number ....................................................................................... 27
3.6.2 Electrical rating plate........................................................................................................ 27

CTR5000 Operating Instructions
ASL operating instructions, model CTR5000 iii
3.6.3 Mains input ......................................................................................................................... 27
3.6.4 Expansion port ................................................................................................................... 27
3.6.5 USB Communication interface connector...................................................................... 28
3.6.6 RS232/LAN/IEEE 488 Communication options interface connector ............................ 28
4. OPERATING THE CTR5000 ..................................................................................................................... 30
4.1 Instrument operating modes ................................................................................................ 30
4.2 Measurement mode .............................................................................................................. 30
4.3 Setting the instrument’s operating conditions..................................................................... 32
4.3.1 Hold key.............................................................................................................................. 33
4.3.2 Zero key.............................................................................................................................. 33
4.3.3 Resolution ........................................................................................................................... 34
4.3.4 Display key......................................................................................................................... 34
4.3.4.1 Normal display ........................................................................................................ 34
4.3.4.2 Full display................................................................................................................ 34
4.3.4.3 Statistical display..................................................................................................... 35
4.3.4.4 Graphical display.................................................................................................... 36
4.3.5 Channel soft-key ............................................................................................................... 36
4.3.6 Editor ................................................................................................................................... 37
4.4 Menu mode ............................................................................................................................ 38
4.4.1 Menu soft-key .................................................................................................................... 38
4.5 Selecting channels................................................................................................................. 41
4.5.1 Channel selection –method 1......................................................................................... 41
4.5.2 Channel selection –method 2......................................................................................... 42
4.5.3 Difference channel selection........................................................................................... 43
4.5.4 Channel selection with CTS5000-8 and CTS5000-16 switchboxes ............................... 45
4.5.4.1 Method A.................................................................................................................. 45
4.5.4.2 Method B .................................................................................................................. 46
4.5.4.3 Method C.................................................................................................................. 48
4.5.5 Channel and probes ......................................................................................................... 50
4.5.6 Probe review and edit....................................................................................................... 51
4.5.6.1 Probe menu.............................................................................................................. 51
4.5.6.2 Probe selection (individual) ................................................................................... 52
4.5.6.3 Probe groups menu (from group).......................................................................... 52
4.5.7 Probe review and editing ................................................................................................. 54
4.5.7.1 Conversion ............................................................................................................... 55
4.5.7.2 Review coeffs........................................................................................................... 56
4.5.7.3 Edit coeffs ................................................................................................................. 56
4.5.7.4 Probe id .................................................................................................................... 57
4.5.7.5 Assign to chan (Unasgn from) ............................................................................... 58
4.5.7.6 Set units..................................................................................................................... 59
4.5.7.7 Set Probe Tmax ........................................................................................................ 59
4.5.7.8 Set Probe Tmin ......................................................................................................... 60
4.5.7.9 Copy probe.............................................................................................................. 61
4.5.8 Set group conversion ........................................................................................................ 61
4.6 Calibration .............................................................................................................................. 62
4.6.1 Calibration menu............................................................................................................... 62
4.6.1.1 Calibration reference resistor ................................................................................ 63
4.6.1.2 Calibration method................................................................................................. 64
4.6.1.3 Automatic instrument calibration.......................................................................... 66

CTR5000 Operating Instructions
iv ASL operating instructions, model CTR5000
4.6.2 Smart probe menu............................................................................................................. 67
4.6.2.1 Reset defaults menu................................................................................................ 69
4.6.3 Utilities menu ...................................................................................................................... 69
4.6.4 Options menu..................................................................................................................... 72
4.6.4.1 Security ..................................................................................................................... 73
4.6.4.2 Buzzer enab… .......................................................................................................... 75
4.6.4.3 Key buz enab… ....................................................................................................... 75
4.6.4.4 Standby enab…....................................................................................................... 75
4.6.4.5 Data separator......................................................................................................... 76
4.6.4.6 Date format .............................................................................................................. 76
4.6.4.7 CTR5000/F250 mode… ............................................................................................ 77
4.6.5 Comms menu .................................................................................................................... 78
4.6.5.1 Talk on and Talk off ................................................................................................. 78
4.6.5.2 View status ............................................................................................................... 78
4.6.5.3 RS232 and IEEE options............................................................................................ 79
4.6.5.4 Time and date.......................................................................................................... 81
4.6.5.5 Contrast .................................................................................................................... 82
4.6.5.6 Diagnostics............................................................................................................... 82
5. INSTRUMENT MEASUREMENT RANGE................................................................................................... 83
5.1 Instrument measurement working range ............................................................................ 83
5.2 Measurement ranges............................................................................................................. 83
6. CALIBRATING THE CTR5000.................................................................................................................. 84
6.1 CTR5000 reference calibration ............................................................................................. 84
6.2 Equipment ............................................................................................................................... 84
6.3 Calibration procedure ........................................................................................................... 84
6.4 Full instrument calibration procedure.................................................................................. 84
7. OBTAINING THE BEST FROM THE CTR5000 BRIDGE ............................................................................. 86
7.1 Procedure................................................................................................................................ 86
8. COMMUNICATIONS - INTERFACE AND PC COMMANDS.................................................................. 87
8.1 Introduction............................................................................................................................. 87
8.2 Interfaces ................................................................................................................................ 87
8.2.1 USB device driver............................................................................................................... 87
8.2.2 IEEE-488.2 interface (optional) ......................................................................................... 88
8.2.3 RS232 interface (optional) ................................................................................................ 90
8.2.4 LAN interface (optional) ................................................................................................... 91
8.3 Instrument PC commands..................................................................................................... 92
8.3.1 Remote mode (local lockout).......................................................................................... 92
8.3.2 Commands and Syntax .................................................................................................... 92
8.3.3 A command ....................................................................................................................... 93
8.3.4 C command....................................................................................................................... 94
8.3.5 E command........................................................................................................................ 94
8.3.6 ! command......................................................................................................................... 94
8.3.7 *I command ....................................................................................................................... 94
8.3.8 F command ........................................................................................................................ 94
8.3.9 H command ....................................................................................................................... 95
8.3.10 Hn command.................................................................................................................... 95

CTR5000 Operating Instructions
ASL operating instructions, model CTR5000 v
8.3.11 I command ....................................................................................................................... 95
8.3.12 L command....................................................................................................................... 95
8.3.13 M command..................................................................................................................... 96
8.3.14 N command ..................................................................................................................... 97
8.3.15 P command ...................................................................................................................... 97
8.3.16 Q or ? command.............................................................................................................. 97
8.3.17 R command ...................................................................................................................... 98
8.3.18 S command ...................................................................................................................... 98
8.3.19 T or D command............................................................................................................... 99
8.3.20 U command...................................................................................................................... 99
8.3.21 Z command ...................................................................................................................... 99
8.3.22 Zn command .................................................................................................................... 99
9. ERROR CODES..................................................................................................................................... 101
10. SPECIFICATIONS............................................................................................................................ 103
10.1 Resistance thermometer measurement ............................................................................ 103
10.2 Display ................................................................................................................................... 104
10.3 Power supply......................................................................................................................... 104
10.4 Environmental ....................................................................................................................... 104
10.5 Dimensions and weight ....................................................................................................... 104
10.6 Approvals .............................................................................................................................. 104
11. CLEANING AND MAINTENANCE.................................................................................................. 106
11.1 Cleaning................................................................................................................................ 106
11.2 Maintenance ........................................................................................................................ 106
12. SERVICE AND WARRANTY ............................................................................................................ 108
12.1 Technical Support ................................................................................................................ 108
13. APPENDIX 1 –DEFINITIONS AND TERMINOLOGY ....................................................................... 109
14. APPENDIX 2 –FIRMWARE UPDATE................................................................................................ 110
14.1 Firmware updates ................................................................................................................ 110
14.2 Firmware update disclaimer ............................................................................................... 110
14.3 Firmware update procedure............................................................................................... 110
15. APPENDIX 3 –CALLENDAR VAN DUSEN ...................................................................................... 112
15.1 Callendar van Dusen equation (CvD) ............................................................................... 112
16. APPENDIX 4 - ITS-90 ...................................................................................................................... 113
16.1 International Temperature Scale (ITS-90) .......................................................................... 113
17. APPENDIX 5 - DIN STANDARD ...................................................................................................... 115
17.1 DIN 90 1980 (EN 60751) ........................................................................................................ 115
17.2 DIN 43760 1980 (IEC 751) ..................................................................................................... 115
18. APPENDIX 6–AC BRIDGE OPERATION......................................................................................... 116
18.1 AC Bridge basics.................................................................................................................. 116
19. APPENDIX 7–REPORT EXAMPLES ................................................................................................. 118

CTR5000 Operating Instructions
vi ASL operating instructions, model CTR5000
19.1 Channel report ..................................................................................................................... 118
19.2 Assigned probes report ....................................................................................................... 119
19.3 All probes report................................................................................................................... 120
19.4 Instrument report .................................................................................................................. 121
19.5 Smart probe report............................................................................................................... 122
INDEX .......................................................................................................................................................... 123

CTR5000 Operating Instructions
ASL operating instructions, model CTR5000 vii
Conventions used in this manual
Structure of manual
The manual is divided into sections. Each section deals with a specific topic or related
topics. Sections are displayed in a regular, bold typeface, for example - 1.0 Introduction.
Sections are sub-divided into sub-headings, for example - 1.1 Features. These may also
be subdivided.
Terminology
The terms CTR5000 Bridge, AC Bridge, CTR5000, bridge and instrument are used
interchangeably in this manual.
Menu selection is shown in shorthand form, for example –
Menu 2 Calibration…
Means Press the Menu soft-key, then move to, and select menu item 2 Calibration…and
then the enter () soft-key.
Warnings and Notices
These appear in the body of the text, clearly displayed with a box surrounding the text.
The first word within the box displays the type - Warning or Note.
A Warning (double box) is designed to draw attention to an aspect that may cause
danger to the user or damage to the instrument. A Note (single box) is used to bring
special attention to something important requiring action or avoidance.
Copyright © 2013. All rights reserved.
Information in this document is subject to change without notice.
Reproduction or modification of the whole or any part of this document (in any form) without ASL’s written
permission is forbidden (except for internal use by an authorised dealer or agent). Customers may make copies
for internal use only.
Whilst efforts have been made to ensure the accuracy of information presented here, ASL can assume no
responsibility for the accuracy of any information presented or the consequences of acting on this information.
ASL also disclaims any representation that the contents are current. However, ASL would be grateful for any
comments on the layout, accuracy or contents of this manual.
ASL shall not be liable for problems or damages arising from the use (or misuse) of items, servicing, equipment,
procedures or options supplied by other companies.
ASL, 4 Gatton Park Business Centre, Wells Place, Merstham, Redhill, RH1 3LG, U.K.
Phone: [phone]. Fax: [phone]. email [email protected]

CTR5000 Operating Instructions
viii ASL operating instructions, model CTR5000
Important safety information
Read and understand the user instruction manual before attempting to use the instrument.
The CTR5000 is an AC bridge designed for measuring passive resistances. It must not be used
for any other purpose.
Warning
The protection provided by the instrument may be impaired if the
equipment is not used in the manner specified.
Only replace items or components with an approved or
equivalent spare part. All spare and consumable parts are
available from ASL.
Warning
The instrument is NOT designed to be used in a potentially
explosive atmosphere or medical environment.
Warning
Do NOT open the case. There are no user serviceable parts inside.
Warning
Inspect cables and probes regularly, ensuring that their insulation
is not damaged.
Warning
The instrument and the internal lithium clock battery must be
disposed of in accordance with local regulations.

CTR5000 Operating Instructions
ASL operating instructions, model CTR5000 ix
Warning
The instrument is sensitive to radiated noise and care must be
taken to ensure a clean mains supply and controlled EM
environment..
General warning symbol. This indicates that a
hazardous condition or general danger may exist.
You must read the relevant sections in the User
Manual before using the instrument.
Refer to manual symbol. When you see this symbol
on the instrument it means that there is more
information relating to this in the User Manual.

CTR5000 Operating Instructions
x ASL operating instructions, model CTR5000
Important installation information
Please ensure that the instrument is installed correctly.
Do NOT use the instrument near water or in damp conditions
Do NOT locate the instrument near a source of heat
Do NOT insert objects into any ventilation openings
Do NOT site the instrument in a draught or near an air-conditioning unit
Do NOT site the instrument near any strong magnetic fields
Do NOT place any weight on top of the instrument
Locate the instrument on a suitable and secure surface
Ensure air can freely circulate around the instrument
Note
As with all precision measurement instruments, best laboratory
practice is required. External sources of electrical noise, such as
motors, should not be allowed to cause excessive interference on
the mains supply or on probe leads.
The instrument uses a universal input voltage power supply. Use a plug to connect to the
mains supply. If in doubt, consult a qualified electrician. The supply connections are shown
below (if a UK cord set is fitted).
Brown wire to Live (Line) - L
Blue wire to Neutral - N
Green and Yellow wire to Earth (Ground) - E
Warning
The instrument is designed to be connected to the mains supply
via a plug and must be effectively earthed.

CTR5000 Operating Instructions
ASL operating instructions, model CTR5000 xi
Important probe safety information
Care must be taken with the probes used with the instrument. The following safety information
must be observed.
Do NOT attempt to lift the CTR5000 by any of the leads
Do ensure that long probe-leads and other leads are kept away from areas where
people could trip over them or become tangled in them
Do ensure the probe-leads and other leads are kept in good condition
Warning
Because of the nature of the instrument, probes can
be excessively HOT or COLD during use. Take suitable
precautionary measures when handling probes.
Take care that you (and other people working in the
same area) do not come into contact with the
metallic probe or the insulating sheath near the probe,
which will also be hot/cold.
Precautions apply both during use or when moving the
probe from one position to another.
Warning
Probes may be immersed in various chemicals during
use. Some of these chemicals may be dangerous or
harmful (even when the probe is cold).
Always assume that the probe has been used this way
and DO NOT touch the probe without suitable
protective clothing.
Warning
DO NOT allow the probe to touch any external
voltages such as MAINS power.

CTR5000 Operating Instructions
xii ASL operating instructions, model CTR5000
Important disposal information
If you are responsible for disposal, then please note that this product may contain
materials that are regulated in their disposal due to environmental considerations. The
presence of these materials is consistent with global regulations applicable at the time
this product was placed on the market.
European Union
This symbol means that the product to be disposed of
should not be mixed with commercial or general
household waste. Used products must be treated
separately in accordance with legislation that requires the
proper treatment, recovery and recycling of the product.
If you wish to discard the product, then please contact
your dealer, supplier or representative who will advise the
correct procedure for disposal.
Disposing of the product correctly will help to save
valuable resources and prevent environmental damage.
Outside the European Union
The symbol only applies within the European Union. If you
need to discard the product, then please contact your
dealer, supplier or the local authorities and ask for the
correct method of disposal.
Batteries
The CTR5000 contains a replaceable lithium cell, held in a
holder on the main PCB. This cell must be disposed of in
accordance with local regulations

CTR5000 Operating Instructions
ASL operating instructions, model CTR5000 xiii
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CTR5000 Operating Instructions
14 ASL operating instructions, model CTR5000
1. Introduction
1.1 Overview
The CTR5000 Precision Thermometer is designed for laboratory, commercial and industrial
temperature measurement and calibration applications. The performance and multi-channel
capabilities make it ideal for a wide range of applications.
The CTR5000 Bridge is based on AC technology and operates with all 4-wire Platinum
Resistance Thermometers (PRTs)
1
. Features include –
Two, four or six channel operation
2
Immunity to most sources of errors present in DC Bridges
0.5 second update rate (to full specification)
4 maccuracy, 0.1mresolution (10mK accuracy and 1mK resolution)
Wide operational range including all 4-wire thermometers with R0 values of Pt100 (100
), Pt25.5 (25.5 ) and Pt0.25 (0.25 )
Graphical LCD for excellent viewing of results and instrument settings
Statistical, graphical and large display modes
User selectable units –- ratio, resistance or temperature display (, C, F or K)
Internal (100 ) reference resistor
Smart probe compatibility
Expandable multi-channel input multiplexing (up to 64 additional channels)
USB communication interface as standard for automated monitoring and calibration
applications
RS232 or IEEE 488 or LAN interface options
Automatic calibration against traceable external resistors
Power-on diagnostic check
1
Two wire PRTs may be used with reduced accuracy.
2
Two channels supplied on the CTR5000 as standard, expandable to four or six .

CTR5000 Operating Instructions
ASL operating instructions, model CTR5000 15
The CTR5000 is ASL’s first AC bridge with Smart probe capability. It is also the fastest
commercially available bridge for its specifications.
Overall system accuracy is better than 4m, (at 20C 5C - see specification section),
equivalent to a temperature measurement accuracy of 10mK.
Two measurement channels (A and B) are provided on the front of the instrument. The
CTR5000 may be expanded up to six channels with the addition of two more channels (C and
D), or four more channels (C, D, E and F) on the rear of the instrument; differential mode
operation is provided for these channels. A separate channel connection is supplied for the
expansion switchboxes.
Up to 64 channels may be added with the addition of external CTS5000 switchboxes. Two
switchbox models are available –the CTS5000–08 and the CTS5000–16 (with 8 or 16 channels
respectively). The switchboxes use an expansion connector on the rear of the instrument.
Channels A, B (C, D, E and F) operate independently of the switchboxes.
Unlike previous instruments, units may be set on a channel basis, so, for example, channel A
may be set to C and channel B to display ohms.
1.2 Definitions and terminology
See appendix 1
1.3 Differences between CTR5000 and F250
The CTR5000 has many more features and options than the F250. The fundamental differences
are –
CTR5000 and F250 –fundamental differences
CTR5000
F250
0.5 s update rate
3 s update rate
2 channels, expandable to 6 channels
2 channels only
Instantaneous temperature conversion
Temperature conversion table takes many seconds
Switchbox uses a separate input
Each switchbox uses one F250 channel
Expandable to 70 channels
32 channels maximum
Units definable per probe
Global units only
Passive and Smart probes
Passive probes only
Full Graphical display
Limited numerical display

CTR5000 Operating Instructions
16 ASL operating instructions, model CTR5000
1.4 Principles of measurement
See appendix 6 for a detailed description.
1.5 Temperature measurement
When using PRTs, the relationship between resistance and temperature varies slightly from
one PRT to another. Therefore, no matter how accurately the CTR5000 measures the PRT
resistance, if the relationship between resistance and temperature for a particular PRT is not
known, accurate temperature measurement is not possible.
The CTR5000 uses PRT calibration data to overcome this problem and calculates the
temperature from conversion functions using calibration data stored in internal non-volatile
memory. This method enables the CTR5000 to convert ratio to temperature, uniquely for each
sensor used. It is very important, therefore, that a sensor is used with the probe’s coefficients
correctly entered into the instrument. The CTR5000 uses the standard DIN90 conversion
method when specific probe calibration data has not been entered. Temperature conversion
occurs in real-time.
Note
Always check that the coefficients are correctly set for
the probe being used. Failure to do so, will almost
certainly lead to incorrect measurements.
System accuracy is a combination of the Bridge’s accuracy in measuring the probe’s
resistance ratio and the calibration uncertainty placed on the reference resistor and PRTs by
the calibrating laboratory.
When calibrated PRTs are used with the CTR5000, either with or without switchboxes, the
calibration data can be entered via the keypad on the front panel, and is stored in internal
memory. Stored PRT calibration data may also be reviewed.
1.6 Measurement units
Units can be set on a per probe basis (probes are assigned to channels). When a new
channel is selected, the CTR5000 will check to see if a probe is assigned to that channel. If it
is, the programmed probe’s units will be used (initially) - this does not prevent the units from

CTR5000 Operating Instructions
ASL operating instructions, model CTR5000 17
being changed later. This feature is useful when calibrating probes (if instrument units are
selected for the probe, units will remain unchanged when it is used).
1.7 Security
Security is important for data integrity and password protection helps to ensure that only
authorised personnel can change calibration or system information. Three levels of protection
are provided.
Note
All examples in the following sections (apart from the
section on security) assume that no security mode is
selected.

CTR5000 Operating Instructions
18 ASL operating instructions, model CTR5000
2. Setting up the CTR5000
2.1 Safety information
Please read the safety information section before operating the CTR5000.
2.2 Unpacking the instrument
When unpacking the CTR5000 Bridge, check that the following items are present before using
the instrument
3
–
CTR5000 precision thermometry bridge
Operator’s handbook on CD
Laminated A5 Reference guide
Test certificate
Mains lead
USB lead
Spare fuses
Please contact the ASL Technical Services Group
4
immediately if any of these items are
missing or damaged.
Please retain the packaging. In case of return, servicing or calibration, use the original
packaging (failure to do so may invalidate the warranty and/or incur additional costs outside
the warranty period). Please contact your agent, dealer or supplier when the original
packaging is unavailable.
To enable accurate resistance to temperature conversion to be carried out by the instrument,
PRT characterisation data may be required.
By default, the CTR5000 operates with DIN90 temperature conversion. The instrument may also
be set to use DIN68 or CvD or ITS90 conversion methods
5
.
3
Thermometer probes and other accessories (if ordered) will be supplied separately.
4
Details are located at the end of the manual (in the Technical support section).
5
Coefficients are fixed for DIN methods. Default values are used for CvD, but these can be changed. ITS90
coefficient data must be entered.

CTR5000 Operating Instructions
ASL operating instructions, model CTR5000 19
The conversion coefficients are fixed for DIN90 (also for CvD and DIN68), so no further data
entry is required. However, if ITS90 is used as a conversion method, coefficient data will have
to be entered using the simple coefficient editor.
A probe’s conversion algorithm and its coefficients are stored in the instrument’s internal non-
volatile memory. Up to 72 probes may be individually defined
6
Set-up details for the probes are covered later in the manual.
2.3 Getting started
Read the manual thoroughly before using the instrument
Unpack the instrument and allow to thermally stabilise before switching on
(particularly if the instrument has been stored in a cold environment)
Connect a 100 ohm resistor (any type will do) to channel A (as described in
section 3.5)
7
Connect the mains lead and switch on. After a short diagnostic check
sequence, the CTR5000 will start measuring the resistance
8
Change one setting at a time to familiarise yourself with each of the options.
Start with the Unit key (below the Unit legend) at the bottom right of the LCD,
changing to C, F, K and back to ohms –
Chan Hold Unit
Press the Chan key under the bottom left of the LCD. The bottom row of the LCD
will change to
9
–
Ch A Ch B More Diff
Press the Ch B key and the display will change to show channel B (indicated at
the top left of the LCD). The bottom line of the LCD will revert to display –
6
The probe’s information also defines its units, which channel uses the probe and an optional probe identifier string.
7
If a probe or resistor is not available, use the internal check resistor by selecting channel 99. To do this, press the 9 key on
the numerical keypad twice (99) and then press the enter key on the keypad. IntR will be displayed at the top left of the
LCD. The internal check resistor will be deselected when the channel is changed to any other (or the CTR5000 turned off).
8
As supplied, the CTR5000 will be set for this measurement.
9
The More menu item will only be present if more than 2 channels are fitted.

CTR5000 Operating Instructions
20 ASL operating instructions, model CTR5000
Chan Hold Unit
The open probe symbol will be displayed (no probe on channel B) –
Press the 1key on the numeric keypad. The top left of the LCD will display a
flashing Cn01, indicating channel 1 (A). Press the key (bottom right of the
keypad). The CTR5000 will return to channel A
Press the blue display key (underneath the 7 on the numerical keypad).
The bottom line of the LCD will change to show –
Full Stats Graph n.nnn
Press the n.nnn key to change the display resolution between 0 and 3 decimal
places (0 and 4 for resistance). Reset to 3 decimal places
These steps cover most of the F250 functionality (apart from coefficient editing
and security modes)
Press the Stats key to display statistics mode. The bottom line of the LCD will
change to –
Chan Clr Hold Unit
(Clr resets the statistics values)
Press the blue display key again. The LCD will change to display –
Num Graph n.nnn
Press the Graph key to display graphical mode
Press the blue display key again and then press Num key to return to numerical
display mode
Finally, press the blue display key and then press Full key to display the result in
large mode. Press the blue key and Norm to return to normal display mode. All
other functions are accessed via the menu system (see section 4)