Mitsubishi AJ65BT-68TD User Manual

AJ65BT-68TD Thermocouple Temperature Input Module
User,s Manual

Mitsubishi Programmable Controller

SAFETY PRECAUTIONS

(Read these precautions before using.)

When using Mitsubishi equipment, thoroughly read this manual and the associated manuals introduced

in this manual. Also pay careful attention to safety and handle the module properly.

These precautions apply only to Mitsubishi equipment. Refer to the CPU module user's manual for a

description of the PLC system safety precautions.

These SAFETY PRECAUTIONS classify the safety precautions into two categories: "DANGER" and

"CAUTION".

DANGER

Procedures which may lead to a dangerous condition and cause death or

serious injury if not carried out properly.

CAUTION

Procedures which may lead to a dangerous condition and cause superficial

to medium injury, or physical damage only, if not carried out properly.

Depending on circumstances, procedures indicated by

CAUTION may also be linked to serious

results.

In any case, it is important to follow the directions for usage.

Store this manual in a safe place so that you can take it out and read it whenever necessary. Always

forward it to the end user.

[DESIGN PRECAUTIONS]

DANGER

 When there are communication errors with the data link, the data of the master module will be held.

Built an interlock circuit into the sequence program that will make sure the system operate safely by using

the communication status information.

CAUTION

 Do not bunch the control wires or communication cables with the main circuit or power wires, or them close

to each other.

They should be installed 100 mm (3.9 in.) or more from each other.
Not doing so could result in noise that would cause malfunction.

[INSTALLATION PRECAUTIONS]

CAUTION

 The module should be used under the environmental conditions listed under the general specifications in

the manual.

Using it under any other environmental conditions could cause problems such as fire, malfunction and

damage to or deterioration of the product.

 The module should be fixed securely with a DIN rail or installation screws, and then make sure to tighten it

within the range of the specified torque of the installation screws.

If the screws are loose, it may result in fallout or malfunction.

Tightening the screws too far may cause damages to the screws and/or the module, resulting in fallout or
malfunction.

 Do not directly touch the module's conductive parts.

Doing so could cause malfunction or trouble in the module.

[WIRING PRECAUTIONS]

CAUTION

 Before beginning any installation or wiring work, make sure all phases of the power supply have been

obstructed from the outside.

Failure to completely shut off the power supply phases may cause damages to the module or malfunction.

 When turning on the power or operating the module after installation or wiring work, be sure the

module’sterminal covers are correctly attached.

Failure to attach the terminal covers may result in short circuit or failure.

 The FG terminals should always be grounded using the class-3 or higher grounding designed specially for

the PLC.

Failure to ground these terminals may cause malfunction.

 Use applicable solderless terminals and tighten them with the specified torque. If any solderless spade

terminal is used, it may be disconnected when the terminal screw comes loose, resulting in failure.

 When wiring the module, check the rated voltage and terminal layout of the wiring, and make sure the wiring

is done correctly.

Connecting a power supply that differs from the rated voltage or wiring it incorrectly may cause fire or

failure.

 Tighten the terminal screws within the range of specified torque.

If the terminal screws are loose, it may result in short circuit or malfunction.

Tightening the terminal screws too far may cause damage to the screws and/or the module, resulting in

short circuit or malfunction.

 Be sure there are no foreign substances such as sawdust or wiring debris inside the module.

Such debris could cause fire, failure or malfunction.

[WIRING PRECAUTIONS]

CAUTION

 Be sure that the wires or cables connected to the module are stored in the duct or fixed with cramps.

Failure to do so may cause a damage to the module or cables due to dangling, shifting or inadvertent

handling of calbes, or malfunction due to bad cable contacts.

 Do not install the control lines together with the communication cables, or bring them close to each other.

Failure to do so may cause malfunctions due to noise.

 Do not grab on the cable when removing the communication cable or power cable connected to the module.

When removing the cable, loose the screws on the side that is connected to the module.

Pulling the cable that is still connected to the module may cause a damage to the module or cable, or

malfunction due to bad contacts.

[STARTING AND MAINTENANCE PRECAUTIONS]

CAUTION

 Do not touch the terminals while the power is on.

Doing so may cause malfunction.

 Make sure to switch all phases of the external power supply off before cleaning or re-tightening screws.

If you do not switch off the external power supply, it will cause failure or malfunction of the module.

If the screws are loose, it may result in fallout, short circuit or malfunction.

Tightening the screws too far may cause damages to the screws and/or the module, resulting in fallout,

short circuit or malfunction.

 Do not disassemble or modify the module.

Doing so could cause failure, malfunction injury or fire.

 Do not drop or give a strong shock to the module because its case is made of resin.

Doing so may cause a damage to the module.

 Make sure to switch all phases of the external power supply off before mounting or removing the module.

If you do not switch off the external power supply, it will cause failure or malfunction of the module.

 Mounting/removing the terminal block is limited to 50 times after using a product. (IEC61131-2-compliant)

 Before handling the module, always touch grounded metal, etc. to discharge static electricity from the

human body.

Failure to do so can cause the module to fail or malfunction.

[DISPOSAL PRECAUTION]

CAUTION

 When disposing of this product, treat it as an industrial waste.

Revisions

* The manual number is noted at the lower left of the back cover.

Print Date *Manual Number Revision

Apr., 1998 SH(NA)-3304-A First printing

Jul., 2005 SH(NA)-3304-B Addition

Conformation to the EMC Directive and Low Voltage Instruction, WARRANTY

Correction

SAFETY PRECAUTIONS, Section 2.2, 5

Dec., 2006 SH(NA)-3304-C Correction

SAFETY PRECAUTIONS, Section 2.1, 3.9.4, 4.3, Chapter 5

Japanese Manual Version SH-3651-E

This manual does not imply guarantee or implementation right for industrial ownership or implementation

of other rights. Mitsubishi Electric Corporation is not responsible for industrial ownership problems caused

by use of the contents of this manual.

© 1998 Mitsubishi Electric Corporation

Introduction

Thank you for purchasing the Mitsubishi Graphic Operation Terminal.

Before using the equipment, please read this manual carefully to develop full familiarity with the functions and

performance of the graphic operation terminal you have purchased, so as to ensure correct use.

Please forward a copy of this manual to the end user.

Table of Contents

1. OVERVIEW 1-1

1.1 Features............................................................................................................................................................1- 1

2. SYSTEM CONFIGURATION 2-1 to 2-2

2.1 Overall Configuration ........................................................................................................................................ 2- 1

2.2 Applicable CPUs ...............................................................................................................................................2- 2

3. SPECIFICATIONS 3-1 to 3-24

3.1 General Specification........................................................................................................................................ 3- 1

3.2 Performance Specifications .............................................................................................................................. 3- 2

3.3 Temperature/Digital Conversion Characteristics............................................................................................... 3- 4

3.4 Maximum Transmission Distance over the CC-Link System ............................................................................ 3- 4

3.5 Data Link Processing Time. .............................................................................................................................. 3- 5

3.6 Twisted Cable Specifications ............................................................................................................................ 3- 6

3.7 Function List...................................................................................................................................................... 3- 7

3.8 I/O Signals in Respect to the Master Module.................................................................................................... 3- 8

3.8.1 I/O signal list .......................................................................................................................................... 3- 8

3.8.2 I/O signal functions ................................................................................................................................ 3-11

3.8.3 Wire breakage detection........................................................................................................................3-16

3.8.4 Conversion enable/disable designation ................................................................................................. 3-17

3.8.5 Sampling processing/travel average processing designation................................................................ 3-18

3.8.6 Thermocouple type selection................................................................................................................. 3-20

3.8.7 Pt100 cold junction compensation enable/disable designation .............................................................3-21

3.9 Remote Register ............................................................................................................................................... 3-22

3.9.1 Remote register assignment.................................................................................................................. 3-22

3.9.2 High and low limit settings ..................................................................................................................... 3-23

3.9.3 Detected temperature value ..................................................................................................................3-24

3.9.4 Scaling value .........................................................................................................................................3-24

4. SETTING AND PROCEDURE BEFORE OPERATION 4-1 to 4-10

4.1 Procedure before Operation .............................................................................................................................4- 1

4.2 Handling Precautions........................................................................................................................................ 4- 2

4.3 Part Identification and Setting ........................................................................................................................... 4- 3

4.4 Error Compensation by the Offset Value/Gain Value Setting ........................................................................... 4- 5

4.4.1 Initial settings for error compensation.................................................................................................... 4- 6

4.4.2 Error compensation procedure .............................................................................................................. 4- 7

4.5 Station Number Setting..................................................................................................................................... 4- 8

4.6 Orientation of Module Installation .....................................................................................................................4- 8

4.7 Wiring................................................................................................................................................................4- 9

4.7.1 Handling precautions for twisted cables ................................................................................................ 4- 9

4.7.2 Wiring example with CC-Link modules .................................................................................................. 4- 9

4.7.3 Precautions when wiring to a thermocouple .......................................................................................... 4-10

4.7.4 Wiring example with thermocouple........................................................................................................ 4-10

5. PROGRAMMING 5-1 to 5-18

5.1 Programming Procedure................................................................................................................................... 5- 1

5.2 Programming Example of Reading Initial Setting and Detected Temperature Value .......................................5- 2

5.3 Program Eamples when QCPU(Q Mode) Is Used ............................................................................................ 5- 5

5.4 Program Eamples when QCPU Is Used ........................................................................................................... 5-10

5.5 Program Eamples when ACPU/QCPU(A Mode) Is Used (Dedicated Instructions)...........................................5-13

5.6 Program Eamples when ACPU/QCPU(A Mode) Is Used (FROM/TO Instructions)........................................... 5-16

6. TROUBLESHOOTING 6-1 to 6-5

6.1 Cause of Errors and Corrective Actions by LED Indication...............................................................................6- 1

6.2 When Wire Breakage Detection Flag is On ...................................................................................................... 6- 3

6.3 When E2PROM Error Flag is On....................................................................................................................... 6- 3

6.4 When Detected Temperature Value cannot be Read ....................................................................................... 6- 3

6.5 When Detected Temperature Value is Abnormal .............................................................................................6- 3

6.6 When There is a Communication Error between Master Station and AJ65BT-68TD ....................................... 6- 4

APPENDIX A-1 to A-28

Appendix 1 Usual Operation Limits and Superheated Operating Limits.................................................................. A- 1

Appendix 2 Allowable Temperature Differences...................................................................................................... A- 1

Appendix 3 Thermal Electromotive Force Chart ...................................................................................................... A- 2

Appendix 3.1 Standard Thermal Electromotive Force of B............................................................................. A- 2

Appendix 3.2 Standard Thermal Electromotive Force of R............................................................................. A- 6

Appendix 3.3 Standard Thermal Electromotive Force of S............................................................................. A-10

Appendix 3.4 Standard Thermal Electromotive Force of K............................................................................. A-14

Appendix 3.5 Standard Thermal Electromotive Force of E............................................................................. A-18

Appendix 3.6 Standard Thermal Electromotive Force of J..............................................................................A-21

Appendix 3.7 Standard Thermal Electromotive Force of T ............................................................................. A-25

Appendix 4 External Dimensions Diagram............................................................................................................... A-27

About This Manual

The following are manuals related to this product.

Request for the manuals as needed according to the chart below.

Related Manuals

Manual Name

Manual No.

(Type code)

Type AJ61BT11/A1SJ61BT11 CC-Link System Master/Local Module User's Manual

This manual explains about the system configuration, performance specifications, functions,
handling, wiring and troubleshooting of AJ61BT11and A1SJ61BT11. (Sold separately)

IB-66721
(13J872)

Type AJ61QBT11/A1SJ61QBT11 CC-Link System Master/Local Module User's Manual

This manual explains about the system configuration, performance specifications, functions,
handling, wiring and troubleshooting of AJ61QBT11and A1SJ61QBT11. (Sold separately)

IB-66722
(13J901)

Type QJ61BT11N CC-Link System Master/Local Module User's Manual

Describes the system configuration, performance specifications, functions, handling, wiring and
troubleshooting of the QJ61BT11N. (Optionally available)

SH-080394E

(13JR64)

Conformation to the EMC Directive and Low Voltage Instruction

When complying with EMC Directives and Low-Voltage Directives by assembling a Mitsubishi PLC
compatible with EMC Directive and Low-Voltage Directives into the user product, refer to Chapter 3 "EMC
Directives and Low-Voltage Directives" in the User’s Manual (Hardware) for the CPU module being used.

The CE logo is printed on the rating plate on the main body of the PLC that conforms to the EMC directive
and low voltage instruction.

To conform this product to the EMC Directive and Low Voltage Directive, refer to the Section of "CC-Link

Modules" in Chapter 3 "EMC Directive and Low Voltage Directive" of the User's Manual (Hardware) of the

CPU module used.

About Generic Terms and Abbreviations

Unless otherwise specified, this manual uses the following generic terms and abbreviations to

explain the AJ65BT-68TD Thermocouple Input Module. Temperature input module.

Generic Term/

Abbreviation

Description

GX Developer Generic product name for product model names SWnD5C-GPPW, SWnD5C-GPPW-A,

SWnD5C-GPPW-V and SWnD5C-GPPW-VA. n in the model name indicates 4 or more.

ACPU Generic term for A0J2CPU, A0J2HCPU, A1CPU, A2CPU, A2CPU-S1, A3CPU, A1SCPU,

A1SCPUC24-R2, A1SHCPU, A1SJCPU, A1SJCPU-S3, A1SJHCPU, A1NCPU, A2NCPU,
A2NCPU-S1, A3NCPU, A3MCPU, A3HCPU, A2SCPU, A2SHCPU, A2ACPU, A2ACPU-S1,
A3ACPU, A2UCPU, A2UCPU-S1, A2USCPU, A2USCPU-S1, A2USHCPU-S1, A3UCPU and
A4UCPU.

QnACPU Generic term for Q2ACPU, Q2ACPU-S1, Q2ASCPU, Q2ASCPU-S1, Q2ASHCPU,

Q2ASHCPU-S1, Q3ACPU, Q4APU and Q4ARCPU.

QCPU (A mode) Generic term for Q02CPU-A, Q02HCPU-A and Q06HCPU-A.

QCPU (Q mode) Generic term for Q02CPU, Q02HCPU, Q06HCPU, Q12HCPU and Q25HCPU.

Master station Station that controls a data link system.

One station is required for one system.

Local station Station that has a PLC CPU and can communicate with the master station and other local

stations.

Remote I/O station Station that handles only bit unit information. (Input/output from/to external device)

(AJ65BTB1-16D, AJ65SBTB1-16D, etc.)

Remote device
station

Station that handles bit unit information and word unit information. (Input/output from/to
external device, analog data conversion)

Remote station Generic term for remote I/O station and remote device station. Controlled by the master

station.

Intelligent device
station

Station that can perform transient transmission, e.g. AJ65BT-R2. (Local station included)

Master module Generic term for QJ61BT11N, QJ61BT11, AJ61BT11, A1SJ61BT11, AJ61QBT11 and

A1SJ61QBT11 used as the master station.

SB Link special relay (for CC-Link)

Bit unit information that indicates the module operation status or data link status of the
master station/local station. Represented as SB for convenience.

SW Link special register (for CC-Link)

16-bit unit information that indicates the module operation status or data link status of the
master station/local station. Represented as SW for convenience.

RX Remote input (for CC-Link)

Information input from a remote station to the master station in bit unit. Represented as RX
for convenience.

RY Remote output (for CC-Link)

Information output from the master station to a remote station in bit unit. Represented as RY
for convenience.

RWw Remote register (write area for CC-Link)

Information output from the master station to a remote device station in 16-bit unit.
Represented as RWw for convenience.

RWr Remote register (read area for CC-Link)

Information input from a remote device station to the master station in 16-bit unit.
Represented as RWr for convenience.

Packing List

This product consists of the following items.

Product name Quantity

AJ65BT-68TD thermocouple input module 1

AJ65BT-68TD Thermocouple Temperarure Input Module User’s Manual (Hardware) 1

1. OVERVIEW MELSEC-A

1-1

1. OVERVIEW

This user's manual explains the specifications, handling, programming methods, etc. of the AJ65BT­68TD Thermocouple Input Module (hereinafter referred to as AJ65BT-68TD) used as a remote device
station for the CC-Link system.

The AJ65BT-68TD is a module that converts the thermocouple input values from outside the PLC to
the temperature values or scaling values of 16-bit signed BIN data.

1.1 Features

The following are the features of the AJ65BT-68TD.

(1) Temperature – digital conversion is possible at eight channels in one module

One AJ65BT-68TD module may perform up to eight channels of temperature – digital
conversions.

(2) Thermocouples conforming the JIS standard may be used.

Seven types of thermocouples (K, E, J, T, B, R and S) that conform to the JIS standard may be
used.
Also, a thermocouple may be chosen independently for each channel

(3) Conversion enabling and disabling

Conversion may be enabled or disabled for each individual channel. By disabling the conversion
of channels that are not used, generation of unnecessary wire breakage detection flags may be
prevented and sampling time may be reduced.

(4) Wire breakage detection is possible

The thermocouple and compensating conductor breakage may be detected for each channel.

(5) Sampling processing and travel average processing may be designated

As a conversion processing method, sampling processing and travel average processing may
designated for each channel.

(6) Cold junction compensation is possible using Pt100 temperature-measuring resistor

Since a Pt100 temperature-measuring resistor is connected, cold junction compensation is
performed automatically.

(7) Pt100 cold junction compensation enable/disable setting is possible

By disabling the cold junction compensation by the Pt100 temperature-measuring resistor, cold
junction compensation may be performed at outside the module.
If the cold junction compensation accuracy ±1 °C of the Pt100 temperature-measuring resistor
may not be ignored as a tolerance, cold junction compensation accuracy may be increased by
installing a high-accuracy ice bus to outside of the module.

(8) Error compensation can be performed by setting the offset/gain value

Error compensation may be performed individually at each channel by setting the offset/gain
value.
Also, the offset/gain value may be selected to use a user setting value or factory setting value.

2. SYSTEM CONFIGURATION MELSEC-A

2-1

2. SYSTEM CONFIGURATION

System configuration when using the AJ65BT-68TD is explained below.

2.1 Overall Configuration

The overall configuration when using the AJ65BT-68TD is shown below.

4 stations occupied
RX/RY 128 points each
RWr/RWw 16 points each

Thermocouple

Temperature detection
target object

Master/local module for CC-Link (master station) Master/local module for CC-Link (local station)

Twisted cable with shield

(Intelligent device station)

(Remote I/O station)

AJ65BT-68TD
(Remote device station)

(Remote device station)

The maximum overall distance for the system is as follows
(varies depending on transmission speed setting).

156 kbps : 1200 m (3937 ft.) 5 Mbps : 150 m (492.1 ft.)
625 kbps : 600 m (1968.5 ft.) 10 Mbps : 100 m (328.1 ft.)

2.5 Mbps : 200 m (656.2 ft.)

2. SYSTEM CONFIGURATION MELSEC-A

2-2

2.2 Applicable CPUs

(1) When the master module is AJ61BT11

• A0J2CPU • A0J2HCPU • A1CPU • A2CPU (S1) • A3CPU

• A1NCPU • A2NCPU (S1) • A3NCPU • A3MCPU • A3HCPU

• A2ACPU (S1) • A3ACPU • A2UCPU (S1) • A3UCPU • A4UCPU

• A73CPU

• A1SCPU (C24-R2) • A1SJCPU • A2SCPU • A2USCPU (S1)

• Q02CPU-A • Q02HCPU-A • Q06HCPU-A

(2) When the master module is AJ61QBT11

• Q2ACPU (S1) • Q3ACPU • Q4ACPU

• Q2ASCPU (S1) • Q2ASHCPU (S1)

(3) When the master module is A1SJ61BT11

• A1SCPU (C24-R2) • A1SHCPU • A1SJCPU • A1SJHCPU • A2SCPU

• A2SHCPU • A2USCPU (S1) • A2USH-S1

(4) When the master module is A1SJ61QBT11

• Q2ASCPU (S1) • Q2ASHCPU (S1)

3. SPECIFICATIONS MELSEC-A

3-1

3. SPECIFICATIONS

This section explains the AJ65BT-68TD the general specifications, performance specifications, and
transmission specifications.

3.1 General Specification

This section explains the AJ65BT-68TD general specifications.

Item Specifications

Ambient operating
temperature

0 to 55

°C

Ambient storage temperature -20 to 75 °C

Ambient operating humidity 10 to 90 %RH, Non-condensing

Ambient storage humidity 10 to 90 %RH, Non-condensing

Frequency Acceleration Amplitude No. of sweeps

10 to 57 Hz —

0.075 mm

(0.0030 in.)

Vibration resistance 57 to 150 Hz 9.8 m/s2 {1 G} —

10 to 57 Hz —

0.035 mm

(0.0014 in.)

57 to 150 Hz 4.9 m/s2 {0.5 G} —

Shock resistance Conforming to JIS B 3502, IEC 61131-2

(147 m/s

2

{15 G}, 3 times in each of 3 directions X Y Z)

Operating ambience No corrosive gases

Operating elevation 2000 m (6562 ft.) max.

Installation location Control panel

Over voltage category *1 II max.

Pollution level *2 2 max.

*1 : This indicates the section of the power supply to which the equipment is assumed to be

connected between the public electrical power distribution network and the machinery within the
premises. Category II applies to equipment for which electrical power is supplied from fixed
facilities. The surge voltage withstand level for up to the rated voltage of 300 V is 2500 V.

*2 : This index indicates the degree to which conductive material is generated in terms of the

environment in which the equipment is used. Pollution level 2 is when only non-conductive
pollution occurs. A temporary conductivity caused by condensation must be expected
occasionally.

10 times each in

X, Y, Z directions

(for 80 min.)

Conforming to
JIS B 3502,
IEC 61131-2

Under intermittent
vibration

Under continuous
vibration

3. SPECIFICATIONS MELSEC-A

3-2

3.2 Performance Specifications

The performance specifications of the AJ65BT-68TD are shown below.

Item Specifications

Temperature Sensor Input (°C) -200 to 1700

Output

Detected
temperature

Scaling value 16-bit signed binary (0 to 2000)

Applicable thermocouples
and temperature
measurement range accuracy

Cold junction compensation
accuracy (°C)

Overall accuracy Depends on *1 calculation expression

Maximum resolution B, R, S : 0.3 °C K, E, J, T : 0.1 °C

Conversion speed
(sampling time) [ms/ch]

Absolute maximum input [V] ± 5

Number of analog input
points

8 channels + Pt100 connection channel

Thermocouple input to CC-Link transmission : Transformer insulation

Between channels : Transformer insulation

16-bit signed binary (-2000 to 17000 : value to one decimal place multiplied by 10)

± 1.0

45 ms/channel *2

Insulation method

Applicable

thermocouple

type

Temperature
measuremen

t range [°C ]

Conversion accuracy

(When ambient operating

temperature is 25 ±5 °C)

Temperature characteristic

(Per 1 °C of ambient operating

temperature change)

B 600 to 1700 ± 2.5 °C ± 0.4 °C

0 to 200 ± 0.4 °C

200 to 1600 ± 0.3 °C

0 to 200 ± 0.4 °C

200 to 1600 ± 0.3 °C

±0.06 °C or ±0.3 % of the measured

temperature, whichever is greater

±0.06 °C or ±0.02 % of the measured

temperature, whichever is greater

±0.06 °C or ±0.3 % of the measured

temperature, whichever is greater

±0.06 °C or ±0.02 % of the measured

temperature, whichever is greater

±0.06 °C or ±0.02 % of the measured

temperature, whichever is greater

±0.06 °C or ±0.3 % of the measured

temperature, whichever is greater

±0.06 °C or ±0.02 % of the measured

temperature, whichever is greater

±0.5 °C or ±0.25 % of the

measured temperature,

whichever is greater

± 2.0 °C

± 2.0 °C

0 to 350

-200 to 0

0 to 750

0 to 800

-200 to 0

-200 to 0

0 to 1200

S

T

J

E

K

R

3. SPECIFICATIONS MELSEC-A

3-3

Item Specifications

CC-Link station type Remote device station

Number of occupied stations 4 Stations : RX/RY 128 points each RWw/RWr 16 points each

Transmission
speed/maximum
transmission distance

Refer to Section 3.4

Maximum number of
connected modules

Connection cable CC-Link dedicated cable

Depends on noise simulator of noise voltage at 500 Vp-p, noise width at 1 ms and noise

frequency at 25 to 60 Hz

Dielectric withstand voltage 500 V AC between DC external terminal batch and ground for 1 minute

10 MΩ or more using insulation resistance meter when 500 V DC between DC external

terminal batch and ground

Connected terminal block 27-point terminal blocks (M3.5 × 7 screws)

Applicable wire size [mm2] 0.75 to 2.00

Applicable solderless terminal RAV 1.25-3.5, RAV 2-3.5 (conforms to JIS C 2805)

Allowable momentary power
failure period [ms]

Screws M4 × 0.7 mm × 16 mm or larger (tightening torque range 78 to 118 N · cm {8 to 12 kg · cm})

May be attached using DIN rails

Applicable DIN rail TH35-7.5Fe, TH35-7.5AI, TH35-15Fe (conforms to JIS C 2812 )

External power supply 24V DC (18 to 30V DC)

Internal consumption current [A] 0.081

Mass [kg (lb)] 0.40 (0.88)

*1 Overall accuracy computation method is as follows:

(Overall accuracy) = (Conversion accuracy) + (Temperature characteristics) × (Ambient operating
temperature change) + (Cold junction compensation accuracy)
The ambient operating temperature change refers to the value that falls outside the range of 25 ±5 °C.
Example) The overall accuracy when using thermocouple K, measured temperature 150 °C,
ambient operating temperature 35 °C will be:
(±0.5 °C) + (±0.06 °C) × (5 °C) + (±1 °C) = ±1.8 °C

*2 Conversion speed is the time required to convert the input temperature to the corresponding digital

value and store it into the remote register.
When using multiple channels, the conversion speed becomes "45ms × number of channels that
are conversion enabled".

16 modules

1

Noise durability

Insulation resistor

Module installation screw

3. SPECIFICATIONS MELSEC-A

3-4

3.3 Temperature/Digital Conversion Characteristics

Since the thermal electromotive force has a non-linear characteristic, it must undergo the linearize
processing before being written in the remote register.
An example of detected temperature characteristic in respect to the thermocouple input value is shown
below.

(1200 °C) 12000

48828 [ µV ]

(1200 °C)

0

0

(0 °C)

(

0 °C

)

V

The diagram at left is an example
of temperature conversion
characteristic example under
the conditions shown below:
Thermocouple used : JIS K type
Terminal block temperature : 0 [°C]

T

e

m

p

e

r

a

t

u

r

e

c

o

n

v

e

r

s

i

o

n

v

a

l

u

e

Thermal
electromotive force

Thermocouple
output characteristic

3.4 Maximum Transmission Distance over the CC-Link System

The maximum transmission distance over the CC-Link system is shown below.

1) Regardless of the setting of the transmission speed, the cable length must be "greater than 2 m
(6.6 ft.)" long between a mater or local station, intelligent device station and the adjacent stations.

2) For 5 Mbps and 10 Mbps transmission speeds, the maximum transmission distance will differ
according to the cable length between the remote I/O station and remote device station, so
exercise caution.

Master
station

Remote I/O station
Remote device station

Remote I/O station
Remote device station

Remote I /O station
Remote device station

Remote I/O station
Remote device station

Local station
Standby master
station
Intelligent device
station

Local station
Standby master
station
Intelligent device
station

1) 1)2) 2)1)

Maximum transmission distance

Maximum transmission

distance

156 kbps 30 cm (11.8 in.) or more 1200 m (3937 ft.)

625 kpbs 30 cm (11.8 in.) or more 600 m (1968.5 ft.)

2.5 Mpbs 30 cm (11.8 in.) or more 200 m (656.2 ft.)

60 cm (23.6 in.) or more 150 m (492.1 ft.)

30 to 59 cm (11.8 to 23.2 in.) 110 m (360.9 ft.)

1 m (3.3 ft.) or more 100 m (328.1 ft.)

10 Mbps 60 to 99 cm (23.6 to 39 in.) 80 m (262.5 ft.)

30 to 59 cm (11.8 to 23.2 in.) 50 m (164 ft.)

2) 1) Transmission speed

2 m (6.6 ft.) or more 5 Mbps

3. SPECIFICATIONS MELSEC-A

3-5

3.5 Data Link Processing Time

For the AJ65BT-68TD, the data link processing time shown below will be required in order to execute
each function.
For details on link scan time, refer to the AJ61BT11/A1SJ61BT11 CC-Link System Master/Local
Module User's Manual or the AJ61QBT11/A1SJ61QBT11 CC-Link System Master/Local Module
User's Manual.

(1) Mater station (RY) → Remote device station (RY) processing time

[Expression]
SM + LS × 3 + Remote device station processing time (90 ms)

[ms]

AJ65BT-68TD

SM : Master station sequence program scan time
LS : Link scan time

(2) Master station (RWw) → Remote device station (RWw) processing time

[Expression]
SM + LS × 3 + Remote device station processing time (90 ms)

[ms]
AJ65BT-68TD
SM : Master station sequence program scan time
LS : Link scan time

(3) Master station (RX) ← Remote Device Station (RX) Processing Time

[Expression]
SM + LS × 2 + Remote device station processing time (1 ms)

[ms]
AJ65BT-68TD
SM : Master station sequence program scan time
LS : Link scan time

(4) Master station (RWr) ← Remote Device Station (RWr) Processing Time

[Expression]
SM + LS × 2 + Remote device station processing time (1 ms)

[ms]
AJ65BT-68TD
SM : Master station sequence program scan time
LS : Link scan time

POINT

The above are examples of processing time until the control of the output signal to the AJ65BT­68TD from the PLC CPU or until input signals or remote registers are read.

The maximum time that takes for updating the detected temperature read by the PLC CPU is
"data link processing time + sampling time."

3. SPECIFICATIONS MELSEC-A

3-6

3.6 Twisted Cable Specifications

The twisted cable specifications and recommended cables for use with the CC-Link is explained
below.
Also, the performance of the CC-Link may not be guaranteed when using cables other than
recommended ones as shown below.
The recommended cable names and specifications are shown in the table below.

Item Specification

Type FANC–SB 0.5 mm2 × 3

Contact

Mitsubishi Electric System Service, Inc.

Kurashige Denkou, Inc.

Cable type Twisted shielded cable

Conductor cross-sectional area 0.5 mm2

Conductor resistance (20 °C) 37.8 Ω/km or less

Conductive resistance 10000 MΩ km or more

Dielectric withstand voltage 500 V DC one minute

Static capacity (1 kHz) 60 nF/km or less

Characteristic impedance (1 MHz) 100 ± 15 Ω

Cross-sectional diagram

blue

white yellow

DA

DB DG

Sheath

Shield

Aluminum tape

Ground wire

External dimensions 7 mm (0.28 in.)

Approximate mass 65 kg / km

3. SPECIFICATIONS MELSEC-A

3-7

3.7 Function List

Below is a function list of the AJ65BT-68TD.

Item Description Reference section

Wire breakage detection

• Detects wire breakage for the connected thermocouple by
channel.

Section 3.8.3

Conversion enable/disable
designation

• Performs conversion enable/disable settings by channel.

• Sampling time may be reduced by disabling the conversion

at channels not in use.

Section 3.8.4

Sampling processing/travel
average processing designation

• Designates sampling processing or travel average
processing by channel.

Section 3.8.5

Thermocouple type selection

• The thermocouple type to be used may be set for each
channel or in batch.

Section 3.8.6

Pt100 cold junction
compensation enable/disable
designation

• Designates the Pt100 cold junction compensation
enable/disable.

• By disabling the Pt100 cold junction compensation, a high­accuracy ice bus is set outside of the module to increase
the cold junction compensation accuracy.

Section 3.8.7

Measured temperature
upper/lower limit value setting

• Sets the upper and lower limits of the measured
temperature by channel.

Section 3.9.2

Detected temperature storage

• A value to one decimal place (16-bit signed binary) will be
stored in the remote register.

Section 3.9.3

Scaling value storage

• The detected temperature value will be scaled to a value
of 0 to 2000 within the upper and lower limits and stored.

Section 3.9.4

Error compensation by
offset/gain value setting

• Error compensation is performed by setting the offset/gain
values.

Section4.4

3. SPECIFICATIONS MELSEC-A

3-8

3.8 I/O Signals in Respect to the Master Module

The assignment of I/O signals and the functions is explained.

3.8.1 I/O signal list

The AJ65BT-68TD uses 128 points for input and 128 points for output in respect to the data for the
master module.
The I/O signal assignment and the name of each signal are shown in the table below.
Device RX indicates an input signal to the master module from the AJ65BT-68TD, and device RY
indicates an output signal from the master module to the AJ65BT-68TD.

Signal direction : AJ65BT-68TD → Master module Signal direction : Master module → AJ65BT-68TD

Device No. Signal name Device No. Signal name

RXn0 CH.1 conversion completion flag RYn0 CH.1 conversion enable flag

RXn1 CH.2 conversion completion flag RYn1 CH.2 conversion enable flag

RXn2 CH.3 conversion completion flag RYn2 CH.3 conversion enable flag

RXn3 CH.4 conversion completion flag RYn3 CH.4 conversion enable flag

RXn4 CH.5 conversion completion flag RYn4 CH.5 conversion enable flag

RXn5 CH.6 conversion completion flag RYn5 CH.6 conversion enable flag

RXn6 CH.7 conversion completion flag RYn6 CH.7 conversion enable flag

RXn7 CH.8 conversion completion flag RYn7 CH.8 conversion enable flag

RXn8 CH.1 wire breakage detection flag RYn8 CH.1 sampling/travel average processing designation flag

RXn9 CH.2 wire breakage detection flag RYn9 CH.2 sampling/travel average processing designation flag

RXnA CH.3 wire breakage detection flag RYnA CH.3 sampling/travel average processing designation flag

RXnB CH.4 wire breakage detection flag RYnB CH.4 sampling/travel average processing designation flag

RXnC CH.5 wire breakage detection flag RYnC CH.5 sampling/travel average processing designation flag

RXnD CH.6 wire breakage detection flag RYnD CH.6 sampling/travel average processing designation flag

RXnE CH.7 wire breakage detection flag RYnE CH.7 sampling/travel average processing designation flag

RXnF CH.8 wire breakage detection flag RYnF CH.8 sampling/travel average processing designation flag

RX (n+1) 0 CH.1 measurement range over flag (lower limit) RY (n+1) 0 CH.1 t ype "K" thermocouple selection flag

RX (n+1) 1 CH.1 measurement range over flag (upper limit) RY (n+1) 1 CH.1 type "E" thermocouple selection flag

RX (n+1) 2 CH.2 measurement range over flag (lower limit) RY (n+1) 2 CH.1 type "J" t hermoc ouple selection flag

RX (n+1) 3 CH.2 measurement range over flag (upper limit) RY (n+1) 3 CH.1 type "T" thermocouple selection flag

RX (n+1) 4 CH.3 measurement range over flag (lower limit) RY (n+1) 4 CH.1 t ype "B" thermocouple selection flag

RX (n+1) 5 CH.3 measurement range over flag (upper limit) RY (n+1) 5 CH.1 type "R" the rmo couple selection flag

RX (n+1) 6 CH.4 measurement range over flag (lower limit) RY (n+1) 6 CH.1 t ype "S" thermocouple selection flag

RX (n+1) 7 CH.4 measurement range over flag (upper limit) RY (n+1) 7 Use pro hibited

RX (n+1) 8 CH.5 measurement range over flag (lower limit) RY (n+1) 8 CH.2 t ype "K" thermocouple selection flag

RX (n+1) 9 CH.5 measurement range over flag (upper limit) RY (n+1) 9 CH.2 type "E" thermocouple selection flag

RX (n+1) A CH.6 measurement range over flag (lower limit) RY (n+1) A CH.2 type "J" t her moc ouple selection flag

RX (n+1) B CH.6 measurement range over flag (upper limit) RY (n+1) B CH.2 type "T" thermoc ouple selection flag

RX (n+1) C CH.7 measurement range over flag (lower limit) RY (n+1) C CH.2 type "B" thermocouple selection flag

RX (n+1) D CH.7 measurement range over flag (upper limit) RY (n+1) D CH.2 type "R" th erm ocouple selection flag

RX (n+1) E CH.8 measurement range over flag (lower limit) RY (n+1) E CH.2 type "S" thermocouple selection flag

RX (n+1) F CH.8 measurement range over flag (upper limit) RY (n+1) F Use pr ohibited

3. SPECIFICATIONS MELSEC-A

3-9

Signal direction : AJ65BT-68TD → Master module Signal direction : Master module → AJ65BT-68TD

Device No. Signal name Device No. Signal name

RX (n+2) 0 CH.1 write data error flag RY (n+2) 0 CH.3 type "K" thermocouple selection flag

RX (n+2) 1 CH.2 write data error flag RY (n+2) 1 CH.3 type "E" thermocouple selection flag

RX (n+2) 2 CH.3 write data error flag RY (n+2) 2 CH.3 type "J" thermocouple selection flag

RX (n+2) 3 CH.4 write data error flag RY (n+2) 3 CH.3 type "T" thermocouple selection flag

RX (n+2) 4 CH.5 write data error flag RY (n+2) 4 CH.3 type "B" thermocouple selection flag

RX (n+2) 5 CH.6 write data error flag RY (n+2) 5 CH.3 type "R" thermocouple selection flag

RX (n+2) 6 CH.7 write data error flag RY (n+2) 6 CH.3 type "S" thermocouple selection flag

RX (n+2) 7 CH.8 write data error flag RY (n+2) 7 Use prohibited

RX (n+2) 8 E2PROM abnormal flag RY (n+2) 8 CH.4 type "K" thermocouple selection flag

RX (n+2) 9 Test mode flag RY (n+2) 9 CH.4 type "E" thermocouple selection flag

RX (n+2) A RY (n+2) A CH.4 type "J" thermocouple selection flag

RX (n+2) B RY (n+2) B CH.4 type "T" thermocouple selection flag

RX (n+2) C RY (n+2) C CH.4 type "B" thermocouple selection flag

RX (n+2) D RY (n+2) D CH.4 type "R" thermocouple selection flag

RX (n+2) E RY (n+2) E CH.4 type "S" thermocouple selection flag

RX (n+2) F RY (n+2) F Use prohibited

RX (n+3) 0 RY (n+3) 0 CH.5 type "K" thermocouple selection flag

RX (n+3) 1 RY (n+3) 1 CH.5 type "E" thermocouple selection flag

RX (n+3) 2 RY (n+3) 2 CH.5 type "J" thermocouple selection flag

RX (n+3) 3 RY (n+3) 3 CH.5 type "T" thermocouple selection flag

RX (n+3) 4 RY (n+3) 4 CH.5 type "B" thermocouple selection flag

RX (n+3) 5 RY (n+3) 5 CH.5 type "R" thermocouple selection flag

RX (n+3) 6 RY (n+3) 6 CH.5 type "S" thermocouple selection flag

RX (n+3) 7 RY (n+3) 7 Use prohibited

RX (n+3) 8 RY (n+3) 8 CH.6 type "K" thermocouple selection flag

RX (n+3) 9 RY (n+3) 9 CH.6 type "E" thermocouple selection flag

RX (n+3) A RY (n+3) A CH.6 type "J" thermocouple selection flag

RX (n+3) B RY (n+3) B CH.6 type "T" thermocouple selection flag

RX (n+3) C Use prohibited RY (n+3) C CH.6 type "B" thermocouple selection flag

RX (n+3) D RY (n+3) D CH.6 type "R" thermocouple selection flag

RX (n+3) E RY (n+3) E CH.6 type "S" thermocouple selection flag

RX (n+3) F RY (n+3) F Use prohibited

RX (n+4) 0 RY (n+4) 0 CH.7 type "K" thermocouple selection flag

RX (n+4) 1 RY (n+4) 1 CH.7 type "E" thermocouple selection flag

RX (n+4) 2 RY (n+4) 2 CH.7 type "J" thermocouple selection flag

RX (n+4) 3 RY (n+4) 3 CH.7 type "T" thermocouple selection flag

RX (n+4) 4 RY (n+4) 4 CH.7 type "B" thermocouple selection flag

RX (n+4) 5 RY (n+4) 5 CH.7 type "R" thermocouple selection flag

RX (n+4) 6 RY (n+4) 6 CH.7 type "S" thermocouple selection flag

RX (n+4) 7 RY (n+4) 7 Use prohibited

RX (n+4) 8 RY (n+4) 8 CH.8 type "K" thermocouple selection flag

RX (n+4) 9 RY (n+4) 9 CH.8 type "E" thermocouple selection flag

RX (n+4) A RY (n+4) A CH.8 type "J" thermocouple selection flag

RX (n+4) B RY (n+4) B CH.8 type "T" thermocouple selection flag

RX (n+4) C RY (n+4) C CH.8 type "B" thermocouple selection flag

RX (n+4) D RY (n+4) D CH.8 type "R" thermocouple selection flag

RX (n+4) E RY (n+4) E CH.8 type "S" thermocouple selection flag

RX (n+4) F RY (n+4) F Use prohibited

3. SPECIFICATIONS MELSEC-A

3-10

Signal direction : AJ65BT-68TD → Master module Signal direction : Master module → AJ65BT-68TD

Device No. Signal name Device No. Signal name

RX (n+5) 0 RY (n+ 5) 0 All CH. batch type "K" thermocouple selection flag

RX (n+5) 1 RY (n+ 5) 1 All CH. batch type "E" thermocouple selection flag

RX (n+5) 2 RY (n+ 5) 2 All CH. batch type "J" thermocouple selection flag

RX (n+5) 3 RY (n+ 5) 3 All CH. batch type "T" thermocouple selection flag

RX (n+5) 4 RY (n+ 5) 4 All CH. batch type "B" thermocouple selection flag

RX (n+5) 5 RY (n+ 5) 5 All CH. batch type "R" thermocouple selection flag

RX (n+5) 6 Use pro hibited RY (n+ 5) 6 All CH. batch type "S" thermocouple selection flag

RX (n+5) 7 RY (n+5) 7 Pt100 cold junction compensation disable flag

RX (n+5) 8 RY (n+5) 8

to to Use prohibited

RX (n+7) 6 RY (n+7) 6

RX (n+7) 7 RY (n+7) 7 Offset/gain value selection flag

RX (n+7) 8 Initial data processing request flag RY (n+7) 8 Initial data processing completion flag

RX (n+7) 9 Initial data setting completion flag RY (n+7) 9 Initial data setting request flag

RX (n+7) A Error status flag RY (n+7) A Error reset request flag

RX (n+7) B Remote READY RY (n+7) B

RX (n+7) C RY (n+7) C

to Use prohibited to Use prohibited

RX (n+7) F RY (n+7) F

n : Addresses assigned to the master module by the station number setting.

POINT

Do not turn on the output signals that are prohibited in respect to the remote device from the
master module.

If the prohibited signals are output, the PLC system may malfunction.

3. SPECIFICATIONS MELSEC-A

3-11

3.8.2 I/O signal functions

The function of each I/O signal for the AJ65BT-68TD is explained below.

(1) Input signal

Device No. Signal name Description

RXn0 to RXn7

CH.



conversion
completion flag

The conversion completion flag turns on when the detected temperature value
converted at each channel is stored in the remote register after power on or a
hardware reset.

If the travel average processing is running, it will turn on when the detected
temperature value is converted and stored in the remote register after the travel
average processing has completed. The conv ersion completion flag changes
according to the conditions listed below.

• When conversion disabled is changed to enabled
The temperature detection of the enabled channels will be commenced.
After the detected temperature values are stored in the remote register, the
conversion completion flag is turned on for the corresponding channel.

• When conversion enabled is changed to disabled
The conversion completion flag is turned off for the corresponding channel.
For the values stored in the remote register, the data immediately prior to the
disable setting are retained.

RXn8 to RXnF

CH.

 wire

breakage
detection flag

For the thermocouple input circuit for all channels, when only a single section of the
I/O signal lines including the thermocouple is broken, the wire breakage detection flag
is turned on for the corresponding channel.

The detected temperature value when a wire breakage detection flag is turned on will
be maintained at the normal value immediately prior to the wire breakage, and then the
conversion completion flag will be turned off.

After the wire breakage has been removed, the wire breakage detection flag may be
turned off by turning on the error reset request flag.

Also, after the breakage has been fixed, the updating of detected temperatures value
will be resumed regardless of whether or not the wire breakage detection flag is reset,
and after the first update has been completed the conversion completion flag will turn
on once again.

CH.



measurement
range over flag

When a detected temperature value that falls outside of the upper and lower limits set
in the remote register is detected, the measurement range over flag is turned on for
the corresponding channel.

When the detected temperature value returns to inside the range, it is reset (off)
automatically.

RX (n+2) 1 to

RX (n+2) 7

CH.

 writ e

data error flag

When a value exceeding the specification is written in the write-only area of the remote
register (upper and lower limit setting) or when multiple types of thermocouples are
selected in the thermocouple selection flag, the write data error is turned on for the
corresponding channel.

After the cause of the write data error has been removed, the flag may be turned off by
turning on the error reset request flag.

RX (n+2) 8

After power on or a hardware reset, the internal memory (E2PROM for offset/gain value

storage) is checked, and it turns on if there is an error.

At such times, the conversion function will stop.

When this flag turns on, the error reset request flag may not be used to reset (off)
because the module itself is malfunctioning (hardware error).

Turns on during test mode.

Turns off when reverted to normal mode.

RX (n+1) 1 to

RX (n+1) F

E

2

PROM

abnormal flag

Test mode flag RX (n+2) 9

3. SPECIFICATIONS MELSEC-A

3-12

Device No. Signal name Description

After power on or a hardware reset, this is turned on because the AJ65BT-68TD

requests the initial data setting .

After the initial data processing is complete (initial data processing request flag
RY(n+7)8 is turned on), it turns off.

Turns on when initial data setting request (initial data setting request flag RY(n+7)9 is

turned on) is made.

After the initial data setting request flag is turned off when initial data setting is
complete, this also turns off.

RX (n+7) A

Turns on when wire breakage detection flag/write data error flag/E

2

PROM error flag

turns on.

After the cause of the error has been removed, the flag may be reset (off) by turning
on the error reset request flag, but since the E

2

PROM error flag cannot be reset, this

flag may also not be reset.

RX (n+7) B

After power on or a hardware reset, this flag turns on when the initial data setting is

complete and the detected temperature value at the conversion-enabled channel has
been stored in the remote register.

Will not turn on when all channels are conversion disabled.

It will turn off for two seconds when the offset/gain switch is set to [OFFSET] during
test mode or when changed from [GAIN] to [SET].

Used as an interlock for read and write in respect to the master module.

Initial data
processing
request flag

RX (n+7) 8

Initial data

setting

completion

flag

RX (n+7) 9

Error status
flag

Remote
READY

3. SPECIFICATIONS MELSEC-A

3-13

(2) Output signal

Device No. Signal name Description

RYn0 to RYn7

CH.



conversion
enable flag

It is possible to designate the conversion enabled or disabled for each channel.

By disabling the conversion at channels not in use, generation of unnecessary wire
breakage detection flags may be prevented and sampling time may be reduced.

ON : Conversion enabled

.....

wire breakage detection is conducted at the same time

the temperature of the target object is taken.

OFF : Conversion disabled

....

neither temperature taking or wire breakage detection

is conducted.

By setting of conversion enable/disable, the following changes are made.

• When conversion is changed from disabled

→ enabled

Temperature detection of the enabled channel is commenced.
After the detected temperature value of the corresponding channel is stored in the
remote register, the conversion completion flag of the corresponding channel is
turned on.

• When the conversion is changed from enabled

→ disabled.

The conversion completion flag is turned off for the corresponding channel.
For the detected temperature value stored in the remote register, the data
immediately prior to the disable setting will be retained.

RYn8 to RYnF

CH.



sampling
processing/
travel average
processing
designation

flag

It is possible to designate the sampling processing or travel average processing for
each independent channel.

ON : Travel average processing

OFF : Sampling processing

In travel average processing, an average value of four detected temperature value
samples that were taken during each sampling time is calculated and stored in the
remote register.

• When changed from sampling processing

→ travel average processing

The conversion completion flag for the corresponding channel is turned off.
An average value of four detected temperature value samples is calculated, and
after it has been stored to the remote register the conversion completion flag of the
corresponding channel is turned on.

• When changed from travel average processing

→ sampling processing

The conversion completion flag is turned off for the corresponding channel.
After the most recent detected temperature value is stored in the remote register,
the conversion completion flag for the corresponding channel is turned on.

Note : This flag is only valid when the initial data processing completion flag (RY (n+7)

8) or initial data setting request flag (RY (n+7) 9) is on.

3. SPECIFICATIONS MELSEC-A

3-14

Device No. Signal name Description

RY (n+1) 0

to

RY (n+1) 6

CH.1
thermocouple
selection flag

RY (n+1) 8

to

RY (n+1) E

CH.2
thermocouple
selection flag

RY (n+2) 0

to

RY (n+2) 6

CH.3
thermocouple
selection flag

RY (n+2) 8

to

RY (n+2) E

CH.4
thermocouple
selection flag

RY (n+3) 0

to

RY (n+3) 6

CH.5
thermocouple
selection flag

RY (n+3) 8

to

RY (n+3) E

CH.6
thermocouple
selection flag

RY (n+4) 0

to

RY (n+4) 6

CH.7
thermocouple
selection flag

RY (n+4) 8

to

RY (n+4) E

CH.8
thermocouple
selection flag

All CH.
batch
thermocouple
selection flag

All channels are selected to the same thermocouple in batch. This flag takes priority
over the thermocouple selection flag for individual channels. The thermocouple
selection flag for individual channels may only be used when this flag is off.

Also, when multiple batch thermocouple selection flags are turned on, the write data
error flag is turned on and the previously selected thermocouple type is retained.

Refer to the I/O signal list for the correspondence between each signal and
thermocouple type.

Note : This flag is only valid when the initial data processing compensation flag

(RY(n+7)8) or initial data setting request flag (RY (n+7) 9) is on.

RY (n+5) 7

The detected temperature value to be stored in the remote register can be selected

from a value that has undergone cold junction compensation by Pt100 temperature­measuring resistor, and a value that has not (the cold junction compensation is
performed externally).

ON : Cold contact compensation is not performed by the Pt100 temperature-

measuring resistor.

OFF : Cold contact compensation is performed by the Pt100 temperature-measuring

resistor.

Note : This flag is only valid when the initial data processing compensation flag

(RY(n+7)8) or initial data setting request flag (RY (n+7) 9) is on.

Selects the type of thermocouple to be connected to each channel.

Only the flags appropriate for the thermocouple to be used are turned on.

It is read as the set value when the initial data processing request flag is turned on.

When the flag is off after power on or a hardware reset, the K type is selected.

Also, when multiple thermocouple selection flags are turned on, the write data error flag
is turned on and the previously selected thermocouple type is retained.

Refer to the I/O signal list for the correspondence between each signal and
thermocouple type.

Note : This flag is only valid when the initial data processing compensation flag

(RY(n+7)8) or initial data setting request flag (RY (n+7) 9) is on.

RY (n+5) 0

to

RY (n+5) 6

Pt100 cold
junction
compensation
disable flag

3. SPECIFICATIONS MELSEC-A

3-15

Device No. Signal name Description

Select whether or not the offset/gain value will be set to "user setting" or "factory

setting."

At the product shipment from factory, the same values for the factory settings are
stored in the E

2

PROM for storing the user setting offset/gain values.

ON : Factory setting (Offset-gain, 100.0

Ω (0 °C equivalent) -300 °C)

OFF : User setting

Note : This flag is only valid when the initial data processing compensation flag (RY

(n+7) 8) or initial data setting request flag (RY (n+7) 9) is on.

RY (n+7) 8

Initial data
processing
completion flag

After power on or hardware reset, the initial data are set in the module by turning this
flag on during the initial data processing request .

Used when designating sampling processing/travel average processing designation,
selecting offset/gain value, setting upper and lower limits, Pt100 cold junction
compensation enable/disable designation or selecting thermocouples.

Turned on when changing the initial values.

Used when designating sampling processing/travel average processing, selecting
offset/gain value, setting upper and lower limits, or Pt100 cold junction compensation
enable/disable designation.

Error reset
request flag

When this flag is turned on, the wire breakage detection flag/write data error flag are
reset (turned off), and the error status flags are reset at the same time. However, the
E

2

PROM error flag may not be reset (turned off) and therefore the error status flag will

remain on.

n : Address assigned to the master module by the station number setting.

RY (n+7) 7

Offset/gain
value selection
flag

RY (n+7) 9

Initial data
setting request
flag

RY (n+7) A

3. SPECIFICATIONS MELSEC-A

3-16

3.8.3 Wire breakage detection

The AJ65BT-68TD detects wire breakage in the thermocouple or compensating conductor used for
each channel, and turns on the wire breakage detection flag (RXn8 to RXnF) for the corresponding
channel.
On the AJ65BT-68TD, the wire breakage detection are performed for channels that are enabled for
conversion.
The relationships between the wire breakage detection and conversion enable/disable are shown
below.

Connection status Conversion enabled/disabled setting Wire breakage detection flag

Conversion enabled

Conversion disabled

Conversion enabled ON

Conversion disabled OFF

Conversion enabled ON

Conversion disabled OFF

POINT

• Be sure to set the channels having no thermocouple attached to "conversion disabled."
If a channel having no thermocouple attached is set to "conversion enabled," the wire
breakage detection flag will turn on.

• The channels for which wire breakage detection turned on will retain the normal detected
temperature value immediately prior to the breakage detection, and the conversion completion
flag for the corresponding channel will turn off.
When the detected breakage is fixed, updating of detected temperature value after repair will
be resumed and the conversion completion flag will be turned on again.

• For thermocouple wiring details, refer to Section 4.7.

+

–

No breakage

+

–

Breakage

+

–

No connection

OFF