Mitsubishi Electric QJ71MB91 User manual

MODBUS Interface Module User's Manual
-QJ71MB91
-GX Configurator-MB (SW1D5C-QMBU-E)

A- 1
SAFETY PRECAUTIONS
(Always read these instructions before using this product.)
Before using this product, please read this manual and the relevant manuals introduced in this manual
carefully and pay full attention to safety to handle the product correctly.
The instructions given in this manual are concerned with this product. For the safety instructions of the
programmable controller system, please read the user's manual of the CPU module used.
In this manual, the safety precautions are classified into two levels: " WARNING" and " CAUTION".
Under some circumstances, failure to observe the precautions given under " CAUTION" may lead to
serious consequences.
Observe the precautions of both levels because they are important for personal and system safety.
Make sure that the end users read this manual and then keep the manual in a safe place for future
reference.
[DESIGN PRECAUTIONS]
WARNING
For the operating status of each station after a communication failure, refer to relevant manuals for
each network.
Failure to do so may result in an accident due to an incorrect output or malfunction.
When connecting a peripheral with the CPU module or connecting an external device, such as a
personal computer, with an intelligent function module to modify data of a running programmable
controller, configure an interlock circuit in the program to ensure that the entire system will always
operate safely.
For other forms of control (such as program modification or operating status change) of a running
programmable controller, read the relevant manuals carefully and ensure that the operation is safe
before proceeding.
Especially, when a remote programmable controller is controlled by an external device, immediate
action cannot be taken if a problem occurs in the programmable controller due to a communication
failure. To prevent this, configure an interlock circuit in the sequence program, and determine
corrective actions to be taken between the external device and CPU module in case of a
communication failure.
Do not write any data to the "system area" of the buffer memory in the intelligent function module.
Also, do not use any "use prohibited" signals as an output signal from the programmable controller
CPU to the intelligent function module.
Doing so may cause malfunction of the programmable controller system.
WARNING
CAUTION
Indicates that incorrect handling may cause hazardous conditions,
resulting in death or severe injury.
Indicates that incorrect handling may cause hazardous conditions,
resulting in minor or moderate injury or property damage.

A- 2
[DESIGN PRECAUTIONS]
[INSTALLATION PRECAUTIONS]
CAUTION
Do not install the control lines or communication cables together with the main circuit lines or power
cables.
Keep a distance of 100mm or more between them.
Failure to do so may result in malfunction due to noise.
CAUTION
Use the programmable controller in an environment that meets the general specifications in the
user's manual for the CPU module used.
Failure to do so may result in electric shock, fire, malfunction, or damage to or deterioration of the
product.
To mount the module, while pressing the module mounting lever located in the lower part of the
module, fully insert the module fixing projection(s) into the hole(s) in the base unit and press the
module until it snaps into place.
Incorrect mounting may cause malfunction, failure or drop of the module.
When using the programmable controller in an environment of frequent vibrations, fix the module
with a screw.
Tighten the terminal screws within the specified torque range.
Undertightening can cause drop of the screw, short circuit or malfunction.
Overtightening can damage the screw and/or module, resulting in drop, short circuit, or malfunction.
Shut off the external power supply (all phases) used in the system before mounting or removing a
module. Failure to do so may result in damage to the product.
Do not directly touch any conductive parts and electronic components of the module.
Doing so can cause malfunction or failure of the module.

A- 3
[WIRING PRECAUTIONS]
]
WARNING
Shut off the external power supply (all phases) used in the system before wiring.
Failure to do so may result in electric shock or damage to the product.
After wiring, attach the included terminal cover to the module before turning it on for operation.
Failure to do so may result in electric shock.
CAUTION
Connectors for external devices must be crimped or pressed with the tool specified by the
manufacturer, or must be correctly soldered.
Incomplete connections may cause short circuit, fire, or malfunction.
Securely connect the connector to the module.
Check the rated voltage and terminal layout before wiring to the module, and connect the cables
correctly.
Connecting a power supply with a different voltage rating or incorrect wiring may cause a fire or
failure.
Place the cables in a duct or clamp them.
If not, dangling cable may swing or inadvertently be pulled, resulting in damage to the module or
cables or malfunction due to poor contact.
Check the interface type and correctly connect the cable.
Incorrect wiring (connecting the cable to an incorrect interface) may cause failure of the module and
external device.
Tighten the terminal screws within the specified torque range.
Undertightening can cause drop of the screw, short circuit or malfunction.
Overtightening can damage the screw and/or module, resulting in drop, short circuit, or malfunction.
When disconnecting the cable from the module, do not pull the cable by the cable part.
For the cable with connector, hold the connector part of the cable.
For the cable connected to the terminal block, loosen the terminal screw.
Failure to do so may result in damage to the module or cable or malfunction due to poor contact.
Prevent foreign matter such as dust or wire chips from entering the module.
Such foreign matter can cause a fire, failure, or malfunction.
A protective film is attached to the top of the module to prevent foreign matter, such as wire chips,
from entering the module during wiring.
Do not remove the film during wiring.
Remove it for heat dissipation before system operation.

A- 4
[STARTUP AND MAINTENANCE PRECAUTIONS]
[DISPOSAL PRECAUTIONS]
WARNING
Do not touch any terminal while power is on.
Doing so will cause electric shock.
Shut off the external power supply (all phases) used in the system before cleaning the module or
retightening the terminal screws or module fixing screws.
Failure to do so may cause the module to fail or malfunction.
Undertightening can cause drop of the screw, short circuit or malfunction.
Overtightening can damage the screw and/or module, resulting in drop, short circuit, or malfunction.
CAUTION
Before performing online operations (especially, program modification, forced output or operating
status change) by connecting a peripheral device to a running CPU, read the manual carefully and
ensure the safety.
Improper operation may damage machines or cause accidents.
Do not disassemble or modify the modules.
Doing so may cause failure, malfunction, injury, or a fire.
Use any radio communication device such as a cellular phone or PHS (Personal Handy-phone
System) more than 25cm away in all directions from the programmable controller.
Failure to do so may cause malfunction.
Shut off the external power supply (all phases) used in the system before mounting or removing a
module.
Failure to do so may cause the module to fail or malfunction.
After the first use of the product, do not mount/remove the module to/from the base unit, and the
terminal block to/from the module more than 50 times (IEC 61131-2 compliant) respectively.
Exceeding the limit of 50 times may cause malfunction.
Before handling the module, touch a conducting object such as a grounded metal to discharge the
static electricity from the human body.
Failure to do so may cause the module to fail or malfunction.
CAUTION
When disposing of this product, treat is as an industrial waste.

A- 5
CONDITIONS OF USE FOR THE PRODUCT
(1) Mitsubishi programmable controller ("the PRODUCT") shall be used in conditions;
i) where any problem, fault or failure occurring in the PRODUCT, if any, shall not lead to any major
or serious accident; and
ii) where the backup and fail-safe function are systematically or automatically provided outside of
the PRODUCT for the case of any problem, fault or failure occurring in the PRODUCT.
(2) The PRODUCT has been designed and manufactured for the purpose of being used in general
industries.
MITSUBISHI SHALL HAVE NO RESPONSIBILITY OR LIABILITY (INCLUDING, BUT NOT
LIMITED TO ANY AND ALL RESPONSIBILITY OR LIABILITY BASED ON CONTRACT,
WARRANTY, TORT, PRODUCT LIABILITY) FOR ANY INJURY OR DEATH TO PERSONS OR
LOSS OR DAMAGE TO PROPERTY CAUSED BY the PRODUCT THAT ARE OPERATED OR
USED IN APPLICATION NOT INTENDED OR EXCLUDED BY INSTRUCTIONS, PRECAUTIONS,
OR WARNING CONTAINED IN MITSUBISHI'S USER, INSTRUCTION AND/OR SAFETY
MANUALS, TECHNICAL BULLETINS AND GUIDELINES FOR the PRODUCT.
("Prohibited Application")
Prohibited Applications include, but not limited to, the use of the PRODUCT in;
• Nuclear Power Plants and any other power plants operated by Power companies, and/or any
other cases in which the public could be affected if any problem or fault occurs in the PRODUCT.
• Railway companies or Public service purposes, and/or any other cases in which establishment of
a special quality assurance system is required by the Purchaser or End User.
• Aircraft or Aerospace, Medical applications, Train equipment, transport equipment such as
Elevator and Escalator, Incineration and Fuel devices, Vehicles, Manned transportation,
Equipment for Recreation and Amusement, and Safety devices, handling of Nuclear or
Hazardous Materials or Chemicals, Mining and Drilling, and/or other applications where there is a
significant risk of injury to the public or property.
Notwithstanding the above, restrictions Mitsubishi may in its sole discretion, authorize use of the
PRODUCT in one or more of the Prohibited Applications, provided that the usage of the PRODUCT
is limited only for the specific applications agreed to by Mitsubishi and provided further that no
special quality assurance or fail-safe, redundant or other safety features which exceed the general
specifications of the PRODUCTs are required. For details, please contact the Mitsubishi
representative in your region.

A- 6
REVISIONS
* The manual number is given on the bottom left of the back cover.
Japanese Manual Version SH-080547-J
© 2005 MITSUBISHI ELECTRIC CORPORATION
Print Date * Manual Number Revision
Nov., 2005 SH(NA)-080578ENG-A First edition
Feb., 2006 SH(NA)-080578ENG-B Modifications
Section 2.1, 2.3, 10.1
Oct., 2006 SH(NA)-080578ENG-C Modifications
SAFETY PRECAUTIONS, Section 2.1, 6.6, 10.1
Jan., 2008 SH(NA)-080578ENG-D Modifications
SAFETY PRECAUTIONS, ABOUT THE GENERIC TERMS AND
ABBREVIATIONS, MEANINGS AND DEFINITIONS OF TERMS, Section 2.1,
2.4, 3.1, 3.2.1, 3.3.1, 3.3.2, 3.4.1, 4.1.6, 5.1, 5.2.1, 6.1, 6.3, 6.4.1, 6.4.2, 6.5.2,
6.6, 7.2.1, 7.3.1, 7.3.2, Chapter 8, 9.1.2, 9.3.1, 9.3.2, 10.2, 10.3, 11.1, 11.2,
11.4.1, 11.4.3, 11.5.1, Appendix 3
Added
Section 2.3
Section 2.3 changed to Section 2.4.
Mar., 2008 SH(NA)-080578ENG-E Modifications
COMPLIANCE WITH EMC AND LOW VOLTAGE DIRECTIVES, Section 2.1, 2.4,
4.16, 6.3, 6.4.1, 8.5, 8.6, Appendix 3
May, 2008 SH(NA)-080578ENG-F Change of a term
"PLC" was changed to "programmable controller".
Modifications
ABOUT THE GENERIC TERMS AND ABBREVIATIONS, Section 2.1, 4.16, 6.1,
6.6, 7.3.1, 8.2.1, 8.3.1, 8.3.3, 8.4, 8.5, 8.6, 10.2, 10.3, 11.4.3
Apr., 2009 SH(NA)-080578ENG-G Modifications
Section 1.1, 2.1, 2.4, 3.1, 3.4.1, 3.5.1, 4.16, 5.2.1, 8.2.1, 9.1.1 to 9.3.2,
10.1 to 10.3, 11.1, 11.4.3
Added
Section 10.4, Appendix 1
Appendix numbers 1 and 2 changed to 2 and 3.
Jan., 2013 SH(NA)-080578ENG-H Modifications
SAFETY PRECAUTIONS, COMPLIANCE WITH EMC AND LOW VOLTAGE
DIRECTIVES, ABOUT THE GENERIC TERMS AND ABBREVIATIONS,
Section 2.1, 2.3, 2.4, 3.3.2, 4.16, 7.1, 8.2.2, 11.4.3
Added
CONDITIONS OF USE FOR THE PRODUCT, Section 9.4
Sep., 2016 SH(NA)-080578ENG-I Modifications
SAFETYABOUT THE GENERIC TERMS AND ABBREVIATIONS, Section 1.1,
2.1, 2.2, 2.3, 2.4, 3.3.1, 4.2.1, 4.16, 5.2.1, 6.3, 9.2.1, 9.2.2, 9.2.3, 9.3.1, 9.3.2,
10.3, Appendix 3
This manual confers no industrial property rights or any rights of any other kind, nor does it confer any patent licenses.
Mitsubishi Electric Corporation cannot be held responsible for any problems involving industrial property rights which may
occur as a result of using the contents noted in this manual.

A- 7
SAFETY PRECAUTIONS .................................................................................................................................A - 1
CONDITIONS OF USE FOR THE PRODUCT..................................................................................................A - 5
REVISIONS.......................................................................................................................................................A - 6
INTRODUCTION...............................................................................................................................................A - 7
CONTENTS ...................................................................................................................................................... A - 7
COMPLIANCE WITH EMC AND LOW VOLTAGE DIRECTIVES................................................................... A - 12
THE MANUAL'S USAGE AND STRUCTURE ................................................................................................A - 13
ABOUT THE GENERIC TERMS AND ABBREVIATIONS ..............................................................................A - 15
MEANINGS AND DEFINITIONS OF TERM ...................................................................................................A - 16
PRODUCT CONFIGURATION ....................................................................................................................... A - 16
CHAPTER1 OVERVIEW 1 - 1 to 1 - 4
1.1 Features........................................................................................................................................... 1 - 1
CHAPTER2 SYSTEM CONFIGURATION 2 - 1 to 2 - 10
2.1 Applicable Systems ......................................................................................................................... 2 - 1
2.2 Network Configuration ..................................................................................................................... 2 - 3
2.3 Precautions for System Configuration ............................................................................................. 2 - 7
2.4 How to Check the Function Version/Software Version .................................................................... 2 - 8
CHAPTER3 SPECIFICATIONS 3 - 1 to 3 - 23
3.1 Performance Specifications ............................................................................................................. 3 - 1
3.2 RS-232 Interface Specification ........................................................................................................ 3 - 3
3.2.1 RS-232 connector specification................................................................................................ 3 - 3
3.2.2 RS-232 cable specification ....................................................................................................... 3 - 5
3.3 RS-422/485 Interface Specification ................................................................................................. 3 - 6
3.3.1 RS-422/485 terminal block specification .................................................................................. 3 - 6
3.3.2 RS-422/485 cable specification ................................................................................................ 3 - 7
3.3.3 Precautions when transferring data using RS-422/485 line ..................................................... 3 - 8
3.4 I/O Signals for Programmable Controller CPU .............................................................................. 3 - 10
3.4.1 I/O signal list ........................................................................................................................... 3 - 10
3.5 Applications and Assignment of Buffer Memory ............................................................................ 3 - 13
INTRODUCTION
Thank you for purchasing the Mitsubishi MELSEC-Q series programmable controllers.
Before using this product, please read this manual and the relevant manuals carefully and develop
familiarity with the functions and performance of the MELSEC-Q series programmable controller to handle
the product correctly.
When applying the program examples introduced in this manual to an actual system, ensure the
applicability and confirm that it will not cause system control problems.
CONTENTS

A- 8
3.5.1 Buffer memory list................................................................................................................... 3 - 13
CHAPTER4 MODBUS STANDARD FUNCTIONS 4 - 1 to 4 - 60
4.1 MODBUS Standard Function Support List ...................................................................................... 4 - 1
4.2 Frame Specifications ..................................................................................................................... 4 - 10
4.2.1 Frame mode ........................................................................................................................... 4 - 11
4.3 Protocol Data Unit Formats by Functions ......................................................................................4-15
4.4 Read Coils (FC: 01) ....................................................................................................................... 4 - 18
4.5 Read Discrete Inputs (FC: 02) ....................................................................................................... 4 - 19
4.6 Read Holding Registers (FC: 03)................................................................................................... 4 - 20
4.7 Read Input Registers (FC: 04)....................................................................................................... 4 - 21
4.8 Write Single Coil (FC: 05) .............................................................................................................. 4 - 22
4.9 Write Single Register (FC: 06)....................................................................................................... 4 - 23
4.10 Read Exception Status (FC: 07) .................................................................................................... 4 - 24
4.11 Diagnostics (FC: 08) ...................................................................................................................... 4 - 25
4.11.1 Return query data (sub-function code: 00) ............................................................................. 4 - 25
4.11.2 Restart communications option (sub-function code: 01)......................................................... 4 - 26
4.11.3 Return diagnostic register (sub-function code: 02) ................................................................. 4 - 28
4.11.4 Change ASCII input delimiter (sub-function code: 03)............................................................ 4 - 30
4.11.5 Force listen only mode (sub-function code: 04)...................................................................... 4 - 31
4.11.6 Clear counters and diagnostic register (sub-function code: 10) ............................................. 4 - 33
4.11.7 Return bus message count (sub-function code: 11) ............................................................... 4 - 35
4.11.8 Return bus communication error count (sub-function code: 12)............................................. 4 - 36
4.11.9 Return bus exception error count (sub-function code: 13)...................................................... 4 - 37
4.11.10 Return slave message count (sub-function code: 14) ............................................................ 4 - 38
4.11.11 Return slave no response count (sub-function code: 15) ....................................................... 4 - 39
4.11.12 Return slave NAK count (sub-function code: 16).................................................................... 4 - 40
4.11.13 Return slave busy count (sub-function code: 17) ................................................................... 4 - 41
4.11.14 Return bus character overrun count (sub-function code: 18) ................................................. 4 - 42
4.11.15 Return IOP overrun error count (sub-function code: 19) ........................................................ 4 - 43
4.11.16 Clear overrun counter and flag (sub-function code: 20) ......................................................... 4 - 44
4.12 Get Communications Event Counter (FC: 11) ............................................................................... 4 - 45
4.13 Get Communications Event Log (FC: 12) ...................................................................................... 4 - 47
4.14 Write Multiple Coils (FC: 15) .......................................................................................................... 4 - 50
4.15 Write Multiple Registers (FC: 16)................................................................................................... 4 - 52
4.16 Report Slave ID (FC: 17) ............................................................................................................... 4 - 53
4.17 Read File Record (FC: 20) (SC: 06) .............................................................................................. 4 - 55
4.18 Write File Record (FC: 21) (SC: 06) .............................................................................................. 4 - 57
4.19 Mask Write Register (FC: 22) ........................................................................................................ 4 - 59
4.20 Read/Write Multiple Registers (FC: 23) ......................................................................................... 4 - 60
CHAPTER5 FUNCTIONS 5 - 1 to 5 - 22
5.1 Function List .................................................................................................................................... 5 - 1

A- 9
5.2 Master Function ............................................................................................................................... 5 - 3
5.2.1 Automatic communication function...........................................................................................5-3
5.2.2 Communication by dedicated instructions .............................................................................. 5 - 16
5.3 Slave Function ............................................................................................................................... 5 - 17
5.3.1 Automatic response function .................................................................................................. 5 - 17
5.3.2 MODBUS device assignment function ................................................................................... 5 - 18
5.3.3 Link operation function ........................................................................................................... 5 - 21
CHAPTER6 PRE-OPERATIONAL PROCEDURES AND SETTINGS 6 - 1 to 6 - 24
6.1 Handling Precautions....................................................................................................................... 6 - 1
6.2 Pre-Operational Procedures and Settings ....................................................................................... 6 - 2
6.3 Part Names...................................................................................................................................... 6 - 4
6.4 Unit Tests......................................................................................................................................... 6 - 6
6.4.1 Hardware test ........................................................................................................................... 6 - 6
6.4.2 Self-loopback test ..................................................................................................................... 6 - 8
6.5 Connection to a Target Device ...................................................................................................... 6 - 11
6.5.1 How to connect the RS-232 interface..................................................................................... 6 - 12
6.5.2 How to connect the RS-422/485 interface.............................................................................. 6 - 14
6.6 Intelligent Function Module Switch Setting .................................................................................... 6 - 19
6.7 Maintenance, Inspection................................................................................................................ 6 - 24
6.7.1 Maintenance, inspection......................................................................................................... 6 - 24
6.7.2 When removing or installing the module ................................................................................ 6 - 24
CHAPTER7 PARAMETER SETTING 7 - 1 to 7 - 31
7.1 Parameter Settings and Setting Procedure .....................................................................................7-1
7.2 Automatic Communication Parameter ............................................................................................. 7 - 4
7.2.1 Automatic communication parameter details........................................................................... 7 - 4
7.3 MODBUS Device Assignment Parameter ..................................................................................... 7 - 11
7.3.1 MODBUS device assignment to the programmable controller CPU device memory ............. 7 - 13
7.3.2 MODBUS extended file register assignment to the programmable controller
CPU file register ..................................................................................................................... 7 - 23
7.3.3 QJ71MB91 buffer memory assignment .................................................................................. 7 - 24
7.3.4 Specifying the error status read device .................................................................................. 7 - 26
7.3.5 Specifying access target when mounted to MELSECNET/H remote I/O station .................... 7 - 29
7.3.6 Specifying the CPU response monitoring timer...................................................................... 7 - 30
CHAPTER8 UTILITY PACKAGE (GX Configurator-MB) 8 - 1 to 8 - 37
8.1 Functions of the Utility Package ...................................................................................................... 8 - 1
8.2 Installing and Uninstalling the Utility Package ................................................................................. 8 - 2
8.2.1 Handling precautions................................................................................................................ 8 - 2
8.2.2 Operating environment ............................................................................................................. 8 - 5
8.3 Utility Package Operation ................................................................................................................ 8 - 7
8.3.1 Common utility package operations ......................................................................................... 8 - 7
8.3.2 Operation overview................................................................................................................. 8 - 10

A- 10
8.3.3 Starting the Intelligent function module utility ......................................................................... 8 - 12
8.4 Initial Setting .................................................................................................................................. 8 - 15
8.4.1 Automatic communication parameter ..................................................................................... 8 - 17
8.4.2 MODBUS device assignment parameter................................................................................ 8 - 19
8.5 Auto Refresh Setting...................................................................................................................... 8 - 22
8.6 Monitor/Test................................................................................................................................... 8 - 24
8.6.1 X/Y Monitor/test ...................................................................................................................... 8 - 29
8.6.2 MODBUS device assignment parameter status ..................................................................... 8 - 31
8.6.3 Automatic communication status ............................................................................................ 8 - 32
8.6.4 Error log .................................................................................................................................. 8 - 34
8.6.5 Communication status ............................................................................................................ 8 - 35
CHAPTER9 PROGRAMMING 9 - 1 to 9 - 45
9.1 Parameter Setting............................................................................................................................ 9 - 1
9.1.1 Automatic communication parameters ..................................................................................... 9 - 1
9.1.2 MODBUS device assignment parameters ................................................................................ 9 - 4
9.2 Program Example for Normal System Configuration....................................................................... 9 - 8
9.2.1 Automatic communication parameters ..................................................................................... 9 - 8
9.2.2 MODBUS device assignment parameters .............................................................................. 9 - 14
9.2.3 When using the automatic communication function and the communication by dedicated
instructions on the same channel .......................................................................................... 9 - 18
9.3 Program Examples for Use in MELSECNET/H Remote I/O Network............................................ 9 - 25
9.3.1 Automatic communication parameters ................................................................................... 9 - 25
9.3.2 MODBUS device assignment parameters .............................................................................. 9 - 37
9.4 Program Examples for the Redundant System ............................................................................. 9 - 45
CHAPTER10 DEDICATED INSTRUCTIONS 10 - 1 to 10 - 32
10.1 Dedicated Instruction List and Available Devices .......................................................................... 10 - 1
10.2 Z(P).MBRW ................................................................................................................................... 10 - 2
10.3 Z(P).MBREQ................................................................................................................................ 10 - 14
10.4 ZP.UINI ........................................................................................................................................ 10 - 25
CHAPTER11 TROUBLESHOOTING 11 - 1 to 11 - 47
11.1 Troubleshooting ............................................................................................................................. 11 - 1
11.2 Checking QJ71MB91 Status........................................................................................................ 11 - 11
11.3 Checking the Communication Status of QJ71MB91.................................................................... 11 - 17
11.4 Error Codes ................................................................................................................................. 11 - 21
11.4.1 Error code storage area........................................................................................................ 11 - 21
11.4.2 Exception code list................................................................................................................ 11 - 28
11.4.3 Error code list........................................................................................................................ 11 - 30
11.5 Turning Off the ERR. LED ........................................................................................................... 11 - 41
11.5.1 Turning off the ERR. LED by GX Configurator-MB............................................................... 11 - 41
11.5.2 Turning off the ERR. LED by sequence program ................................................................. 11 - 45
11.5.3 Turning off the ERR. LED by request message from the master ......................................... 11 - 47

A- 11
APPENDICES App - 1 to App - 13
Appendix 1 Function Upgrade of the QJ71MB91 ................................................................................App - 1
Appendix 2 A Series Modules .............................................................................................................App - 2
Appendix 2.1 Comparisons in performance specifications.............................................................App - 2
Appendix 2.2 Functional comparisons ...........................................................................................App - 3
Appendix 2.3 Utilization of existing programs ................................................................................App - 4
Appendix 3 Processing Time............................................................................................................... App - 7
Appendix 4 External Dimensions.......................................................................................................App - 13
INDEX Index - 1 to Index - 2

A- 12
COMPLIANCE WITH EMC AND LOW VOLTAGE DIRECTIVES
(1) Method of ensuring compliance
To ensure that Mitsubishi programmable controllers maintain EMC and Low Voltage
Directives when incorporated into other machinery or equipment, certain measures
may be necessary. Please refer to one of the following manuals.
• QCPU User's Manual (Hardware Design, Maintenance and Inspection)
• Safety Guidelines
(This manual is included with the CPU module or base unit.)
The CE mark on the side of the programmable controller indicates compliance with
EMC and Low Voltage Directives.
(2) Additional measures
No additional measures are necessary for the compliance of this product with EMC
and Low Voltage Directives.

A- 13
THE MANUAL'S USAGE AND STRUCTURE
This manual lists the process and functions up to systems operation using
the MODBUS interface module (QJ71MB91), divided into subjects.
Refer to the corresponding section when you need to know the following:
(1) Features ( CHAPTER 1)
CHAPTER 1 describes the features of the QJ71MB91.
(2) System Configuration ( CHAPTER 2)
Section 2.1 lists the applicable programmable controller CPU and corresponding
software package.
Section 2.2 lists network configuration example.
(3) Performance and Specifications ( CHAPTER 3)
Section 3.1 lists the performance specifications of the QJ71MB91.
Section 3.2 and 3.3 list the specifications of each interface.
Section 3.4 and 3.5 list the I/O signals and buffer memory of the QJ71MB91.
(4) MODBUS Standard Functions Supporting QJ71MB91 ( CHAPTER 4)
Section 4.1 lists the MODBUS standard functions supporting QJ71MB91.
Section 4.2 to 4.20 list the frame specifications of the MODBUS standard functions
supporting QJ71MB91.
(5) Usable Functions ( CHAPTER 5)
CHAPTER 5 describes the functions of the QJ71MB91.
(6) Settings and Procedures Necessary for System Operation
(CHAPTER 6)
CHAPTER 6 describes the pre-operation settings and procedures.
(7) Parameter Settings of the QJ71MB91 ( CHAPTER 7)
CHAPTER 7 describes the parameter setting procedures and parameter details.
(8) Setting Parameters from the Utility Package ( CHAPTER 8)
CHAPTER 8 describes how to use the utility package.
(9) Setting Parameters from the Sequence Program ( CHAPTER 9)
CHAPTER 9 describes the I/O signals used for parameter settings, the I/O signal
timing charts, and program examples.
(10)Reading from/Writing to the MODBUS Device using the Sequence
Program ( CHAPTER 10)
CHAPTER 10 describes the dedicated instructions designed to read or write
MODBUS device data with sequence programs.

A- 14
(11)Error Code and Corresponding Process Details ( CHAPTER 11)
Section 11.1 lists troubleshooting.
Section 11.2 lists the confirmation methods of the module conditions.
Section 11.3 lists the confirmation of the communication conditions.
Section 11.4 lists the storage location and details of the error codes.
Section 11.5 lists the methods to turn off the ERR. LED.
About the notation of the numerical values used in this manual
In this manual, the numerical values with the suffix "H" are displayed in
hexadecimal values.
(Example) 10......Decimal
10H....Hexadecimal

A- 15
ABOUT THE GENERIC TERMS AND ABBREVIATIONS
Unless otherwise specified, this manual uses the following generic terms
and abbreviations to explain the QJ71MB91 MODBUS interface module.
General term/Abbreviation Description
QJ71MB91 Abbreviation for the QJ71MB91 MODBUS interface module.
GX Developer The product name of the software package for the MELSEC programmable controllers
GX Works2
MODBUS Protocol Generic term for the protocol designed to use MODBUS protocol messages.
FC Abbreviation for the function code.
SC Abbreviation for the sub code.
Programmable controller
CPU
Generic term for the Q00JCPU, Q00CPU, Q01CPU, Q02CPU, Q02HCPU, Q06HCPU,
Q12HCPU, Q25HCPU, Q02PHCPU, Q06PHCPU, Q12PHCPU, Q25PHCPU, Q12PRHCPU,
Q25PRHCPU, Q00UJCPU, Q00UCPU, Q01UCPU, Q02UCPU, Q03UDCPU, Q03UDVCPU,
Q03UDECPU, Q04UDHCPU, Q04UDVCPU, Q04UDEHCPU, Q06UDHCPU, Q06UDVCPU,
Q06UDEHCPU, Q10UDHCPU, Q10UDEHCPU, Q13UDHCPU, Q13UDVCPU,
Q13UDEHCPU, Q20UDHCPU, Q20UDEHCPU, Q26UDHCPU, Q26UDVCPU,
Q26UDEHCPU, Q50UDEHCPU, and Q100UDEHCPU
Basic model QCPU Generic term for the Q00JCPU, Q00CPU, and Q01CPU
Redundant CPU Generic term for the Q12PRHCPU and Q25PRHCPU
Universal model QCPU
Generic term for the Q00UJCPU, Q00UCPU, Q01UCPU, Q02UCPU, Q03UDCPU,
Q03UDVCPU, Q03UDECPU, Q04UDHCPU, Q04UDVCPU, Q04UDEHCPU, Q06UDHCPU,
Q06UDVCPU, Q06UDEHCPU, Q10UDHCPU, Q10UDEHCPU, Q13UDHCPU,
Q13UDVCPU, Q13UDEHCPU, Q20UDHCPU, Q20UDEHCPU, Q26UDHCPU,
Q26UDVCPU, Q26UDEHCPU, Q50UDEHCPU, and Q100UDEHCPU
C Controller module Generic term for the Q06CCPU-V-H01, Q06CCPU-V, Q06CCPU-V-B, Q12DCCPU-V,
Q24DHCCPU-V, Q24DHCCPU-VG, Q24DHCCPU-LS, and Q26DHCCPU-LS
Master The side from which a request is sent to execute a function.
Slave The side where the execution request from the master is processed and its execution
result is sent.
Master function The function that allows communication with the MODBUS compatible slave device as the
master of MODBUS.
Slave function The function that allows communication with the MODBUS compatible master device as the
slave of MODBUS.
Request message
The message used to give a function execution request to the slave In the MODBUS
protocol, a function execution request is given from the master to the slave.
A function execution request cannot be given from the slave to the master.
Response message The message with which the slave returns a function execution result to the master.
Target device
Abbreviation of the connected communication targets (devices corresponding to personal
computers, other QJ71MB91 MODBUS interface modules, MODBUS protocols) for data
communication.
Personal computer Abbreviation for DOS/V personal computers of IBM PC/AT and compatible.
MELSECNET/H Abbreviation of the MELSECNET/H network system.
MBRW Abbreviation for Z.MBRW or ZP.MBRW.
MBREQ Abbreviation for Z.MBREQ or ZP.MBREQ.
UINI Abbreviation for ZP.UINI.
Windows 7
Generic term for the following:
Microsoft Windows 7 Starter Operating System,
Microsoft Windows 7 Home Premium Operating System,
Microsoft Windows 7 Professional Operating System,
Microsoft Windows 7 Ultimate Operating System,
Microsoft Windows 7 Enterprise Operating System

A- 16
MEANINGS AND DEFINITIONS OF TERM
The following explains the meanings and definitions of the terms used in
this manual.
PRODUCT CONFIGURATION
The following indicates the product configuration of the QJ71MB91
MODBUS interface module.
Windows Vista
Generic term for the following:
Microsoft Windows Vista Home Basic Operating System,
Microsoft Windows Vista Home Premium Operating System,
Microsoft Windows Vista Business Operating System,
Microsoft Windows Vista Ultimate Operating System,
Microsoft Windows Vista Enterprise Operating System
Windows XP
Generic term for the following:
Microsoft Windows XP Professional Operating System,
Microsoft Windows XP Home Edition Operating System
Term Description
MODBUS protocol Protocol used on an open MODBUS network which performs master-slave communications
over a serial bus or TCP/IP
MODBUS device Device used for communication using the MODBUS protocol
Sequence program
Programming system devised to make a contact type sequence compatible with the
programmable controller language as-is. Draw two vertical control buses and describe
contacts, etc.
between the buses to perform programming.
Device memory Memory provided for the programmable controller CPU to record the data handled in
sequence program operation.
Listen only mode Mode detaching the slave station from the circuit.
Model Product name Quantity
QJ71MB91
QJ71MB91 MODBUS interface module 1
Terminal resistor 3301/4 W (for RS-422 communication) 2
Terminal resistor 1101/2 W (for RS-485 communication) 2
SW1D5C-QMBU-E GX Configurator-MB Version 1 (1-license product) (CD-ROM) 1
SW1D5C-QMBU-EA GX Configurator-MB Version 1 (Multiple-license product) (CD-ROM) 1
General term/Abbreviation Description

1OVERVIEW
1.1 Features
1- 1
1
OVERVIEW
2
SYSTEM CONFIGURATION
3
SPECIFICATIONS
4
MODBUS STANDARD FUNCTIONS
5
FUNCTION
6
PRE-OPERATIONAL PROCEDURES AND SETTINGS
7
PARAMETER SETTING
8
UTILITY PACKAGE (GX Configurator-MB)
CHAPTER1 OVERVIEW
This manual explains the specifications, functions, programming, and troubleshooting of
the MELSEC-Q series QJ71MB91 MODBUS interface module (hereinafter referred to as
QJ71MB91).
The QJ71MB91 is used when a MELSEC-Q series programmable controller is connected
to the MODBUS protocol system.
1.1 Features
(1) Supporting the master function of MODBUS communication
The QJ71MB91 supports the master function of the MODBUS communication, which
is an open network system for factory automation, and thereby is compatible with
various MODBUS slave devices (hereinafter referred to as slave) of other
manufacturers.
The master function includes the following two functions.
(a) Automatic communication function
By setting the automatic communication parameters, MODBUS device data can
be automatically read from or written to the slaves at the specified intervals using
the QJ71MB91 buffer memory.*1
Data can be transferred between the QJ71MB91 buffer memory and
programmable controller CPU device memory by making the auto refresh setting
with the utility package (GX Configurator-MB) or by accessing any intelligent
function module device with a sequence program.
* 1 The MODBUS device is defined as a device area of the slave where data can be read/written in
response to a request from the master.
Figure 1.1 Communication using the automatic communication function
MODBUS slave device
(Third party sensor, etc)
MODBUS slave device
(Third party programmable
controller)
Device memory
MODBUS slave device
(Third party remote I/O, etc)
Holding register
Holding register
Holding register
RS-485
Programmable controller CPU
Device memory
Auto Refresh
QJ71MB91 (Master function)
Read
Read
Read
Write
Buffer memory
Automatically issues the
MODBUS device read/write
request message to Slave.

1- 2 1.1 Features
1OVERVIEW
(b) Communication using dedicated instruction
Dedicated instructions can be used to make communication from sequence
programs at any timing.
The following dedicated instructions are available for the QJ71MB91. (
CHAPTER 10)
1) MBRW instruction
Reads or writes MODBUS device data from or to a slave.
This enables reading slave data to the programmable controller CPU device
memory or writing programmable controller CPU data to slaves.
2) MBREQ instruction
The user-determined request message format (function code + data unit) can
be issued to the slaves.
Figure 1.2 Communication using dedicated instruction
[Z.MBRW ]
Command
QJ71MB91
(Master
function)
400500
Programmable
controller CPU
Device memory
1234H
Request message
(Read request for holding register 400500)
Response message
(Holding register 400500 = 1234H)
1234H
Holding register
MODBUS Slave device
RS-232, RS-422 or RS-485