Mitsubishi Electric QJ71DN91 User manual

DeviceNet Master-Slave Module
User's Manual
-QJ71DN91

A - 1 A - 1
SAFETY PRECAUTIONS 
(Read these precautions before using this product.)
Before using this product, please read this manual and the relevant manuals carefully and pay full
attention to safety to handle the product correctly.
The precautions given in this manual are concerned with this product only. For the safety precautions of
the programmable controller system, refer to the user's manual for 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
If a communications error occurs on a DeviceNet network, faulty nodes will behave as follows:
(1) The master node (QJ71DN91) holds input data which had been received from slave nodes
before the error occurred.
(2) Whether output signals of a slave node are turned off or held is determined by the slave
node's specifications or the parameters set at the master node. When the QJ71DN91 is
used as a slave node, it holds data that have been input from the master node before the
communication error.
Utilizing communications states of slave nodes, create an interlock circuit on sequential
programs and provide safety mechanism externally so that the system will operate safely.
CAUTION
Do not install control wires or communication cables together with the main circuit or power
wires, or bring them close to each other.
Keep a distance of 300mm or more between them.
Failure to do so may cause malfunctions due to noise.
!
!

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[INSTALLATION PRECAUTIONS]
CAUTION
Use the programmable controller in an environment that meets the general specifications
contained in the User's Manual of the CPU module used.
Using it in an environment that does not meet them may result in an electric shock, fire,
malfunction, and damage to or deterioration of the product.
While pressing the installation lever on the lower part of the module, insert the module fixing
projection into the hole in the base unit. Then, securely mount the module.
Incorrect module mounting may cause the module to malfunction, fail or fall off.
Secure the module with screws especially when it is used in an environment where constant
vibrations may occur.
Tighten the screws within the specified torque range.
If the screws are loose, it may cause falling, short circuits, or malfunction.
If the screws are tightened too much, it may cause damage to the screw and /or the module,
resulting in falling, short circuits or malfunction.
Before mounting/dismounting the module, be sure to shut off all phases of the external power
supply used by the system. Failure to do so may cause product damage.
Do not directly touch the conductive area or electric components of the module.
Doing so may cause malfunction or failure in the module.
[WIRING PRECAUTIONS]
WARNING
Before installation or wiring, shut off all phases of the external power supply used in the system.
Failure to do so may cause an electric shock, damage to the product or malfunction.
CAUTION
Be careful to prevent foreign matter such as dust or wire chips from entering the module.
It may cause a fire, failure or malfunction.
The module has an ingress prevention label on its top to prevent foreign matter, such as wire
chips, from entering the module during wiring. Do not peel this label during wiring. Remove it for
heat dissipation before system operation.
Place the communication cables and power cables connected to the module in a duct or clamp
them.
Otherwise, dangling cables may swing or inadvertently be pulled, resulting in damage to the
module or cables or malfunctions due to poor cable contact.
Do not pull the cable part when disconnecting the cable from the module. To disconnect a cable
with connector, hold the connector that is plugged into the module. To disconnect a cable
without connector, loosen the screws used for fastening.
Pulling the cable that is still connected to the module may damage the module and/or cable, or
cause a malfunction due to poor contact.
!
!
!

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[STARTUP/MAINTENANCE PRECAUTIONS]
CAUTION
Do not touch any terminal unless all phases of the external power supply have been shut off.
Doing so may cause a malfunction.
Always turn off all phases of the external power supply before cleaning or retightening the
terminal screws.
Failure to do so may result in a malfunction.
Do not disassemble or remodel the module.
Doing so will cause failure, malfunctions, injuries, or a fire.
Before mounting/dismounting the module, be sure to shut off all phases of external power supply
used by the system.
Failure to do so may cause module failure or malfunctions.
Do not install/remove the module to/from the base unit more than 50 times after the first use of
the product. (IEC 61131-2 compliant)
Failure to do so may cause malfunction.
Before handling the module, touch a grounded metal object to discharge the static electricity
from the human body.
Failure to do so may cause a failure or malfunctions of the module.
[DISPOSAL PRECAUTION]
CAUTION
When disposing of this product, treat it as industrial waste.
!
!

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CONDITIONS OF USE FOR THE PRODUCT 

A - 5 A - 5
REVISIONS
*The manual number is given on the bottom left of the back cover.
Print Date *Manual Number Revision
Dec. 2000 SH (NA)-080143-A First Printing
Jun. 2001 SH (NA)-080143-B
Addition
Section 2.3, 2.4
Delete
Section 2.2.1, 2.2.2
Correction
SAFETY PRECAUTIONS, About the Generic Terms and Abbreviations,
Product Configuration, Section 2.2, 2.4, Section 6.2, 6.2.1, 6.2.2, 6.3.3,
6.5
Feb. 2002 SH (NA)-080143-C
Correction
About the Generic Terms and Abbreviations, Section 2.2, Section 6.2.1,
6.2.2
Dec. 2002 SH (NA)-080143-D
Addition
Section 2.5
Correction
Section 2.2, Section 3.3.2, 3.4.1, Section 6.1, 6.2.1, 6.3.2, 6.4, 6.5,
Section 9.2.1, 9.2.2
Feb. 2003 SH (NA)-080143-E
Correction
SAFETY PRECAUTIONS, INTRODUCTION, CONTENTS, Section 6.2.2,
Section 6.3.3, Section 6.4, Section 6.5
May. 2003 SH (NA)-080143-F
Correction
Section 6.3.1
Jun. 2004 SH (NA)-080143-G
Correction
Section 2.2, 2.3, Section 3.3.2, Section 4.2.1, Section 6.3.2, 6.5, 6.6,
Section 7.3.2, Section 8.1, 8.3, Section 9.3
Feb. 2006 SH (NA)-080143-H
Correction
SAFETY PRECAUTIONS, Compliance with the EMC and Low Voltage
Directives, Section 1.1, Section 2.1, 2.3, Section 3.2.1, 3.4, 3.5, Section
4.1, 4.2.1, Chapter 5, Chapter 6 (screen change), Section 6.2.2, Section
7.1, 7.2, 7.3.1, 7.4, 7.5.2, 7.7, Section 8.3, Section 9.3, Appendix 3
Mar. 2006 SH (NA)-080143-I
Addition
Section 2.5, 3.4.1
Correction
Section 3.4.1

A - 6 A - 6
*The manual number is given on the bottom left of the back cover.
Print Date *Manual Number Revision
Jan. 2008 SH(NA)-080143-J
Correction
Generic Terms and Abbreviations, Section 1.1, 2.1 to 2.3, 3.4, Chapter 4,
Section 5.1 to 5.4, 5.6, 6.1, 6.2, 6.4, 6.5, Chapter 7 and 8, Section 9.1,
9.2, Appendix 6
Addition
Definitions of Terminology, Section 2.4, 3.2, 6.5.1 to 6.5.17, 7.3.1, 7.4.1,
8.2.1, 8.3.1, 9.1.5, 9.2.3, Appendix 2
Deletion
Section 2.4 to 2.6, Chapter 5
Section Numbers Changed
Section 3.2 -> Chapter 4, Section 3.3.2 -> Sections 3.3.2 and 3.3.3,
Section 3.4.2 -> Section 3.4.2 to 3.4.14, Chapter 4 -> Chapter 5,
Appendix 2 to 6 -> Appendix 3 to 7
May. 2008 SH(NA)-080143-K
Correction
SAFETY PRECAUTIONS, Compliance with the EMC and Low Voltage
Directives, Generic Terms and Abbreviations, Section 2.2, 2.3, 5.2.1,
6.2.1, 6.3.3, 6.4, 6.5
Jun. 2011 SH(NA)-080143-L
Addition
CONDITIONS OF USE FOR THE PRODUCT, Chapter 9, Section 3.4.15,
3.4.16
Section Numbers Changed
Chapter 9 -> Chapter 10
Correction
GENERIC TERMS AND ABBREVIATIONS, Section 1.1, 2.2, 2.3, 3.4.1,
3.4.3, 3.5.1, 4.1, 4.3, 6.2.1, 7.1, 7.3, 7.4.2, 7.8, 8.3.2, 10.2.1, Appendix 2
Sep. 2014 SH(NA)-080143-M
Addition
Appendix 4, 5
Section Numbers Changed
Section 3.5.1 -> Section 3.5.3, Section 3.5.3 -> Section 3.5.1, Appendix 4
to 7 -> Appendix 5 to 8, Appendix 5 to 8 -> Appendix 6 to 9
Correction
COMPLIANCE WITH THE EMC AND LOW VOLTAGE DIRECTIVES,
GENERIC TERMS AND ABBREVIATIONS, Section 2.1, 2.2, 2.3, 3.4.12,
3.5.3, 4.3, 5.2.1, 6.2.1, 6.2.2, 9.1, 9.2, 9.3, 9.4, 9.5, Appendix 3.5

A - 7 A - 7
*The manual number is given on the bottom left of the back cover.
Print Date *Manual Number Revision
Sep. 2018 SH(NA)-080143-N Correction
MANUALS, Chapter 1, Section 2.1, 2.4, 4.6, Chapter 6, Section 6.1,
6.2.2, 6.7, 7.1, 7.8.1, 7.9.1, 9.1, 9.2, 9.4.2, 9.4.3, 9.5
Deletion
Section 4.2.3
Section Numbers Changed
Appendix 5 to 9 -> Appendix 2 to 6
Japanese Manual Version SH-080125-P
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.
2000 MITSUBISHI ELECTRIC CORPORATION

A - 8 A - 8
INTRODUCTION
Thank you for purchasing the Mitsubishi Electric MELSEC-Q series programmable controller.
Before using the product, please read this manual carefully to understand the functions and performance of
the Q series programmable controller to ensure correct use.
CONTENTS
SAFETY PRECAUTIONS..............................................................................................................................A- 1
CONDITIONS OF USE FOR THE PRODUCT .............................................................................................A- 4
REVISIONS ....................................................................................................................................................A- 5
INTRODUCTION............................................................................................................................................A- 8
CONTENTS....................................................................................................................................................A- 8
COMPLIANCE WITH THE EMC AND LOW VOLTAGE DIRECTIVES.......................................................A-11
GENERIC TERMS AND ABBREVIATIONS .................................................................................................A-12
DEFINITIONS OF TERMINOLOGY..............................................................................................................A-13
PACKING LIST...............................................................................................................................................A-14
1 OVERVIEW 1- 1 to 1- 3
1.1 Features ................................................................................................................................................... 1- 1
2 SYSTEM CONFIGURATION 2- 1 to 2- 7
2.1 Overall Configuration ............................................................................................................................... 2- 1
2.2 Applicable Systems.................................................................................................................................. 2- 3
2.3 How to Check the Function Version and Serial Number ........................................................................ 2- 4
2.4 Precautions on System Configuration ..................................................................................................... 2- 6
3 SPECIFICATIONS 3- 1 to 3-50
3.1 Performance Specifications ..................................................................................................................... 3- 1
3.1.1 Maximum trunk line distance when using thick and thin cables ...................................................... 3- 2
3.2 Function Lists ........................................................................................................................................... 3- 3
3.3 I/O Signals for Programmable Controller CPU ....................................................................................... 3- 4
3.3.1 I/O signal list ...................................................................................................................................... 3- 4
3.3.2 I/O signals for the master function .................................................................................................... 3- 5
3.3.3 I/O signals for the slave function....................................................................................................... 3-13
3.4 Buffer Memory.......................................................................................................................................... 3-17
3.4.1 Buffer memory list ............................................................................................................................. 3-17
3.4.2 Message communication area for master function .......................................................................... 3-20
3.4.3 Own node status area for master function ....................................................................................... 3-25
3.4.4 Node status area for master function ............................................................................................... 3-28
3.4.5 Master function parameter setting area............................................................................................ 3-31
3.4.6 Communication data area for master function ................................................................................. 3-36
3.4.7 Link scan time area for master function ........................................................................................... 3-38
3.4.8 Own node status area for slave function .......................................................................................... 3-39
3.4.9 Parameter setting area for slave function......................................................................................... 3-40
3.4.10 Communication data area for slave function.................................................................................. 3-41
3.4.11 Own node information area ............................................................................................................ 3-42

A - 9 A - 9
3.4.12 Hardware test area.......................................................................................................................... 3-43
3.4.13 Parameter saving area selection area............................................................................................ 3-45
3.4.14 Auto communication start setting area ........................................................................................... 3-45
3.4.15 Operation Setting Area For Bus Off Error ...................................................................................... 3-46
3.4.16 Data consistency dedicated instruction area ................................................................................. 3-47
3.5 Communication Performance .................................................................................................................. 3-48
3.5.1 Link scan time.................................................................................................................................... 3-48
3.5.2 Communication cycle time ................................................................................................................ 3-49
3.5.3 Transmission delay ........................................................................................................................... 3-50
4 FUNCTIONS 4- 1 to 4-15
4.1 Master Function (I/O Communication Function) ..................................................................................... 4- 1
4.2 Master Function (Message Communication Function)........................................................................... 4- 9
4.3 Slave Function (I/O Communication Function) ....................................................................................... 4-12
5 SETUP AND PREPARATION 5- 1 to 5-14
5.1 Pre-operation Procedures........................................................................................................................ 5- 1
5.1.1 When using the master function ....................................................................................................... 5- 1
5.1.2 When using the slave function.......................................................................................................... 5- 2
5.1.3 When using both the master and slave functions ............................................................................ 5- 3
5.2 Implementation and Installation............................................................................................................... 5- 4
5.2.1 Handling precautions ........................................................................................................................ 5- 4
5.2.2 Installation environment .................................................................................................................... 5- 4
5.3 Part Names and Settings......................................................................................................................... 5- 5
5.3.1 LED indications ................................................................................................................................. 5- 6
5.3.2 Node number switches ..................................................................................................................... 5- 7
5.3.3 Mode switch....................................................................................................................................... 5- 7
5.4 Hardware Test.......................................................................................................................................... 5- 8
5.5 Wiring........................................................................................................................................................ 5- 9
5.6 Communication Test ................................................................................................................................ 5-10
5.7 Precautions for Network Power Supply................................................................................................... 5-11
5.7.1 Network power supply unit position .................................................................................................. 5-11
5.7.2 Network power supply unit position and current capacity calculation ............................................. 5-12
6 FUNCTIONS FOR DeviceNet OF GX Works2 6- 1 to 6- 3
6.1 Functions for DeviceNet of GX Works2 .................................................................................................. 6- 1
6.2 Handling precautions ............................................................................................................................... 6- 2
7 PROGRAMMING FOR EXECUTING THE MASTER FUNCTION 7- 1 to 7-32
7.1 Programming Precautions ....................................................................................................................... 7- 1
7.2 System Configuration............................................................................................................................... 7- 4
7.3 Parameters for Master Function .............................................................................................................. 7- 7
7.3.1 Program example using the functions for DeviceNet of GX Works2 .............................................. 7-10
7.3.2 Program example not using the functions for DeviceNet of GX Works2 ........................................ 7-18
7.4 I/O Communication Function ................................................................................................................... 7-22
7.4.1 Program example using the functions for DeviceNet of GX Works2 .............................................. 7-22

A - 10 A - 10
7.4.2 Program example not using the functions for DeviceNet of GX Works2 ........................................ 7-24
7.5 Message Communication Function......................................................................................................... 7-27
7.5.1 Example of reading message communication data ......................................................................... 7-27
7.5.2 Example of writing message communication data........................................................................... 7-29
7.6 Obtaining Error Information ..................................................................................................................... 7-30
7.7 Allocating Transmit/Receive Data Storage Devices for Future Expansion............................................ 7-31
8 PROGRAMMING FOR EXECUTING THE SLAVE FUNCTION 8- 1 to 8-10
8.1 System Configuration............................................................................................................................... 8- 1
8.2 Parameters for Slave Function ................................................................................................................ 8- 1
8.2.1 Program example using the functions for DeviceNet of GX Works2 .............................................. 8- 3
8.2.2 Program example not using the functions for DeviceNet of GX Works2 ........................................ 8- 4
8.3 I/O Communication Function ................................................................................................................... 8- 6
8.3.1 Program example using the functions for DeviceNet of GX Works2 .............................................. 8- 6
8.3.2 Program example not using the functions for DeviceNet of GX Works2 ........................................ 8- 8
8.4 Obtaining Error Information ..................................................................................................................... 8-10
9 DEDICATED INSTRUCTIONS 9- 1 to 9- 6
9.1 Precautions .............................................................................................................................................. 9- 2
9.2 G.DNTMRD .............................................................................................................................................. 9- 3
9.3 G.DNTMWR ............................................................................................................................................. 9- 4
9.4 G.DNTSRD............................................................................................................................................... 9- 5
9.5 G.DNTSWR.............................................................................................................................................. 9- 6
10 TROUBLESHOOTING 10- 1 to 10-18
10.1 Problem Identification .......................................................................................................................... 10- 2
10.1.1 Checking the LEDs ....................................................................................................................... 10- 2
10.1.2 When unable to communicate with all slave nodes (when using master function) .................... 10- 3
10.1.3 When unable to communicate with a specific slave node (when using master function)........... 10- 4
10.1.4 When unable to communicate with master node (when using slave function) ........................... 10- 5
10.1.5 Troubleshooting for other cases ................................................................................................... 10- 6
10.2 Error Codes .......................................................................................................................................... 10- 8
10.2.1 Communication error codes......................................................................................................... 10- 8
10.2.2 Execution error codes of message communication (for the master function only)..................... 10-13
10.2.3 General DeviceNet error codes of message communication (for the master function only)...... 10-16
10.3 Checking the QJ71DN91 Status by system monitor in GX Works2 .................................................. 10-17
APPENDIXES App- 1 to App- 6
Appendix 1 External Dimensions...............................................................................................................App- 1
Appendix 2 How to Use the QJ71DN91 in System of MELSEC iQ-R Series ..........................................App- 2
Appendix 3 Parameter Setting Sheet (For the Master Function) .............................................................App- 3
Appendix 4 Parameter Setting Sheet (For the Slave Function) ...............................................................App- 4
Appendix 5 List of Communication Parameters of Slave Nodes from Various Manufactures .............. App- 5
Appendix 6 EDS File of the QJ71DN91 ....................................................................................................App- 6
INDEX Index- 1 to Index- 2

A - 11 A - 11
COMPLIANCE WITH THE 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 the
EMC and Low Voltage Directives.

A - 12 A - 12
GENERIC TERMS AND ABBREVIATIONS
Unless otherwise specified, this manual uses the following generic terms and
abbreviations to explain the QJ71DN91 DeviceNet master/slave module.
Generic term/abbreviation Description
GX Works2 The product name of the software package for the MELSEC programmable controllers
QCPU
A generic term for the Q00JCPU, Q00UJCPU, Q00CPU, Q00UCPU, Q01CPU, Q01UCPU,
Q02CPU, Q02HCPU, Q02PHCPU, Q02UCPU, Q03UDCPU, Q03UDVCPU, Q03UDECPU,
Q04UDHCPU, Q04UDVCPU, Q04UDPVCPU, Q04UDEHCPU, Q06HCPU, Q06PHCPU,
Q06UDHCPU, Q06UDVCPU, Q06UDPVCPU, Q06UDEHCPU, Q10UDHCPU,
Q10UDEHCPU, Q12HCPU, Q12PHCPU, Q12PRHCPU, Q13UDHCPU, Q13UDVCPU,
Q13UDPVCPU, Q13UDEHCPU, Q20UDHCPU, Q20UDEHCPU, Q25HCPU, Q25PHCPU,
Q25PRHCPU, Q26UDHCPU, Q26UDVCPU, Q26UDPVCPU, Q26UDEHCPU,
Q50UDEHCPU, and Q100UDEHCPU
QJ71DN91 The abbreviation for the QJ71DN91 DeviceNet master/slave module
DNTMRD The abbreviation for G.DNTMRD
DNTMWR The abbreviation for G.DNTMWR
DNTSRD The abbreviation for G.DNTSRD
DNTSWR The abbreviation for G.DNTSWR

A - 13 A - 13
DEFINITIONS OF TERMINOLOGY
Terms used in this manual and their definitions are listed below.
Term Definition
I/O communication function Function that allows I/O (input/output) data communications between master and slave
nodes.
Message communication
function
Function that allows reading or writing of slave node’s attribute data in response to a
request message. For further details, refer to the DeviceNet common service in the
DeviceNet Specifications (Release2.0).
Master node Device that exchanges I/O data with slave nodes which are configured with the master
function parameters.
Slave node Device that exchanges I/O data with a master node.
Master/slave node Device that operates as a master and slave node.
Master function
parameters
Parameters for setting information such as connection type or I/O points, which are used to
exchange I/O data with respective slave nodes when the QJ71DN91 is used as a master
node.
Configured in sequence programs or the functions for DeviceNet of GX Works2.
Auto configuration
Function that detects slave nodes on the network and automatically creates master function
parameters.
Two options are available: "All configuration" used for detecting all slave nodes on the
network and "Add configuration" used for detecting the slave nodes added to the network.
This function can reduce programming steps for master function parameter setting.
Executed in sequence programs or the functions for DeviceNet of GX Works2.
Slave function parameters
Parameters provided for changing the number of I/O points for a slave node when the
QJ71DN91 is used as a slave node.
Configured in sequence programs or the functions for DeviceNet of GX Works2.
Auto communication start
setting
Setting by which I/O communications automatically start at power-up.
Configured in sequence programs or the functions for DeviceNet of GX Works2.
Buffer memory
Memory inside the QJ71DN91, in which data are temporarily stored.
Used for storing parameter settings and I/O data.
Parameters are stored on a flash ROM after debugging.
I/O data are transferred to devices of a programmable controller CPU by automatic refresh
or sequence program.
Flash ROM
Memory inside the QJ71DN91, which stores parameters saved in the following buffer
memory areas:
• Master Function Parameters (Address: 01D4H to 03CFH)
• Slave Function Parameters (Address: 060EH, 060FH)
• Auto Communication Start Setting (Address: 0631H)
Parameters saved on the flash ROM are automatically loaded to the buffer memory when
power is turned on from off or when the CPU module is reset.
Automatic refresh
Automatic data transfer between the buffer memory and devices of a programmable
controller CPU.
Configured in Auto refresh setting in the functions for DeviceNet of GX Works2.

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PACKING LIST
The following are included in the package.
Model Product name Quantity
QJ71DN91
QJ71DN91 DeviceNet master/slave module 1
Terminating resistor 121 , 1/4W 2
Connector 1

1 - 1 1 - 1
MELSEC-Q
1 OVERVIEW
1 OVERVIEW
This manual provides descriptions such as the specifications and parts names of the
QJ71DN91 DeviceNet master/slave module, which is used in combination with a
MELSEC-Q series programmable controller CPU.
For the DeviceNet specifications, refer to the DeviceNet Specifications (Release 2.0)
Volumes 1 and 2.
DeviceNet is a trademark of ODVA, Inc.
POINT
The QJ71DN91 is assumed to be compatible with most of DeviceNet products on
the market. However, the compatibility with products manufactured by other
vendors is not guaranteed.
1.1 Features
This section explains the features of the QJ71DN91.
(1) Operating as a DeviceNet master node
The QJ71DN91 is compliant with the DeviceNet Specifications (Release2.0) and
can operate as a master node.
(a) I/O communication function (Refer to Section 4.1.)
1) The QJ71DN91 can exchange I/O data with slave nodes (max. 63
nodes) using its own buffer memory.
Communications of 512 bytes of inputs (up to 256 bytes per node) and
512 bytes of outputs (up to 256 bytes per node) are available.
*1: Performed by automatic refresh or sequence program.
2) One of the following connection types can be selected for each slave
node.
• Polling
• Bit strobe
• Change of state
• Cyclic
Programmable controller CPU QJ71DN91
SET Y11 I/O Communication
Request
Master
Function
Receive
Data area
0700H
07FFH
Master
Function
Transmit
Data area
0900H
09FFH
Transmit
Receive
X
Y
Master node
*1
*1
Slave node
1

1 - 2 1 - 2
MELSEC-Q
1 OVERVIEW
(b) Message communication function (Refer to Section 4.2.)
Using the buffer memory of the QJ71DN91, attribute data can be read from
or written to slave nodes.
For details of other message communications, refer to the DeviceNet
common service in the DeviceNet Specifications (Release2.0).
At one time, 240 bytes of message data can be transferred.
(c) Creating master function parameters using auto configuration
The QJ71DN91 can detect slave nodes on the network and automatically
create master function parameters.
Since programming steps for setting master function parameters are not
required, steps for the overall sequence program can be reduced.
(2) Operating as a DeviceNet slave node
The QJ71DN91 is compliant with the DeviceNet Specifications (Release2.0) and
can operate as a DeviceNet slave node.
(a) I/O communication function (Refer to Section 4.3.)
1) The QJ71DN91 can exchange I/O data with a master node using its
own buffer memory.
It can exchange 128 bytes of inputs and 128 bytes of outputs.
2) The connection type is polling.
*1: Performed by automatic refresh or sequence program.
Programmable controller CPUQJ71DN91
Master node
SET Y11
I/O Communication
Request
Slave
Function
Receive
Data area
0B00H
0B3FH
Slave
Function
Transmit
Data area
0C00H
0C3FH
Transmit
Receive
X
Y
Slave node
*1
*1
1

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MELSEC-Q
1 OVERVIEW
(3) Operating as a DeviceNet master/slave node
The QJ71DN91can operate as a master and slave node concurrently.
(4) Preventing inconsistency of I/O data
When I/O data is read from/written to the buffer memory of the QJ71DN91, data
inconsistency can be avoided using Data consistency dedicated instruction
(DNTMRD, DNTMWR, DNTSRD, DNTSWR). (Refer to Chapter 9.)
(5) Easy setting using GX Works2
The number of sequence programs can be reduced since settings of the
QJ71DN91 can be configured on GX Works2.
Also, GX Works2 simplifies checking of the module settings and operation status.
24V power
supply
QJ71DN91 master
(node No.1)
DeviceNet slave
(node No.2)
QJ71DN91 master/slave
(node No.4)
DeviceNet slave
(node No.3)
DeviceNet slave
(node No.5)
DeviceNet slave
(node No.6)
Master function Master function
No communication between
DeviceNet slaves
I/O communication Slave function
I/O
communication
I/O
communication
I/O
communication
I/O
communication

2 - 1 2 - 1
MELSEC-Q
2 SYSTEM CONFIGURATION
2 SYSTEM CONFIGURATION
This chapter explains the system configuration of DeviceNet.
2.1 Overall Configuration
The number of modules connectable to a DeviceNet network is 64, including master,
slave and master/slave nodes.
The QJ71DN91 can be used as a master node, a slave node or a master/slave node.
The following shows an example of a system configuration:
(1) DeviceNet cables, taps and terminating resistors
DeviceNet cables are used as a trunk line and drop lines.
Each node is connected to the trunk line directly, or connected to a drop line via a
tap from the trunk line. Nodes need not be wired in order of node numbers.
Connect terminating resistors at both ends of the trunk line.
(2) Network power supply unit and power supply tap
In addition to power supply for each node, connect a network power supply unit
to distribute power to the communication circuit.
Connect a power supply tap to the trunk line, and install a network power supply
unit.
POINT
To minimize the affect of noise, keep DeviceNet cables, power cables, and signal
lines of I/O modules away from each other.
Terminating resistor
(121, 1/4W)
Slave node
Slave node
Slave node Slave node
Terminating resisto
r
(121, 1/4W)
Network power supply
unit (24V DC)
Tap
Drop line (branch line)
Power supply tap
Drop line
Trunk line (main line)
QJ71DN91
Master node
QJ71DN91
Slave node
2