Mitsubishi MELSEC Q Series User manual

A - 1 A - 1
SAFETY PRECAUTIONS 
(Always read these instructions before using this equipment.)
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 MELSEC communication protocol. For the safety
instructions of the programmable controller system, please read the user's manual for the CPU module to
use.
In this manual, the safety instructions are ranked as " !WARNING" and " !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.
Note that the !CAUTION level may lead to a serious consequence according to the circumstances.
Always follow the instructions of both levels because they are important to personal safety.
Please save this manual to make it accessible when required and always forward it to the end user.
[Design Precautions]
!WARNING
When changing data of the running programmable controller from a peripheral connected to the
CPU module or from a personal computer connected to an intelligent function module, configure
an interlock circuit in the sequence program to ensure that the entire system will always operate
safely.
For program modification and operating status change, read relevant manuals carefully and
ensure the safety before operation.
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

A - 2 A - 2
[Operation Precautions]
!CAUTION
When changing data and operating status, and modifying program of the running programmable
controller from a personal computer connected to an intelligent function module, read relevant
manuals carefully and ensure the safety before operation.
Incorrect change or modification may cause system malfunction, damage to the machines, or
accidents.
While set values in the buffer memory are being registered to the flash ROM in the module, do
not turn off the power to the module and do not reset the CPU module.
Doing so will affect the flash ROM data, and setting to the buffer memory and registration to the
flash ROM need to be performed again.
Also, it may cause failure or malfunction of the module.

A - 3 A - 3
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 - 4 A - 4
REVISIONS
The manual number is given on the bottom left of the back cover.
Print Date Manual Number Revision
Dec., 1999 SH(NA)-080008-A First edition
Oct., 2000 SH(NA)-080008-B Reflect the contents of the function version B.
Put Windowsbase software products together from Mitsubishi
Programmable Controller MELSEC series to Mitsubishi integrated FA
software MELSOFT series. Standardize the name from software package
(GPP function) to product name (GX Developer).
Correction
Contents, Entire manual (change MELSECNET/10H to
MELSECNET/H), About Manuals, About the Generic Terms and
Abbreviations, Section 1.1(5), Section 2.2, 2.4, 2.6, 2.7 (g), 2.9, 2.10,
Section 3.1.1, 3.1.2 (figure), 3.1.3, 3.1.4 (figure), 3.1.5 (figure), 3.1.6
(5), REMARKS, 3.2 (table), 3.3.1 (table 6.3), 3.3.8 (POINT (screen)),
3.8.1 (2)(a), 3.8.2 (4), 3.8.5, 3.8.6, Section 4.1 (figure), Section 5.1.1,
5.1.2 (figure), 5.1.3, 5.1.5 (table)*3, 5.2.1 (2) (table), 5.2.8, 5.4.2, 5.4.3,
Section 6.1.1, 6.1.2 (figure), 6.1.3, 6.2*3 (table), 6.3.1 (2) (table), 6.3.8
POINT (3), 6.4.9POINT (3), Appendix 1, 2
Jun., 2001 SH(NA)-080008-C Standardize the name from utility package (QSCU) to product name (GX
Configurator-SC).
Correction
About Manuals, The Manual's Use and Structure, About the Generic
Terms and Abbreviations, Meanings and Descriptions of Terminology,
Section 1.1(5), Section 2.2(table), 2.6.1(1)(table), 2.6.2(table), 2.10(4),
Section 3.2(table), 3.3.1(table), 3.3.2, 3.3.3, 3.3.7, 3.3.8(2)(3),
3.3.9(2)(3)(4), 3.3.10(4), 3.4.3, 3.5, 3.6, 3.8.5(2), 3.8.16, 3.17.2, Section
4.4, Section 5.2.8(2)POINT, 5.5, Section 6.2 3, 6.3.1(2), Appendix 3.1
Addition
Section 2.11
Jan., 2003 SH(NA)-080008-D
Additional model
QJ71C24N,QJ71C24N-R2, QJ71C24N-R4
Correction
The Manual's Use and Structure, About the Generic Terms and
Abbreviations, Section 1.1(5), Section 2.5(3), 2.6.1, 2.8, Section
3.1.2(1)(5), 3.1.3(3), 3.2, 3.3.1, 3.3.10(5)POINT, 3.5.2, 3.6.1POINT,
3.6.7, 3.13, Section 5.1.5, 5.2.1POINT, 6.1.2(1)
Apr., 2003 SH(NA)-080008-E
Additional model
QJ71E71-B5
Deleted model
QJ71E71
Correction
About the Generic Terms and Abbreviations, Section 2.6.1(2), Section
3.5.2, Section 6.1.3(4)
Jun., 2004 SH(NA)-080008-F
Correction
About the Generic Terms and Abbreviations, Section 2.6.1, 2.6.3,
2.10(4)(b), 3.1.3(2)(3), 3.1.6(5), 3.2, 3.3.1(3), 3.5.2(1), 3.6.7, 3.8.1,
3.8.11 POINT, Section 6.1.3(4), 6.3.1(2)

A - 5 A - 5
The manual number is given on the bottom left of the back cover.
Print Date Manual Number Revision
Aug., 2005 SH(NA)-080008-G
Correction
About the Generic Terms and Abbreviations, Meanings and
Descriptions of Terminology, Section 2.7, Section 3.3.2 POINT
Addition
Chapter 3 (4E frame)
Jun., 2006 SH(NA)-080008-H
Correction
Section 3.2, 3.3.1, 3.3.8, 3.3.9, 3.5.2
Jul., 2007 SH(NA)-080008-I
Change of a term
"PLC" was changed to "programmable controller".
Correction
About the Generic Terms and Abbreviations, Section 1.2(2), Section
2.2, 2.4, 2.6.1, 2.6.2, 2.6.3, 2.9, 2.10(2)(4), Section 3.1.3(1), 3.1.6(5),
3.2*11, 3.3.1(3), 3.5.2(1), 3.13.1, 3.6.7, Section 5.1.3(4), Section
6.1.3(3), 6.3.1(2), Appendix 3.1
Nov., 2007 SH(NA)-080008-J
Correction
Section 1.1(5), 2.1(3), 2.6.1(1), 3.5.2, 5.1.5, 5.2.1(2), 6.2
Aug., 2008 SH(NA)-080008-K
Correction
About the Generic Terms and Abbreviations, Section 1.1, 1.2, Section
2.1, 2.2, 2.4 to 2.6, 2.8 to 2.11, 3.1.3, 3.1.6, 3.2, 3.3.1 to 3.3.10, 3.5.2,
3.6.7, 3.18, Section 5.1.3, 5.1.5, 5.2.1, Section 6.1.3, 6.2, 6.3.1,
Appendix 1, 1.2, 1.3, 2
Addition
Section 2.12
Feb., 2009 SH(NA)-080008-L
Correction
About the Generic Terms and Abbreviations, Section 2.1(3), 2.6.1,
Section 3.2*12, 3.5.2, 3.6.7, Section 5.1.5*7, 5.2.1, Section 6.2*7,
6.3.1*2
Jan., 2010 SH(NA)-080008-M
Additional model
LJ71C24, LJ71C24-R2
Correction
SAFETY PRECAUTIONS, RELEVANT MANUALS,
MANUAL PAGE ORGANIZATION,
GENERIC TERMS AND ABBREVIATIONS, TERMS, Section 2.6.1,
Section 3.1.6, 3.2, 3.3.1, 3.6.7, 3.8.1, 3.8.6, 3.8.7, 3.8.10, 3.8.12,
3.8.13, 3.8.15, 3.11.1, 3.13.1, Section 5.1.5, Appendix 1.3, 3.1
Addition
CONDITIONS OF USE FOR THE PRODUCT
Apr., 2010 SH(NA)-080008-N
Correction
GENERICTERMS AND ABBREVIATIONS, Section 1.1, 2.2, 2.6, 2.6.3,
2.9 to 2.11, 3.1.3, 3.1.6, 3.2, 3.3.2 to 3.3.10, 3.6.7, 5.1.3, 6.1.3, Appendix
1.3, 2

A - 6 A - 6
The manual number is given on the bottom left of the back cover.
Print Date Manual Number Revision
May, 2011 SH(NA)-080008-O
Correction
Section 2.1, 2.2, 2.6.1, 2.7.2, 3.1.3, 3.1.6, 3.2, 3.6.1, 3.7.3, 3.8, 3.8.1,
3.8.2, 3.8.9, 3.8.10, 3.8.11, 3.8.12, 3.8.13, 3.9.2, 3.9.3, 3.14, 4.3, 5.1.3,
5.1.5, Appendix 1.2
Jul., 2011 SH(NA)-080008-P
Correction
Section 1.1, 2.6.1, 2.11, 3.6.7, 5.2.1, 6.3.1
Oct., 2011 SH(NA)-080008-Q
Correction
Section 2.4, 2.6.1, 2.7.2, 2.8, 2.10, 2.12, 3.2, 3.3.1, 3.4.1, 3.11.1,
3.11.2, 3.18, 6.1.3, 6.2, 6.3.1, Appendix 3.1
Feb., 2013 SH(NA)-080008-R
Additional model
LJ71E71-100
Correction
RELEVANT MANUALS, GENERIC TERMS AND ABBREVIATIONS,
TERMS, Section 2.6.1, 2.7.1, 3.2, 3.3.1, 3.6.7, 3.8.1, 3.8.7, 3.8.12,
3.8.13, 3.8.15, 6.2, Appendix 1.2, 3.1
Japanese Manual Version SH-080003-X
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.
1999 MITSUBISHI ELECTRIC CORPORATION

A - 7 A - 7
INTRODUCTION
Thank you for purchasing the MELSEC-Q/L series programmable controller.
This manual describes the functions of the MELSEC-Q/L 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-L series programmable controller to handle the product
correctly.
Please always forward this manual to the end user.
CONTENTS
SAFETY PRECAUTIONS ........................................................................................................................A- 1
CONDITIONS OF USE FOR THE PRODUCT .......................................................................................A- 3
REVISIONS ..............................................................................................................................................A- 4
INTRODUCTION......................................................................................................................................A- 7
RELEVANT MANUALS............................................................................................................................A- 13
MANUAL PAGE ORGANIZATION ..........................................................................................................A- 15
GENERIC TERMS AND ABBREVIATIONS ...........................................................................................A- 17
TERMS .....................................................................................................................................................A- 19
1 OVERVIEW 1- 1 to 1- 4
1.1 Overview of the MELSEC Communication Protocol............................................................................ 1- 1
1.2 Features of the MELSEC Communication Protocol ............................................................................ 1- 3
2 DATA COMMUNICATION USING THE MELSEC COMMUNICATION PROTOCOL 2- 1 to 2- 34
2.1 Types and Applications of Data Communication Frames ................................................................... 2- 1
2.2 Accessible Range of Each Data Communication Frames .................................................................. 2- 3
2.3 How to Read the Control Procedures of the MC Protocol................................................................... 2- 5
2.4 Access Timing of the Programmable Controller CPU Side................................................................. 2- 6
2.5 Setting Method for Writing to the Programmable Controller CPU during RUN .................................. 2- 8
2.6 Accessing Other Stations ..................................................................................................................... 2- 9
2.6.1 Accessible programmable controllers of other stations ................................................................ 2- 9
2.6.2 Example of accessible station when each frame is used ............................................................. 2- 12
2.6.3 Example of designating data items for accessing other station designated within each data
communication frame .................................................................................................................... 2- 16
2.7 Precautions on Data Communication................................................................................................... 2- 19
2.7.1 When using E71 ............................................................................................................................. 2- 19
2.7.2 When using C24............................................................................................................................. 2- 21
2.8 Time Chart and Communication Time of the Transmission Sequence of
the Serial Communication Module ....................................................................................................... 2- 22
2.9 Transmission Time When Accessing Other Stations via CC-Link IE Controller Network,
CC-Link IE Field Network, MELSECNET/H, MELSECNET/10........................................................... 2- 25
2.10 Compatibility with Multiple CPU Systems .......................................................................................... 2- 28
2.11 Compatibility with the Serial Communication Function in the CPU Module ..................................... 2- 32
2.12 Compatibility with Programmable Controller CPU with Built-In Ethernet Port.................................. 2- 34

A - 8 A - 8
3 WHEN COMMUNICATING USING THE QnA COMPATIBLE 3E/3C/4C FRAMES OR 4E FRAME
3- 1 to 3- 303
3.1 Message Formats ................................................................................................................................. 3- 2
3.1.1 How to read the command description sections ........................................................................... 3- 2
3.1.2 Message format and control procedures of QnA compatible 3E frame and 4E frame................ 3- 3
3.1.3 Data designation items for QnA compatible 3E frame and 4E frame .......................................... 3- 13
3.1.4 Message formats and control procedures of QnA compatible 3C frame ..................................... 3- 16
3.1.5 Message formats and control procedures of QnA compatible 4C frame ..................................... 3- 25
3.1.6 Data designation items for QnA compatible 3C/4C frames.......................................................... 3- 36
3.1.7 Character area transmission data ................................................................................................. 3- 49
3.2 List of Commands and Functions for the QnA Compatible 3E/3C/4C Frames and 4E Frame.......... 3- 54
3.3 Device Memory Read/Write.................................................................................................................. 3- 62
3.3.1 Commands, character area contents and device range............................................................... 3- 62
3.3.2 Multiple block batch read and batch write ..................................................................................... 3- 76
3.3.3 Batch read in bit units (command: 0401)....................................................................................... 3- 85
3.3.4 Batch write in bit units (command: 1401) ...................................................................................... 3- 87
3.3.5 Random write in bit units (test) (command: 1402) ........................................................................ 3- 89
3.3.6 Batch read in word units (command: 0401) .................................................................................. 3- 91
3.3.7 Batch write in word units (command: 1401) .................................................................................. 3- 95
3.3.8 Random write in word units (test) (command: 1402) .................................................................... 3- 99
3.3.9 Random read in word units (command: 0403).............................................................................. 3-102
3.3.10 Monitoring device memory........................................................................................................... 3-120
3.4 Buffer Memory Read/Write ................................................................................................................... 3-129
3.4.1 Commands and buffer memory..................................................................................................... 3-129
3.4.2 Reading buffer memory (command: 0613) ................................................................................... 3-131
3.4.3 Writing to buffer memory (command: 1613).................................................................................. 3-133
3.5 Reading from and Writing to the Buffer Memory of an Intelligent Function Module ........................... 3-134
3.5.1 Commands and buffer memory..................................................................................................... 3-134
3.5.2 Accessible intelligent function modules......................................................................................... 3-139
3.5.3 Reading the buffer memory of an intelligent function module (command: 0601) ........................ 3-141
3.5.4 Writing to the buffer memory of an intelligent function module (command: 1601) ...................... 3-143
3.6 Programmable Controller CPU Status Control .................................................................................... 3-144
3.6.1 Commands, control contents, and character area contents......................................................... 3-144
3.6.2 Remote RUN (command: 1001) .................................................................................................... 3-146
3.6.3 Remote STOP (command: 1002) .................................................................................................. 3-147
3.6.4 Remote PAUSE (command: 1003) ............................................................................................... 3-148
3.6.5 Remote RESET (command: 1006)................................................................................................ 3-149
3.6.6 Remote latch clear (command: 1005) ........................................................................................... 3-150
3.6.7 CPU model name read (command: 0101) ....................................................................................3-151
3.7 Drive Memory Defragmentation (for Other Station QnACPU) ............................................................ 3-153
3.7.1 Commands and contents of character area..................................................................................3-154
3.7.2 Reading the status of the drive memory usage (command: 0205) .............................................. 3-157
3.7.3 Drive memory defragmentation (command: 1207) ....................................................................... 3-158
3.8 File Control ............................................................................................................................................ 3-160
3.8.1 Commands and contents of character area..................................................................................3-161
3.8.2 Precautions on file control.............................................................................................................. 3-176

A - 9 A - 9
3.8.3 File control execution procedure for the Q/LCPU ......................................................................... 3-178
3.8.4 File control execution procedure for the QnACPU........................................................................ 3-183
3.8.5 Read directory/file information (command: 1810): for the Q/LCPU.............................................. 3-187
3.8.6 Search directory/file information (command: 1811): for the Q/LCPU........................................... 3-189
3.8.7 Open file (command: 1827): for the Q/LCPU................................................................................3-190
3.8.8 Close file (command: 182A): for the Q/LCPU ...............................................................................3-192
3.8.9 Read file (command: 1828): for the Q/LCPU ................................................................................3-193
3.8.10 Create new file (command: 1820): for the Q/LCPU .................................................................... 3-195
3.8.11 Write to file (command: 1829): for the Q/LCPU .......................................................................... 3-196
3.8.12 Delete files (command: 1822): for the Q/LCPU .......................................................................... 3-198
3.8.13 Copy files (command: 1824): for the Q/LCPU ............................................................................3-200
3.8.14 Change date of file creation (command: 1826): for the Q/LCPU ............................................... 3-203
3.8.15 Change file attributes (command: 1825): for the Q/LCPU.......................................................... 3-204
3.8.16 Read file information list: for the QnACPU .................................................................................. 3-206
3.8.17 Reading file presence information (file search) (command: 0203): for the QnACPU................ 3-212
3.8.18 Registering and clearing file locks (command: 0808): for the QnACPU .................................... 3-214
3.8.19 Reading the contents of a file (command: 0206): for the QnACPU ........................................... 3-216
3.8.20 Creating a new file (filename registration) (command: 1202): for the QnACPU........................ 3-218
3.8.21 Writing to a file (command: 1203): for the QnACPU................................................................... 3-220
3.8.22 Deleting files (command: 1205): for the QnACPU ...................................................................... 3-224
3.8.23 Copying files (command: 1206): for the QnACPU ...................................................................... 3-226
3.8.24 Changing the file information (command: 1204): for the QnACPU ............................................ 3-228
3.9 Registering, Deleting and Reading User Frames: for Serial Communication Modules .....................3-234
3.9.1 Commands and contents of character area..................................................................................3-234
3.9.2 Registering and deleting user frames (command: 1610).............................................................. 3-237
3.9.3 Reading user frames (command: 0610)........................................................................................ 3-239
3.10 Global Function: for Serial Communication Modules ........................................................................3-241
3.10.1 Commands and contents of the character area.......................................................................... 3-241
3.10.2 Control procedure of the global function (command: 1618) ....................................................... 3-243
3.11 Data Transmission to an External Device (On-Demand Function): for
Serial Communication Modules ......................................................................................................... 3-245
3.11.1 Execution procedure of the on-demand function ........................................................................ 3-246
3.11.2 Data transmission format of the on-demand function ................................................................. 3-249
3.11.3 Control procedure of the on-demand function (command: 2101) .............................................. 3-251
3.12 Initializing the Transmission Sequence: for Serial Communication Modules ................................... 3-256
3.12.1 Commands ................................................................................................................................... 3-256
3.12.2 Transmission sequence initialization (command: 1615)............................................................. 3-257
3.13 Mode Switching: for Serial Communication Module.......................................................................... 3-258
3.13.1 Commands and contents of the character area.......................................................................... 3-259
3.13.2 Mode switching (command: 1612) .............................................................................................. 3-263
3.14 Turning Off Displayed LEDs and Initializing Communication Error Information and
Error Code: for Serial Communication Module.................................................................................. 3-265
3.14.1 Commands and contents of the character area.......................................................................... 3-265
3.14.2 Turning off displayed LEDs and initializing communication error information and
error code (command: 1617) ....................................................................................................... 3-268
3.15 Turning Off the COM.ERR.LED: for E71 ........................................................................................... 3-269
3.15.1 Commands and contents of the character area.......................................................................... 3-269
3.15.2 Turning off the COM.ERR.LED (command: 1617) ..................................................................... 3-270

A - 10 A - 10
3.16 Loopback Test..................................................................................................................................... 3-271
3.16.1 Commands and contents of character area................................................................................ 3-271
3.16.2 Loopback test (command: 0619) ................................................................................................. 3-272
3.17 Registering or Canceling Programmable Controller CPU Monitoring:
for Serial Communication Modules.................................................................................................... 3-273
3.17.1 Commands and contents of the character area.......................................................................... 3-276
3.17.2 Programmable controller CPU monitoring registration (command: 0630) ................................. 3-282
3.17.3 Canceling programmable controller CPU monitoring (command: 0631) ................................... 3-285
3.17.4 Data transmitted by the programmable controller CPU monitoring function ............................. 3-286
3.18 Remote Password Unlock/Lock ......................................................................................................... 3-297
3.18.1 Contents of the command and character section ....................................................................... 3-301
3.18.2 Remote password unlock/lock (command: 1630, 1631) ............................................................ 3-302
4 WHEN COMMUNICATING USING THE QnA COMPATIBLE 2C FRAMES 4- 1 to 4- 16
4.1 Control Procedures and Message Formats ......................................................................................... 4- 1
4.2 Contents of the Data Designation Items .............................................................................................. 4- 7
4.3 List of Commands and Functions for QnA Compatible 2C Frames.................................................... 4- 8
4.4 Precautions on the Data Communication ............................................................................................ 4- 9
4.5 Example of Data Communication Using QnA Compatible 2C Frames............................................... 4- 10
5 WHEN COMMUNICATING USING THE A COMPATIBLE 1C FRAMES 5- 1 to 5- 54
5.1 Control Procedures and Message Formats ......................................................................................... 5- 1
5.1.1 How to read the control procedure and command reference sections ........................................ 5- 2
5.1.2 Control procedures and message formats .................................................................................... 5- 4
5.1.3 Contents of data designation items of A compatible 1C frames .................................................. 5- 9
5.1.4 Understanding transmission data in the character areas ............................................................. 5- 14
5.1.5 List of Commands and functions for A compatible 1C frames ..................................................... 5- 15
5.2 Device Memory Read/Write.................................................................................................................. 5- 18
5.2.1 Commands and device range........................................................................................................ 5- 18
5.2.2 Batch read in bit units (command: BR, JR) ................................................................................... 5- 23
5.2.3 Batch write in bit units (command: BW, JW) ................................................................................. 5- 24
5.2.4 Test in bit units (random write) (command: BT, JT)...................................................................... 5- 25
5.2.5 Batch read in word units (command: WR, QR)............................................................................. 5- 26
5.2.6 Batch write in word units (command: WW, QW)........................................................................... 5- 28
5.2.7 Test in word units (random write) (command: WT, QT) ............................................................... 5- 30
5.2.8 Monitoring device memory............................................................................................................. 5- 31
5.3 Extension File Register Read and Write .............................................................................................. 5- 36
5.3.1 ACPU common commands and addresses.................................................................................. 5- 36
5.3.2 AnA/AnUCPU common commands and device numbers ............................................................ 5- 37
5.3.3 Precautions when reading and writing in the extension file register ............................................ 5- 40
5.3.4 Batch reading of the extension file register (command: ER) ........................................................ 5- 41
5.3.5 Batch writing of the extension file register (command: EW) ......................................................... 5- 42
5.3.6 Direct reading of the extension file register (command: NR)........................................................ 5- 43
5.3.7 Direct writing of the extension file register (command: NW)......................................................... 5- 44
5.3.8 Test of extension file register (random write) (command: ET) ..................................................... 5- 45
5.3.9 Monitoring extension file register ................................................................................................... 5- 46

A - 11 A - 11
5.4 Reading and Writing in the Buffer Memory of an Intelligent Function Module.................................... 5- 49
5.4.1 Commands and processing ........................................................................................................... 5- 49
5.4.2 Understanding the intelligent function module number in the control procedure......................... 5- 50
5.4.3 Reading from the buffer memory of an intelligent function module (command: TR) ................... 5- 52
5.4.4 Writing to the buffer memory of an intelligent function module (command: TW)......................... 5- 53
5.5 Loopback Test....................................................................................................................................... 5- 54
6 WHEN COMMUNICATING USING THE A COMPATIBLE 1E FRAMES 6- 1 to 6- 63
6.1 Message Formats and Control Procedures ......................................................................................... 6- 2
6.1.1 How to read the command reference section ............................................................................... 6- 2
6.1.2 Message format and control procedure......................................................................................... 6- 4
6.1.3 Contents of data designation items of A compatible 1E frames................................................... 6- 7
6.1.4 Understanding transmission data in the character areas ............................................................. 6- 14
6.2 List of Commands and Functions for A Compatible 1E Frames ......................................................... 6- 15
6.3 Device Memory Read/Write.................................................................................................................. 6- 18
6.3.1 Commands and device range........................................................................................................ 6- 18
6.3.2 Batch read in bit units (command: 00)........................................................................................... 6- 25
6.3.3 Batch write in bit units (command: 02) .......................................................................................... 6- 27
6.3.4 Test in bit units (random write) (command: 04) ............................................................................ 6- 29
6.3.5 Batch read in word units (command: 01) ...................................................................................... 6- 31
6.3.6 Batch write in word units (command: 03) ...................................................................................... 6- 33
6.3.7 Test in word units (random write) (command: 05) ........................................................................ 6- 35
6.3.8 Monitoring device memory............................................................................................................. 6- 37
6.4 Extension File Register Read and Write .............................................................................................. 6- 42
6.4.1 ACPU common commands and addresses .................................................................................. 6- 42
6.4.2 AnA/AnUCPU common commands and device numbers ............................................................ 6- 43
6.4.3 Precautions when reading and writing from/to the extension file register.................................... 6- 46
6.4.4 Batch reading of the extension file register (command: 17) ......................................................... 6- 47
6.4.5 Batch writing of the extension file register (command: 18)........................................................... 6- 49
6.4.6 Direct reading of the extension file register (command: 3B)......................................................... 6- 51
6.4.7 Direct writing of the extension file register (command: 3C) .......................................................... 6- 53
6.4.8 Test of extension file register (random write) (command: 19) ...................................................... 6- 54
6.4.9 Monitoring extension file registers ................................................................................................. 6- 55
6.5 Reading and Writing in the Buffer Memory of an Intelligent Function Module.................................... 6- 58
6.5.1 Commands and processing ........................................................................................................... 6- 58
6.5.2 Understanding the intelligent function module numbers in the control procedure....................... 6- 59
6.5.3 Reading from the buffer memory of an intelligent function module (command: 0E) ................... 6- 61
6.5.4 Writing to the buffer memory of an intelligent function module (command: 0F) .......................... 6- 63
APPENDICES APPX- 1 to APPX- 30
Appendix 1 Reading and Writing by Designation of the Device Memory Extension ......................... APPX- 1
Appendix 1.1 Data order and contents in the character areas when the
device memory extension is designated................................................................. APPX- 3
Appendix 1.2 Device memory which can have designated extensions and
an example of designation ...................................................................................... APPX- 8
Appendix 1.3 Restrictions when designating the device memory extension ................................ APPX- 16

A - 12 A - 12
Appendix 2 Reading from and Writing to the Buffer Memory ............................................................. APPX- 17
Appendix 3 Processing Time of the Programmable Controller CPU Side While Communicating
Using the MC Protocol..................................................................................................... APPX- 19
Appendix 3.1 Processing time of the programmable controller CPU (increase in scan time)...... APPX- 19
INDEX INDEX- 1 to INDEX- 2

A - 13 A - 13
RELEVANT MANUALS
The details on the MELSEC communication protocol can be confirmed in this manual.
In addition, use the following manuals according to the intended use.
(1) Relevant manuals for the C24
Manual name Manual number
(model code)
Q Corresponding Serial Communication Module User's Manual (Basic)
This manual provides an overview of the module and describes the applicable system configuration, the
specifications, the procedures prior to operations, the basic methods of communicating with the external
device, maintenance and inspection, and the troubleshooting of the serial communication module.
(Sold separately)
SH-080006
(13JL86)
MELSEC-L Serial Communication Module User's Manual (Basic)
This manual provides an overview of the module and describes the applicable system configuration, the
specifications, the procedures prior to operations, the basic methods of communicating with the external
device, maintenance and inspection, and the troubleshooting of the serial communication module.
(Sold separately)
SH-080894ENG
(13JZ40)
MELSEC-Q/L Serial Communication Module User's Manual (Application)
This manual contains information on how to perform data communication with external devices using the
serial communication module's special functions. (Sold separately)
SH-080007
(13JL87)
(2) Relevant manuals for the E71
Manual name Manual number
(model code)
Q Corresponding Ethernet Interface Module User's Manual (Basic)
This manual contains information on the specifications of the Ethernet interface module, the procedures
for data communications with external devices, circuit connection (open/close), fixed buffer exchange,
random access buffer exchange, and the troubleshooting. (Sold separately)
SH-080009
(13JL88)
MELSEC-L Ethernet Interface Module User's Manual (Basic)
This manual contains information on the specifications of the Ethernet interface module, the procedures
for data communications with external devices, circuit connection (open/close), fixed buffer exchange,
random access buffer exchange, and the troubleshooting. (Sold separately)
SH-081105ENG
(13JZ73)
MELSEC-Q/L Ethernet Interface Module User's Manual (Web function)
This manual explains how to use the Web function of the Ethernet interface module. (Sold separately)
SH-080180
(13JR40)

A - 14 A - 14
(3) CPU module user’s manual
Manual name Manual number
(model code)
QnUCPU User's Manual (Function Explanation, Program Fundamentals)
Functions, methods, and devices for programming (Sold separately)
SH-080807ENG
(13JZ27)
Qn(H)/QnPH/QnPRHCPU User's Manual(Function Explanation, Program Fundamentals)
Functions, methods, and devices for programming (Sold separately)
SH-080808ENG
(13JZ28)
MELSEC-L CPU Module User's Manual (Function Explanation, Program Fundamentals)
Functions, methods, and devices for programming (Sold separately)
SH-080889ENG
(13JZ35)
QnUCPU User's Manual (Communication via Built-in Ethernet Port)
Functions of the built-in Ethernet port of the CPU module (Sold separately)
SH-080811ENG
(13JZ29)
MELSEC-L CPU Module User's Manual (Built-In Ethernet Function)
Functions of the built-in Ethernet port of the CPU module (Sold separately)
SH-080891ENG
(13JZ37)
(4) Operating manual
Manual name Manual number
(model code)
GX Works2 Version1 Operating Manual (Common)
System configuration, parameter settings, and online operations (common to Simple project and
Structured project) of GX Works2. (Sold separately)
SH-080779ENG
(13JU63)
GX Developer Version 8 Operating Manual
Operating methods of GX Developer, such as programming, printing, monitoring, and debugging.
(Sold separately)
SH-080373E
(13JU41)

A - 15 A - 15
MANUAL PAGE ORGANIZATION
• How to use this manual
This manual explains the communication functions via the MC protocol, with each
section covering a specific function.
(1) To learn about the communication functions using the MC protocol
• A summary of the data communication using the MC protocol is explained in
Section 1.1
• The main data communication functions using the MC protocol are explained in
Section 1.2
(2) To learn about the types and access ranges of frames for the MC
protocol
(a) To learn how to read the frame names for the MC protocol
• How to read the frame names is explained in Chapter 1.
• The correspondence between the communication frames of the
conventional modules and those for the MC protocol are explained in
Section 2.1.
(b) To learn about the types and access ranges of frames
• The types of frames that can be used for the serial communication
modules and Ethernet Interface modules are explained in Section 2.1.
• The application and access range of each frame are explained in Section
2.2 and succeeding sections.
(3) When communicating through the MC protocol
• The common information on communication through the MC protocol is
explained in Chapter 2, Section 2.3 and succeeding sections.
• The commands, message formats, and control procedures for A
compatible 1C frame are explained in Chapter 5.
• The commands, message formats, and control procedures for A
compatible 1E frame are explained in Chapter 6.
• The commands, message formats, and control procedures for QnA
compatible 2C frame are explained in Chapter 4.
• The commands, message formats, and control procedures for QnA
compatible 3E, QnA compatible 3C, QnA compatible 4C frames, and 4E
frame are explained in Chapter 3.

A - 16 A - 16
• Structure of this manual
The explanations of the message formats and the control procedures while
communicating through the MC protocol are given in the following format:
[Control procedure]
(1) Reading eight points of data from internal
relays M100 to M107 in communication in
ASCII code
30
H34 H30H31 H30H30 H30H31 H4D H2A H30 H30H30 H31 H30 H30 H30H30H30H38 H
04010001M 0001000008
H--LH- L H----LH--L
Command
Subcommand
Device code
Head device
Number of
device points
30
H30 H30 H31H30 H30 H31H30 H
00010010
Data for the number of
designed device points
Number of device points to be read
M107 = OFF
M106 = ON
M100 = OFF
(Refer to Section 3.1.5.)
0 (30H) indicates off
1 (31H) indicates on.
Number of points to be read
(Refer to Section 3.3.1.)
(Data name)
External device
side
(Example)
(Data name)
Programmable controller
CPU side
(Example)
An asterisk ( ) in both the command message and the response message indicates the same order of data
items as in the control procedures when other commands are used.
(The head and end sections of the command and response messages.)
Confirm the order of data items in the fields marked with " " by referring to the reference sections listed
below.
The order of data items in the fields marked with " " differs between Ethernet interface modules and serial
communication modules.
(1) When communicating via an Ethernet Interface module
A compatible 1E frame : Refer to Section 6.1.
QnA compatible 3E frame : Refer to Section 3.1.2.
4E frame : Refer to Section 3.1.2.
(2) When communicating via a serial communication module
A compatible 1C frame : Refer to Section 5.1.
QnA compatible 2C frame : Refer to Section 4.1.
QnA compatible 3C frame : Refer to Section 3.1.4.
QnA compatible 4C frame : Refer to Section 3.1.5.
This is a description of the
request from the external
device side for the control
procedure explained in the
example.
This diagram illustrates the
sequence of data items in the
command message to be sent
by the external device.
This diagram illustrates the
sequence of data items in the
response message (the
message providing the
processing result) to be sent by
the programmable controller
CPU side for the request sent
from the external device side.

A - 17 A - 17
GENERIC TERMS AND ABBREVIATIONS
This manual uses the following generic terms and abbreviations to explain the serial communication modules,
Ethernet interface modules, and devices for data communication unless otherwise specified.
(1) Generic terms and abbreviations for CPU modules
For the module model names, refer to the manual for the CPU module used.
Generic term
/abbreviation Description
ACPU
Generic term for AnNCPU, AnACPU, AnUCPU, QCPU (A mode).
A series programmable controller CPUs accessible from external devices using the MC protocol communication
functions.
AnACPU Generic term for A2ACPU, A2ACPU-S1, A2ACPUP21/R21, A2ACPUP21/R21-S1, A3ACPU, A3ACPUP21/R21.
AnA/AnU/QnACPU Generic term for AnACPU, AnUCPU, QnACPU.
AnNCPU Generic term for A1NCPU, A1NCPUP21/R21, A2NCPU, A2NCPU-S1, A2NCPUP21/R21, A2NCPUP21/R21-S1,
A3NCPU, A3NCPUP21/R21.
AnUCPU Generic term for A2UCPU, A2UCPU-S1, A2ASCPU, A2ASCPU-S1, A3UCPU, A4UCPU.
AnU/QnACPU Generic term for AnUCPU, QnACPU.
LP25/BR15 Generic term for AJ72LP25, AJ72BR15.
QCPU Generic term for the Basic model QCPU, High Performance model QCPU, Process CPU, Redundant CPU, and Universal
model QCPU.
QnUDVCPU Generic term for Q03UDVCPU, Q04UDVCPU, Q06UDVCPU, Q13UDVCPU, Q26UDVCPU.
QCPU (A mode) Generic term for Q02CPU-A, Q02HCPU-A, Q06HCPU-A.
Basic model QCPU Generic term for Q00JCPU, Q00CPU, Q01CPU.
High Performance model
QCPU Generic term for Q02CPU, Q02HCPU, Q06HCPU, Q12HCPU, Q25HCPU.
Process CPU Generic term for Q02PHCPU, Q06PHCPU, Q12PHCPU, Q25PHCPU.
Redundant CPU Generic term for Q12PRHCPU, Q25PRHCPU.
Universal model QCPU
Generic term for Q00UJCPU, Q00UCPU, Q01UCPU, Q02UCPU, Q03UDCPU, Q03UDVCPU, Q03UDECPU,
Q04UDHCPU, Q04UDVCPU, Q04UDEHCPU, Q06UDHCPU, Q06UDVCPU, Q06UDEHCPU, Q10UDHCPU,
Q10UDEHCPU, Q13UDHCPU, Q13UDVCPU, Q13UDEHCPU, Q20UDHCPU, Q20UDEHCPU, Q26UDHCPU,
Q26UDVCPU, Q26UDEHCPU, Q50UDEHCPU, Q100UDEHCPU.
LCPU Generic term for MELSEC-L series CPU modules.
Safety CPU Generic term for QS001CPU. When characteristics in common with QCPUs are described, however, it is referred to as
QCPU or Q series CPU.
QCPU station Abbreviation for the programmable controller with QCPU installed.
QE71 Generic term for AJ71QE71N3-T, AJ71QE71N-B5, AJ71QE71N-B2, AJ71QE71N-T, AJ71QE71N-B5T,
A1SJ71QE71N3-T, A1SJ71QE71N-B5, A1SJ71QE71N-B2, A1SJ71QE71N-T, A1SJ71QE71N-B5T.
QLP21/QBR11 Generic term for AJ71QLP21, AJ71QBR11.
QLP25/QBR15 Generic term for AJ72QLP25 (G), AJ72QBR15, A1SJ72QLP25, A1SJ72QBR15.
QnACPU Generic term for Q2ACPU, Q2ACPU-S1, Q2ASCPU, Q2ASCPU-S1, Q2ASHCPU, Q2ASHCPU-S1, Q3ACPU, Q4ACPU,
Q4ARCPU.
QnACPU station Abbreviation for the programmable controller with QnACPU installed.
C24 Abbreviation for QJ71C24N, QJ71C24N-R2, QJ71C24N-R4, QJ71C24, QJ71C24-R2, LJ71C24 and LJ71C24-R2 serial
communication modules.
E71 Abbreviation for QJ71E71-100, QJ71E71-B5, QJ71E71-B2 and LJ71E71-100 Ethernet interface modules.
Generic term for the modules below.
Q series QJ71C24N, QJ71C24N-R2, QJ71C24N-R4, QJ71C24, QJ71C24-R2.
L series LJ71C24, LJ71C24-R2.
Serial communication
module
QnA series AJ71QC24, AJ71QC24-R2, AJ71QC24-R4, A1SJ71QC24, A1SJ71QC24-R2, AJ71QC24N,
AJ71QC24N-R2, AJ71QC24N-R4, A1SJ71QC24N, A1SJ71QC24N-R2.
UC24
Computer link module
Generic term for AJ71UC24, A1SJ71UC24-R2, A1SJ71UC24-R4, A1SJ71UC24-PRF, A1SJ71C24-R2, A1SJ71C24-R4,
A1SJ71C24-PRF, A2CCPUC24, A2CCPUC24-PRF.
A series computer link module

A - 18 A - 18
(2) Generic terms and abbreviations for manuals
Generic term/abbreviation Description
User’s Manual (Basic)
• Serial communication module
Q Corresponding Serial Communication Module User’s Manual (Basic)
MELSEC-L Serial Communication Module User’s Manual (Basic)
• Ethernet interface module
Q Corresponding Ethernet Interface Module User’s Manual (Basic)
MELSEC-L Ethernet Interface Module User’s Manual (Basic)
User’s Manual (Application)
• Serial communication module
MELSEC-Q/L Serial Communication Module User’s Manual (Application)
• Ethernet interface module
MELSEC-Q/L Ethernet Interface Module User’s Manual (Application)
(3) Other generic terms and abbreviations
Generic term/abbreviation Description
Buffer memory
Generic term for the memory of the intelligent function module or special function module
for storing the transmission/reception data when communicating with the programmable
controller CPU (such as setting values and monitor values).
Computer Generic term for a unit in the external device that can communicate data through the MC
protocol or bidirectional protocol.
Data communication function Generic term for the MC protocol, pre-defined protocol, non-procedure protocol, or
bidirectional protocol.
I/F Abbreviation for Interface.
MELSECNET/10 Abbreviation for MESECNET/10 Network System.
MELSECNET/H Abbreviation for MESECNET/H Network System.
ONDEMAND Abbreviation for G.ONDEMAND or GP.ONDEMAND.
RS-232 (interface) Abbreviation for Interface that conforms to the RS-232 interface.
RS-422/485 (interface) Abbreviation for Interface that conforms to either the RS-422 or RS-485 interface.
Switch setting Generic term for intelligent function module switch setting.