Mitsubishi Electric MELSEC Q Series Owner's manual

MELSEC-Q/L/F Structured
Programming Manual (Fundamentals)

A-1
SAFETY PRECAUTIONS
(Read these precautions before using this product.)
Before using MELSEC-Q, -L, or -F series programmable controllers, please read the manuals included with each
product and the relevant manuals introduced in those manuals carefully, and pay full attention to safety to handle
the product correctly.
Make sure that the end users read the manuals included with each product, and keep the manuals in a safe
place for future reference.

A-2
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-3
REVISIONS
The manual number is written at the bottom left of the back cover.
Print date Manual number Revision
Jul., 2008 SH(NA)-080782ENG-A First edition
Jan., 2009 SH(NA)-080782ENG-B
Q00UJCPU, Q00UCPU, Q01UCPU, Q10UDHCPU, Q10UDEHCPU,
Q20UDHCPU, Q20UDEHCPU, FX series
MANUALS
Generic Terms and Abbreviations in This Manual, Section 1.3, Section 4.3.3,
Section 4.3.4, Section 4.4.1, Section 4.4.2, Appendix 1
Jul., 2009 SH(NA)-080782ENG-C
Q00JCPU, Q00CPU, Q01CPU
Section 3.5, Section 3.6, Section 4.4, Section 4.4.1, Section 4.4.2, Section 4.4.3,
Section 4.4.4, Section 4.4.5, Section 4.4.6, Section 4.6, Section 4.8, Appendix 1
PURPOSE OF THIS MANUAL is changed to Section 1.2,
Generic Terms and Abbreviations in This Manual is changed to Section 1.3,
Section 1.5, Section 4.2.8, Section 4.3.4, Section 4.5 is changed to Section 4.4.7,
Section 4.5.2, Section 4.5.3, Section 4.6 is changed to Section 4.4.8,
Appendix 2, Appendix 3, Appendix 1 to 2 are changed to Appendix 2 to 3
Oct., 2009 SH(NA)-080782ENG-D
Section 1.3, Section 5.2.2, Appendix 2
Jan., 2010 SH(NA)-080782ENG-E
L02CPU, L26CPU-BT
CONDITIONS OF USE FOR THE PRODUCT
MANUALS, Section 1.2, Section 1.3, Section 1.5, Section 4.4.1, Section 4.4.4,
Section 4.5.1, Section 4.5.2, Section 4.6
Apr., 2010 SH(NA)-080782ENG-F
Q50UDEHCPU, Q100UDEHCPU
Section 1.2, Section 1.3, Section 1.5, Appendix 2
Sep., 2010 SH(NA)-080782ENG-G
Section 4.4.7, Section 5.1.1, Section 5.1.3, Appendix 2
Jan., 2011 SH(NA)-080782ENG-H
Section 1.2, Section 5.1.1
Mar., 2011 SH(NA)-080782ENG-I
Section 4.2.5, Section 5.2.3, Section 5.2.4
Section 1.2, Section 4.2.2, Section 4.2.3, Section 4.2.4, Section 4.2.8,
Section 4.3.4, Section 4.4.4, Section 4.4.7, Section 4.6, Section 5.1.3,
Section 5.1.5
Model Addition
Addition
Correction
Model Addition
Addition
Correction
Correction
Model Addition
Addition
Correction
Model Addition
Correction
Correction
Correction
Addition
Correction

A-4
Japanese manual version SH-080735-R
2008 MITSUBISHI ELECTRIC CORPORATION
Jul., 2011 SH(NA)-080782ENG-J
L02CPU-P, L26CPU-PBT
Section 5.2.5
Section 1.3, Section 1.4, Section 1.5, Section 4.2.6, Section 4.2.7, Section 4.4.2,
Section 4.4.3, Section 4.4.4, Section 5.1.3, Section 5.1.6, Section 5.2,
Section 5.2.2
May, 2012 SH(NA)-080782ENG-K "PLC" was changed to "programmable controller".
FX3GC
INTRODUCTION, MANUALS, Section 1.2, Section 1.3, Section 1.5, Section 4.1.3,
Section 4.2.7, Section 4.3.5, Section 4.4.4, Section 4.4.6, Section 4.5.1,
Section 5.2.4, Appendix 2
Feb., 2013 SH(NA)-080782ENG-L Overall revision due to addition of a Process CPU, Redundant CPU, Universal
model QCPU, and LCPU
Q02PHCPU, Q06PHCPU, Q12PHCPU, Q25PHCPU, Q12PRHCPU,
Q25PRHCPU, Q03UDVCPU, Q04UDVCPU, Q06UDVCPU, Q13UDVCPU,
Q26UDVCPU, L02SCPU, L06CPU, L26CPU
Jul., 2013 SH(NA)-080782ENG-M
L02SCPU-P, L06CPU-P, L26CPU-P, FX3S
Section 1.2, Section 1.3, Section 1.5, Section 4.3.5, Section 4.4.4, Section 4.6
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.
Print date Manual number Revision
Model Addition
Addition
Correction
Model Addition
Correction
Model Addition
Model Addition
Correction

A-5
INTRODUCTION
Thank you for purchasing the Mitsubishi MELSEC-Q, -L, or -F series programmable controllers.
Before using this product, please read this manual and the relevant manuals carefully and develop familiarity with
the programming specifications 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
SAFETY PRECAUTIONS .................................................................................................................................A - 1
CONDITIONS OF USE FOR THE PRODUCT .................................................................................................A - 2
REVISIONS.......................................................................................................................................................A - 3
INTRODUCTION...............................................................................................................................................A - 5
CONTENTS ......................................................................................................................................................A - 5
MANUALS.........................................................................................................................................................A - 8
1. OVERVIEW 1 - 1 to 1 - 8
1.1 Overview 1 - 2
1.2 Purpose of This Manual 1 - 2
1.3 Terms 1 - 6
1.4 Features of Structured Programs 1 - 7
1.5 Applicable CPU Modules 1 - 8
1.6 Compatible Software Package 1 - 8
2. STRUCTURED DESIGN OF SEQUENCE PROGRAMS 2 - 1 to 2 - 4
2.1 What is a Hierarchical Sequence Program? 2 - 2
2.2 What is a Structured Sequence Program? 2 - 3
3. PROCEDURE FOR CREATING PROGRAMS 3 - 1 to 3 - 2
3.1 Procedure for Creating Sequence Programs in Structured Project 3 - 2
4. PROGRAM CONFIGURATION 4 - 1 to 4 - 58
4.1 Overview of Program Configuration 4 - 2
4.1.1 Project ........................................................................................................................................... 4 - 3
4.1.2 Program files.................................................................................................................................. 4 - 3
4.1.3 Tasks ........................................................................................................................................... 4 - 4
4.2 POUs 4 - 5
4.2.1 Types of POU ................................................................................................................................ 4 - 5
4.2.2 Program ......................................................................................................................................... 4 - 6
4.2.3 Functions ....................................................................................................................................... 4 - 6
4.2.4 Function blocks.............................................................................................................................. 4 - 7
4.2.5 Operators....................................................................................................................................... 4 - 7
4.2.6 Ladder blocks ................................................................................................................................ 4 - 8
4.2.7 Programming languages for POUs................................................................................................ 4 - 9
4.2.8 Functions, function blocks, and operators ................................................................................... 4 - 10

A-6
4.2.9 EN and ENO ................................................................................................................................ 4 - 13
4.3 Labels 4 - 15
4.3.1 Global labels ................................................................................................................................ 4 - 15
4.3.2 Local labels.................................................................................................................................. 4 - 15
4.3.3 Label classes ............................................................................................................................... 4 - 16
4.3.4 Setting labels ............................................................................................................................... 4 - 17
4.3.5 Data types.................................................................................................................................... 4 - 18
4.3.6 Expressing methods of constants................................................................................................ 4 - 20
4.4 Method for Specifying Data 4 - 21
4.4.1 Bit data......................................................................................................................................... 4 - 22
4.4.2 Word (16 bits) data ...................................................................................................................... 4 - 23
4.4.3 Double word (32 bits) data........................................................................................................... 4 - 26
4.4.4 Single-precision real/double-precision real data.......................................................................... 4 - 29
4.4.5 String data ................................................................................................................................... 4 - 33
4.4.6 Time data..................................................................................................................................... 4 - 34
4.4.7 Arrays .......................................................................................................................................... 4 - 35
4.4.8 Structures .................................................................................................................................... 4 - 37
4.5 Device and Address 4 - 38
4.5.1 Device.......................................................................................................................................... 4 - 38
4.5.2 Address........................................................................................................................................ 4 - 39
4.5.3 Correspondence between devices and addresses...................................................................... 4 - 40
4.6 Index Setting 4 - 43
4.7 Libraries 4 - 55
4.7.1 User libraries................................................................................................................................ 4 - 56
4.8 Precautions on Assigning a Name 4 - 57
5. WRITING PROGRAMS 5 - 1 to 5 - 20
5.1 ST 5 - 2
5.1.1 Standard format ............................................................................................................................. 5 - 2
5.1.2 Operators in ST language.............................................................................................................. 5 - 3
5.1.3 Syntax in ST language................................................................................................................... 5 - 4
5.1.4 Calling functions in ST language ................................................................................................... 5 - 9
5.1.5 Calling function blocks in ST language........................................................................................ 5 - 10
5.1.6 Precautions when using conditional syntax and iteration syntax................................................. 5 - 11
5.2 Structured Ladder/FBD 5 - 13
5.2.1 Standard format ........................................................................................................................... 5 - 13
5.2.2 Ladder symbols in structured ladder/FBD language.................................................................... 5 - 14
5.2.3 Executing order............................................................................................................................ 5 - 16
5.2.4 Ladder branches and compilation results ....................................................................................5-17
5.2.5 Precautions on creating programs with structured ladder/FBD ................................................... 5 - 19

A-7
APPENDICES App - 1 to App - 14
Appendix 1Correspondence between Generic Data Types and Devices App - 2
Appendix 2Character Strings that cannot be Used in Label Names and Data Names App - 6
Appendix 3Recreating Ladder Programs App - 9
Appendix 3.1Procedure for creating a structured program ...................................................................App - 9
Appendix 3.2Example of creating a structured program.....................................................................App - 10
INDEX Index - 1 to Index - 2

A-8
MANUALS
The manuals related to this product are listed below.
Please place an order as needed.
(1) Structured programming
(2) Operation of GX Works2
Operating manuals in PDF format are stored on the CD-ROM of the software package. Printed
manuals are sold separately. To order manuals, please provide the manual number (model
code) listed in the table above.
Manual name Manual number
(Model code)
MELSEC-Q/L Structured Programming Manual (Common Instructions)
Specifications and functions of common instructions, such as sequence instructions, basic instructions,
and application instructions, that can be used in structured programs
(Sold separately)
SH-080783ENG
(13JW07)
MELSEC-Q/L Structured Programming Manual (Application Functions)
Specifications and functions of application functions that can be used in structured programs
(Sold separately)
SH-080784ENG
(13JW08)
MELSEC-Q/L Structured Programming Manual (Special Instructions)
Specifications and functions of special instructions, such as module dedicated instructions, PID control
instructions, and built-in I/O function instructions, that can be used in structured programs
(Sold separately)
SH-080785ENG
(13JW09)
FXCPU Structured Programming Manual [Device & Common]
Devices and parameters for structured programming provided in GX Works2
(Sold separately)
JY997D26001
(09R925)
FXCPU Structured Programming Manual [Basic & Applied Instruction]
Sequence instructions for structured programming provided in GX Works2
(Sold separately)
JY997D34701
(09R926)
FXCPU Structured Programming Manual [Application Functions]
Application functions for structured programming provided in GX Works2
(Sold separately)
JY997D34801
(09R927)
Manual name Manual number
(Model code)
GX Works2 Version 1 Operating Manual (Common)
System configuration, parameter settings, and online operations of GX Works2, which are common to
Simple projects and Structured projects
(Sold separately)
SH-080779ENG
(13JU63)
GX Works2 Version 1 Operating Manual (Structured Project)
Operations, such as programming and monitoring in Structured projects, of GX Works2
(Sold separately)
SH-080781ENG
(13JU65)
GX Works2 Beginner’s Manual (Structured Project)
Basic operations, such as programming, editing, and monitoring in Structured projects, of GX Works2.
This manual is intended for first-time users of GX Works2.
(Sold separately)
SH-080788ENG
(13JZ23)

1
OVERVIEW
2
STRUCTURED DESIGN OF SEQUENCE PROGRAMS
3
PROCEDURE FOR CREATING PROGRAMS
4
PROGRAM CONFIGURATION
5
WRITING PROGRAMS
A
APPENDICES
I
INDEX
1
1-1
OVERVIEW
1.1 Overview. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-2
1.2 Purpose of This Manual . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-2
1.3 Terms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-6
1.4 Features of Structured Programs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-7
1.5 Applicable CPU Modules . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-8
1.6 Compatible Software Package . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-8

1-2 1.1 Overview
1.1 Overview
This manual describes program configurations and content for creating sequence programs
using a structured programming method, and provides basic knowledge for writing programs.
1.2 Purpose of This Manual
This manual explains programming methods, programming languages, and other information
necessary for creating structured programs.
Manuals for reference are listed in the following table according to their purpose.
For information such as the contents and number of each manual, refer to the list of 'Related
manuals'.
(1) Operation of GX Works2
Purpose
GX Works2
Installation
Instructions
GX Works2
Beginner's Manual
GX Works2 Version 1
Operating Manual
Simple
Project
Structured
Project Common Simple Project
Structured
Project
Intelligent
Function
Module
Installation
Learning the
operating
environment and
installation method
Learning a USB
driver installation
method
Operation of
GX Works2
Learning all functions
of GX Works2
Learning the project
types and available
languages in GX
Works2
Learning the basic
operations and
operating procedures
when creating a
simple project for the
first time
Learning the basic
operations and
operating procedures
when creating a
structured project for
the first time
Learning the
operations of
available functions
regardless of project
type.
Learning the
functions and
operation methods
for programming
Learning data setting
methods for
intelligent function
module
Details
Details
Outline
Outline
Details
Details
Details
Outline
Details
Details
Details

1.2 Purpose of This Manual
1-3
1
OVERVIEW
(2) Operations in each programming language
For details of instructions used in each programming language, refer to the section 3 on the
next page.
Purpose
GX Works2
Beginner's Manual
GX Works2 Version 1
Operating Manual
Simple
Project
Structured
Project
Simple
Project
Structured
Project
Simple
Project
Ladder
SFC
ST
Structured
Project
Ladder
SFC
Structured ladder/
FBD
ST
*1: MELSAP3 and FX series SFC only
Outline Details
*1
Outline Details
Outline
Details
Outline Details
*1
Outline
Details
Outline
Details
Outline
Details

1-4 1.2 Purpose of This Manual
(3) Details of instructions in each programming language (for QCPU (Q mode)/LCPU)
Purpose
MELSEC-
Q/L/F
Structured
Programming
Manual
MELSEC-Q/L
Structured Programming Manual
MELSEC-
Q/L
Programming
Manual
MELSEC-Q/L/QnA
Programming Manual
MELSEC-Q
Programming
/Structured
Programming
Manual
Manual for
module to
be used
Fundamentals
Common
Instructions
Special
Instructions
Application
Functions
Common
Instructions
PID Control
Instructions
SFC
Process
Control
Instructions

All
languages
Learning details of
programmable
controller CPU
error codes,
special relays, and
special registers
Using
ladder
language
Learning the types
and details of
common
instructions
Learning the types
and details of
instructions for
intelligent function
modules
Learning the types
and details of
instructions for
network modules
Learning the types
and details of
instructions for the
PID control
function
Learning the types
and details of the
process control
instructions
Using SFC
language
Learning details of
specifications,
functions, and
instructions of SFC
(MELSAP3)
Using
structured
ladder/FBD
/ST
language
Learning the
fundamentals for
creating a
structured program
Learning the types
and details of the
common
instructions
Learning the types
and details of
instructions for
intelligent function
modules
Learning the types
and details of
instructions for
network modules
Learning the types
and details of
instructions for the
PID control
function
Learning the types
and details of
application
functions
Learning the types
and details of the
process control
instructions
*1: Refer to the User's Manual (Hardware Design, Maintenance and Inspection) for the CPU module used.
Details
*1
Details
Details
Details
Details
Details
Details
Details
Details
Outline
Details
Outline
Details
Outline Details
Details
Details

1.2 Purpose of This Manual
1-5
1
OVERVIEW
(4) Details of instructions in each programming language (for FXCPU)
Purpose
MELSEC-
Q/L/F
Structured
Programming
Manual
FXCPU Structured Programming
Manual FXCPU Programming Manual
Fundamentals
Device &
Common
Basic &
Applied
Instruction
Application
Functions
FX0, FX0S,
FX0N, FX1,
FXU, FX2C
FX1S, FX1N,
FX2N,
FX1NC,
FX2NC
FX3S, FX3G,
FX3U,
Fx3GC,
FX3UC
Using ladder
language
Learning the types
and details of basic/
application
instructions,
descriptions of
devices and
parameters
Using SFC
language
Learning details of
specifications,
functions, and
instructions of SFC
Using
structured
ladder/FBD/
ST
language
Learning the
fundamentals for
creating a structured
program
Learning the
descriptions of
devices, parameters,
and error codes
Learning the types
and details of
sequence
instructions
Learning the types
and details of
application functions
Details
Details
Details
Details Details
Details
Details
Details
Details
Details

1-6 1.3 Terms
1.3 Terms
This manual uses the generic terms and abbreviations listed in the following table to discuss the
software packages and programmable controller CPUs. Corresponding module models are also
listed if needed.
Term Description
GX Works2
The product name of the software package for the MELSEC programmable controllersGX Developer
GX IEC Developer
Basic model QCPU A generic term for the Q00JCPU, Q00CPU, and Q01CPU
High Performance model
QCPU A generic term for the Q02CPU, Q02HCPU, Q06HCPU, Q12HCPU, and Q25HCPU
Process CPU A generic term for the Q02PHCPU, Q06PHCPU, Q12PHCPU, and Q25PHCPU
Redundant CPU A generic term for the Q12PRHCPU and Q25PRHCPU
Universal model
QCPU
A 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
High-speed Universal
model QCPU A generic term for the Q03UDVCPU, Q04UDVCPU, Q06UDVCPU, Q13UDVCPU, and Q26UDVCPU
QCPU (Q mode) A generic term for the Basic model QCPU, High Performance model QCPU, Process CPU, Redundant
CPU, and Universal model QCPU
LCPU A generic term for the L02SCPU, L02SCPU-P, L02CPU, L02CPU-P, L06CPU, L06CPU-P, L26CPU,
L26CPU-P, L26CPU-BT, and L26CPU-PBT
FXCPU A generic term for MELSEC-FX series programmable controllers
(FX0S, FX0, FX0N, FX1, FX1S, FX1N, FX1NC, FXU, FX2C, FX2N, FX2NC, FX3S, FX3G, FX3GC, FX3U, FX3UC)
CPU module A generic term for the QCPU (Q mode), LCPU, and FXCPU
QnU(D)(H)CPU A generic term for the Q02UCPU, Q03UDCPU, Q04UDHCPU, Q06UDHCPU, Q10UDHCPU,
Q13UDHCPU, Q20UDHCPU, and Q26UDHCPU
QnUDVCPU A generic term for the Q03UDVCPU, Q04UDVCPU, Q06UDVCPU, Q13UDVCPU, and Q26UDVCPU
QnUDE(H)CPU A generic term for the Q03UDECPU, Q04UDEHCPU, Q06UDEHCPU, Q10UDEHCPU,
Q13UDEHCPU, Q20UDEHCPU, Q26UDEHCPU, Q50UDEHCPU, and Q100UDEHCPU
Personal computer The generic term for personal computers where Windows®operates
IEC 61131-3 The abbreviation for the IEC 61131-3 international standard
Common instruction
A generic term for the sequence instructions, basic instructions, application instructions, data link
instructions, multiple CPU dedicated instructions, multiple CPU high-speed transmission dedicated
instructions, and redundant system instructions
Special instruction A generic term for the module dedicated instructions, PID control instructions, socket communication
function instructions, built-in I/O function instructions, and data logging function instructions
Application function A generic term for the functions, such as functions and function blocks, defined in IEC 61131-3.
(The functions are executed with a set of common instructions in a programmable controller.)

1.4 Features of Structured Programs
1-7
1
OVERVIEW
1.4 Features of Structured Programs
This section explains the features of structured programs.
(1) Structured design
A structured design is a method to program control content performed by a programmable
controller CPU, which are divided into small processing units (components) to create
hierarchical structures. A user can design programs knowing the component structures of
sequence programs by using the structured programming.
The following are the advantages of creating hierarchical programs.
• A user can start programming by planning the outline of a program, then gradually work
into detailed designs.
• Programs stated at the lowest level of a hierarchical design are extremely simple and
each program has a high degree of independence.
The following are the advantages of creating structured programs.
• The process of each component is clarified, allowing a good perspective of the program.
• Programs can be divided and created by multiple programmers.
• Program reusability is increased, and it improves the efficiency in development.
(2) Multiple programming languages
Multiple programming languages are available for structured programs. A user can select
the most appropriate programming language for each purpose, and combine them for
creating programs.
Different programming language can be used for each POU.
Table 1.4-1 Programming languages that can be used for structured programs
For outlines of the programming languages, refer to the following section.
Section 4.2.7. Programming languages for POUs
For details on each programming language, refer to the following chapter.
Chapter 5. WRITING PROGRAMS
The ladder/SFC languages used in the existing GX Developer and Simple projects of GX
Works2 can be used.
For details on writing programs, refer to the following manuals.
Programming manuals for each CPU
(3) Improved program reusability
Program components can be stored as libraries. This means program assets can be utilized
to improve the reusability of programs.
Name Description
ST (structured text) A text language similar to C language, aimed for computer engineers.
Structured ladder A graphic language that is expressed in form of ladder by using elements such as contacts and coils.
FBD A graphic language that is expressed in form of ladder by connecting elements such as functions and
function blocks with lines.

1-8 1.5 Applicable CPU Modules
1.5 Applicable CPU Modules
The following table shows the applicable CPU modules for programs in the Structured project.
Table 1.5-1 Applicable CPU modules
1.6 Compatible Software Package
The following programming tool is used for creating, editing, and monitoring the programs in the
Structured project.
Table 1.6-1 Compatible software package
(1) What is GX Works2?
GX Works2 is a software package used for editing and debugging sequence programs,
monitoring programmable controller CPUs, and other operations. It runs on a personal
computer in the Microsoft®Windows®Operating System environment.
Created sequence programs are managed in units of 'projects' for each programmable
controller CPU. Projects are broadly divided into 'Simple project' and 'Structured project'.
This manual explains the basic programming by referring the Structured project in
GX Works2.
Programmable controller type
Basic model QCPU Q00JCPU, Q00CPU, Q01CPU
High Performance model QCPU Q02CPU, Q02HCPU, Q06HCPU, Q12HCPU, Q25HCPU
Process CPU Q02PHCPU, Q06PHCPU, Q12PHCPU, Q25PHCPU
Redundant CPU Q12PRHCPU, Q25PRHCPU
Universal model QCPU
Q00UJCPU, Q00UCPU, Q01UCPU, Q02UCPU, Q03UDCPU,
Q03UDVCPU, Q03UDECPU, Q04UDHCPU, Q04UDVHCPU,
Q04UDEHCPU, Q06UDHCPU, Q06UDVCPU, Q06UDEHCPU,
Q10UDHCPU, Q10UDEHCPU, Q13UDHCPU, Q13UDVCPU,
Q13UDEHCPU, Q20UDHCPU, Q20UDEHCPU, Q26UDHCPU,
Q26UDVCPU, Q26UDEHCPU, Q50UDEHCPU, Q100UDEHCPU
LCPU L02SCPU, L02SCPU-P, L02CPU, L02CPU-P, L06CPU,
L06CPU-P, L26CPU, L26CPU-P, L26CPU-BT, L26CPU-PBT
FXCPU FX0S, FX0, FX0N, FX1, FX1S, FX1N, FX1NC, FXU, FX2C, FX2N,
FX2NC, FX3S, FX3G, FX3GC, FX3U, FX3UC
Software package name Model name
GX Works2 SW1DNC-GXW2-E

1
OVERVIEW
2
STRUCTURED DESIGN OF SEQUENCE PROGRAMS
3
PROCEDURE FOR CREATING PROGRAMS
4
PROGRAM CONFIGURATION
5
WRITING PROGRAMS
A
APPENDICES
I
INDEX
2
2-1
STRUCTURED DESIGN OF SEQUENCE PROGRAMS
2.1 What is a Hierarchical Sequence Program?. . . . . . . . . . . . . . . . . . . . . . . . . . . 2-2
2.2 What is a Structured Sequence Program? . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-3

2-2 2.1 What is a Hierarchical Sequence Program?
2.1 What is a Hierarchical Sequence Program?
The hierarchy is to create a sequence program by dividing control functions performed in a
programmable controller CPU into a number of levels.
In higher levels, the processing order and timing in a fixed range is controlled.
With each move from a higher level to a lower level, control content and processes are
progressively subdivided within a fixed range, and specific processes are described in lower
levels.
In the Structured project, hierarchical sequence programs are created with the configuration that
states the highest level as the project, followed by program files, tasks, and POUs (abbreviation
for Program Organization Units).
Project
POUs
Task (Initialization)
Initial process
Lamp test
Program file(Operationpreparation)
Task (StationA control)
Conveyor driveA
Data process A
Program file(StationA)
Task (StationB control)
Task (Indicator control)
Conveyor driveB
Data process B
Indicator output
Program file(StationB)
Initial process
Lamp test
Conveyor driveA
Conveyor driveB
Data process A
Data process B
Indicator output