Chapter 1 Overview - Mitsubishi Electric MELSEC iQ-R Series Programming Manual

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OVERVIEW
This manual describes program configurations, contents, and coding methods required for programming.
For information on creating, editing, and monitoring programs using an engineering tool, refer to the following.
 GX Works3 Operating Manual
Programming languages
With the MELSEC iQ-R series, an optimal programming language can be selected and used according to the application.
Programming language
Ladder diagram (Ladder)
Structured text language (ST)
Function block diagram/ladder diagram (FBD/LD)
Sequential function chart (SFC program)
■ Ladder diagram (Ladder)
For details, refer to the following.
Page 54 LADDER DIAGRAM
■ Structured text language (ST)
For details, refer to the following.
Page 59 STRUCTURED TEXT LANGUAGE
Description
A graphic language which describes ladders consisting of contacts and coils.
This language is used to describe logical ladders using symbolized contacts and coils to enable
easy-to-understand sequence control.
A textual language used to describe programs using statements (such as IF) and operators.
Compared with the ladder diagram, this language can describe hard-to-describe operation
processing concisely and legibly, and therefore is suitable for programming complicated
arithmetic operations and comparison operations. Also, as with C, ST language can describe
syntax control such as selective branches with conditional statements and repetitions with
iteration statements, and thus can describe easy-to-understand, concise programs.
A graphic language which describes programs by connecting blocks that perform predefined
processing, variable elements, and constant elements along the flow of data and signals.
This language facilitates programming of DDC (direct digital control) processing which is difficult
to describe in ladder diagram, and improves the productivity of programs.
SFC is a program description format in which a sequence of control operations is split into a
series of steps to enable a clear expression of each program execution sequence and execution
conditions.
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