Programming Languages; Text Editors - Mitsubishi Electric FX Series Training Manual

Programming

Programming Languages

3.3
GX IEC Developer provides separate editors for all the following programming languages,
which can be used to program the bodies of your programs:

Text Editors

b Instruction List (IEC and MELSEC)
b Structured Text
Graphic Editors
b Ladder Diagram
b Function Block Diagram
b Sequential Function Chart
With the exception of the Sequential Function Chart language, all the editors divide PLC pro-
grams into sections, referred to as "Networks". These Networks can be given names (labels),
which can consist of up to a maximum of 8 characters terminated with a colon (:). These net-
works are numbered consecutively and can be used as destinations for branching commands.
3.3.1 Text Editors
Instruction List (IL)
The Instruction List (IL) work area is a simple text editor with which the instructions are entered
directly.
An Instruction List consists of a sequence of statements or instructions. Each instruction must
contain an operator (function) and one or more operands. Each instruction must begin in a new
line. You can also add optional Labels, Modifiers and comments to each instruction.
Two different types of Instruction List are used:
b IEC Instruction List
IEC Instruction Lists are entered and edited in exactly the same way as MELSEC Instruc-
tion Lists. The following programming differences need to be observed, however:
– MELSEC networks in IEC IL
You can include MELSEC networks in IEC Instruction Lists, thus providing access to
the MELSEC system instructions.
– The accumulator
The accumulator is a result management system familiar from high-level languages.
The result of every operation is stored in the bit accumulator directly after execution of
the instruction. The accumulator always contains the operation result of the last instruc-
tion executed. You do not need to program any input conditions (execution conditions)
for the operations; execution always depends on the content of the accumulator.
For more information about IEC Instruction List, please refer to chapter 15.
b MELSEC Instruction List
MELSEC Instruction Lists are entered and edited in exactly the same way as IEC Instruc-
tion Lists. However, you can only use the MELSEC instruction set; IEC standard program-
ming is not possible.
Training Manual GX IEC Developer
Programming Languages
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