Mitsubishi Electric FX2N-32CAN, Руководство по обучению

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3.3
Programming Languages
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
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Instruction List (IEC and MELSEC)
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Structured Text
Graphic Editors
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Ladder Diagram
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Function Block Diagram
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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:
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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.
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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.
Programming Programming Languages
Training Manual GX IEC Developer 3 - 11