Ladder Branches And Compilation Results - Mitsubishi Electric MELSEC Q Series Programming Manual

Ladder branches and compilation results

When the ladder is branched, different compilation results are produced for the program after the branch depending on the
program up to the branch. The following explains the precautions on compilation results depending on ladder branches.
One contact is used up to the branch
The instruction of the contact is used multiple times in the compilation result.
< Example >
■Precautions
When the device in which the value changes during one scan (such as SM412) is used, only a part of the sequence program
after the branch is executed, and the rest of the sequence program may not be executed.
< Example >
When executing multiple instructions against one contact, connect the instructions in series. Since the sequence program
uses the LD instruction only once in the compilation result, all sequence programs are executed.
< Example >
< Compile Result >
< Compilation result >
< Compilation result >
If the value of SM412
changes during one scan,
a part of the program may
not be executed.
The LD instructions are
created using the contact.
5 WRITING PROGRAMS
5.2 Structured Ladder/FBD
5
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