Mitsubishi Electric MELSEC Q Series Programming Manual page 85

Precaution 2
When Q00UCPU, Q00UJCPU or, Q01UCPU is used, and the string type is applied to Boolean expression (conditional
expression) with conditional syntax or iteration syntax, a compilation error may occur.
■Program example which causes compilation error
ST program
Compilation error occurs
when specifying string type data.
To avoid a compilation error, create the function blocks of the string type comparison with ladder or structured ladder/FBD,
and apply the operation result of function blocks to the conditional expression of conditional syntax or iteration syntax.
The following is an example when creating the function blocks with structured ladder/FBD.
■Program creation example which avoids compilation error
1.
Create the function blocks of the string type comparison with structured ladder/FBD program
Function block (EQFB_01)
2.
Apply the operation result of function blocks (EQFB_01) to the conditional expression in ST program.
Label setting
ST program
Apply the operation result of
function blocks (EQFB_01)
5 WRITING PROGRAMS
5.1 ST
5
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