Mitsubishi Electric MELSEC Q Series Structured Programming Manual page 94

(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
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
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➁
5.1 ST
5-12
5.1.6 Precautions when using conditional syntax and iteration syntax
Compilation error occurs
when specifying string type data.
Create the function blocks of the string type comparison with structured ladder/FBD
program.
Apply the operation result of function blocks (EQFB_01) to the conditional expression
in ST program.
ST program
Function block (EQFB_01)
Label setting
ST program
Apply the operation result of
function blocks (EQFB_01)