Specifications

5.1 ST
5.1.6 Precautions when using conditional syntax and iteration syntax
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WRITING PROGRAMS
5.1.6 Precautions when using conditional syntax and iteration syntax
The following explains the precautions when creating ST programs using conditional syntax and
iteration syntax.
(1) Once the conditions (boolean expression) are met in the conditional syntax or iteration
syntax, the bit device which is turned ON in the <syntax> is always set to ON.
• A program whose bit device is always set to ON
To avoid the bit device to be always set to ON, add a program to turn the bit device OFF as
shown below.
• A program to avoid the bit device to be always set to ON.
*1 The above program can also be written as follows.
Y0 := M0;
or
OUT(M0,Y0);
Note that, when the OUT instruction is used in <syntax> of conditional syntax or iteration syntax, the program
status becomes the same as the program whose bit device is always set to ON.
ST program
Structured ladder/FBD program
equivalent to ST program
ST program
*1
Structured ladder/FBD program
equivalent to ST program