Very Basic Instruction in STEP7

Plectrotion

What is the difference between OR /AND instruction in the first line of the code.

A M 0.0
XN M 0.1
= M 0.2


and following


O M 0.0
XN M 0.1
= M 0.2

The First check (the first code after a assignment or a conditional statement )
has a specific meaning for the CPU and CPU gets this value as the new
RLO and the previous RLO will be lost. So it is not important to use
AND ,OR,XOR in the first check. Just, for clarity of codes it is preferred
the operation (AND ,OR,XOR ) selected at first check should be same as
desired operation.

Best regards