The Move (MOV) is an output instruction in ladder logics moves the source value to the destination location. As long as the rung remains true, the instruction moves the data each scan.
Move (MOV) Instruction
Source is the address or constant of the data you want to move.
Destination is the address where the instruction moves the data.
If you wish to move one word of data without affecting the math flags, use a copy (COP) instruction with a length of 1 word instead of the MOV instruction.
Using MOV for Variable Initialization
S:1/15 is a bit in the status date file that is energized for exactly one PLC scan when the PLC is placed in run mode.
It Can be used to condition the initialization of variables used elsewhere in the ladder logic.