The @MOV (or any instruction with an @ in front) will execute ONCE per false-to-true transition of the input condition(s).
Example LD 0001 MOV 113 DM100 will constantly - every scan - copy the contents of address 113 to address DM100, until the input 001 goes off.
What you will get in DM100 is the value that was in 113 _just_ before the input went off.
Eg: with MOV
scan # - IN0001 - 113 - DM100
1 off 10 0 (or last saved value)
2 on 20 20
3 on 30 30
4 off 40 30
Eg: with @MOV
scan # - IN0001 - 113 - DM100
1 off 10 0 (or last saved value)
2 on 20 20
3 on 30 20
4 off 40 20
Hope it helps!
RT