Mitsubishi Electric MELSEC-Q Series Programming Manual page 46

• When a transition to the next step occurs before the reset instruction of the counter is executed, the present value of the
counter and the ON/OFF status of the contact are held if the corresponding step becomes inactive. To reset the counter,
use the RST instruction, etc. at another step.
PLS or P instruction used for the operation output of any step
The PLS or P instruction used for the operation output of any step is executed every time the corresponding step turns from
an inactive to an active status.
The program shown above is actually executed in a ladder as shown below. Because the step conditions contact is ON when
the step is active and OFF when the step is inactive, the PLS or P instruction will be executed every time the corresponding
step becomes active.
4 SFC PROGRAM CONFIGURATION
44
4.2 Steps
When the counter (C0) is reset at step "n+1" (or subsequent step), the present value
will be cleared, and the contact will be switched OFF.