Allen-Bradley LOGIX 5000 Reference Manual page 107

Process Control Instructions Chapter 1
Producing Output Pulses
The following diagram shows the three primary states of the POSP instruction.
Calculating Open and Close Pulse Times
OpenOut is pulsed whenever SP > Position feedback. When this occurs, the
instruction sets CloseTime = 0 and the duration for which OpenOut is to be
turned on is calculated as:
If OpenTimen-1 < CycleTime, then add Deadtime to OpenTime.
If OpenTime > MaxOnTime, then limit to MaxOnTime.
If OpenTime < MinOnTime, then set OpenTime = 0.
If any of the following conditions exist, OpenOut is not pulsed and OpenTime =
0.
OpenFB is true or PositionPercent 100
CycleTime = 0
OpenRate = 0
Rockwell Automation Publication 1756-RM006K-EN-P - November 2018 107