Rockwell Automation Publication 1756-RM003N-EN-P - October 2011 503
Special Instructions (FBC, DDT, DTR, PID) Chapter 13
Execution:
Condition: Relay Ladder Action
Prescan
End
Compare.EN bit is cleared.
Compare.FD bit is cleared.
Rung-condition-out is set
to false.
Examine
Compare.DN bit.
Compare.DN = 0
Compare.DN = 1
Compare.DN bit is cleared.
Compare.POS value is cleared.
Result.DN bit is cleared.
Result.POS value is cleared.