496 Rockwell Automation Publication 1756-RM003N-EN-P - October 2011
Chapter 13 Special Instructions (FBC, DDT, DTR, PID)
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.