Relay ladder rung condition – Rockwell Automation 1794-Lxxxx PhaseManager User Manual
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Publication LOGIX-UM001B-EN-P - April 2010
Appendix A
Equipment Phase Instructions (PSC, PCMD, POVR, PFL, PCLF, PXRQ, PRNP, PPD, PATT, PDET)
Relay Ladder Rung Condition
The controller evaluates ladder instructions based on the rung condition
preceding the instruction (rung-condition-in). Based on the rung-condition-in
and the instruction, the controller sets the rung condition following the
instruction (rung-condition-out), which in turn, affects any subsequent
instruction.
If the rung-in condition to an input instruction is true, the controller evaluates
the instruction and sets the rung-out condition based on the results of the
instruction. If the instruction evaluates to true, the rung-out condition is true;
if the instruction evaluates to false, the rung-out condition is false.
input instruction
rung-in
condition
output instruction
rung-out
condition