Allen-Bradley Logix5000 Reference Manual page 66

Chapter 1 FactoryTalk Alarms and Events Logix-based Instructions (ALMD, ALMA)
Condition
prescan
instruction first scan
instruction first run
EnableIn is cleared
EnableIn is set
postscan
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Execution:
Condition
Prescan
Rung-condition-in is false
Rung-condition-in is true
Postscan
Function Block Action
All operator requests, timestamps, and delivery flags are
cleared.
All the xInAlarm parameters are cleared and all alarm
conditions are acknowledged.
No action taken.
No action taken.
The instruction does not execute.
EnableOut is cleared.
The instruction executes.
EnableOut is set.
No action taken.
Rockwell Automation Publication 1756-RM003N-EN-P - October 2011
Relay Ladder Action
The rung-condition-out is set to false.
All the xInAlarm parameters are cleared and all alarm conditions
are acknowledged.
All operator requests, timestamps, and delivery flags are cleared.
The instruction does not execute.
EnableOut is cleared.
The instruction executes.
EnableOut is set.
The rung-condition-out is set to false.
Structured Text Action
All operator requests, timestamps, and delivery flags are
cleared.
All the xInAlarm parameters are cleared and all alarm
conditions are acknowledged.
No action taken.
No action taken.
The instruction executes.
EnableOut is always set.
The instruction executes.
EnableOut is always set.
No action taken.