Controller-Based Alarm Execution - Allen-Bradley Logix5000 Reference Manual

Chapter 1 FactoryTalk Alarms and Events Logix-based Instructions (ALMD, ALMA)
Controller-based Alarm
Execution
Source
Alarm tag members
Client messages
82
Controller-based alarms process inputs from two sources.
Description
Alarm tag members are, for the most part, processed when the user application scans the alarm
instruction. This includes:
· processing changes to configuration parameters.
· evaluating the alarm condition.
· measuring elapsed time for MinDuration.
· capturing InAlarmTime and RetToNormalTime timestamps.
· capturing associated tag values.
· processing Prog and Oper commands.
In addition, these alarm tag status members are updated as alarm messages are delivered to each
subscriber, asynchronously to the program scan:
· DeliveryEN, DeliveryER, DeliveryDN
· NoSubscriber, NoConnection, CommError, AlarmBuffered, SubscNotified
Client messages are processed as they are received, asynchronously to the program scan:
· Reset, Acknowledge, Disable/Enable, and Suppress/Unsuppress commands from an RSLogix
5000 terminal
· Reset, Acknowledge, Disable/Enable, and Suppress/Unsuppress commands from a FactoryTalk
View SE alarm subscriber
Rockwell Automation Publication 1756-RM003N-EN-P - October 2011