A NormalProcess: OK Alm: OK Ack: Ack

Alarm Occurs

Re-Alarm Process RTN Alarm Clears Operator Acks Alarm or Auto Ack

B UnackAlarmProcess: Alarm Alm: Alarm Ack: Unack

Operator Resets Alarm

C AckAlarmProcess: Alarm Alm: Alarm Ack: Ack

Operator Acks Alarm

Alarm Occurs

Process RTN Process RTN Alarm Clears

D RTN UnackProcess RTN Process: OK Alm: OK Ack: Unack Operator Resets Alarm Operator Acks Alarm

F Latch AckProcess: OK Alm: Alarm Ack: Ack

E Latch UnackProcess: OK Alm: Alarm Ack: Unack

Shelv e

Un-shelv e

Designed Suppression

Designed Un-suppression

Remov e f rom Serv ice

Return to Serv ice

G ShelvedProcess: N/A Alm: N/A

H Suppressed By DesignProcess: N/A Alm: N/A

I Out Of ServiceProcess: N/A Alm: N/A

Note 1: States G, H, and I can connect to any alarm state in the diagram. Note 2: The dotted line indicates an infrequently implemented option.

Figure 5 Alarm State Transition Diagram

ISA 18.02 2009 CDV 04/2009

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