ISA 18.2 Alarm State Transition Diagram
Hyper Alarm Server supports ISA 18.2-2009 alarms state machine in two modifications—full modification and without a Latch. The diagram depicts the full modification.
Alarm states show letter identifiers (A, B, C, D...), the abbreviated state name, the process conditions, and the alarm status and acknowledgment.
Updates to Alarm Messages (ISA 18.2 State Machine)
The table correlates with all the states and transitions in the ISA 18.2 state machine. Each column specifies if the alarm message field is updated from its related inputs (Yes) or stays unmodified (NO) from its previous state. Not applicable (NA) indicates transitions are unsupported or do not apply. Audible bit behavior values are also assigned to each ISA 18.2 alarm state.
Audible bit Behavior for in individual alarm states
|
ISA 18.2 Alarm State |
Audible Bit ID |
|---|---|
|
Normal |
0 |
|
Unacknowledged |
1 |
|
Acknowledged |
0 |
|
Return to Normal State Unacknowledged |
0 |
|
Latch Unacknowledged |
1 |
|
Latch Acknowledged |
0 |
|
Shelved |
0 |
|
Suppressed by Design |
0 |
|
Out-of-Service |
0 |