In the DeltaV system, alarms have six potential states, determined by the values of the fields of the alarm parameter. The following table shows the relationship between the alarm states and values of the alarm parameter fields:
| State | OPSUP field | OOS field | ENAB field | CUALM field | LAALM field | NALM field |
|---|---|---|---|---|---|---|
|
Suppressed (1) |
0 ("NO") or1 ("YES") |
0 ("NO") or1 ("YES") |
0 ("NO") or1 ("YES") |
Determined by alarm state |
Determined by alarm state |
Forced to 0 ("NO") |
|
Disabled |
0 ("NO") |
0 ("NO") |
0 ("NO") |
Forced to 0 ("OK") |
Forced to 0 ("OK") |
Forced to 0 ("NO") |
|
Inactive acknowledged |
0 ("NO") |
0 ("NO") |
1 ("YES") |
0 ("OK") |
0 ("OK") |
0 ("NO") |
|
Active unacknowledged |
0 ("NO") |
0 ("NO") |
1 ("YES") |
Non-zero (alarm word) |
Non-zero (alarm word) |
1 ("YES") |
|
Active acknowledged |
0 ("NO") |
0 ("NO") |
1 ("YES") |
Non-zero (alarm word) |
Non-zero (alarm word) |
0 ("NO") |
|
Inactive unacknowledged |
0 ("NO") |
0 ("NO") |
1 ("YES") |
0 ("OK") |
Non-zero (alarm word) |
1 ("YES") |
Any time the state of an alarm changes, the system updates the alarm's information in the operating environment and generates an alarm state change event that can be recorded in the Event Chronicles.