Alarm state
Description
Alarm condition*
Alarm**
E
Unacknowledged latched alarm
No
Active
F
Acknowledged latched alarm
No
Active
*Note: The alarm condition that triggers the alarm, typically the
Set point,
may be present
Yes
or not present
No
.
**Note: Any alarm may be
Active
or
Inactive
in the system. If active the alarm
Action
is also active.
INFO
Inhibited, shelved, or out of service alarm states force the alarm to be
Inactive
in the system, even if the
Alarm condition
is
still present.
Automatic actions
The controller's alarm handling system can perform the following automatic actions:
•
Horn/siren output
•
Inhibit
•
Auto acknowledge
•
Control alarm state
•
Suppress action
More information
See
Horn outputs
later in this chapter for more information on the alarm horn outputs.
Operator alarm actions
An operator can perform the following alarm actions:
•
Acknowledge
•
Shelve
•
Out of service
•
Latch reset
•
Silence alarm horn/siren
INFO
Alarm actions are controlled by the group and user permissions.
4.4.2 Acknowledge
Alarms that have no
Auto acknowledge
require acknowledging by operator action. The operator must take action regarding the
alarm condition. The operator can mark the alarm as
acknowledged
.
INFO
Acknowledging an alarm has no influence on the alarm
Action
.
DESIGNER'S HANDBOOK 4189340911K UK
Page 105 of 521