An alarm type defines a set of characteristics that determine how alarms appear on displays and in the Event Chronicle. Each standard alarm is associated with one of these alarm types. If you create a custom alarm, you select or create the alarm type associated with it. Device alarms do not require alarm types. The alarm words are defined by the device's definition data, and the information communicated from the device is automatically converted into device alarm messages.
Note that the alarm type does not define a custom alarm calculation for the alarm, you must define the alarm calculation for custom alarms. A single alarm type can be assigned to several alarms to give them the same display characteristics.
There are 19 predefined alarm types. You can use these alarm types as they are, modify them, or create additional ones. Alarm type names are case sensitive.
| Alarm type name | Alarm word | Category | Alarm message |
|---|---|---|---|
|
Adapt Alarm Active |
ADAPT |
INSTRUMENT |
Adapt Alarm Active %P1 |
|
Advanced Alarming |
ALARM |
PROCESS |
Any Alarm Value %P1 |
|
Any Alarm |
ANY |
SYSTEM |
Any Alarm Value %P1 |
|
Change From Normal |
CFN |
PROCESS |
Change From Normal Value %P1 |
|
Change of State |
COS |
PROCESS |
Change of State |
|
Communication Error |
COMM |
INSTRUMENT |
Communication Error |
|
Deviation Alarm |
DEV |
PROCESS |
Deviation Alarm Target %P1 Actual %P2 |
|
Discrete Device |
FAILED |
PROCESS |
%P1 |
|
Floating Point Error |
FLT |
SYSTEM |
Floating Point Error |
|
General I/O Failure |
IOF |
INSTRUMENT |
General I/O Failure |
|
High Alarm |
HIGH |
PROCESS |
High Alarm Value %P1 Limit %P2 |
|
High High Alarm |
HIHI |
PROCESS |
High High Alarm Value %P1 Limit %P2 |
|
Inspect Limit Active |
INSPECT |
INSTRUMENT |
Inspect Limit Active %P1 |
|
Low Alarm |
LOW |
PROCESS |
Low Alarm Value %P1 Limit %P2 |
|
Low Low Alarm |
LOLO |
PROCESS |
Low Low Alarm Value %P1 Limit %P2 |
|
New Alarm |
NEW |
SYSTEM |
New Alarm Value %P1 |
|
Open Circuit Detected |
OCD |
INSTRUMENT |
Open Circuit Detected |
|
Overrange |
OVER |
INSTRUMENT |
Overrange Value %P1 |
|
Rate of Change |
RATE |
PROCESS |
Rate of Change Rate %P1 Limit %P2 |
|
Statistical Alarm |
ERROR |
SYSTEM |
Statistical Alarm Type %P1 Value %P2 |
|
Underrange |
UNDER |
INSTRUMENT |
Underrange Value %P1 |
%P1 and %P2 represent the values of user-defined parameters. When configuring an alarm with Control Studio, check to see if the alarm message expects any user-defined parameters. If so, configure which parameter in that module should be read at the time of alarm detection to replace the %P1 (and %P2) in the alarm message. User-defined parameters typically capture the value that caused the alarm, the limit value that was in effect at the time the alarm was detected, and so on.
When the custom alarm requires a message that is different from the available Alarm Types messages, you must create a new alarm type. Before trying to use the alarm type in assigning an alarm to a module, you must create the new alarm type.
The following figure shows the dialog in the Explorer for an alarm type.
An alarm type defines the following:
Appears in the operating environment when the alarm is active or unacknowledged. The alarm word can appear in the alarm banner, the Alarm List picture, and in the detail and faceplate displays for the standard DeltaV modules. When you create a custom display or an Alarm List, you have the option to configure the alarm word or the alarm name to appear in the display.
Although device and hardware alarms do not have an alarm type, they do have one of the following alarm words: COMM, FAILED, MAINT, ADVISE, and ABNORM (device alarm only).
Appears in the Event Chronicle for every alarm state change. You can use the category for sorting and filtering alarm data inside Event Chronicle.
Appears in the standard Alarm List picture. The alarm message is defined as the Description field. The message is also logged in the Event Chronicle.
For process alarms, the alarm message is a combination of text strings and variables that you supply in the following form:
text string %P1 text string %P2
where %P1 and %P2 represent parameter values. You define the parameters in the Optional Alarm Message Parameters section of the Alarm Type Properties dialog through the Explorer.
For example, if you want the operator to see a message like the following for an alarm:
High Alarm 80 Alarm Limit 72
you would type the following in the alarm message box:
High Alarm %P1 Alarm Limit %P2
and use the following parameters for %P1 and %P2:
Parameter 1: PV
Parameter 2: HI_LIM
For process alarms, the alarm message affects all the alarms associated with the alarm type unless you override both the message and message parameters for a specific alarm in Control Studio.
For device alarms, the alarm message is determined by the information available from the device for the most recent condition that caused the alarm. A device can report multiple alarms (for example, Failed, Maintenance and Advisory). Fieldbus devices that support PlantWeb alerts and the reannunciation feature report subsequent condition changes associated with the same alarm (Failed, Maintenance, or Advisory). This results in an unacknowledged alarm state. All other fieldbus devices do not report a second condition until the first condition clears.
Device alerts are resynchronized when you download the device or when communication with the device is disrupted and then restored. When resynchronization occurs, the alert condition reported may not be the most recent because the reporting order is not available in the device.