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AVEVA™ Plant SCADA

Supported Alarm Properties

  • Last UpdatedFeb 06, 2024
  • 4 minute read

The following properties can be used for every alarm type. Remember, the return value relates to the description. For example, for a digital, if 1 is returned, that means the description is TRUE, whereas 0 (zero) means it is FALSE.

Property

Description

Return Type

.On

Alarm active

The .On property for analog alarms is true if any alarms associated with the alarm tag are active.

Digital

.Ack

Alarm acknowledged

Digital

.AcqErr

Data acquisition error

Integer

.Category

Alarm category

Integer

.ComBreak

For Multi-Digital alarms, the property is set to 1 if the device cannot read data from the underlying tag at start-up for a time greater than [Alarm]ArgyleTagValueTimeout value. The property is set to 0 and re-alarms the corresponding alarm, when the alarm server receives valid data from the device.

For every Disabled and Display Disabled alarms (except Time Stamped Digital and Time Stamped Analog alarms) the property is set to 1, when they are being Enabled. The property is set to 0 and re-alarms the corresponding alarm, when the alarm server receives valid data from the device.

Digital

.Custom1
.Custom2
.Custom3
.Custom4
.Custom5
.Custom6
.Custom7
.Custom8

Custom Field.

String(64 bytes)

.Disabled

Alarm disabled (see note below)

Digital

.Historian

Alarm can be historized and published in CitectHistorian.

Digital

.Item

The name of the item with which the alarm is associated.

String

.Millisec

The milliseconds part of the time the alarm was triggered

Long

.Name

Alarm name

String (80 bytes)

.OnTime

The time the alarm was triggered.

Long

.Paging

Alarm paged

Boolean

.PagingGroup

Paging group alarm belongs to.

String (80 bytes)

.Priority

Alarm priority

Integer

.State

An alarm's state value. An alarm state value is a combination of state enumeration and action bit masks described below.

State enumerations

0 – Alarm OFF state or state 000 for Multi-Digital alarm

1 – Alarm ON state or state 00A for Multi-Digital alarm

2 – State 0B0 for Multi-Digital alarm

3 – State 0BA for Multi-Digital alarm

4 – State C00 for Multi-Digital alarm

5 – State C0A for Multi-Digital alarm

6 – State CB0 for Multi-Digital alarm

7 – State CBA for Multi-Digital alarm

8 – Analog deviation from set point High

9 – Analog deviation from set point low

10 – Analog rate of change alarm state

11 – Analog low limit alarm state

12 – Analog high limit alarm state

13 – Analog low low limit alarm state

14 – Analog High High limit alarm state

Alarm action masks

32 – Unable to get the status of underlying tag at start-up

64 – Alarm cleared bit mask

128 – Alarm acknowledged but held

256 – Alarm unacknowledged bit mask

512 – Alarm disabled bit mask

1024 – Argyle type alarm bit mask

2048 – Argyle type alarm ON bit mask

4096 – Analog alarm threshold value changed

8192 – User generated event

16384 – Event already logged

32768 – Disable the alarm display

Example:

A digital alarm called "AlmDigital1" that is ON and unacknowledged, the value of the state property will be:

AlmDigital1.State = 1 (ON state) + 256 (Unacknowledged alarm) = 257

Short

.Tag

Alarm tag

String (80 bytes)

.Time

The time at which the alarm changed state (hh:mm:ss).

You can use the following parameters to change this default behavior:

[Alarm]SetTimeOnAck — sets the property to the time the alarm is acknowledged.

[Alarm]SetTimeOnOff — sets the property to the time the alarm becomes inactive.

Long

Note: Once an alarm is disabled, it cannot be re-enabled unless you use the function AlarmEnable or AlarmEnableRec.

For digital alarms, time stamped alarms, time stamped digital alarms, multi digital alarms, advanced alarms and double point status alarms, the following property can also be used.

Property

Description

Return Type

.Desc

Alarm description

String (128 bytes)

Note: Desc exists for every alarm type but will not return meaningful data for analog or time-stamped analog alarms.

For digital alarms, time-stamped digital alarms, advanced alarms and double point status alarms,the following property can also be used.

Property

Description

Return Type

.Delay

Alarm delay

Long

For analog alarms and time-stamped analog alarms, the following properties can also be used.

Property

Description

Return Type

.DevDelay

Deviation delay

Long

.DeadBand

Deadband

Real

.Deviation

Deviation

Real

.HighHigh

High High

Real

.High

High

Real

.LowLow

Low Low

Real

.Low

Low

Real

.HHDelay

High High delay

Long

.HDelay

High delay

Long

.LDelay

Low delay

Long

.LLDelay

Low Low delay

Long

.Rate

Rate

Real

.Setpoint

Setpoint

Real

.Value

 Alarm tag Value

Real

For the digital properties below, only one can be true at any point in time for each alarm. They are arranged in order of priority, from lowest to highest.

.DVL

Deviation alarm triggered (Low)

Digital

.DVH

Deviation alarm triggered (High)

Digital

.R

Rate of Change alarm triggered

Digital

.L

Low alarm triggered

Digital

.H

High alarm triggered

Digital

.LL

Low Low alarm triggered

Digital

.HH

High High alarm triggered

Digital

Note: DVL and DVH are only evaluated if Deviation > 0. R is only evaluated if Rate > 0.

Some alarm properties return configuration data. If the user has not defined this information, the following defaults are provided:

Property

Default

.Setpoint

0

.HighHigh

3.4e+38

.High

3.4e+38

.LowLow

-3.4e+38

.Low

-3.4e+38

.Rate

0

.Deviation

0

.Deadband

0

.Category

0

.Priority

0

See Also

Write to Alarm Properties

Set Up Alarm Properties

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