Flatline alarming

Analog instruments and rate instruments register a value that increases or decreases depending on process conditions. AVEVA Enterprise SCADA can monitor the change in this value. The change is determined by subtracting the last scanned value from the current value. A flatline alarm is generated if the analog or rate value does not change within a specified time period (timeout).

Note: The flatline monitoring process runs once a minute; therefore, you can delay the generation of a flatline alarm by one minute.

Important: Flatline alarms and the Processing Deadband enhancement cannot be used at the same time. For information on the enhancement, refer to Processing Deadband enhancement.

Flatline Alarm Message

The message text that indicates that an analog, a rate, a status, or a reservoir record is in a flatline alarm:

Analog: (or Rate: or Reservoir: or Status:) <name> in Flatline state for N minutes. Value = M

Where:

• <name> = The name of the point.

• N = The configured timeout

• M = The point value. Alarm Severity: High

The message text that indicates that an analog, a rate, a status, or a reservoir record returned from a flatline alarm:

Analog: (or Rate: or Reservoir: or Status:) <name>: RTN from state. Value = M

Alarm Severity: Low.

Flatline Alarm Conditions

A flatline alarm is declared when an analog or rate record value does not change within a configured amount of time (timeout).

A flatline alarm is not declared, if the flatline alarm is disabled or the record is:

• Manual-entry or calculated

• In instrument failure

• Offscan

• Manual

• Configured to have a timeout of zero

• Stale