Threshold Alert Block

| Overview

The Threshold Alert Block monitors a numeric value and generates an alert only when the value remains outside the configured threshold for a specified duration. This helps prevent false alarms caused by short-term spikes or dips.

The block includes built-in Hold Down and Fix Hold Down parameters, eliminating the need for separate Persist or Offset blocks in the sequence.

| Block parameters

Parameter	Description
Value	The numeric input being monitored.
Enable Upper Limit	Turns monitoring of the upper threshold on or off.
Upper Limit	The value above which an upper limit alert may be generated.
Upper Limit Hold Down (mins)	The time the value must continuously remain above the upper limit before an alert is generated.
Upper Limit Fix Hold Down (mins)	The time the value must continuously remain below the upper limit before the alert is cleared.
Enable Lower Limit	Turns monitoring of the lower threshold on or off.
Lower Limit	The value below which a lower limit alert may be generated.
Lower Limit Hold Down (mins)	The time the value must continuously remain below the lower limit before an alert is generated.
Lower Limit Fix Hold Down (mins)	The time the value must continuously remain above the lower limit before the alert is cleared.

| How the block works

Alert generation: When the monitored value crosses the configured upper or lower threshold, the block starts the corresponding Hold Down timer. The alert is generated only if the value remains outside the threshold for the full configured duration.
Timer reset: If the value returns to the normal range before the hold-down timer expires, the timer resets and the alert is not generated.
Alert clearance: Once an alert is active, the block starts the corresponding Fix Hold Down timer when the value returns to the normal range. The alert is cleared only if the value remains in range for the full configured duration.
Example configuration
Upper Limit: 78
Upper Limit Hold Down: 5 minutes
Upper Limit Fix Hold Down: 10 minutes
Lower Limit: 68
Lower Limit Hold Down: 3 minutes
Lower Limit Fix Hold Down: 5 minutes

| Example behavior

If the monitored value rises above 78 and remains above 78 for 5 minutes, an Upper Limit Alert is generated.
If the value drops below 78 before 5 minutes elapse, the hold-down timer resets and no alert is generated.
If the value later returns below 78 and remains below 78 for 10 minutes, the Upper Limit Alert is automatically cleared.

| Benefits

Reduces nuisance alerts from temporary fluctuations.
Provides independent timing control for high and low threshold violations.
Simplifies sequence creation by removing the need for separate Persist or Offset blocks.
Makes alert configurations easier to understand, maintain, and troubleshoot.

| Validation considerations

Ensure that Upper Limit and Lower Limit values are configured correctly for the monitored point.
Configure corresponding Fix Hold Down values to control when alerts should automatically clear.
Use appropriate hold-down durations based on the expected behavior of the monitored system.

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