About periodic time events
- Last UpdatedApr 07, 2025
- 2 minute read
The periodic time event item enables you to define an event that occurs periodically, that is, repeats at regular intervals.
Uses for periodic timers
In general, there are three main uses for timers:
-
As a trigger for a capture condition.
-
As a trigger for an executable, such as a function or a code item.
-
As a trigger for evaluating an expression, such as a variable.
Use a periodic timer to trigger a capture condition
You can use a periodic time event to trigger data capture in a capture condition. Data is captured every time the timer turns ON for the length of time specified in the Duration property .
The following graph shows a 1 minute timer that turns on every minute for 10 seconds. In each 1 minute cycle the timer is True for 10 seconds and False for 50 seconds before the timer fires again.
Use a periodic timer to trigger an executable
Another use for the periodic time event is to use as a trigger for an executable, such as:
-
Action item. For more information, see About actions.
-
Code item. For more information, see About code items
You can point to a periodic time event, specified by the Dependencies property, to configure an action item to execute a code item, specified by the Function property, periodically. This method doesn't return a data result. Each time the periodic timer becomes True, the action item executes the code as defined in the code item.
Use a periodic timer to evaluate an expression
A third use for the periodic time event is to trigger the evaluation of an expression, in items such as variables.
-
Accumulator variable
-
Calculated variable
-
Integral variable
In the case of variables, you can configure a timer as a dependency to trigger the expression that is defined by the variable. The variable can then pass the result to a recipient within AVEVA Production Management, such as a field.
You can specify the timer on the Dependencies tab of the HistoricalExpression property dialog box.
