Use the Persistence field near the top of the OPC tab to prevent a change in value from affecting the point state until the point has been in that state for a specified time. This allows the driver to ignore fleeting changes in point value, and prevents ClearSCADA raising change of state alarms and logging change of state events when a point value is fluctuating.
When the point changes value, any change of point state is delayed until the point remains in the new state for a specified amount of time. If the point does not remain in the new state for the required amount of time, no change in point state is recorded.
- Persistence—Use this field to specify the period, in seconds, that a point needs to remain in a new state before the Simple OPC driver updates the ClearSCADA database with a change of value.