Configure Event Trends for a DRI Driver

If a variable tag is associated with a driver that supports the Driver Runtime Interface (see Retrieving Time-stamped Data from I/O Devices), you can define a trend tag as pure-event trend.

This means each sample value and timestamp is automatically populated to the trend tag by the driver whenever the I/O value changes.

To define a pure-event trend:

1. Follow the procedure described in Add a Trend Tag.

2. Set the trend Type to "TRN_EVENT".

3. Set the Expression to a variable tag from an I/O device that uses a DRI driver.

4. Set the Trigger to blank.

Under this configuration, trend sample updates are controlled by the driver. The Deadband setting will be based on what is defined in the variable tag instead of the trend tag.

See Also

Trend Interpolation

Create Pages for Trend Graphs