How to change the update rate for variables read from an OPC server in Vista server.

Issue

How to change the update rate for variables read from an OPC server in Vista server.  Vista in this case is running as the OPC client and therefore determines the request rate from the OPC server.

Product Line

TAC Vista

Environment

Vista 5.1.X

OPC client (built in in Vista)

3rd party OPC server.

Cause

To optimise communication loads and efficiency it may be desirable to set the update interval for values read from an OPC server. A user may wish to reduce the update from a couple of milliseconds to 1 minute for example for values that don't fluctuate that much.

Resolution

The default value (which can be found on the Properties tab for the OPC server object in Vista under "Requested Update rate (ms) ) is set to 0ms. This is effectively "update as often as possible" and the actual update rate can be seen under the "Actual Update rate" property. To select another update interval, simply set "Requested Update Rate (ms)" to the desired value.