OFS Group Management

The OFSOPC driver uses OFS groups to prioritize and manage device communication.

For each device instance, the driver creates three groups in OFS, each with a different update rate. Items are then allocated to a group according to a detected polling rate. For example, status tags and heavily sampled items fall into the fastest group, rarely accessed items are added to the slowest group.

The subscription rate used for each Plant SCADA tag is then adjusted to match the polling rate set for the group to which the related OFS item is allocated. Tags will be dynamically moved between the groups in response to changes in demand for an item.

It is possible to manually adjust the update rate for each group either globally or per I/O device. This requires adjustments to the citect.ini file, and is only recommended for advanced users.

See Group Management Parameters.