With the release of version 7.20, CitectSCADA supports the retrieval of time-stamped data directly from field devices. This capability is enabled by the Driver Runtime Interface (DRI), a component that is used by the following device drivers:
Note: Check with Technical Support if new drivers are available that support the DRI.
The DRI allows a driver to push time-stamped data from field devices into a CitectSCADA system. This means time-stamped digital alarms, time-stamped analog alarms and event-based trends can be updated directly from devices.
No configuration is necessary, as when these drivers start up they scan the system for time-stamped digital alarms, time-stamped analog alarms and event-based trends. If the driver receives updated information for any detected tags, it will pass it directly on. Regular I/O server polling is no longer used.
This mechanism can work in tandem with the tag extension feature (also introduced in version 7.20) to enable access to field-generated timestamp and quality tag values (see Tag Extensions).
Note: Prior to version 7.20, time-stamped data was manually pushed into CitectSCADA using the Cicode functions AlarmNotifyVarChange and TrnSetTable. If you are upgrading a project to a version 7.20 system with a driver that uses the new DRI push mechanism, you will no longer need to use these functions.
IO Server parameters
Events pushed from a DRI-supported driver can be buffered on an I/O server while an alarm or trend server is offline. The way this mechanism operates can be configured via the following parameters:
For more information, see IOServer Parameters.