Massaging OPC is necessary sometimes

摘要

Jonas Berge (SMAR) addressed Greg Potter's (Azimuth-Solutions) problems in developing OLE for process control (OPC) over a wide-area network to consolidate operations of two pipeline terminals. Potter said there was almost no information returned to the application (in this case, the operator interface) by the application program interface; hence the diagnostic information presented to the operator interface application was extremely limited, and third-party tools were necessary to observe what was going on within the communication system. Said Berge, OPC reports several error codes for problems with the OPC server as a whole, as well as a different status for each item (tag). It is also possible to check the overall OPC server state. Truth be told, not every OPC server out there is well implemented, and some of them may not propagate the diagnostics information. Different OPC clients have different abilities when it comes to displaying this information; some simply do not show you this information even if it is available in the OPC server.