īy 2002, the specification was compared to Fieldbus and other previous standards. The OPC Alarms and Events specification is maintained by the OPC Foundation, and defines the exchange of alarm and event type message information, as well as variable states and state management. In contrast to the real time data that is accessible with OPC DA, OPC HDA allows access and retrieval of archived data. In addition OPC DA specification, the OPC Foundation maintains the OPC Historical Data Access (HDA) specification. However, a client could be written that does not support the older functions since everything can be done using the newer ones, thus a DA-3-compatible client will not necessarily work with a DA 1.0 Server. Versions are backwards compatible, in that a version 3 OPC Server can still be accessed by a version 1 OPC Client, since the specifications add functionality, but still require the older version to be implemented as well. OPC DA itself has gone through three major revisions since its inception. When vendors refer to "OPC" generically, they typically mean OPC Data Access (OPC DA). The most common OPC specification is OPC Data Access, which is used for reading and writing real-time data. IDL and methods for use in process control and manufacturing automation applications to facilitate interoperability. The specification defined a standard set of objects, interfaces e.g.
Opc modbus server free windows#
The OPC specification' was based on the OLE, COM, and DCOM technologies developed by Microsoft Corporation for the Microsoft Windows operating system family.
NET Framework, XML, and even the OPC Foundation's binary-encoded TCP format. OPC has also grown beyond its original OLE implementation to include other data transportation technologies including Microsoft Corporation's. The change in name reflects the applications of OPC technology for applications in building automation, discrete manufacturing, process control and others. Since OPC has been adopted beyond the field of process control, the OPC Foundation changed the name to Open Platform Communications in 2011. OPC specifies the communication of real-time plant data between control devices from different manufacturers.Īfter the initial release in 1996, the OPC Foundation was created to maintain the standards. They are based on Object Linking and Embedding (OLE) for process control.Īn industrial automation task force developed the original standard in 1996 under the name OLE for Process Control.
Opc modbus server free series#
Open Platform Communications ( OPC) is a series of standards and specifications for industrial telecommunication.
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