What is OPC?
Data Logging
OLE for Process Control (OPC) is a specific specification of Microsoft’s Object Linking and EmbeOPCding (OLE) and Component Object Model (COM) that is administered by the OPC Foundation (150 member companies including Microsoft Corporation). OPC provides a common interface for devices and applications to communicate. Devices that gather or originate data become OPC servers, providing data to OPC client applications in a consistent fashion. At the heart of OPC is the client/server model in which the OPC server provides and interfaces to the OPC object, allowing client applications to control devices and manage device data in a generic fashion. OPC servers can be accessed through most HMI software and through a variety of languages, including C++, Visual Basic, and Delphi. The OPC server collects data from physical devices for distribution to OPC client applications and also has the responsibility for updating device data when an OPC client issues a write.
An OPC client connects to and communicates with an OPC server through one of two interfaces defined in the OPC specification. The OLE automation interface allows users to access data through the use of a common, easily understood scripting language. The COM interface is more complex, but provides finer levels of control and flexibility for developers and users proficient in languages such as C or C++. OPC client applications can access OPC servers locally within a computer or from a networked server.
Diagnostics
A client application can control logging through OPC variables. The client can start/stop logging or just log a single record.
For diagnostic purposes,
For more information see the section
With
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