Example OPC Server Application

The image below demonstrates a typical distributed system layout incorporating different computer system platforms can be brought together using OPC to gather and process data from distributed networked instrumentation.

The example belows shows the NDACS 6000 and 8000 systems connected together on a local area network. The custom applications can handle the PLC controls for the NDACS 8000 on several of the distributed computer platforms leaving User specific

General OPC Information

OLE for Process Control (OPC tm) has been designed to allow third party applications running a common data transfer protocol to access plant floor data in a consistent manner, The plant floor data being information from instruments supplied from different manufactures and operating at different rates. With wide industry acceptance OPC with provide many benefits:

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Provides customers with more choices when developing integrated measurement and control systems.

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Allows hardware manufacturers to supply a single software component providing for the integration of the instrumentation for customers to utilise in their applications.

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Software developers will not have to re-write drivers because of feature changes or modifications in a new hardware release.

OPC Client Application Architecture

OPC draws a line between hardware suppliers and software developers and provides a mechanism to access information from a data source and communicates this data to any client application software in a standard way. An OPC vendor can now develop a reusable, highly optimised server to communicate data to third party applications.

Although OPC is primarily designed for accessing data from a networked server, OPC interfaces can be used in many places within an application. At the lowest level they can get raw data from the physical devices into SCADA or DCS, or from a SCADA system into other applications. The architecture of the OPC Server makes it possible to construct an OPC Server that allows client applications to access data from many OPC Servers provided by different vendors running on different computing platforms via a single object.

operations available on the smaller PCs. The Keynes Controls OPC server currently only operates for instrumentation on a local area network or for suitably configured systems on a WAN where data is suitably accessed.

Using OPC data servers there is in practice no limit to the number of separate applications that can access and process the data obtained from the instruments.