what is an opc server?

Answer 1

OPC technology can eliminate expensive custom interfaces and drivers traditionally required for moving information easily around the enterprise. It promotes interoperability, including amongst different computing solutions and platforms both horizontally and vertically in the enterprise. It therefore cuts costs, speeds development and promotes increased operating efficiency.

OPC specifications are proven in hundreds of plants and thousands of applications. The OPC Foundation is dedicated to creating and maintaining the OPC specifications. Established in 1996 by just five companies the Foundation now has over 360 members who both use and promote the technology. Members also further the advancement of open OPC standards by participating in Foundation activities.

Answer 2

OLE for Process Control (OPC) is a new technology designed to bridge Windows based applications and process control hardware. It is an open standard that permits a consistent method of accessing field data from plant floor devices. This method remains the same regardless of the type and source of data. Therefore, end users are free to choose the software and hardware that meets their primary production needs, without having to consider the availability of proprietary drivers.

OPC components fit into two categories: OPC clients and OPC servers. A client is typically a data sink -- an application that uses data in some way, such as an MMI or SCADA package. A server is a data source -a device specific program that collects data from a field device, and then makes it available to an OPC client.

A client interacts with a server using a well defined OPC interface. Therefore, any OPC client can communicate with any OPC server, regardless of the type of device the server is designed to collect data from.

OPC is built using Microsoft's OLE technology, which is a well tested and proven foundation. Also, the OPC specification was designed by an open foundation to meet the general needs of industry - not the specific needs of a few software or hardware manufacturers. The specification also provides for a robust evolution of functionality over time, so OPC components can stay on top of the emerging needs of industry.

Traditionally, any time an application required access to a process control device, a custom interface, or driver, was required and needed to be custom written. Because OPC defines a common interface, a server can be written once, then reused by any business, SCADA, MMI, or custom software package. In addition, OPC servers can be easily accessed and controlled from Visual Basic applications, such as Microsoft Excel macros or Microsoft Access applications. OPC clients can be written in any current windows development environment - no special software or toolkits are required.

With OPC, end users are now able to choose from large pool of OPC servers, such as those in Matrikon's OPC Component family, to communicate with their specific devices. They then either develop a client to communicate with the server, or choose a client such as a Matrikon OPC Client for their specific application.

Answer 3

Here's a link to a presentation that might be helpful.