OPC (OLE for Process Control) is a standard designed for real-time data exchange between a software application and process control devices such as PLCs. OPC defines an interface independent of the device type. As a result, the end user is almost not limited in the choice of hardware and software for his/her application. The only requirement is OPC compatibility.
There are two kinds of OPC components: OPC client and OPC server.
An OPC client is a program that gets (reads) the data from an OPC server for further processing. The typical examples are MMI and SCADA/HMI systems.
An OPC server is a program that provides data to OPC clients. It is usually designed to read data from a specific hardware device. An OPC client communicates with an OPC server through a strictly defined interface. As a result, any OPC client can communicate to any OPC server regardless of the type of device for which the server has been created.
The OPC standard is developed by the OPC Foundation organization grouping hundreds of software companies and hardware manufacturers worldwide. New features are continuously added to keep the standard up to date.
A tutorial demonstrating the basic aspects of the OPC standard is available on the website of Matrikon, a renowned OPC product developer company.
OPC server Honeywell Excel 5000
OPC server Landis & Staefa RWP80
Further information about the OPC servers at .