What is OPC?

OPC is the acronym of OLE for Process Control. To better understand the meaning of OPC, let us first start by describing the problem before the creation of OPC, then we present the solution coming with it.

Assume that, in an industrial devices’ manufacturer, there are three different equipments (E1, E2, and E3) communicating respectively to three different providers (P1, P2 and P3), and we need to display exchanged real time data between these equipments in form of trends. The solution was to develop a specific module per provider; each one ensures communication with the correspondent equipment using the API of the provider related. Then, these modules are integrated to compose the final solution. Therefore, we developed as many modules as providers.

But what about this issue: How much we may investigate time and money to reuse this solution to support a different provider?

From here the industrials’ need emerged for the standardization of the way to read and write data to their devices. It is OPC!!

Now I will try to respond to the following questions. What is OPC? Who is the OPC creator? How did OPC resolve the issue described above?

OPC is a set of interfaces based on the COM/DCOM technology developed by Microsoft that provides interoperability between software applications and industrial equipments. OPC is based on a client/server architecture that allows one application to consume the services exposed by another one. A typical OPC solution is based on two components: on one hand, an OPC server to ensure communication with the device to get and/or to set data and on the other one, an OPC Client to access data made available by the server through its exposed interfaces.

OPC is defined by the OPC Foundation organization (www.opcfoundation.org) that has the responsibility to create and maintain the different OPC specifications (for more information about OPC Foundation, you can refer to the following link: http://www.opcfoundation.org/Default.aspx/01_about/01_history.asp?MID=AboutOPC)

Now, to respond to the last question about how did OPC resolve the issue described above? and according to the above description, using OPC, the industrial devices’ manufacturer could write three OPC servers applications that collect data respectively from P1, P2 and P3 and one and only one OPC Client application that communicates with the server applications to access and expose data as trends.

If you need additional information or you have any question, please do not hesitate to contact me at hassen.kouki@gmail.com. I would be more than happy to answer your requests.