Incorporating Web-IOs into SCADA systems using OPC

In automation technology and building monitoring, the hardware from various manufacturers is generally combined into an over all system. Exchanging the required process data is handled differently depending on the manufacturers involved. Sometimes RS485-based bus systems are used, other manufacturers use for example the local network for data exchange.

To support the various components in a common application, each individual component would require costly adapting of the programming.

With OPC (OLE for Process Control) a uniform and manufacturer-neutral software interface was created in the mid 1990’s.

The concept of OPC is quite simple: One OPC server each is installed on the PC for the components of the individual manufacturers. The OPC server assumes the function of a process data translator. The OPC server processes the manufacturer-specific communication with the terminal device (RS485, RS232, CAN, LON, TCP/IP...) and makes the process data available to the application in the form of standardized ITEMs.

The SCADA application (Supervisory Control and Data Acquisition) has for its part an OPC client interface for taking the process data and forwarding instructions to the components.

With the help of the Wiesemann & Theis OPC Server Web-IO Digitals and relays, Web-IO Thermometers and Thermographs as well as Web-IOs for analog signals in OPC capable applications can be integrated. Even different Com-Server models are supported.

The configuration of the OPC server service is done using a simple interface and requires only a little effort.

Then the entered W&T devices are available in all OPC-capable visualization applications and process control systems, such as FactorySuite/InTouch from Wonderware or WEBfactory from ecom WEBfactory GmbH.

You can find the W&T OPC Server on the product CD included with our products or as a download.