OPC simplifies integration of process vision, quality control systems

Author : Edited by Renee Robbins, senior editor, Control Engineering News Desk

08 March 2010

Logicpark, a Swiss engineering and system integration company, recently used the OPC DataHub from Cogent Real-Time Systems to network an ABB quality control system to a new Viconsys process vision system at the Kimberly-Clark production facility in Niederbipp, Switzerland.

"The requirements for this project were challenging," said Bruno Maurer, head of solutions at Logicpark. "The OPC interface gave us a good foundation, and we used the OPC DataHub to get the most out of it."

OPC is a software interface standard for allowing Microsoft Windows programs to communicate with industrial hardware devices. Any kind of hardware with an OPC server can communicate easily with any software that is an OPC client. In this case, however, there was no hardware/software connection. Two pieces of hardware had to connect directly, and interact on a common data set. "We had to connect the ABB and Viconsys OPC servers," said Maurer. "What we needed was an 'OPC bridge' that could act as a client to each OPC server, and pass the data between them."

A second difficulty was in networking. OPC uses DCOM for networking, which was not built for industrial applications. Most factory systems are protected by firewalls, and using DCOM with firewalls poses both configuration challenges and security risks. "The data had to go across the network," said Maurer. "Using DCOM for networking was out of the question, because it would open too many ports in the firewalls, and it is difficult to configure. What we needed was a way to tunnel the data across the network, and also bridge the OPC servers at either end of the tunnel."

To achieve these goals, Maurer turned to the OPC DataHub, which offers both OPC tunneling and bridging in a single, integrated product. He installed one OPC DataHub on the same machine as the ABB quality control system, and connected it to that OPC server. He then installed a second OPC DataHub on the Viconsys computer, and connected it to the Viconsys OPC server.

When Maurer configured the OPC tunnel, he was able to see both sets of data on both OPC DataHubs. From there, it was a straightforward task to configure the necessary bridges to write data from one OPC server to the other OPC server. Maurer had a test connection running in a few hours, and couple of days later the new system was completely functional.

"The OPC standard is very good, but we were faced with a special challenge on this project," said Maurer, "how to connect two OPC servers together to share data across a firewall. The OPC DataHub gave us a complete and reliable way to network real-time data."

Cogent Real-Time Systems, founded in 1995, provides real-time cross-platform data integration between Windows, Linux and QNX. Customers include the Bank of Canada, Cadbury Chocolate and the European Space Agency.

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