Goulston Technologies - USA
Last year plant engineer Warren Eads was faced with a difficult proposition. He needed to integrate data between Goulston's proprietary PLC system and their Windows network. He had to find or develop an application that would be equally at home in Windows and Linux, and reliably transfer data between the two systems. In a web search he came across Cogent's OPC DataHub and Cascade DataHub for Linux. He ran some preliminary tests and the results were positive, so he set up a working system in development mode.
Warren first configured the OPC DataHub in Windows to mirror data across the network to the Cascade DataHub in Linux. Next, using the Cogent API in Linux, Warren wrote a small interface program to connect his PLC network directly to the Cascade DataHub. With this program running, he was then able to read the data coming off his PLCs directly from his OPC client in Windows.
Throughout the testing and for the duration of the project, the PLC network was live. Warren had to move forward carefully, step by step, often working after hours. Once the OPC client was reading data from the PLCs, he developed a separate application to write data back to the PLCs from the OPC client.
"We couldn't be more pleased with how the project has gone," said Warren. "We started running 900 data points every 15 seconds, and sped it up quite easily until we reached the latency of the PLC connection. At first we ran in parallel with our residual network, and when the DataHubs proved reliable, we removed the gateways and went straight to Ethernet, serving the data directly."
The system has been online for months now, meeting or exceeding all of Warren's requirements. "We weren't quite sure how we were going to integrate live processes between Linux and Windows." he said. "But the OPC DataHub and Cascade DataHub made our work simple and straightforward."
OPC DataHub is a trademark of Cogent Real Time Systems. Software Toolbox is a trademark of Software Toolbox, Inc.