A leading automotive manufacturer desired to maximize supply chain efficiency in its newest automotive manufacturing facility in North America. With twenty-one of its key suppliers located in close proximity to the main plant, work-in-process buffers were very short. Real-time data exchange between the automation systems of suppliers and the manufacturer was essential.The resulting solution would need to be highly reliable and would need to securely pass data through a firewall. The manufacturer worked with solution consultants from ACE Technologies, Inc., of Rochester Hills, Mich., to identify the following design issues:•Security concerns with PLC-to-PLC communicationsºIn general, PLC communication security can be very difficult, and in some cases impossible to manage, especially between two different companies with different brands of programmable logic controllers (PLCs).•Many types of hardware, so a common interface methodology was needed ºThe interface would need to be highly reliable, would need to securely pass data through a firewall, and would need to easily bring several types of automation equipment and applications together.ºEach supplier often had their own standards for automation equipment, usually incorporating custom applications and various PLC brands.ACE Technologies worked with the manufacturer to design a standardized, flexible and secure communication infrastructure to all of its suppliers, using a combination of off-the-shelf software products by Kepware Technologies. Kepware is based in Portland, Maine, and specializes in OPC and device-communication technologies for the industrial automation market.Inside the manufacturer’s plant, a single SQL server database was used as the secure communications mechanism. Data exchange needed to be bi-directional, so the database was set up with SQL authentication to allow each supplier access to a “Send” and “Recv” table. Each vendor would need to collect data from its own PLC or automation equipment, then send the data through the firewall to the “Recv” table inside the manufacturer’s SQL database. Inside the facility, the application reads this table and then sends the data to the PLCs. Data going back to the suppliers from the manufacturer uses the same mechanism with a “Recv” table. Refer to the diagram to see how PLC and ODBC driver plug-ins to Kepware’s OPC server KEPServerEX were used to handle the device and database connectivity. The OPC server-bridging product, LinkMaster, was used to “link” the data bi-directionally between OPC items in KEPServerEX (between PLC items and ODBC items). The end result was a highly reliable and secure mechanism between the suppliers and the manufacturer on completely isolated networks. The system incorporates OPC and ODBC to maximize future scalability and interoperability, which should allow it to connect to virtually any manufacturing equipment or custom application. For more information about OPC solutions from Kepware Technologies, visit www.kepware.com.
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