OPC Provides Cross-Platform Connectivity

Sept. 1, 2005
A press manufacturer deploys OPC technology from Kepware to communicate data among disparate control systems, allowing the real-time transfer of integer and Boolean information.

SCHMIDT Technology Corp., a wholly owned subsidiary of SCHMIDT Technology GmbH, Germany, offers a comprehensive line of precision manual, air-powered and hydro-pneumatic presses for manufacturing industries in the United States, Mexico and Canada. With its most recent introduction of five ServoPress models, SCHMIDT Technology’s control engineering staff was presented with certain challenges in how to communicate electronic data between control systems.

The SCHMIDT Technology PRC4000 six-axis ServoPress controller is an “open source” logic and servo control unit that provides sequencing, calculating, process monitoring, statistical process control (SPC) and motion control, as well as a built-in human-machine interface (HMI). This controller also contains an OPC server that is used as an interface to allow for real-time exchange of data with OPC clients. By using an OPC interface, any word or Boolean information can be easily exchanged between the SCHMIDT controller and another personal computer-based control, HMI or programmable logic controller (PLC).

In a recent medical application, the PRC4000 ServoPress controller was required to provide force data to a GE Fanuc PLC that was functioning as a master controller on an assembly line. This application also required the involvement of providing status of force monitoring, sequence information, and real-time access to additional force and position data from two ServoPress modules.

Since SCHMIDT does not support a direct driver link to a GE Fanuc PLC, SCHMIDT engineers decided to review the KEPServerEX OPC server suite, from Kepware Technologies, based in Portland, Maine, as well as Kepware’s OPC system bridging software package, called LinkMaster. KEPServerEX would provide the Ethernet connection to the GE Fanuc PLC, and LinkMaster would bridge or “link” the OPC data between the SCHMIDT OPC server and KEPServerEX. During the development stage of this project, the fully functioning two-hour demo packages of KEPServerEX and LinkMaster were downloaded from the Kepware website.

Supports multiple PLCs

It is important to note that, during this process, SCHMIDT engineers did not have a GE Fanuc PLC in-house to test the data transfer. However, they did have several Allen Bradley Micrologix PLCs on hand. Because KEPServerEX also provides connectivity to Allen Bradley PLCs, the SCHMIDT team was able to install the KEPServerEX OPC server suite and the LinkMaster application on the PRC4000 controller. The team used Kepware's Allen Bradley DF1 connectivity to communicate directly to the PLC through a serial port. Next, LinkMaster was quickly configured to acquire the data to/from the SCHMIDT OPC server, and map the integer and Boolean data directly to available integers and bits within the Allen Bradley PLC.

Due to the reliability and ease of use of the in-house evaluation system, SCHMIDT engineers made the decision to use Kepware's solution at the customer site. Kepware's OPC server provides a single consistent interface to a variety of industrial protocols. This made the transition from the in-house Allen Bradley PLC to the on-site GE Fanuc PLC connectivity fast and easy. KEPServerEX with GE Fanuc connectivity and the bridge application, LinkMaster, were installed on the PRC4000 controller, allowing a successful and seamless exchange of data through the on-board Ethernet port. This fast, easy and reliable solution provided by LinkMaster prompted a final configuration featuring the use of LinkMaster to transfer data and status/control bits between three PRC4000 controllers and the GE Fanuc PLC.

More information about Kepware Technologies can be found at www.kepware.com.

More information about Schmidt Technology Corp. can be found at www.schmidtpresses.com.