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Industrial process control has been dominated by closed architectures and proprietary protocols for the last three decades. In the late 1990’s, the advent of open fieldbus and middleware standards has greatly changed the process control arena. Fieldbus has pushed control closer and closer to the process itself. Middleware standards have exposed real-time process data to higher level software applications. Control systems can now be designed to minimize the reconfiguration costs associated with design changes. How can Advanced Life Support (ALS) benefit from these technologies? We consider designing the control system for the BIO-Plex and evaluate how complex it will be, the effort it will require, and how much it will it cost. Various fieldbus technologies were compared and Foundation Fieldbus was chosen for detailed evaluation. This new fieldbus was integrated with an existing ALS system.

This paper gives a description of OPC (Object Linking and Embedding for Process Control) standards for process control and outlines the experiences at JSC with using these standards to interface with I/O hardware from three independent vendors. The I/O hardware was integrated with a commercially available SCADA/HMI software package to make up the control and monitoring system for the Environmental Systems Test Stand (ESTS). OPC standards were utilized for communicating with I/O hardware and the software was used for implementing monitoring, PC-based distributed control, and redundant data storage over an Ethernet physical layer using an embedded din-rail mounted PC.