Access to industrial process periphery via Java for process control (JFPC)

Using Java for real world I/O requires its availability in real-time (RT) systems. It is widely accepted that in a plain Java environment, RT characteristics get lost and the required programming interfaces are missing. So there are several ongoing standardization efforts for RT Java. An essential aspect (also important for non-RT systems) is the access to external I/Os. The Siemens product Java for process control (JFPC), which is based on the ideas of OLE for process control (OPC) addresses this aspect. It is available under the proprietary RT kernel RMOS and under Windows NT. Forschungszentrum Julich developed different JFPC providers in order to access industrial components via PROFIBUS DP using an experimental version of JFPC under Linux. The paper presents the status of the different standardization efforts for RT Java and the key features of JFPC. It describes the implementation of a JFPC provider for PROFIBUS DP and shows how it can be used to access industrial sensors and actuators. Experiences and performance results are discussed.