Fuzzy-control with a PEARL-based multi-loop controller

To serve the demand for fuzzy control components in automation systems, manufacturers extend the function block libraries of their multi loop and PLC software by respective function blocks. Other demands are for the openness of PLC software and its adaptation to the IEC 1131 standard which, for the first time, gives recommendations with respect to a task model and task communication. The unique idea of the PEARL PLC is to use an adequate high level real time language for PLC software design and implementation facilitating all mentioned user demands in a totally open form. Definition and verification of fuzzy components are described in the paper and further advantages of the use of high level real time languages in PLCs with respect to safety critical aspects are mentioned.