GF_LL_SMC2000_oct_2000
 Frey,G.; Litz, L.:
Formal methods in PLC programming
         Proceedings of the IEEE SMC 2000, Nashville, October 08-11,  2000, pp. 2431-2436.
-          A detailed generic model of the control design process is  introduced and discussed. It is used for surveying different formal  approaches in the context of PLC-programming. The survey focuses on  formal methods for verification and validation (V&V). The varying  works in this area are categorized using three criteria: the general  Approach to the task (model based, constrained based or without a  model), the Formalism (Petri net, automata,...) used to state the formal  description, and the Method (Model-Checking, Reachability Analysis,  ...) used to analyze the properties. Based on these three criteria  (A-F-M) a three letter code for V&V approaches is introduced. Some  works from the multitude of V&V research are presented and  categorized using this new system.