Observer based verification of IEC 61499 function blocks

IEC 61499 is an international standard for designing Industrial Process Control Systems using artefacts such as Function Blocks and Execution Control Charts. The existing approaches towards formal verification of function blocks lack the natural expression for specifying the system properties. We suggest an approach for performing formal verification of IEC 61499 designs using observers expressed as function blocks. This method provides the IEC 61499 designer with an intuitive way of expressing system properties and also makes the verification result easier to map to the original design. We have implemented two different algorithms, a tableau based CTL model checker and a reachability analyzer, to support the verification of observers. Experimental evaluation over a range of benchmarks have shown better performance as compared to Esterel based verification in terms of computation time.