On construction and verification of PLC programs

A review of methods and approaches for programming of “discrete” problems for programmable logic controllers (PLC) based on the example of constructing a program for controlling a code lock. The usability of the analysis of a program correctness by the model checking method with respect to a Cadence SMV automatic verification tool is evaluated for these approaches. Possible PLC program vulnerabilities arising at some approaches for programming of PLC are revealed.