Method for verifying an application program of an error-free memory-programmable control device and memory-programmable control device for carrying out the method

摘要

The method involves forming a signature (SIG-S-1) by an application program or program modules (F-FBx, F-DBx, F-FCx), and storing a copy of the signature in a memory-programmable control device (SPS). Another copy of the signature is stored in an external component (ES), and the former copy is compared with the latter copy. Another signature (SIG-l) is determined from an application program stored in a main memory (AS). The latter signature is compared with the former copy, where the control device is transferred to a safe operating condition during discrepancy in the comparisons. An independent claim is also included for a memory-programmable control device comprising a comparison unit.