Safety proof of Combinations of CRC for Industrial Communication

Cyclic Redundancy Check (CRC) is an established coding method to ensure a low probability of undetected errors (residual error probability, Pre) in industrial communication. Since CRC is very efficient it is obvious to analyze combinations of CRC in order to decrease Pre and to reduce equipment costs. The contribution presents results of analysis of four combinations of CRC. It is shown by means of examples, that Pre can be decreased by choosing the right combination. Especially, the correct determination of Pre of nested CRC in communication layers is explained. It allows the reduction of worst case assumptions in safety proofs.