Certification is the process by which a PROFINET product is tested in a PITL for conformance and, upon successful completion of the testing, issued a certificate by PI. Products are certified to verify the correct behavior of communication according to IEC 61158 and IEC 61784. Specifically, PROFINET devices are tested for the correct implementation of the following items: Hardware interface PROFINET mandatory and optional functionality Reaction on faulty behavior Robustness against netload Proper operation in a reference automation environment State machines GSD file