The PROFIBUS Protocol Observation

PROFIBUS is a very complex protocol created in 3 layers of the reference communication model. The paper shows experimental way to explain the behaviour of devices on bus under normal traffic and diagnostic events. The paper deals with two communication experiments performed on the same devices on the bus. For measurements on PROFIBUS DP physical layer the professional tester was used. It provides an overview of the signal conditions on the bus and detects the signal quality of each device on the bus. A universal tool for PROFIBUS protocol analysis can perform online bus traffic monitoring. It is able to detect and analyse the PROFIBUS frames for education and diagnosis purposes.