7. Profibus-PA

The Profibus-PA protocol is designed to interconnect sensor and actuator field devices, moving towards the "zero cabinet" concept. Profibus-PA also meets the requirements of the continuous process industries for fieldbus-based control, guaranteeing intrinsically safe use of the network in hazardous areas in accordance with IEC 61158-2, on a type H1 bus [4] . Profibus-PA is an alternative to analog 4-20 mA wiring.

Profibus-PA defines both a secure communication protocol, based on the seven layers of the OSI model and incorporating the services of the DP protocol, and a specialized communication profile for sensor/actuator field instrumentation management applications. Equipment I/O is accessed by the cyclic read/write service of the master, while parameter-setting functions are performed by acyclic...