ABSTRACT
PROFIBUS is an open fieldbus standard designed for process industries. It has three variants: PROFIBUS– fieldbus message specification (FMS), PROFIBUS- process automation (PA), and PROFIBUS- decentralized periphery (DP). Network speed is between 9.6 kbps and 12 Mbps. It operates in master-slave, multimaster-slave configurations.
Field devices are connected to PROFIBUS-PA. PROFIBUS-DP handles fast communications with multimaster options. PROFIBUS-FMS is a peer-to-peer type communication. All the three versions use a standard bus access protocol which is implemented by layer 2 of open systems interconnection (OSI). In this case it is termed as fieldbus data link (FDL) which handles data security and error correction. DP is of three types: DP-V0, DP-V1, and DP-V2. DP-V0 offers basic functionalities like cyclic communication and diagnostic reporting. DP-V1 offers both cyclic and acyclic communication and alarm services, diagnostics, parameterization, and field device control. Apart from the above functionalities, DP-V2 is particularly useful in the field of drive control.
PROFIBUS devices can be classified into three categories: DPM1, DPM2, and PROFIBUS slaves. DPM1 is used for cyclic data exchange with slaves, DPM2 for device and system commissioning, and PROFIBUS slaves respond to master polling by sending device data. Devices on PROFIBUS-PA are accessed by segment coupler and link.
PROFIBUS has a time stamp profile to time stamp occurrence of some events like diagnosis and faults. Various redundancies like master, slave, media, segment coupler, and ring redundancies can be implemented.
