ProfiBus (PROcess FIeld BUS) is a widely accepted international networking standard, generally found in process control and in larger assembly and material dealing with machines. It helps single-cable wiring of multi-input sensor blocks, pneumatic valves, complex intelligent devices, smaller sub-networks (corresponding AS-i), and operator interfaces. ProfiBus is nearly common in Europe and likewise popular in North America, South America, and parts of Africa and Asia. It's an open, vendor independent standard. It adheres to the OSI model and ensures that devices from a variety of different vendors can communicate together easily and effectively. It has been standardized under the German National Standard as DIN 19 245 part 1 and 2 and, in addition, has also been ratified under the European National Standard EN 50170 Volume 2.
ProfiBus supports two main types of devices, namely, masters and slaves:
• Master devices control the bus and once they have the right access the bus, they might transfer messages without remote request. These are referred to as active stations
• Slave devices are usually peripheral devices i.e. transmitters/sensors and actuators. They might solely acknowledge received messages or, at the request of a master, transmit messages to that master. These are additionally referred to as passive stations.
There are several versions of the standard, particularly, ProfiBus DP (master/slave), ProfiBus FMS (multi-master/peer to peer), and ProfiBus PA (intrinsically safe).
• ProfiBus DP (distributed peripheral) permits the use of multiple master devices, by which case every slave device is assigned to one master. This implies that multiple masters can read inputs from the device but only one master can write outputs to that device. ProfiBus-DP is designed for high speed data transfer at the sensor/actuator stage (as opposed to ProfiBus- FMS which tends to focus on the higher automation level) and relies around DIN 19 245 parts 1 and 2 since 1993. It is suitable as a replacement for the costly wiring of 24V and 4-20 mA measurement signals. The data exchange for ProfiBus-DP is usually cyclic in nature. The central controller, which acts as the master, reads the input data from the slave and sends the output information back to the slave. The bus cycle time is much shorter than the program cycle time of the controller (lower than 10 mS).
ProfiBus supports two main types of devices, namely, masters and slaves:
• Master devices control the bus and once they have the right access the bus, they might transfer messages without remote request. These are referred to as active stations
• Slave devices are usually peripheral devices i.e. transmitters/sensors and actuators. They might solely acknowledge received messages or, at the request of a master, transmit messages to that master. These are additionally referred to as passive stations
There are several versions of the standard, particularly, ProfiBus DP (master/slave),
ProfiBus FMS (multi-master/peer to peer), and ProfiBus PA (intrinsically safe).
• ProfiBus DP (distributed peripheral) permits the use of multiple master devices, by which case every slave device is assigned to one master. This implies that multiple masters can read inputs from the device but only one master can write outputs to that device. ProfiBus-DP is designed for high speed data transfer at the sensor/actuator stage (as opposed to ProfiBus- FMS which tends to focus on the higher automation level) and relies around DIN 19 245 parts 1 and 2 since 1993. It is suitable as a replacement for the costly wiring of 24V and 4-20 mA measurement signals. The data exchange for ProfiBus-DP is usually cyclic in nature. The central controller, which acts as the master, reads the input data from the slave and sends the output information back to the slave. The bus cycle time is much shorter than the program cycle time of the controller (lower than 10 mS)
• ProfiBus FMS (Fieldbus message specification) is a peer to peer messaging format, which permits masters to communicate with one another. Simply as in ProfiBus DP, up to 126 nodes are available and all will be masters if desired. FMS messages consume more overhead than DP messages
• ‘COMBI mode’ is when FMS and DP are used simultaneously in the same network, and some units (such as Synergetic's DP/FMS masters) support this. That is mostly used in conditions where a PLC is being used in conjunction with a PC, and the primary master communicates with the secondary master through FMS. DP messages are sent via the same network to I/O devices
The ProfiBus PA protocol is the same as the most recent ProfiBus DP with V1 diagnostic extensions, except that voltage and current ranges are lowered to meet the requirements of intrinsic security (class I division II) for the process industry. Many DP/FMS master cards support ProfiBus PA, but barriers are required to convert between DP and PA. PA devices are usually powered by the network at intrinsically safe voltage and current level, utilizing the transmission technique specified in IEC 61158-2. (which Foundation Fieldbus H1 uses as well)