■ Introduction to Profibus DP

   For the exchange of information among automation systems and between automation systems and the connected distributed field devices, serial fieldbus systems are mainly used today as the communication system. Thousands of applications have proved impressively that cost savings of up to 40 % in wiring, commissioning, and maintenance are achieved by using fieldbus technology .While in the past the fieldbus systems used were often manufacturer specific and incompatible with other bus systems, the systems employed today are almost exclusively open and standardized. This means that the user does not depend on individual suppliers and can choose the best product at the most competitive price.
  Profibus DP is the leading open fieldbus system in Europe, which is also used successfully throughout the world. The application range includes automation in the areas of manufacturing, processing, and building. Profibus DP is an international, open fieldbus which has been standardized in the fieldbus standard EN 50 170. This standardization ensures that the investments of manufacturers and users are protected to the best possible degree and the independence of the manufacturer is guaranteed.

■ Basic Characteristics

   Profibus DP defines the technical and functional features of a serial fieldbus system allowing the interconnection of distributed, digital automation devices. Profibus DP distinguishes between master and slave devices. Profibus DP is designed for fast data transmission on the field level. Here, central control devices, such as a PLC or PC, communicate via a fast serial connection with peripheral field stations such as input/output devices, valves, and actuators.
   The interchange of data among these field devices is based on cyclic communication. The necessary communication functions are defined by the Profibus DP basic functions according to EN 50 170.
Master devices control the data traffic on the bus. A master is allowed to send messages without an external request. Masters are also called ‘active devices’ in the Profibus protocol.
Slave devices such as AUMA Profibus DP actuators are peripheral devices.Typical slave devices are input/output devices, valves, actuators, and measuring transmitters. They do not have bus access, i.e. they may only acknowledge received messages or, at the request of a master, transmit messages to that master. Slaves are also called ‘passive stations’.

■ Basic Functions of Profibus DP

  The master reads the input information cyclically from the slaves and writes the output information cyclically to the slaves. In addition to this cyclic data transfer of the process representation, Profibus DP also provides powerful functions for diagnostics and commissioning purposes. The data traffic is monitored through the monitoring functions on the master and slave side.

▲ Functionality

• Peer-to-peer (process data exchange [DATA EX]) or Multicast (control commands to all slaves).
• Cyclic process data exchange (DATA EX) between DP master and DP slaves.
• Dynamic activation or de-activation of individual DP-slaves.
• Checking the configuration of the DP slaves.
• Synchronization of inputs and/or outputs.

▲ Protection functions

• All messages are transmitted with Hamming Distance HD=4.
• Watchdog timer at DP slaves.
• Access protection for the inputs/outputs of the DP slaves
• Process data exchange (DATA EX) monitoring with configurable timer interval at the master.
• Adjustable failure behaviour.

 For more information of our Profibus Valve Actuator/Motorized Valve, please feel free to contact us.Thanks!