Many different fieldbus systems are available on the market. Certain preferences have evolved on a regional level or specifically to certain plant applications. Since AUMA actuators are implemented in all types of technical process plants around the globe, they are available with interfaces for the different established fieldbus systems within the process automation industry.
Overall, AUMA devices are available with digital and analogue inputs to connect additional sensors to the fieldbus.
Profibus
Profibus offers a complete family of fieldbus versions: Profibus PA for process automation, Profinet for data transmission based on Ethernet and Profibus DP for automating plants, power plants and machines. Due to its simple and robust data transmission physical layer principle (RS-485) and the different service levels DP-V0 (fast cyclic and deterministic data exchange), DP-V1 (acyclic access to device parameters and diagnostic data) as well as DP-V2 (further functions such as time stamp or redundancy), Profibus DP is the ideal solution for plant automation.
Modbus
In comparison with other fieldbus technologies, Modbus is simple but has a multi-functional fieldbus protocol. It offers all services required for plant automation, e.g. exchange of simple binary information, analogue values, device parameters or diagnostic data.
For plant automation and similar to Profibus, the simple and robust physical layer RS-485 is often used.
On the basis of this physical layer, Modbus supports various telegram formats, e.g. Modbus RTU or Modbus ASCII. Using the Modbus TCP/IP version based on Ethernet, vertical integration into a host automation system is often implemented.
Foundation Fieldbus (FF)
Foundation Fieldbus (FF) was explicitly adapted to the requirements of process automation. Transmission physics of the FF H1 protocol used at field level is based on IEC 61158-2 and ISA SP 50.02. These standards define the framework conditions for data transmission and energy supply of simple field devices using the same cable pair. FF H1 supports various topologies. In combination with junction boxes or segment barriers, extremely flexible cable installations are possible. Apart from conventional line and tree structures, FF H1 supports point-to-point topology or other structures with one trunk combined with individual spurs leading to the field devices.
Foundation Fieldbus data interfaces are based on standardised function blocks, for example AI (Analog Input), or AO (Analog Output) whereby their inputs and outputs can be linked.
Therefore, FF field devices can directly communicate with each other provided that the segment is equipped with a Link Active Scheduler (LAS) to coordinate FF communication.