HART makes use of the known 4 – 20 mA standard signal for analogue data transmission. HART communication is modulated as additional signal to the analogue signal. Advantages: Simultaneous transmission of the digital and the analogue HART signals. Existing 4 – 20 mA infrastructure is also available for digital communication. Facilitates reading additional parameter and diagnostic data from field devices.


HART is based on the master/slave principle. The optional multidrop topology essentially complies with the line structures of fieldbus systems. In most cases, the conventional 4 – 20 mA point-to-point commmunication is used.


  • International standard (www.hartcomm.org)

  • Worldwide distribution

  • Large installation baseStandardised integration within the DCS (FDT, EDD)

  • Large selection of devices


AUMA actuators with HART


  • 4 – 20 mA HART analogue signal either for setpoint transmission or alternatively to communicate the actual position.
  • Transmission of parameter and diagnostic data via digital HART communication
  • approx. 500 ms per actuator for digital communication
  • Integration within the DCS via EDDL
  • Length of cable approx. 3 km