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: The digital HART signal can be transmitted simultaneously to the digital signal. The existing 4 – 20 mA infrastructure is thus also available for digital communication. Consequently, this allows for reading additional parameters and diagnostic data from field devices.
HART is based on the host-field device principle. The optional multidrop HART topology essentially complies with the line structures of fieldbus systems. In most cases, the conventional 4 – 20 mA point-to-point communication is used.