HART (Highway Adressable Remote Transducer) is a standardised communication protocol for digital communication between several industrial field instruments (e.g. digital measuring devices) by means of a so-called data bus. HART harnesses the widespread 4…20 mA standard for analogue sensor signals, so existing wiring can be used for both types of signal. Developed in the 1980s, the HART protocol has been included into the international IEC 61158 standard for field buses since 2007.