ABSTRACT
HART, an acronym for Highway Addressable Remote Transducer, is an open process control network protocol and was introduced in the late 1980s. It is a hybrid communication protocol that uses the Bell 202 Frequency Shift Keying (FSK) technique to superimpose digital communication signal on top of the analog 4-20 mA current loop signal. It is supported by the HART Communication Foundation (HCF). Unlike the other “open” digital communication technologies applied to process instrumentation, HART is compatible with existing systems.
