The HART protocol was developed in the late 1980s and handed over to the HART Foundation in the early 1990s.

It has been updated several times since then.

Each protocol update ensures that the update is backwards compatible with previous versions.

The current version of the HART protocol is version 7.3.

"7" represents the major revision number, while "3" represents the minor revision number.

The HART protocol implements layers 1, 2, 3, 4, and 7 of the Open Systems Interconnection (OSI) 7-layer protocol model: It defines the commands, responses, data types, and status reports supported by the protocol.

At the application layer, the public commands of the protocol are divided into four categories: Common commands - provide functions that must be implemented in all field devices. Common commands - provide functions that are common to many devices, but not all fields.

Device-specific commands - Provide functions unique to a particular field device, as specified by the device manufacturer Device family commands - Provide a standardized set of functions for instruments of a specific measurement type, allowing them to be used without the need for device-specific instructions

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