For about 30 years, the HART Communication Protocol (Highway Addressable Remote Transducer Protocol) has been a part of process automation industry.
Examining the current status and future outlook for this widespread industrial automation protocol – why has HART turned out to be such a success and how do you benefit from HART?
A significant advantage of HART is its worldwide application and acceptance throughout different markets and industries. Independent from manufacturers and vendors, open communication is proceeded via standardized, established commands. For today’s generation of field devices, the support of HART functionalities is a standard feature. Process control systems support HART connectivity as well.
Almost all major manufacturers offer their products with HART interfaces. In simple terms: HART dominates across process automation installations. According to the HART Communication Foundation, more than 30 million devices installed worldwide are HART ready.
The HART Communication Foundation coordinates worldwide activities referring to the application and continuous progress of the HART protocol. Devices have changed. Applications have changed. Requirements have changed: HART has kept up with all of these and offered support through the work of the HART Communication Foundation.
As HART technology is based on conventional wiring, existing plants can be continuously expanded. This means that when opting for HART, field installations remain unchanged as most 4 mA … 20 mA devices are HART capable devices. The HART protocol is also fully compatible with analog standards and digital communication methods. Additional wiring or hardware and software parameterization is not needed.
Most of today's automated plants are based upon the proven 4 mA … 20 mA wiring concept. Each measuring device provides its “main” measured value on the current loop of the standard signal. Due to HART technology, these devices offer more process information, as additional digital information gets transmitted simultaneously on the analog signal. For instance, pressure transmitters also provide temperature values.
With the help of a HART multiplexer, HART enables the connection of field devices to asset management systems. When a sensor provides more information than the measured value, this additional information is made accessible for the control side via HART. HART also enables the transmission of status and diagnostic information for maintenance and parameterization of field devices. The HART protocol also allows the implementation of partial stroke tests, which are relevant in safety-related applications.