- By Michael Carolan
- October 25, 2022
- Moore Industries-International, Inc.
The Fieldcomm Group asserts that with 40 million HART instruments installed, HART is by far the most dominant communications protocol used in process manufacturing facilities around the world.
The Fieldcomm Group asserts that with 40 million HART instruments installed, HART is by far the most dominant communications protocol used in process manufacturing facilities around the world. Although HART has become a standard instrument protocol, users often state that they only use the HART for setting up their instrumentation and valves. This widely-held perception of the purpose for using HART means that users are not taking advantage of the powerful features that the protocol offers.
In addition, many existing control and monitoring systems do not support HART communication for devices with 4-20 mA input/output. For many end users this leaves a void between the intelligence available in HART enabled devices and the DCS, PLC/RTU or plant asset management system that is not able to accept and handle the valuable data that HART delivers. The challenge facing users with these systems is how to tap into wealth of device diagnostic information now largely stranded within these intelligent devices without requiring a major upgrade or migration project.
HART gateways with 4-20mA input and Ethernet output allow end users to interface their installed base of HART devices to their control systems progressively. Including such ad hoc implementation into maintenance budgets negates the need to allocate capital funds. This approach also enables engineers to strategically select those devices that add the most value to their operation. This strategy allows engineers to immediately start using the HART diagnostic data and additional process variables included on the HART data string such as Secondary Variable (SV), Tertiary Variable (TV) and Quaternary Variable (QV).
The new communication channel that HART provides gives transparent access to existing HART field devices via Ethernet and is easily integrated into higher layers for further processing and analysis in downstream applications leaving the core automation tasks unaffected. Enabling the migration of these assets begins the affordable and effective transformation into the age of digitalization with continuous data flow, inherently establishing a seamless plant floor to Ethernet backbone.
To succeed in the current business climate, companies must adapt to the changing conditions. Environmental impact and water use has become an increasingly important consideration, leading major companies to establish and promote their “green” credentials. However, many industries rely on the availability of significant water usage for their processes.
Mining, manufacturing, and other industries use about 20% of all water consumed in Australia. Traditionally there is a high demand for water in minerals processing since water is favoured for its low cost and low energy requirements for transporting materials between processes. Other uses include physical separation of minerals through chemical process, centrifuges, scrubbers and the suppression of dust.
The primary water source is saline water from underground bores, and the process owner is accountable for the water use. Monitoring the digital data that HART delivers provides improvement in accuracy over the existing 4-20mA loop from the magnetic flowmeters to their PLC, where they have also identified the totalisation of the pulse count from meter is not accurate.
With an existing magnetic flowmeter, the user can tap into the improved digital resolution of the meter using HART. The HART Gateway is connected in parallel with the existing 4-20mA loop, and reads the Primary process variable (PV) → Volume flow plus Second process variable (SV) → Totalizer.
Many sites today use a variety of instrument manufacturers within their processes with a common theme amongst them: the majority are HART based. HART gateways can assist in delivering an immediate and impactful Ethernet-based solution without affecting capital budgets or the existing control and monitoring systems reliability, regardless of which vendor’s products are installed.
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