• 1660318019698 Fcghartforthe21centuryhero

    HART for the 21st century

    Dec. 8, 2021
    Todayā€™s HART standard spans the process industryā€™s control and instrumentation communication needs, from 4-20mA analog loops to wireless and now Ethernet- APL and the cloud, too

    The HART protocol was first released to the control and instrumentation community back in the late 1980s, when a common digital communications protocol for so called ā€œsmartā€ instruments was envisioned to unify the proprietary efforts of the major instrumentationĀ and control system suppliers.

    So began HARTā€™s push to establish andĀ preserve the interoperability among variousĀ suppliersā€™ products that end users had come to expect from their strictly analog instrumentsā€”aĀ central mission for the digital age that continuesĀ in the work of FieldComm Group. ThroughoutĀ HARTā€™s various incarnations that were yet toĀ come, the HART protocol maintains what hasĀ become the industryā€™s best example of ecosystemĀ interoperability among different suppliersā€™Ā devices and systems.

    The original HART protocol still communicatesĀ via a digital signal superimposed on theĀ 4-20mA analog instrumentation current loopsĀ first standardized in the 1950s. Today, tens ofĀ millions of 4-20mA HART instruments constituteĀ the vast majority of instruments installedĀ around the world. Even today, it dominatesĀ shipments of new instruments to the globalĀ process industries.

    So, when the need to connect wireless sensorsĀ arose in the 2000s, industry called on HARTĀ once again, this time implemented over a wirelessĀ mesh network as WirelessHART. But onceĀ gathered at a WirelessHART access point, thereĀ was a need to transmit move that data onto theĀ plantā€™s Ethernet-based control and informationĀ infrastructure. So was born HART-IP, whichĀ was simply the long-trusted HART ā€œapplicationĀ layerā€ protocol, this time deployed over the InternetĀ Protocol (IP) network-layer on Ethernet.

    Enabling digital transformation

    The leap to Ethernet has positioned HART to continueĀ to lead the process industryā€™s ongoing digitalĀ transformation in two very important ways.

    First, with Ethernet-APL now providingĀ intrinsically safe, two-wire, 10-Mbps field communicationsĀ at the device level (see companionĀ article on p16), HART-IP is positioned to enableĀ the high-speed, high-power field communicationsĀ revolution that Ethernet-APL promises,Ā while also preserving the familiar tools andĀ established work processes of instrumentationĀ techs and control engineers worldwide.

    FCG-HART-for-the-21-century-figure-3

    At the field level, todayā€™s HART-IP pairedĀ with Ethernet-APL replaces the 4-20mAĀ analog signal used for process variables withĀ an all-digital signal. It alsoĀ now includes a standardizedĀ methodology for writingĀ instructions to final controlĀ elements. In short, HARTĀ functionality is no longerĀ limited to monitoring andĀ diagnosticsā€”with HART-IPĀ it does control, too. TestsĀ performed on Ethernet-APLĀ indicate bandwidth thatĀ is more than sufficient forĀ closing the loop on mostĀ process control applications.Ā (Visit go.fieldcommgroup.org/HART-IP-Control to downloadĀ paper.) For example,Ā even with 150 devices reportingĀ 20 updates per secondĀ over a 10 Mbps segment, onlyĀ 30% of available bandwidthĀ was consumed. Version 7.7 ofĀ the HART standard also includesĀ an integrated securityĀ model for HART-IP, pavingĀ the way for a proper cybersecurityĀ posture on the comingĀ generation of Ethernet-APLĀ field devices.

    The second way in whichĀ HART-IP is helping to advanceĀ industryā€™s digitalĀ transformation, is to securelyĀ communicate HART dataĀ out to enterprise systems andĀ cloud-based Industrial IoTĀ applications to help analyzeĀ and benchmark performanceĀ across units, sites and entireĀ enterprises. A growing numberĀ of progressive processĀ manufacturers already areĀ using multiplexer technologyĀ to extract all that rich,Ā digital HART data from theirĀ 4-20mA analog loopsā€”andĀ are using that data to effectivelyĀ advance their digitalĀ transformation initiatives.

    Increasingly, digital transformationĀ of operations entailsĀ performance-driven analyticsĀ and prescriptive maintenanceĀ enabled by HART data.Ā HART-IP also facilitatesĀ secure communications withĀ enterprise systems and privateĀ or public cloud services, suchĀ as AWS, Microsoft Azure andĀ Google Cloud. Here, HART-IPĀ complements IIoT technologiesĀ such as MQTT, AMQT, JSON
    and OPC UA.

    And as HART-IP usageĀ spreads to field networks andĀ up into enterprise systems andĀ the cloud, that access will onlyĀ be simpler, faster and easier.

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