While the big play forĀ Ethernet-APL will ultimatelyĀ be in new greenfieldĀ projects, those clean-sheetĀ designs with fully convergedĀ IT/OT architectures are stillĀ a few years out. Meanwhile,Ā select instruments are set to hitĀ the market by mid-2022, andĀ progressive end-user organizationsĀ will be looking for moreĀ isolated use cases at brownfieldĀ facilities to test out and proveĀ the new technologyās worth.
Many of the most apparentĀ use cases for HART-IP overĀ Ethernet-APL derive from theĀ increased availability of dataĀ that higher bandwidth affords.Ā In a brownfield context, thisĀ is most relevant when addingĀ complex new instruments thatĀ generate more data of diagnosticĀ significanceāespeciallyĀ in hazardous area installationsĀ that require Ethernet-APLāsĀ intrinsic safety capabilities.
Real-time access to valveĀ signature data from a valveĀ controller, for example, canĀ be used to diagnose a rangeĀ of issues before they lead toĀ unscheduled process downtime.Ā The same can be saidĀ for Coriolis meters, magneticĀ flowmeters and radar levelĀ gauges. Process analyzers,Ā in particular, will benefitĀ from the order of magnitudeĀ increase in power made availableĀ to instruments by Ethernet-
APL relative to 4-20mA,Ā representing a less expensiveĀ installation than the powerĀ supply plus four-wire EthernetĀ connections that otherwiseĀ might have been needed.
But the larger context ofĀ increased secondary dataĀ bandwidth is the ability toĀ collaborate more effectively,Ā and to send that more nuancedĀ secondary data more easily toĀ the individualsāand applicationsāthat can make effectiveĀ use of it.
Hybrid environmentsĀ
For most end usersāespeciallyĀ in the US, where few greenfieldĀ facilities are expected to beĀ built in the near termātheirĀ first experiences of Ethernet-APL will be in hybrid environments that also include 4-20mA HART devices.Ā On the positive side, with the debut of fullyĀ configurable input/output (I/O) systems some 10Ā years ago, industry already is on its way to movingĀ I/O from control room environments outĀ into field junction boxes.
Configurable I/O has delivered substantialĀ benefits of its own, helping to decouple hardwareĀ design from system software developmentĀ and taking instrumentation and control systemĀ design off the critical path of project execution.Ā Itās also reduced costs and system footprint,Ā eliminating traditional marshalling cabinets inĀ many newer facilities. Like fieldbus before it,Ā Ethernet-APL effectively distributes I/O evenĀ further, relocating the transition between analogĀ sensor signals and the digital world of onesĀ and zeroes into the field devices themselves.
From a practical perspective, this meansĀ that the remote junction box is where 4-20mAĀ HART and Ethernet-APL are most likely toĀ converge. That remote junction box couldĀ relatively easily include both configurableĀ I/O as well as an Ethernet-APL switchābothĀ of which speak HART-IP over Ethernet upĀ into the control system architecture. Further,Ā a potential mix of Ethernet-APL with traditionalĀ 4-20mA HART devices will likely entailĀ a range of network infrastructure devices designedĀ to accommodate the transitional hybridĀ architectures required.
While dual devices sharing an Ethernet connectionĀ in the same box are easy to imagine hybridĀ approaches are also likely. Analog Devices,Ā one of the suppliers of chipsets for Ethernet-APLĀ as well as the multiplexers that extract HARTĀ data from 4-20mA loops, has envisioned a deviceĀ with hybrid functionality. And for suppliersĀ like Emerson, which uses a physical module toĀ characterize its remote I/O channels (rather thanĀ software), a new Ethernet-APL module underĀ development will allow these new digital channelsĀ to coexist side-by-side with their 4-20mAĀ HART counterparts.
In all three of these scenarios, a shared commitmentĀ to the HART ecosystem and dataĀ model will ease the industryās ultimate transitionĀ to Ethernet-APL as the standard physical layerĀ for field instrument communications
Toward a clean-sheet design
In the not-too-distant future, a greenfield facilityĀ or new production unit offers the most fertileĀ ground for Ethernet-APL technology, since theĀ baseline will involve comparing proven Ethernet-APL plus HART-IP technologies with the 4-20mAĀ plus HART status quo. A greenfield design needĀ not weigh sunk costs against new benefits. Rather,Ā a clean-sheet design will allow end users to realizeĀ the full benefits of a secure, high-speed digitalĀ infrastructure that reaches fromĀ field devices to enterprise systemsĀ and the cloud.
From an architecture perspective,Ā tomorrowās Ethernet-APL systems wonāt look allĀ that different from the remote,Ā configurable I/O systemsĀ of today. Indeed, replacingĀ remote enclosures filled withĀ configurable I/O with remote enclosures filled with Ethernet-APL switches may even allowĀ system designers more flexibilityĀ when it comes to howĀ many devices can be connectedĀ through a remote enclosure ofĀ given dimensions.Ā
In any case, the transitionĀ to Ethernet-APL spurs (out toĀ individual instruments) shouldĀ be a relatively straightforwardĀ adjustment from a designĀ perspective. The addition of theĀ APL trunk concept will allowĀ for new distribution models inĀ areas lacking infrastructure forĀ power and communications.Ā And when it comes to installingĀ and commissioning this newĀ breed of devices in a greenfieldĀ facility, users will really beginĀ to benefit from the dramaticĀ improvements in communicationsĀ speed that the move toĀ Ethernet-APL represents.