While industry awaits the opportunity to deploy a critical mass of Ethernet-APL devices in a new plant or unit, we’ll also be looking for opportunities to verify the benefits of the new technology when adding new instruments to an existing operation. These “best bet” use cases that can begin to bring value in the absence of a full architectural shift will be those instruments that will benefit most from the dramatically faster data rates or higher power that Ethernet-APL can deliver. Here, then, a roll call of top prospects.
Digital valve controllers are among the most promising use cases for Ethernet-APL plus HART-IP in part because there’s so much HART data related to their operation that it’s hard to gain an accurate picture of their operation in a timely fashion via traditional HART communications. That usually means a trip out into the field with a handheld communicator or PC, but “running a detailed valve analysis might still take 15 or 20 minutes to complete,” notes Kurtis Jensen, valve instrumentation portfolio manager, Emerson. “But with HART-IP over Ethernet-APL, engineers and technicians will be able to see things that they hadn’t before.”
Coriolis meters are similarly complex and pack a lot of localized intelligence such as for remote verification that the meter’s operating characteristics have remained unchanged since installation. With today’s communication technologies, most users rely on a simple pass/fail command to transmit their verification status back to the control room, but the increased bandwidth of HART-IP over Ethernet-APL would allow personnel to dig into the raw data behind the test and determine the root cause—all from the relative safety and comfort of the control room or even a remote service center.
Magnetic flowmeters also include sophisticated onboard diagnostics to verify the continued integrity of the tube, coil and electronics. Again, HART-IP over Ethernet-APL would allow a remote user the ability to dig into the raw data behind these pass/fail tests.
Radar level gauges are a third group of instruments whose sensors have a characteristic signature that can be used to verify proper operation or alert the operator to problems such as an antenna coating interfering with its proper operation. Such signatures consist of a large amount of data that cannot be efficiently communicated via traditional HART and would benefit from HART-IP over Ethernet-APL.
Process analyzers are a good candidate for Ethernet-APL because the new physical layer can deliver nearly 10 times the intrinsically safe power of a 4-20mA analog loop. So, one may be able to provide both power and high-speed communications over a single, two-wire Ethernet-APL connection rather than the power wiring plus four-wire Ethernet connection traditionally required.
Multivariable measurements are yet another promising use case for HART-IP over Ethernet-APL, making it easier to power and communicate HART diagnostics from multiple related instruments, such as the multiple sensors included in a temperature-compensated, differential-pressure flowmeter. It could also allow for one Ethernet-APL spur to connect with multiple temperature sensors, obviating the need for separate transmitters.
