Ethernet for process and discrete devices

Think Again: Separate efforts aim to extend Ethernet to process and discrete devices. Standards can promote interoperability for devices and software if standards are specific enough.

By Mark T. Hoske December 14, 2019

Ethernet communication efforts are moving to economically extend the protocol to devices, one for process control devices using existing two-wires often in place in many applications, and the other for discrete applications.

Advanced Physical Layer for industrial Ethernet

The Advanced Physical Layer for industrial Ethernet consists of IEEE P802.3cg 10Mbits single twisted pair long reach Ethernet (from IEEE Task Force; approved Nov. 7) plus Power on Single Twisted Pair plus an Intrinsically safe frontend (both from APL Industry Partners R&D project). The goal is to update industrial Ethernet specifications in 2020 (FieldComm Group, ODVA and PI). First infrastructure and field devices are expected in 2021. Companies involved so far include Endress+Hauser, Pepperl+Fuchs, Rockwell Automation, and Samson, to bring interoperability, Ethernet communications, and hazardous area protection to field instruments.

Discrete Ethernet communications

Extending the discrete Ethernet side, Festo’s CPX-AP-I Remote I/O, launched in October, extends performance of mixed valve terminals and I/O systems and is compatible with most communication protocols, including industrial Ethernets, such as ODVA’s EtherNet/IP, PI’s Profinet, and Ethernet Technology Group’s EtherCAT.

Latency is virtually nonexistent, Festo said: “Scan cycles for a mix of both valve terminals and I/O are below one millisecond and are expected to approach microseconds.” The I/O has a theoretical upper limit of 500 I/O modules with 164 ft (50 m) between modules. A future safety implementation is under consideration.

With 19 active projects, study groups, and ad hoc efforts underway, think again about helping future Ethernet communications promote interoperability, as work in the IEEE 802.3 Ethernet Working Group continues.

Mark T. Hoske, content manager, Control Engineering, CFE Media,


IEEE Ethernet


PI North America

EtherCAT Technology Group

FieldComm Group

Control Engineering Europe discusses “Connectivity in real-time – IO Link, and the Automation Platform Network

Learn more from Festo at Search on “CPX-AP-I”

Author Bio: Mark Hoske has been Control Engineering editor/content manager since 1994 and in a leadership role since 1999, covering all major areas: control systems, networking and information systems, control equipment and energy, and system integration, everything that comprises or facilitates the control loop. He has been writing about technology since 1987, writing professionally since 1982, and has a Bachelor of Science in Journalism degree from UW-Madison.