Everything you need to know about EtherNet/IP

Field Network

Everything you need to know about EtherNet/IP

Solutions based on Ethernet and wireless communication have begun to gain ground in the industry. Like the classic fieldbus, we can also find different standards for Ethernet, but all bring the same benefits. So let’s look at EtherNet/IP, one of the most popular Ethernet protocols out there.

The history of EtherNet/IP

In the 1990s, a group at ControlNet International Ltd. began developing EtherNet/IP. Then in 2000, this group needed support to continue its work and turned to ODVA.

ODVA, a global association of automation manufacturers founded in 1995, agreed to a partnership to further the technology. Finally, the agreement concluded in 2009, giving ODVA and its members control of EtherNet/IP.

ODVA also supports Common Industrial Protocol (CIP™) and its adaptations, such as ControlNet™, CompoNet™, and DeviceNet™. On top of that, ODVA espouses interoperability across brands and systems. For this, it encourages the adoption of commercial-off-the-shelf, unmodified Internet and Ethernet technologies.

What’s EtherNet/IP?

EtherNet/IP is a flexible protocol, based on CIP, that follows the Open Systems Interconnection (OSI) model. You can use it to connect field devices, monitoring systems, and controllers. It works for power control (soft starters, motors, drivers, etc.) and discrete control (safety controllers, safety I/O, robots, etc.) as well.

Image of EtherNet/IP
Image courtesy of interempresas.net

You’ll also find it in the convergence of industrial automation technology (IAT) and information technology (IT). You can use EtherNet/IP on IP cameras, IP phones, WiFi, and more.

Standards

EtherNet/IP supports many standards:

  • IEEE 802.3 – Standard, Ethernet, Precision Time Protocol (IEEE-15088)
  • IEC – International Electrotechnical Commission – IEC 61158
  • ODVA – Common Industrial Protocol (CIP)
  • IETF – Internet Engineering Task Force, Standard Internet Protocol (IP)

The OSI model defines the protocol framework in seven layers. And EtherNet/IP adds CIP to the session layer and all above it.

  • Application – Layer 07: network services to the user application (CIP IEC 61158)
  • Presentation – Layer 06: encryption and other processing (CIP IEC 61158)
  • Session  – Layer 05: process management (CIP IEC 61158)
  • Transport – Layer 04: end-to-end delivery and error correction
  • Network – Layer 03: packet delivery and routing (routers)
  • Data link  – Layer 02: data framing and error checking (switches)
  • Physical – Layer 01: signal type, cable type, etc. (cabling)

EtherNet/IP allows different protocols to work in the same network. So you can have HTTP, Modbus TCP, CIP, and more working together. It doesn’t guarantee interoperability, but you can buy gateways that can translate. And communication among the layers uses encapsulation and decapsulation through the OSI stack.

With EtherNet/IP, you have many ways to communicate – fiber, wireless, copper cables, etc. – making the physical layer independent. The data link layer also works independently, allowing different standards depending on the physical layer, such as IEEE 802.3 (fiber), IEEE 802.3 or 802.1 (copper), and IEEE 802.11 (WiFi).

EtherNet/IP topology

With an isolated network and a single controller, you can have one of three network structures: star, linear, or ring. And these can work as standalone systems, as an example, we can mention process skids.

Image of EtherNet/IP
Image courtesy of rockwellautomation.com

You can also have an isolated network with multiple controllers. Here, you can use the same topologies, but you’ll connect all your layer-2 switches using a layer-3 switch.

Last, you can have an integrated control system using ODVA terminology. Here, you have multiple topologies connecting industrial and non-industrial devices in zone levels 0 to 3.

Image of EtherNet/IP
Image courtesy of rockwellautomation.com

Conclusion

EtherNet/IP as a protocol aligns with the concept of Industry 4.0 and the Industrial Internet of Things (IIoT). So you have a slew of options when you can mix and match protocols and topologies with local or remote connections. And best of all, the market already has plenty of devices with the EtherNet/IP protocol.

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