EtherNet/IP

EtherNet/IP (Ethernet Industrial Protocol) is an industrial application layer protocol designed for industrial automation applications. It is supported by ODVA.

Built on the standard TCP/IP protocols, it utilizes long established Ethernet hardware and software to define an application layer protocol for configuring, accessing and controlling industrial automation devices.

EtherNet/IP classifies Ethernet nodes as predefined device types with specific behaviors. This allows for:

1.) Transfer of basic I/O data via UDP. For example: digital or analog I/O. (Implicit messaging)

2.) Uploading and downloading of parameters, setpoints, programs and recipes via TCP. (Explicit messaging)

3.) Polled, Cyclic and Change-of-State via UDP. For example RPI and COS in Allen Bradley's ControlLogix system.

4.) One-to-one(unicast), one-to-many(multicast), and one-to-all(broadcast) via TCP.

The EtherNet/IP application layer protocol is based on the Common Industrial Protocol (CIP) layer used in both DeviceNet, CompoNet and ControlNet. Building on these protocols, Ethernet/IP provides a seam-less integrated system from the Industrial floor to the enterprise network. An overview of the EtherNet/IP technology can be found here: [1]

ODVA is the organization that supports network technologies built on the Common Industrial Protocol (CIP). These currently include the network adaptations of CIP—EtherNet/IP, DeviceNet and CompoNet—and major application extensions to CIP: CIP Safety, CIP Motion and CIP Sync. More information on the CIP technologies and standardization can be found here: [2]

History

EtherNet/IP was developed in the late 1990’s by Rockwell Automation as part of Rockwell’s industrial Ethernet networking solutions. With little or no input taken from other ODVA members, Rockwell gave EtherNet/IP its moniker and handed it over to ODVA, which now manages the protocol and assures multivendor system interoperability by requiring adherence to established standards whenever new products that utilize the protocol are developed.

Today, EtherNet/IP is most commonly used in industrial automation settings (e.g., water processing plants, manufacturing facilities, utilities) in the US and Asia for communication to and from Rockwell Automation’s Allen Bradley-brand control systems. However, other industrial automation and control system vendors, including Opto 22 and WAGO Corporation, have developed programmable automation controllers and I/O capable of communicating via EtherNet/IP.

Technical Details

EtherNet/IP classifies Ethernet nodes as predefined device types with specific behaviors. Among other things, this enables: 1) Transfer of basic I/O data via UDP-based implicit messaging 2) Uploading and downloading of parameters, setpoints, programs and recipes via TCP (i.e., explicit messaging.) 3) Polled, cyclic and change-of-state monitoring via UDP, such as RPI and COS in Allen Bradley's ControlLogix control systems. 4) One-to-one (unicast), one-to-many (multicast), and one-to-all (broadcast) communication via TCP.

The EtherNet/IP application layer protocol is based on the Common Industrial Protocol (CIP) standard used in both DeviceNet, CompoNet and ControlNet.

As EtherNet/IP is now an open technology, it was suggested to publish the Level 2 source codes via www.sourceforge.net. However, in lieu of this, freeware source code can now be downloaded from ODVA's website at [3].