Advances in Ethernet technology and reduced component costs are today fuelling a massive growth of Ethernet in plant floor networks. The application of Ethernet and Internet technologies is permeating every aspect of manufacturing automation - control, safety, configuration and diagnostics, synchronisation and motion, and information.
The Open DeviceNet Vendors Association (ODVA) has been addressing this requirement since it introduced EtherNet/IP in 2001, providing users with the tools to deploy standard Ethernet technology for manufacturing applications while enabling Internet and enterprise connectivity. EtherNet/IP combines Ethernet and TCP/IP technologies with CIP, the Common Industrial Protocol - the same protocol used by DeviceNet, ControlNet and CompoNet.
CIP encompasses a comprehensive suite of messages and services for a variety of manufacturing automation applications, including control, safety, synchronisation, motion, configuration and information. As a truly media-independent protocol that is supported by hundreds of vendors around the world, CIP provides users with a unified communication architecture throughout the manufacturing enterprise.
Today EtherNet/IP is the most developed, proven and complete industrial Ethernet network solution available for manufacturing automation, with more than 1.4 million nodes installed worldwide and projected double digit growth rates over the coming years. The protocol is supported by companies across the spectrum of automation product development, and is featured in well over 400 different product types, including PLCs, HMIs, I/O blocks, valve manifolds, weigh scales, motion controllers, drives, resolver interfaces, vision systems and more.
The specification is being continually enhanced to meet the needs of evolving automation applications, delivering increased ease of configuration for users. The latest update to EtherNet/IP provides new specifications for industrially hardened cables and provides active interface design requirements for industrial interfaces, while still supporting commercial products and interfaces. In line with international standards, a minimum of Category 5e cabling components is now recommended. In addition, the specifications for the physical layer have been made more comprehensive through the addition of support for physical media dependants (PMDs), such as TP-PMD and fiber PMD.
ODVA is also in the midst of three major co-operative initiatives, expanding CIP to Sercos, FDT and most recently Modbus/TCP. The integration of Modbus devices in the CIP architecture will provide seamless access from CIP originator devices to Modbus target devices consistent with the existing CIP model, providing a standard translation of a subset of CIP functions into the appropriate Modbus functions.
Users will benefit through significantly increased interoperability between the largest installed base of industrial Ethernet networks - EtherNet/IP and Modbus/TCP, which according to a recent study from ARC Advisory Group represent over 50% worldwide market share - as well as between automation products from a growing number of vendors. Combined, these benefits will reduce cost, time and risk for users deploying and maintaining their network architectures. This extension requires no change to existing Modbus/TCP target devices or EtherNet/IP target devices in order to take advantage of the seamless connectivity offered. In addition, no changes are required for installed CIP-Modbus gateway devices.
Schneider Electric, the company behind Modbus, became one of ODVA's principal members in April 2007, significantly increasing its level of support for the organisation, and reflecting its plans to deploy EtherNet/IP as a foundation of its network strategy. It is a major indication of industry's continued push to adopt network technologies for automation that use standard, unmodified Ethernet and Internet technologies.
The initiative to integrate Modbus devices into CIP came hot on the heels of announcements regarding Sercos and FDT. Sercos International (SI) has committed to adopting CIP Safety - the safety extension to CIP - as its functional safety protocol. SI and ODVA are jointly developing and establishing conformance testing for devices implementing CIP Safety on Sercos to help ensure compliance with the collective body of specifications and enable interoperability of these devices in multi-vendor systems.
The initiative meets the needs of users for a single, worldwide network protocol for safety applications. Further, the joint support of CIP Safety by ODVA and SI will facilitate technical and market synergies for users and vendors of functional safety networks.
The joint initiative with FDT adds a DTM configuration option to the CIP specification. The first result of ongoing joint work between FDT and ODVA joint interest groups, it allows configuration of CIP devices using FDT compliant software.
The pace of adoption of EtherNet/IP is increasing at a fast rate, and that adoption is global. Key markets include China, where EtherNet/IP is already an established standard. It was adopted in 2006 by the National Development and Reform Commission (NDRC) of the People's Republic of China as a machinery industry standard JB/T 10308.2-2006:"Digital data communication for measurement and control - Fieldbus for use in industrial control systems".
To further assist CIP Network developers in this important market, ODVA and TÜV Rheinland have just announced that a conformance Test Service Provider for DeviceNet and EtherNet/IP will be established in mainland China at TÜV Rheinland operations in Shanghai. Conformance testing is a necessary step required by ODVA of all vendors seeking ODVA Declarations of Conformity for their ODVA technology-compliant products.
Furthermore, conformance testing provides general industry with the vendor-independent assurance that products built to the ODVA specifications comply with the ODVA specifications and interoperate in multi-vendor installations.
With its foundations of standard, unmodified Ethernet, its use of CIP, and with these latest developments fuelling its impressive growth rates, EtherNet/IP is quickly becoming the de facto standard for industrial Ethernet.
Katherine Voss is ODVA executive director