EtherNet/IP – Joining Two Worlds

  • September 12, 2011
  • Feature

September 2011 By Chris Bowman, TR Electronic It has become increasingly important that communication between field devices and controllers be as quick and efficient as possible.  The development of Ethernet based communication protocols is obviously a step in the right direction to not only drive system performance, but also to simplify factory floor networks.   However, with the potential for industrial Ethernet to blend with traditional office networks, it is equally important that organizations recognize and address some of the common concerns with bringing Ethernet technology to the factory floor. I have heard all too often how internal politics “get in the way of best practices and reason.”  IT departments in many companies have been perceived as difficult to work with, and unwilling to change policy or permissions to accommodate unique user requirements; Controls Engineering wants to keep their systems separate and out of the hands of IT.  It is critical that we, Controls Engineers (Control Freaks), take the lead and recognize the legitimacy of IT concerns.  We have to help educate them, to see how our needs differ from that of E-mail and Web Servers.  Inversely we also have to ensure we educate ourselves, to be able to understand the impact that our systems will have on a corporate network. There is often resistance to change.  Collaboration between Controls and IT will help to reduce this resistance.  Many companies have begun to employ Industrial Network Engineers, giving them the responsibility to bridge the gap between the two organizations.   This is a great first step to understanding and realizing the true benefits of industrial Ethernet protocols, such as EtherNet/IP. Many people make the assumption that EtherNet/IP control networks will be directly affected by regular office network traffic.  This is true, if there is no planning, or if networks are not laid out and configured properly.  One will hear people discussing Latency and Jitter with regard to EtherNet/IP, these are all valid concerns, however can be easily addressed with proper consideration prior to commissioning your network.  Although a control network can run on the same medium and utilize the same hardware as office networks; most IT departments would like to have separation of the two, as would the Controls group.  This separation is easy to attain and enhancements can be adopted to improve EtherNet/IP in an industrial application; with VLANs, Subnets, QoS, and other networking tools.  These tools and enhancements are well understood by those working in the IT world, and are relatively new to us in the control field. The idea of EtherNet originated on a napkin over 40 years ago, and has since grown into our everyday lives.  It is only the last few years when it has started to become mainstream on the factory floor.  Initially the setup and configuration of EtherNet/IP devices can be overwhelming.  Most of us have had experience with different forms of EtherNet, typically setting up our own home networks.  However with integrated web servers for configuration, integration becomes very simple and easy.  Having these tools also creates potential security issues, making systems more vulnerable to deliberate and accidental tampering.  Like any industrial communications, there are advantages and disadvantages to using EtherNet/IP.  Informing oneself of the limitations will help you to determine if EtherNet/IP is the right way for your installation. TR Electronic has had the opportunity to work on many installations of EtherNet/IP with our customers.  Initially there was apprehension, as to the ability of EtherNet/IP to close a motion loop.  Those concerns were put to rest with the installation of a managed switch.  Not only did this address concerns over IP Addressing, but it took care of packet routing and collision control as well.  During one customer visit, I had actually heard a Production Manager ask an employee if they could run to a local electronics store and purchase a new switch, because the one they had burned out.  Although this is not a recommended practice, it does give some flexibility in cases of emergency.  I believe that this is not only critical in driving down costs, using consumer technology in an industrial setting, but it also pushes the technology forward as demands on both the consumer and industrial side increase. There are many advantages to being able to have factory floor data all the way up to the enterprise level.  The ability to drill down and conduct remote diagnostics of a device from around the world is also easily realized with EtherNet/IP.  The support of the ODVA with Free Training Seminars, as well as the network of members supporting the protocol also gives users a wealth of knowledge and experience to draw from.  Always remember your three E’s when starting down any new project; Educate (read articles, attend seminars, ask questions, and listen to answers), Experience (Test demo units from suppliers), Evaluate (Compare all options to find which is going to work for you). Author Bio Chris Bowman is the Technical Product and Service Manager for TR Electronic North America.  With over 15 years in Automation, Chris has extensive knowledge of automation systems and real world experience in Manufacturing, Maintenance, Engineering and Technical Education.  TR Electronic has been providing customers with EtherNet/IP devices for over a year and continues to see significant growth in this communication protocol.  TR Electronic can provide full service and support and look forward to seeing this grow in the future.  

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