Collaboration key to industrial Ethernet
Industrial Ethernet is making connectivity between industrial devices better than ever. But is this giving design engineers a headache? Justin Cunningham reports.
There is a big push at the moment in the mainstream IT world towards integration. Youtube can now be watched on your TV or your phone. Emails and contacts on a PC are synced to Facebook which is also synced to the phone. Calendars are synced with events from Outlook, Facebook, Twitter, LinkedIn and all the other social media outlets, that for many have become an increasingly common part of everyday life.
At some point, these systems started talking to each other and the companies behind both the hardware and software decided on standards with which to work. But is the same happening in the industrial world as Ethernet networks increasingly get put to use?
For the most part, the physical cabling and interconnection between hardware has become fairly generic and universal. Unfortunately, different communication protocols – essentially the digital codes used to transmit data between computer systems – are at odds with each other. There are numerous protocols available that will send data between all sorts of industrial equipment, from Human Machine Interfaces (HMIs) to Programmable Logic Controllers (PLCs) to sensors and robotics. But whether that data is received and understood is another question.
"To use an analogy, any two people can pick up a phone and call each other," says Mark Daniels, field business leader at Rockwell Automation, "but if they are speaking different languages, communication is impossible. And this is something designers need to be aware of: although it might all connect together because it is Ethernet, there are a number of different protocols which exist within Industrial Ethernet that are not compatible."
There are several major protocols that have managed to secure a large portion of the market. These include EtherNET IP, ProfiBUS/ProfiNET and other more niche protocols such as EtherCAT. Andrew Starr, Professor of maintenance systems and head of integrated maintenance centre at Cranfield University says: "Where software doesn't work together very well is when there are arbitrary proprietary protocols. So if you can only buy non-standardised software from one or two companies. This makes things incompatible. However, depending on the size of the corporation, they may or may not have to give in on that.
"For example, sending someone a document is Microsoft Word is not a standard, it just has dominance in the market, so it's become a de facto standard." And this is the position of the Industrial Ethernet market at the moment: several companies pushing different, incompatible standards to try and gain enough market share to become the de facto standard.
However, this can all cause a headache for design engineers tasked with bringing to life Ethernet systems in and around a firm's operations. Obtaining equipment that all speaks the same language is often not simple and straightforward. And for many engineers, although venturing into the IT domain is a little out of the comfort zone, it is often a necessary step.
Starr adds: "There is a tendency for some of our colleagues to believe we can compartmentalise the design process or segment it. But there are great benefits to be had from early integration. It's wise that the total concept is thought through from the outset in a collaborative and integrated manner. You can see products and devices that are fundamentally well integrated in terms of mechanical, electrical, and electronic engineering; really common things from washing machines to cars. They are good designs because integration has been fundamental to its core."
However, while it is advisable to seek the advice of IT colleagues, engineers should remain mindful that the requirement of an Industrial Ethernet network is very different from a commercial one and will require very different equipment and infrastructure.
For example, redundancy recovery time – basically the time it takes for a computer to find the RAM and disk space to perform a function – could be between 1 and 30 seconds in an office network. This is fine if you are waiting for an email, but if part of your high-speed production line drops out, even for a few seconds, it will create massive problems. It requires separate and distinct infrastructure to be put in place.
John Jackson, UK electronics and strategic channel manager, at Weidmuller says: "You do not want a Windows update from the IT department broadcasting out into a PLC which is controlling an arc welder or a furnace and shutting it down. That has happened. You need separate infrastructure as the needs in terms of mean-time-before-failure, operating temperatures, redundancy requirements is much greater in an industrial environment. Cabling is also very important; to fit a £2 patch lead into important equipment such as a welder would go against the grain of good practice."
Given the pace at which connectivity and interoperability is currently accelerating, careful consideration toward scalability of an initial implementation should be taken. Given the need for the physical hardware to have a lifecycle of 15 to 20 years, future support, compatibility, robustness and longevity of that equipment should be at the forefront of any engineers' decision making.
"We always recommend having as much spare capacity on the network as possible," says Jackson. "Think about not just what you might put on the network today, but what you might want to put on to it in the future. If you are putting in an Ethernet network on the plant floor, we would recommend 1Gb on the backbone."
As PLCs get faster, HMIs improve and data collection and data logging become much more prevalent, the network will then have the capacity to move large chunks of data around effectively without causing latency issues to the plant it is connecting to.
So the aim is that one network has a multitude of applications. With a managed switched infrastructure. It is then possible to separate the network in to Virtual Networks, make use of Cloud Computing, as well as adding on additional capability such as voice-over-internet, CCTV within the plant infrastructure, barcode systems and vision systems; all of which would not normally have the potential to plug on to the network.
Daniels says: "When you start opening up all these technologies, you start to integrate enterprise applications into your industrial applications, and when you do that you get some fantastic benefits. It starts to give you completely connected enterprise, which means data information about every part of your firms operations can be used across the whole enterprise. That is a tremendously powerful tool that will allow both engineers and management to make the right strategic decisions at the right time and run a much more effective business."
Industrial Wireless Ethernet coming of age? Applications for wireless technologies are increasingly finding the way into industry, often to get round the challenges of difficult cabling. There is now enough experience out there to know how to deploy wireless in the industrial workplace; where it will work, and where it doesn't.
"You need to look at a site survey to see what reflections and physical space you are working in so you can deploy the technology in a way that you can gain yourself a reliable signal as possible," says Mark Daniels, field business leader at Rockwell Automation. "You do have to understand very clearly what your particular work space will look like and then deploy the aerials in appropriate places to make it work."
Wireless has, to date, been quite attractive to the process industry, for example, where instrumentation is generally used for lower speed applications. It's also found use in plants where cabling can be difficult to implements, such as on overhead cranes inside warehouses.
However, despite the enthusiasm, it is likely that many design engineers will always design, where possible, with hard cables because of their predictable, reliable nature. So, despite advances, wireless still seems to give engineers concerns in terms of reliability of data transmission and security. "Although everyone talks about it," says Daniels, "and there are definitely good applications for it, it still has a long way to go before it is considered the future of industrial connectivity."
What is industrial Ethernet? Ethernet is the name given to a method of creating a certain types of computer network. Specifically, Ethernet refers to a method of cabling, and the way the data is transmitted. Industrial Ethernet essentially uses the Ethernet family of computer network technologies but in an industrial environment, for automation and process control. A number of techniques are employed to make Ethernet suitable for industrial processes, which require real-time behaviour. This allows a plethora of data from multiple plants and sites to be available instantly, and integrated together.
The technology could be applied to large infrastructures such as offshore wind turbines to multi-national manufacturers to monitor plants all over the world, or equally to smaller tier1 and tier 2 suppliers to more thoroughly manage their production and supply chains. It allows real-time information about the latest batch of parts, the bearing wear on the machines that made them, CCTV access to bottlenecks in production, wastage level information, energy usage all synced to production schedules, output levels, live deliveries, financial predictions and anything else that the user can think they would want from the system.
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