Electronic devices in automation are not only improving the reliability of safety systems, but are also enhancing production control. And now one network can be used to manage both. Katherine Crichton reports.
IN the past, the process control technology available was only designed to alert plant managers of stoppages in their production lines but today’s manufacturers want more: easy access to information and diagnostics, reliably and quickly.
This is a trend Justin Farrell, product manager with Siemens, has noticed, saying there is an increased demand for streamlined processes integrating several functions in one controller.
“The demand for information about the condition of machines and how efficiently they are running is increasing. We are also seeing a higher demand for devices with safety controls built in.
“Combing safety and control devices result in a more seamless transference of information, as well as less hardware and software the end user has to maintain,” Farrell explained.
“The integration of safety functions into the controller is a major advancement in automation. To ensure the safety stops do not cause loss of production or even worse, damage to the machine, a lot of work must be done in communicating between older style safety controllers and machine controllers to ensure control and safety work as one. If the two are more cohesively selected, then this is more likely to happen.”
Farrell says the move from mechanical to electronic safety devices has also contributed to better communications distribution, with electronic devices allowing manufacturers immediate access to detailed information and diagnostics.
“This is one of the most important factors in replacing mechanical systems with electronic ones. If equipment fails and operations stop, manufacturers need to know why as quickly as possible,” he told Manufacturers’ Monthly.
Derrin Drew from Schneider Electric agrees, and says with mechanical devices such as position switches becoming electronic by using non-contact technology, a large failure mode for those types of devices has been greatly reduced.
“By having more diagnostic information, manufacturers can work this into their preventative maintenance, whereas with a mechanical/traditional position switch you have to wait for it to fail and then swap it over which causes downtime in production,” he said.
Systems are also becoming more compact, taking up less space on the factory floor, and are easier and faster to install resulting in less downtime for manufacturers.
Field bus or Profibus are commonly used for networking or linking electronic devices and PLCs but both Derrin and Farrell believe Industrial Ethernet will potentially be the network of the future.
Getting connected With the ability to provide users with increased speed, bandwidth and better interoperability, offering users one network for control, safety, configuration and synchronisation, Industrial Ethernet is quickly gaining popularity.
“Operators are able to control the movements of a robot for example while also knowing how many parts it has made,” Farrell explained.
He said that another key advantage of Ethernet is the fact it is an ‘open’ network, meaning it can be used by other vendors who can add their own protocols to the existing network, helping to reduce cost, time and risk for users deploying and maintaining their network architectures.
Drew advises when choosing a network, manufacturers need to ensure it is widely supported.
“The technology is moving at a very rapid pace. Features are getting more advanced and you have to keep up with market trends.
“The reality is, typically the most popular features the wider community is using, will ensure whether or not a particular network is supported well into the future,” he told Manufacturers’ Monthly.
Drew also added because very few safety and automation systems remain static, manufacturers need to consider whether or not they will be upgrading their networks in the future and how they will be doing this.
“If you have the right system in the beginning, then adding or subtracting from it can be quite pain free and cost effective as well.”
Farrell said some of the challenges of using Ethernet are not due to the technology itself, but users not understanding exactly what it can do.
“Often it comes down to what the expectations are. Manufacturers need to consider their application and what network features they need to accomplish it successfully,” he said.
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