Plant Floor Control Network Considerations, Advantages and Innovations

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Nearly every item you own has been through the manufacturing cycle at one point or another. Automation and Process Control have only been growing in the recent decades. With the introduction of technologies, commonly umbrellaed by buzzwords such as IoT, big data, connectivity and others, we see the rise and constant need to expand our networks. In other words, we’re looking to collect as much data as possible at the plant level in order to make smart decisions about productivity, preventive maintenance, improvement opportunities and much more. Historically, many technologies have been introduced to the plants. Some of the most known are ControlNet, DeviceNet and most recently: EtherNet.

The Importance of ControlNet and DeviceNet

I’m almost positive that all of you know about EtherNet. You use it every single to connect to the internet. However, we didn’t have this luxury a few decades ago. Something we take for granted today, wasn’t nearly as readily available and reliable a few decades ago. The solution was a suite of networks which had a specific purpose. Each had a drawback and an advantage over another.

DeviceNet Network

DeviceNet was a network protocol pioneered by Allen Bradley. The goal was to create a small yet reliable and easy to implement device level protocol. It is able to have up to 64 nodes on a single card and has very slow update rates compared to the other solutions. You would typically see DeviceNet node inside of a module with several input & output devices tied to it. The nodes themselves would go back to a central panel where a Programmable Logic Controller (PLC) would aggregate all the data and make process decisions.

From a hardware standpoint, DeviceNet nodes are extremely easy to setup, modify and troubleshoot. All you have is a pair of cables which need to be landed on a particular node and an address assigned to it. Once that’s in place, your PLC can communicate with that node. If you get in trouble, it’s easy to alter the wiring to figure out which node in the chain is not working properly.

ControlNet – Scheduled Network for High Speed Applications

One of the biggest flaws you will hear about when it comes to “other” networks is that they aren’t deterministic. What that really means is that you can’t reliably receive process critical data exactly when you need it. A good analogy for this concept would be an inexpensive letter sent abroad. The mailing service will give you a timeframe of 2 to 5 weeks without any guarantee. On the other side, you can pay a premium to make sure your letter is delivered exactly in 2 days; that’s ControlNet.

ControlNet is a reliable network protocol which allows the user to send scheduled packets between the nodes. This is an absolute must if you’re working with coordinated motion, positioning or any high speed task. If you’ve configured the network to send you the same data every 5 milliseconds, it will do so like clockwork.

On the hardware side, ControlNet is a little more involved than DeviceNet and EtherNet. It sends data over a coaxial cable which is typically more difficult to manage and requires more nodes, splitters and fine tuning in the field. It could take quite a bit of time before you can reliably determine the issue on this network.

There’s a reason why EtherNet became one of the most popular household & industrial protocols. Significant advancements have been made in order to make it reliable, safe, scheduled and highly scalable. There are so many angles to EtherNet when it comes to plant networks that I’m going to leave it for the next article on this topic. Stay tuned.

EtherNet as the Future of Plant Networks

There’s a reason why EtherNet became one of the most popular household & industrial protocols. Significant advancements have been made in order to make it reliable, safe, scheduled and highly scalable. There are so many angles to EtherNet when it comes to plant networks that I’m going to leave it for the next article on this topic. Stay tuned.

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By | 2017-09-22T16:50:13+00:00 September 22nd, 2017|Manufacturing|Comments Off on Plant Floor Control Network Considerations, Advantages and Innovations

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