An Introduction to KNX

Ed Wenck | Mar 16, 2021


KNX – if you’re a custom integrator in Europe, you’ve likely at least heard of it. In the Americas, not so much.

This post from the Canadian firm Optigo has a terrific explainer:

KNX is an open protocol that’s popular in European building networks … [but while] its adoption isn’t on par with BACnet in North America, Hidden Wires adds that it is growing in popularity in the US.

KNX … uses a “decentralized topology,” according to IoT for All: essentially, a KNX network doesn’t work off of a central unit, meaning that the components are self-sufficient. “There is no need for centralized control centers since all devices speak the same language and communicate via the same Bus,” as Build Your Smart Home explains. More importantly, if any single network piece breaks down, the others can still function normally.  

Additionally, KNX works on all different transmission types: twisted-pair, Ethernet, radio, or powerline, according to WAGO. Users can network together all different systems, including lighting and HVAC. And according to Build Your Smart Home, KNX has low energy consumption.

Phil Juneau, CCO of Automated Technology Company, LLC is a convert. “I was a BACnet guy for years, he says. “I was in the HVAC controls business. I’d be speaking to the electrical guys -- and they're like talking a whole different language -- and then they bring up KNX.

“This got me interested – and now, I’m of the opinion that me it’s one of the best field protocols you can ad. I'm a controls engineer. And I’ve always been taught that the lowest point of control is the best type of control. And that's what KNX is. The brains are in the devices. The sensor knows what it has to do. It's all on one communication platform.”

A Change in Thinking

Juneau notes that he had to shift his mindset when he began using the technology. “If you look at a BACnet controller, that's central IO -- you've got a centralized controller and a lot of various inputs and outputs, analog and digital, and it comes back to one central control. And then that controller is networked in the topology of BACnet.”

“If you go to KNX, okay, the IO is built into the device and that's a whole different way of thinking. That device has an address, so the controls aspect is going to be much different in the way you apply it.”

Casto Canavate of the KNX Association (he’s team leader of the marketing department) gives us some background: “We've been doing this technology for 30 years. We started from lighting control and then we moved beyond that into ventilation control, HVAC control, and today the protocol covers everything, including AV.”

Unofficially, Canavate says, KNX is built into 8,000 “families” of devices (that includes variations of a single device, such as different finishes, for example.) Those devices are offered by 500 certified manufacturers, and as Canavate notes, “If one product disappears from the market – for any reason – another KNX-certified device that performs the same function can replace it – and you’re not tied to a specific brand.”

Sign up for CEDIA’s KNX in the Home Conference to learn more: https://cedia.net/education-events/knx-in-the-home-conference


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