How to Select Which KNX Dimmer to Use

If you're investigating which KNX universal dimmers to use - we are here to make it simple, so just ask.

Here are a few pointers to get you started.

Maximum Rating

This is the most relevant information particularly as the advertised rating may not apply to all lighting types. The rating for mains voltage LEDs or CFLs, will be a lot lower - sometimes as low as 25% of the total. This is also affected by the electronics of the LED which is why manufacturers are slowly releasing new compatibility reports and revising the ratings. As an example, Theben have recently advised there is no need to downrate trailing edge mains LED.

Also check whether channels can be paired to increase the loading, or if additional boosters are available. This is a big plus when the electrician forgets to tell you he added another row of downlights.

Minimum Rating

Most KNX dimmers have a minimum rating of 5w, but this was not always the case. If you have used an older KNX dimmer in the past and the LEDs are not turning off properly, check the minimum loading as this will be the culprit.

DIN Rail Width

This is a fairly easy one as most KNX dimmers take up 2 modules per channel.

Ease of configuration

Where possible stick to dimmers that are commissioned directly in ETS. Whilst there may be some benefits to external plugins the additional work this creates when returning to the project, or when software versions change, far outweighs these benefits. 

Look for an ETS application that allows the copy of parameters from one channel to the next is a big time saver.

Additional features

These are sometimes overlooked but they can make a big difference to the installation time or the final project cost. For example the Theben DMG 2 T/ DME 2 T dimmers have a removable bus coupler so it can be installed on site and commissioned separately. Or the Zennio DIMinBOX 2CH which has 2 analogue or digital inputs and an advanced logic engine.

Price

This can easily be calculated as a price per channel, but there is more to consider such as the reputation of the brand and route to market. It only takes a warranty not to be accepted to wipe out any profit made from finding a cheaper product.

At the end of the day there is not much between the main KNX manufacturers products, but it is still worth doing your research and finding a product that best suits your needs. Failing that, give the sales team a call for some more advice.