No KUX, just Loxone

Integration of Velux roof components into home automation systems has been often criticized in many smart home forums [1,2,3]. The usage of proprietary protocol is making this “black box” difficult to integrate and
to interact with any other solutions. The overall architecture is a bit weird, utilizing a control unit KUX 100 which is receiving the IO radio commands and then sending these to the window over the 24V line. There are several drawbacks, like space requirements, stand-by consumption, price and scalability. Moreover, who wants to have a box full of remote controls these days, or a separate mobile app for each of the device you have at home? That approach is similar to the so called “smart bulbs” you control over an app in your phone to give you the “(not a real) smart home” feeling. 🙂
I am sure you are familiar with some of these limitations because you reached out to this post. Let’s have a look how I integrated my Velux equipment (Shutters, Rollers, Power Windows) in the house, without the KUX 100 or 110 control unit.

Velux Roller Shutters

I have two rooms with Velux SML shutters. Now it is important to say, that all these Velux products are expected to be controlled by their dedicated control unit, for instance the already mentioned KUX 100. The problem with these units is that they only listen to the paired remote, and the device is not designed to accept any external commands. This makes it extremely difficult to connect to any master system. After some research I learned that due to some compatibility reasons these shutters can work in a polarity driven simple mode without the control unit.

Known fact is that once you connect the shutter to the original KUX controller, since that moment the shutter no longer listens to the polarity change and expects KUX to give instructions. There are several guides found on internet about how to reset the shutter from the “smart” back to the legacy mode working with polarity reversal (+-24VDC).

Velux Roller Shutters (SML) - closed
Velux Roller Shutters (SML) – closed

In my case, one of the four shutters I installed refused to follow the legacy polarity control. We can just speculate about the reasoning here, it could be that someone have tested that piece before shipment and thus the roller was already connected to the Velux KUX control system which enabled the “smart” control modulated on the power-line.

This is a critical scenario. I did not find a way how to reset the roller without the KUX unit. So I had to borrow one just for the purpose or the reset procedure.

If the motor has been connected, it can be reset in the following procedure:
* Connect and apply voltage on the KUX 100
* Press 5 seconds on the reset button of the transformer, not the remote control
* The motor will enter a test-run
* Disconnect the supply before the motor quits the test phase (after ± 2 seconds)
* After that the shutter will work on any 24VDC polarity change

Original here, author Pedro

But there is one more interesting thing I was not aware of. If two or more SML shutters are connected to one power supply, they immediately stop. It has nothing to do with the load, but it seems that there is built in protection avoiding hooking more than one window to one KUX. Once the shutter listens the modulated signal of the other, they both refuse to work until you switch off the relays or power supply, and enable just one of these to complete its function. So in reality, if you are planning to hook all shutters to your industrial 24VDC power supply and control these via relay boards using the polarity change, you may need to go over an additional hurdle.

The thing is that the modulated control signals needs to be filtered out. I have been experimenting here for a quite a while, and I have two workable solutions. Both require to mount filtering device directly in the upper window space, where the connections are fit.

  • Option one is to use ready made filtering module board from an old computer power supply. It usually consists of one twin-coil chokes (coil for each of the input wire) and few capacitors. It works with AC so it is polarity friendly. The advantage here is that these boards have higher total current limits and are pretty solid. You connect both input wires through the module and take the output from the other side into the shutter.
  • Option two is to purchase coil chokes (two single ones for each window, or one double) and connect each wire through one coil. Please make sure that the Imax current limit of the coil is higher than the consumption of the shutter. Few examples here:
    • Talema 42V3020, 2 x 5.6mH / 2A, Rdc(max) = 0.17 Ohm [datasheetlink]
    • Talema DPO150A1, 150uH / 1A, Rdc (max) = 0.123 Ohm [datasheet, link]

Both are very small electronic parts (size of 3 cm or similar), so it is relatively easy to put these between the connection points of the shutter. And yes, there will be slight voltage drop caused by the resistance, but you won’t notice any difference during the operation.

What it does is it eliminates any high frequency signals from the line, passing just the DC voltage there. This way you isolate the rollers that are connected to the same source. If you have 2 rollers, it should be enough to put the filtering module just to one of these, but I finally added it into all of the rollers, there is plenty of space for that.

The Velux Roller Shutters is one of the best products for these windows in my opinion. It has a clever design, allowing the window fully open when the shutter is open, and limit the opening angle only when they closed. But still you can have the window partially open when the shutter is closed. They do remember the end positions from the test drive and return smoothly back to these. Apart from the closed communication protocol I already mentioned, this is a reliable and robust product, I must say.  I never had an issue with these since 2015.

Velux Blinds

Velux DML (indoor electric blackout blinds) are the easiest to integrate. These are simpler devices so the problem of not having KUX controlling device is not applicable here, or at least I didn’t have any issues. You can easily control these using 24V polarity change. The only trouble that might appear is again the protection against multiple blinds on one power source. If you experience such issue, the same steps needs to be taken using the current chokes. This really depends on the individual installation, cabling lengths and type as well as the PSU type. I have three windows with these Velux DMLs, and I had to install chokes only after I did some rearrangements in the cabling and power supplies.

Velux blackout blinds (DML)
Velux blackout blinds (DML)

One recommendation here

If you are considering the options how to reduce the sun heat in your rooms, or even if you just look for options how to make your bedroom completely dark, in both cases go with the external roller shutters rather than the internal blackout ones. I know these are more expensive, but the quality and durability is on a higher level. And more importantly, the inside blackout blinds does not help you reduce the heat much. They do ensure total darkness, however the heat radiates inside of the room! The only time when you can get into troubles with the external roller shutters is when you get a lot of snow. Only then there is some advantage of having the indoor blinds, which are not impacted by that. In all other situations the roller shutters are better.

Few issues with Velux DML electric blackout blinds

Also, I think is fair to say here, that during the last three years I had few issues with the Velux DML’s. After a while they started to jam the fabric randomly, so I had to call the warranty service guy who has been trying to resolve that. Although we selected premium fabric, there are already few small holes in it. I have no clue how these happened, as we control these blinds only electrically. If I had to choose again, I would go with the external roller shutters SML,rather than these DML.

Velux motor KMG 100 WW

And here is the most difficult part. Some of my Velux windows are equipped with the KMG 100 WW motors from Velux. These allow automated opening and closing of the windows that cannot be reached by hand. Unlike other Velux equipment (Shutters, Rollers) which are easier to connect with Loxone, these motor actuators cannot be easily controlled via polarity change +/- 24V. The reason I heard was security or safety, but in reality Velux wants to sell their own solution, which is unfortunately not friendly to any other systems. The only way I found to integrate these roof window electric motors is to order third party PCB and replace the original board in each or the actuators. I ordered the VNX modules here. It fits perfectly into the original housing and works like a charm. Kudos to
Michał Byrecki for his amazing job!

Velux motorized window
Velux motor KMG 100 WW installed

The installation is simple and is well described in detail in the manual. You just open the plastic case, unsolder two wires, exchange the modules, solder the motor back, assemble back the case and voila, now you can control your window opening motor using the polarity change of +/- 24 V.

Original Velux board on the top, alternative from Techniline below.
Original Velux board on the top, alternative from Techniline below.

The new board still preserves the original functionality of reducing the chain and gears tension by reversing the direction for few steps at the endpoints.

With Loxone you can also use the micro-ventilation feature of Velux roof windows, that can be set-up in the blinds control module as a “shade” option (parameter “Tr”).

Slight downside you might mention is that you obviously loose any warranty as soon as you open the original motor housing, and also the additional costs (49 EUR) associated with purchase of the driver unit. But it is definitely less than you would have to spend on other extras in order to make the motor work with your system. I am using this solution since summer 2015 and I haven’t had any single issue with that.

Please note…

Finally, be aware that commercial products evolve over time and what I tested in 2015 might not be applicable to any potential newer revision of the same device. I always recommend to test or check your planned setup before you make any bulk orders.

Connecting to Loxone

Switching of the Velux components is managed using Loxone extensions with relay outputs (red connectors on Miniserver, Extension or Relay Extension). The only additional component you will need is reversing relay, which is needed for switching the polarity of 24V.  It can be done without it, but let me explain why is it better to use that.

Loxone components are not prepared for polarity switching output. To make this happen, we need to either use four Loxone relay outputs for each component.

Here is an example how Loxone can control DC motors which are often used with blinds, awnings and curtains. As you can see, it uses four relay outputs.

Or we can use only relays outputs two plus additional reversing relay. If for instance we have more windows in one room and we do not expect these to go the opposite direction at the same time, we can save few relay outputs by creating a group of blinds or shutters, but still preserve the option to control each individually if needed.

Here is how you Loxone can control the polarity change relay and individual DC motors.

Here is how you Loxone can control the polarity change relay and individual DC motors.

I have my roller shutters and blinds connected using the reversing relay. So if a room has three windows, I am using just one reversing relay for all three, and then just three individual outputs for each motor. That makes me use 4 Loxone relays and one external reversing one,  compared to 12 if I would follow the upper diagram. The only disadvantage is that I cannot run blinds the opposite direction at a time. But this I identified as very rare scenario.

As an external relay I am using Finder which consists of three parts: 24VDC relay coil with 8A contacts FINDER 40.52.9.024.0000, a base for DIN rail mount FINDER 95.05 and a clip holding these two pieces together FINDER 095.01

Config

Programming in the Loxone config is just an additional logic around the blinds control block. If you want to be extra finicky, you can also add controlling logic to prevent opposite direction runs of multiple blinds in one room (connected to one common reversing relay).

Velux motor config

Please note that the above config maintains just the basic functionality. There needs to be additional programming done for rain protection, as well as central functions. This probably deserves separate post.

Velux blinds config

The blinds modules are configured for two windows here, can be controlled separately in the app or joint using a wall switch.

I hope this might help someone when considering the options how to automate and control the roof windows accessories.

5 Comments

  • This is so great that you shared this info!
    Unfortunately the links to the VNX-driver and manual seem to be offline. Is the module maybe not up to date anymore for the newest Velux windows? Would you know an alternative for this replacement module ?
    Thank a lot

      • Hi Bart,
        well how to say that… Now I know what is behind, the modules are (and will be) available, however there has to be done some forced update in the doc and web presentation. I believe the info will be back online soon, please stay tuned.

          • I just checked the Techniline website again, and the manuals are back online. They now contain some forced warnings about the implications of the HW modification (requested removal of CE certification, and so on..).
            It is interesting that Velux is going after these HW customizations rather than making the device open and naturally compatible with multiple systems.

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