Product Guide

Blind Control with KNX

Blind Control

KNX offers a solution for every method of controlling blinds.


From 1 channel flush mount actuators to 8 channel actuators, there are numerous products to control 230v blinds. Most have auto end stop detection and travel detection allowing a fairly accurate positional control. Some use an interlocking relay whilst others use two channels with a software interlock.

Although very easy to put multiple blinds on the same channel, this needs to be avoided due to the potential for feedback from one motor once the end stop is reached. This can cause each motor to feedback in a cycling loop and cause irrevocable damage.


In the same way as 230v it is important to wire each blind to an individual channel ensuring there is no erroneous feedback or operation of the builds.

Most KNX 24VDC blind controls do not generate the 24VDC supply, this needs to be provided separately. The actuator will then pass the voltage on reversing the polarity to run the blind in the opposite direction.

Contact Closures

A 230v blind actuator can be used to control blinds with low voltage inputs, but this will still provide a closed signal for the parameterised run time of the blinds. If a pulsed output is needed, use a standard relay/switching actuator.

One of the largest manufacturers of blind motors, Somfy, have direct interfaces to KNX. The key product is the RS485 gateway which allows 8 blind motors to be interconnected using a proprietary bus, then a KNX Gateway is used to offer exact positional control. They also produce DIN Rail mounted controllers in the 230VAC and 24VDS formats detailed above.

SMI or Serial Motor Interface is a European standard for blind control. This is a digital bus, which can support 8 blinds per line each individually or grouped. A separate 230v or 24VDC feed will be required as SMI is the control bus only.

Energy Saving

When using blinds as part of the wider building control system it is very easy to realise real energy savings and increase the comfort of the living environment. For example if the internal temperature exceeds 25º, no one is home and the sun is shining, the blinds can be automatically closed to prevent solar gain.

But if someone is home the system will tilt the blinds to maintain the natural light but prevent direct sunlight.

Weather Stations

Integrating a weather station with solar tracking will allow the blinds to protect internal surface or furniture or just close to prevent heat build up. Some such as the Theben weather station have three separate lux sensors along with GPS and all the inertial logic to track sunlight from east to west.

All these products can be found in our shop.