KNX is the only open protocol building automation system, with manufacturers and installers in every part of the world it is quickly growing to become the worldwide standard for automation and large-scale applications. With so many different manufacturers and products it is essential that there is an easy way to get them to all work together, the solution to this is ETS. ETS is the programming software used for all KNX projects. In this blog you will find a glimpse into how programming is done in ETS along with how KNX devices are physically installed. The first step is the installation of the devices.
Installation:
The key difference when wiring KNX is all the switched circuits have their own feeds that run directly back to the switchboard, this usually includes: Lights, Fans, UFH, Heaters, Towel Rails & in some cases electric blinds. The reason for this is because it all gets switch via KNX relays so every circuit is switched in the switchboard.
Next step is the switching, KNX cable is commonly daisy chained from one switch to another reducing cable used; below you can see an example of this, each switch has a KNX switching interface that requires a KNX cable, these work as contacts that send a commands that are programmed to do whatever is required. KNX cable is also used for sensors and Touch panels.
Programming:
At this stage all the lighting and KNX devices have been installed but do nothing, so now we have to tell each device what is does. To keep everything tidy and straight foward there’s some preparation we do to the ETS project as shown below
Once we have done this all of our controls are neatly in the file so no we must link each of these group addresses with the devices that it interacts with, these being the inputs and outputs. The function of the group address is simply to organize communications between devices for each individual circuit. Below you can see all the devices in our project, the “Universal Interfaces” are our switch modules that toggle when switched, the Z40 is our Touch screen panel and the “Switch, Staircase 24-fold” is our 24 Channel Relay that does the actual switching of the loads. From here we can go into each devices parameters to change settings and what it is linked to.
Below you can see our 24-way relay and what it is linked to, so here we link each individual channel with the group address of the circuit in that channel, as an example Channel A on our relay switches the Living room lights so we link the switching function to the switching group address (1/1/1) and the status function with the status group address (1/4/1) the first 1 corresponding to the main group (Lighting), the second 1 corresponding to the sub group (Switching) and the third 1 being the function (Living) and for status all we change is the subgroup from switching (1) to Status (4)
Now we have all the outputs linked to their corresponding group address its time to add our inputs. As an example this is the garage 2 gang switch that also has long press functions. Input A (top switch) is sending a toggle to the Garage lights (1/1/14) and updating the status (1/4/14), the long press is sending an ON to our “Welcome home” central group (This is a group address that we have linked with the outputs for multiple circuits of lights around the entry). Input B toggles the Laundry Fan (1/1/4) and updates the status (1/4/4) and the long press sends an OFF to the “All Off” central group (A group address we have linked to every lighting circuit)
This covers the general basics of a KNX installation and has hopefully helped give a better understanding of how the system is structured in a visual sense, If you have enjoyed reading this or would like to learn even more we offer Training courses that help cover more of the theory and give you some hands on experience. But also check out some of our guides as they also have some more info on the basic parts of KNX.
