Ok, now let’s think about the topic from a practical perspective. I’m quite familiar with KNX, but I can’t really come up with a scenario where KNX would clearly benefit us. Here are our floor plans again:
According to the current planning status, roller shutters will be installed everywhere (current planning status!). There will be a large sun sail to shade the central window and the dining room window from the sun. The dining room window facing east and the kitchen window will be in the shade shortly after noon.
A heat pump with cooling function and a ground loop exchanger for the controlled ventilation system are planned. Simple logic functions, such as bypass for the controlled ventilation or controlling the underfloor heating based on outside and return temperatures, are handled by the devices themselves. In winter, when the sun heats the floor, the return flow temperature rises, and the heat pump realizes it needs to heat less because of the external heat input. The ventilation system detects when the bypass should be activated.
Individual room control is pointless, or so everyone says in the pink forum. At least for our KfW55-standard building, it’s probably very unnecessary. Night setback is also not needed.
Energy-saving functions don’t interest me because the investment cost will always be higher than the electricity savings. Conventional smoke detectors will be installed, and please no hysterical discussions about this. There will be no gas, oil, or fireplace in the house. And if the house burns down while we’re away, it’s insured. There will be no photovoltaic system, and I’m not interested in any other extreme energy-saving measures. The washing machine has its own timer. Usually, we just load it in the afternoon and hang the laundry in the evening. It doesn’t need to run for three hours at night because of lower tariffs to save 0.3 cents per wash cycle.
The living/dining/kitchen area will have six roller shutters and four dimmable lights. Three shutters and two lights each will be controlled from switches next to the living room door and the kitchen door. The switches are arranged side by side so that the leftmost switch controls the left side of the room, and so on. So the west, south, and central living areas are controlled from the living room door; the south dining area, east dining area, and east kitchen are controlled from the kitchen door. For shading, only the two roller shutters next to the living room are relevant (south living room, as it is not under the sun sail, and west living room).
Currently, in the old building, we have internal blinds and a large west-facing facade. Apart from the five warmest days of the year, we don’t fully shade the windows. We just want to avoid direct sunlight where we are sitting, working, playing, etc. Depending on the situation, some blinds go up and others go down, and so on.
Constant light regulation is not desired. Even now, we switch lights on and off based on feeling. When we want to go to bed soon, the lights are usually off or more distant lights are on (kind of indirect lighting). I have different lighting preferences than my wife, and when we are together in the room, naturally, a compromise solution applies.
I sometimes work flexible hours, and sometimes I might sleep only four hours one night and seven hours the next day. A rule like “dim after xx o’clock” won’t work.
There is no defined TV lighting plan. It depends on the program. For briefly watching the news, all lighting can remain as is. For a moderately interesting football game, only the direct light is turned off, but indirect lighting can stay. For a ‘Game of Thrones’ episode or a good movie, everything should be off, especially since these often have dark scenes. Sometimes, for example, the hallway light stays on as indirect lighting for the living area (which makes sole hallway lighting with motion sensors pointless now).
Hallway lighting will have switches (two-way switches) next to each door, which can turn the lighting of the respective floor on and off. So yes, exactly one switch next to each door. The two lamps upstairs will switch on and off simultaneously. It is a floor-level switch. At stair landings, of course, there are exactly two switches: one for upstairs and one for downstairs. So, coming down the stairs, you can operate both switches to turn lights off upstairs and on downstairs. Or you turn off the upstairs light at the bottom of the stairs (top switch off = upstairs off; makes perfect sense to me).
Stair lighting could theoretically be controlled similarly, but that also depends a bit on the show effect, right? It could also be done with a timer or motion sensor. And if pets trigger the stair lighting, well, that’s just how it is. At the moment, we don’t have pets.
As for roller shutter control in the living/dining/kitchen areas, as I said before: short press for fully up/down and hold for precise positioning. But half-positioning is discouraged because temperature differences across the glass can cause damage. For example, next to the living room door, pressing the button three times briefly will raise (or lower) the three shutters. All other roller shutters follow the same principle and are arranged next to their respective doors. Only for bedrooms could I imagine a switch with a timer function, and I would only program the opening time for the next morning. I don’t need a closing time. A short press closes the roller shutter. But if I set my alarm clock to 6:53, I also set the roller shutter to 6:53 so that daylight wakes me at the same time (in the future, we will have joint wake-up times again, and my wife won’t have shift work anymore). BUT: all this can be done conventionally and very simply. So: the office (guest room), bedroom, and two children's rooms will have a switch (short = fully up/down) that allows an opening time to be set.
Just to summarize the shading logic during the day: roller shutters go down in the morning when leaving the room/living area and stay down until the first person returns home in the afternoon. This covers the first 10–12 hours of sunlight exposure.
The lighting in many rooms will be dimmable, but I don’t want expensive color lighting effects. The bulbs should have low blue light and good quality.
So, I think I’ve described the most important areas: roller shutters, lighting, heating, and a few other things...
How can automation like KNX help us now? What comfort gains are possible? What should we automate and why?
According to the current planning status, roller shutters will be installed everywhere (current planning status!). There will be a large sun sail to shade the central window and the dining room window from the sun. The dining room window facing east and the kitchen window will be in the shade shortly after noon.
A heat pump with cooling function and a ground loop exchanger for the controlled ventilation system are planned. Simple logic functions, such as bypass for the controlled ventilation or controlling the underfloor heating based on outside and return temperatures, are handled by the devices themselves. In winter, when the sun heats the floor, the return flow temperature rises, and the heat pump realizes it needs to heat less because of the external heat input. The ventilation system detects when the bypass should be activated.
Individual room control is pointless, or so everyone says in the pink forum. At least for our KfW55-standard building, it’s probably very unnecessary. Night setback is also not needed.
Energy-saving functions don’t interest me because the investment cost will always be higher than the electricity savings. Conventional smoke detectors will be installed, and please no hysterical discussions about this. There will be no gas, oil, or fireplace in the house. And if the house burns down while we’re away, it’s insured. There will be no photovoltaic system, and I’m not interested in any other extreme energy-saving measures. The washing machine has its own timer. Usually, we just load it in the afternoon and hang the laundry in the evening. It doesn’t need to run for three hours at night because of lower tariffs to save 0.3 cents per wash cycle.
The living/dining/kitchen area will have six roller shutters and four dimmable lights. Three shutters and two lights each will be controlled from switches next to the living room door and the kitchen door. The switches are arranged side by side so that the leftmost switch controls the left side of the room, and so on. So the west, south, and central living areas are controlled from the living room door; the south dining area, east dining area, and east kitchen are controlled from the kitchen door. For shading, only the two roller shutters next to the living room are relevant (south living room, as it is not under the sun sail, and west living room).
Currently, in the old building, we have internal blinds and a large west-facing facade. Apart from the five warmest days of the year, we don’t fully shade the windows. We just want to avoid direct sunlight where we are sitting, working, playing, etc. Depending on the situation, some blinds go up and others go down, and so on.
Constant light regulation is not desired. Even now, we switch lights on and off based on feeling. When we want to go to bed soon, the lights are usually off or more distant lights are on (kind of indirect lighting). I have different lighting preferences than my wife, and when we are together in the room, naturally, a compromise solution applies.
I sometimes work flexible hours, and sometimes I might sleep only four hours one night and seven hours the next day. A rule like “dim after xx o’clock” won’t work.
There is no defined TV lighting plan. It depends on the program. For briefly watching the news, all lighting can remain as is. For a moderately interesting football game, only the direct light is turned off, but indirect lighting can stay. For a ‘Game of Thrones’ episode or a good movie, everything should be off, especially since these often have dark scenes. Sometimes, for example, the hallway light stays on as indirect lighting for the living area (which makes sole hallway lighting with motion sensors pointless now).
Hallway lighting will have switches (two-way switches) next to each door, which can turn the lighting of the respective floor on and off. So yes, exactly one switch next to each door. The two lamps upstairs will switch on and off simultaneously. It is a floor-level switch. At stair landings, of course, there are exactly two switches: one for upstairs and one for downstairs. So, coming down the stairs, you can operate both switches to turn lights off upstairs and on downstairs. Or you turn off the upstairs light at the bottom of the stairs (top switch off = upstairs off; makes perfect sense to me).
Stair lighting could theoretically be controlled similarly, but that also depends a bit on the show effect, right? It could also be done with a timer or motion sensor. And if pets trigger the stair lighting, well, that’s just how it is. At the moment, we don’t have pets.
As for roller shutter control in the living/dining/kitchen areas, as I said before: short press for fully up/down and hold for precise positioning. But half-positioning is discouraged because temperature differences across the glass can cause damage. For example, next to the living room door, pressing the button three times briefly will raise (or lower) the three shutters. All other roller shutters follow the same principle and are arranged next to their respective doors. Only for bedrooms could I imagine a switch with a timer function, and I would only program the opening time for the next morning. I don’t need a closing time. A short press closes the roller shutter. But if I set my alarm clock to 6:53, I also set the roller shutter to 6:53 so that daylight wakes me at the same time (in the future, we will have joint wake-up times again, and my wife won’t have shift work anymore). BUT: all this can be done conventionally and very simply. So: the office (guest room), bedroom, and two children's rooms will have a switch (short = fully up/down) that allows an opening time to be set.
Just to summarize the shading logic during the day: roller shutters go down in the morning when leaving the room/living area and stay down until the first person returns home in the afternoon. This covers the first 10–12 hours of sunlight exposure.
The lighting in many rooms will be dimmable, but I don’t want expensive color lighting effects. The bulbs should have low blue light and good quality.
So, I think I’ve described the most important areas: roller shutters, lighting, heating, and a few other things...
How can automation like KNX help us now? What comfort gains are possible? What should we automate and why?
@Grym: you haven’t understood the basics of KNX yet....
I’ll give you an example using one light switch and one roller shutter up/down.
The active side, meaning 230V (230V)
Roller Shutter
A 5-conductor cable runs from the distribution board to the roller shutter. On the roller shutter side, it’s connected to the motor. On the distribution board side, it connects to the actuator: one conductor for up, one for down, plus protective earth (PE) and neutral conductor.
That’s it.
Light
Similar to the roller shutter. A 5-conductor cable runs from the distribution board to the light. One conductor connects to the actuator and one to the light, plus PE and neutral as usual (the two spare conductors are just for potential future upgrades).
That’s all there is to it. With this setup, you can always switch, for example, a line to 24V later since it runs from the consumer to the distribution board.
If you want to make a switched light dimmable, you simply connect the conductor in the distribution board to a dimmer. The wiring for sockets/outlets is similar. This allows you to first switch everything on/off inexpensively and upgrade to dimming later (dimming actuators are more expensive per channel).
Basically, this matches classical installation, just using different devices. Instead of switches, you have actuators.
Now comes the ‘magical’ KNX part. These actuators (switching relays) are connected to the bus, listen to it, and react to the commands configured for them on the KNX bus.
The sensors (push buttons or classic switches) are completely separated from the actuators. All sensors—whether presence detectors, motion sensors, push buttons, home servers, etc.—are connected to the bus. When you press a sensor or push button, or a sensor detects movement, or a thermoelement reaches a switch threshold, it sends the preset command onto the bus. For example, you can configure a switch in the living room to send the command “close all roller shutters.” All actuators programmed to respond to that command then react accordingly.
You can assign more than one command code to the actuator. For example, tell the actuator to respond to ‘Close all roller shutters,’ ‘Close kitchen roller shutter 1,’ or ‘Close all kitchen roller shutters.’
If you assign a button to ‘Close all roller shutters’ and press it, it sends that command. Assign another button to ‘Close all kitchen roller shutters,’ and it sends that on the bus. The actuators programmed for those commands then execute them.
That’s the advantage. You can install any number of sensors anywhere and configure them accordingly. No matter where you press in the house, the actuators respond. If you have four identically configured switches in one room, it doesn’t matter which one you press; the same action will take place.
This is the huge benefit of KNX: actions and reactions are configurable.
The bus supports many commands: on/off, dimming, up/down, time, positions, and so on. All devices, regardless of manufacturer, follow these commands. This means if a B&J device sends the “up” command, ABB or MDT actuators will understand it too.
Now, about the server: it basically does the same thing. Software runs on it that can send and receive commands on the bus. You can create links (so-called logics). Many current actuators and sensors already have simple logic functions built in, allowing you to do a lot with them.
If you wire lighting and roller shutters in a star topology and then add one or two lines per room for sockets and distribute those within the room, you can later add corresponding ‘switch extensions’ in the distribution board. If you don’t want to switch or monitor, the respective lines are simply bridged.
I hope this explanation helps you a little. Because if you don’t understand the basics, there’s no point in getting into the details.
I’ll give you an example using one light switch and one roller shutter up/down.
The active side, meaning 230V (230V)
Roller Shutter
A 5-conductor cable runs from the distribution board to the roller shutter. On the roller shutter side, it’s connected to the motor. On the distribution board side, it connects to the actuator: one conductor for up, one for down, plus protective earth (PE) and neutral conductor.
That’s it.
Light
Similar to the roller shutter. A 5-conductor cable runs from the distribution board to the light. One conductor connects to the actuator and one to the light, plus PE and neutral as usual (the two spare conductors are just for potential future upgrades).
That’s all there is to it. With this setup, you can always switch, for example, a line to 24V later since it runs from the consumer to the distribution board.
If you want to make a switched light dimmable, you simply connect the conductor in the distribution board to a dimmer. The wiring for sockets/outlets is similar. This allows you to first switch everything on/off inexpensively and upgrade to dimming later (dimming actuators are more expensive per channel).
Basically, this matches classical installation, just using different devices. Instead of switches, you have actuators.
Now comes the ‘magical’ KNX part. These actuators (switching relays) are connected to the bus, listen to it, and react to the commands configured for them on the KNX bus.
The sensors (push buttons or classic switches) are completely separated from the actuators. All sensors—whether presence detectors, motion sensors, push buttons, home servers, etc.—are connected to the bus. When you press a sensor or push button, or a sensor detects movement, or a thermoelement reaches a switch threshold, it sends the preset command onto the bus. For example, you can configure a switch in the living room to send the command “close all roller shutters.” All actuators programmed to respond to that command then react accordingly.
You can assign more than one command code to the actuator. For example, tell the actuator to respond to ‘Close all roller shutters,’ ‘Close kitchen roller shutter 1,’ or ‘Close all kitchen roller shutters.’
If you assign a button to ‘Close all roller shutters’ and press it, it sends that command. Assign another button to ‘Close all kitchen roller shutters,’ and it sends that on the bus. The actuators programmed for those commands then execute them.
That’s the advantage. You can install any number of sensors anywhere and configure them accordingly. No matter where you press in the house, the actuators respond. If you have four identically configured switches in one room, it doesn’t matter which one you press; the same action will take place.
This is the huge benefit of KNX: actions and reactions are configurable.
The bus supports many commands: on/off, dimming, up/down, time, positions, and so on. All devices, regardless of manufacturer, follow these commands. This means if a B&J device sends the “up” command, ABB or MDT actuators will understand it too.
Now, about the server: it basically does the same thing. Software runs on it that can send and receive commands on the bus. You can create links (so-called logics). Many current actuators and sensors already have simple logic functions built in, allowing you to do a lot with them.
If you wire lighting and roller shutters in a star topology and then add one or two lines per room for sockets and distribute those within the room, you can later add corresponding ‘switch extensions’ in the distribution board. If you don’t want to switch or monitor, the respective lines are simply bridged.
I hope this explanation helps you a little. Because if you don’t understand the basics, there’s no point in getting into the details.
B
Bauexperte30 Aug 2016 08:25@Tom
A very well-written and easy-to-understand explanation. Thank you very much for that!
Bauexperte
A very well-written and easy-to-understand explanation. Thank you very much for that!
Bauexperte
Tom1607 schrieb:
@Grym : you haven’t understood the basics of KNX yet....Essentially, what you are describing is my understanding of KNX. At least since yesterday...
Lighting
Similar to the roller shutter. From the distribution board, a 5-core cable goes to the lamp. One core is connected to the actuator and one to the lamp, PE and neutral as usual (the two spare cores are just there to allow for later retrofitting). From the circuit breaker, one core goes to the actuator, and then the live conductor from the 5x1.5 NYM cable connects to the actuator? The neutral conductor goes directly from the 5x1.5 NYM cable to the circuit breaker? Is that now my understanding?
So, live conductor: circuit breaker -> actuator -> lamp
Neutral conductor: circuit breaker -> lamp
Plus: 2 spare cores and PE
That’s it. Nothing more than that. And with this, you can always rewire a line to 24 V later, since it goes from the consumer back to the distribution board. Should you use a cable with a larger cross-section for 24 V due to voltage drop?
If you want to make a dimmable lamp from a switched lamp, you simply connect the core in the distribution board to a dimmer. The wiring for the sockets is similar to this. This way you can first switch everything on and off ‘cheaply’ and then later switch to dimming (dimming actuators are more expensive per channel). That is clear to me. I could first make all the lamps switchable and leave the sockets without switching. Later, I could make the lamps dimmable and use the switching actuator for the sockets. But if desired, I could also make everything dimmable from the start where dimming is needed.
This is the huge advantage of KNX: action and reaction are configurable. That’s why I said I would first program roller shutter 1 up, roller shutter 1 down, lamp 1 on, lamp 1 off, etc., to the pushbuttons. And once we know exactly what we want, I would change it again and maybe combine some functions or configure scenes.
There are now a lot of commands for the bus: on/off, dimming, up/down, time, positions, and so on. And all devices, no matter the manufacturer, follow these commands. This means if a B&J device sends the “up” command, an ABB or MDT actuator understands it as well.
Now, about the server: it basically does the same thing. It runs software that can send commands to the bus and receive commands. You can then create links (so-called logics). Many current actuators and sensors already have simple logics built-in, so you can already do a lot with them. Yep. And if I want to set the wake-up time in the evening via a web interface (server in the intranet), then that is probably only possible with a server. On the other hand, that’s not essential, so the basic functions (roller shutters, lights) are parametrized directly, and the wake-up time (light slowly dimming up, roller shutter opening, etc.) is controlled via the server.
question 1: The neutral conductor is connected to the neutral potential from the RCD. Only the live conductor goes to the circuit breaker.
question 2: It depends on the distance to the load and the power. It wouldn’t cause any damage, but it costs more, and if you don’t need it, the money is wasted.
question 3: Yes.
question 4: Exactly, although I would consider grouping. For example, it probably doesn’t make sense to control just one roller shutter in the bedroom.
question 5: No, there is an affordable glass control panel from MDT for around €150 (about $160), I believe. You can install it 1.55m (5 feet) above the switch (if you like the design). It allows you to set everything easily via the display. You won’t find anything better at such a low price. You can trigger various functions based on time or events. There are also standard enclosures for the control cabinet that are in the same price range.
Of course, you could also use something like EDOMI for little money. The software itself is freeware, and the required PC costs around €100 (about $110). It’s a really clever and very user-friendly logic/visualization software based on a Linux system.
I use it too, and it’s really great!
Additionally, I run FHEM on a Raspberry Pi to integrate my photovoltaic system into the KNX bus, and another Raspberry Pi with KNXD as a router. But for that, you need a certain level of enthusiasm for tinkering.
For the ‘normal user,’ a simple IP interface from MDT for about €150 (around $160) is sufficient. You need it anyway for parameterizing.
question 2: It depends on the distance to the load and the power. It wouldn’t cause any damage, but it costs more, and if you don’t need it, the money is wasted.
question 3: Yes.
question 4: Exactly, although I would consider grouping. For example, it probably doesn’t make sense to control just one roller shutter in the bedroom.
question 5: No, there is an affordable glass control panel from MDT for around €150 (about $160), I believe. You can install it 1.55m (5 feet) above the switch (if you like the design). It allows you to set everything easily via the display. You won’t find anything better at such a low price. You can trigger various functions based on time or events. There are also standard enclosures for the control cabinet that are in the same price range.
Of course, you could also use something like EDOMI for little money. The software itself is freeware, and the required PC costs around €100 (about $110). It’s a really clever and very user-friendly logic/visualization software based on a Linux system.
I use it too, and it’s really great!
Additionally, I run FHEM on a Raspberry Pi to integrate my photovoltaic system into the KNX bus, and another Raspberry Pi with KNXD as a router. But for that, you need a certain level of enthusiasm for tinkering.
For the ‘normal user,’ a simple IP interface from MDT for about €150 (around $160) is sufficient. You need it anyway for parameterizing.
Tom1607 schrieb:
question 1: The neutral conductor connects to the neutral potential from the RCD. Only the live conductor goes to the circuit breaker And that is exactly what an electrician should properly prepare, for example with terminal blocks and a neutral busbar. Then the homeowner could theoretically wire the actuators themselves. This also allows for later modifications without any problems. At the moment, for example, most of the sockets intended for switching are bridged. I just need to remove the bridge and connect the actuator channel in between, then I can actually switch the socket.
@Uwe82: That's exactly how it's done. However, since I assumed the original poster only needed this for understanding, I didn’t go into much detail. Nowadays, you need at least 2 RCDs (residual current devices).
I have 6 installed: 1 RCD for lighting, 1 RCD for kitchen cooling appliances/freezer chest, 1 RCD for outdoor area, 1 RCD for sockets/blinds, 1 RCD for kitchen, 1 RCD for internal distribution panel.
I have 6 installed: 1 RCD for lighting, 1 RCD for kitchen cooling appliances/freezer chest, 1 RCD for outdoor area, 1 RCD for sockets/blinds, 1 RCD for kitchen, 1 RCD for internal distribution panel.