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AleXSR7009 May 2020 12:38Hello everyone,
some of you might know that I’m new here and slowly getting familiar with the relevant topics. As a very tech-savvy person, I am particularly interested in automation.
I’m surprised that the current trend in advice for new builds leans towards connecting everything via bus cables. This involves a huge amount of planning with a very high likelihood of retrofitting over the next 30 years. A wireless solution or a powerline communication system would technically be completely feasible, requires much less planning, and involves hardly any extra work for the electrician. Every component to be controlled is powered anyway. Therefore, each component could be addressed via the regular power cable. And if someone wants to save a bit during construction, they could simply upgrade certain components like lighting later on and operate them manually until then. There are no additional costs for a non-smart installation of a light fixture.
Or is this already the case, and I have misunderstood the recommendations for implementing bus systems like KNX and others?
Best regards,
Matthias
some of you might know that I’m new here and slowly getting familiar with the relevant topics. As a very tech-savvy person, I am particularly interested in automation.
I’m surprised that the current trend in advice for new builds leans towards connecting everything via bus cables. This involves a huge amount of planning with a very high likelihood of retrofitting over the next 30 years. A wireless solution or a powerline communication system would technically be completely feasible, requires much less planning, and involves hardly any extra work for the electrician. Every component to be controlled is powered anyway. Therefore, each component could be addressed via the regular power cable. And if someone wants to save a bit during construction, they could simply upgrade certain components like lighting later on and operate them manually until then. There are no additional costs for a non-smart installation of a light fixture.
Or is this already the case, and I have misunderstood the recommendations for implementing bus systems like KNX and others?
Best regards,
Matthias
bauenmk20209 May 2020 14:53As long as bus systems are not offered by a standard electrician, homeowners with conventional electrical installations are more or less “shortchanged.” Those who want more need a higher budget and a skilled electrician.
However, I believe that a wireless solution with decentralized switching actuators, for example in (deep) flush-mounted boxes, can also be a viable option.
However, I believe that a wireless solution with decentralized switching actuators, for example in (deep) flush-mounted boxes, can also be a viable option.
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AleXSR7009 May 2020 15:20Okay, I will continue researching, but this is what I have gathered so far:
- There are wireless solutions
- There are powerline solutions
- It is said that powerline solutions are slower
- It is said that powerline solutions are less reliable or simply "worse"
Technically, I don’t quite understand this. A powerline system in IT can achieve real speeds of 300 Mbit/s or even higher.
However, I would say that apart from sensors like rain sensors, wind sensors, etc., no continuous communication consumes bandwidth. Window opening status, for example, can be monitored as a state and doesn’t require continuous communication.
So why would powerline be slow or poor for home automation?
In principle, IT logic also states that LAN cables are better than Wi-Fi. In reality, I run a pure Wi-Fi network with almost 15 devices and never reach the system’s overall limits. Only direct communication speeds sometimes drop to 5 MB/s (not bits), and that is due to the components, not the network. Even that should be sufficient.
Technically, both should work without problems. The only issue with Wi-Fi I see is higher power consumption because the connection is usually maintained constantly and consumes more energy than cable.
So why is there a tendency to choose the complicated and hard-to-fix wired solution?
- There are wireless solutions
- There are powerline solutions
- It is said that powerline solutions are slower
- It is said that powerline solutions are less reliable or simply "worse"
Technically, I don’t quite understand this. A powerline system in IT can achieve real speeds of 300 Mbit/s or even higher.
However, I would say that apart from sensors like rain sensors, wind sensors, etc., no continuous communication consumes bandwidth. Window opening status, for example, can be monitored as a state and doesn’t require continuous communication.
So why would powerline be slow or poor for home automation?
In principle, IT logic also states that LAN cables are better than Wi-Fi. In reality, I run a pure Wi-Fi network with almost 15 devices and never reach the system’s overall limits. Only direct communication speeds sometimes drop to 5 MB/s (not bits), and that is due to the components, not the network. Even that should be sufficient.
Technically, both should work without problems. The only issue with Wi-Fi I see is higher power consumption because the connection is usually maintained constantly and consumes more energy than cable.
So why is there a tendency to choose the complicated and hard-to-fix wired solution?
But let's start from the beginning:
Just as information: It was introduced in 1979!
And KNX is not standing still. Everything that proves itself eventually gets integrated.
Currently, KNX offers four types of communication (all bidirectional and integrated):
KNX-TP (Twisted Pair)
KNX-PL (Powerline)
KNX-RF (Wireless)
KNX-IP (Ethernet/IP)
More communication methods will follow. Via gateways, KNX commands can also control and utilize manufacturer-specific and other media, communication standards, and protocols such as Wi-Fi, EnOcean, ZigBee, Z-Wave, Bluetooth, DMX, RS-485, etc.
AleXSR700 schrieb:Why the mistaken assumption?
So why the tendency toward complicated and hard-to-fix wired solutions?
AleXSR700 schrieb:Well, people generally want to have peace of mind for several decades when investing in a house. The lights should turn on when you press the switch or enter the room, and the rest of the technology should work invisibly in the background—even 10, 20, or 30 years later. This is relatively easy to achieve with KNX. Other approaches tend to have difficulties with this. History has shown us that, and we should learn from it.
I'm just surprised that the trend in new builds is to connect everything via bus cables.
AleXSR700 schrieb:You should definitely put in the planning effort. Before buying a new TV or lawn mower, people read reviews and compare technical specifications. Strangely, it’s different with electrical installations—often it’s just “one electrical installation, please.” But especially today, with all the available options, it’s important to engage more with this. Beyond simple series wiring and outlets with timer functions, that is. As for the likelihood of retrofitting, you’re on the wrong track. RS-485, for example, is experiencing a renaissance right now.
An enormous planning effort with a very high likelihood of retrofitting over the next 30 years.
Just as information: It was introduced in 1979!
And KNX is not standing still. Everything that proves itself eventually gets integrated.
AleXSR700 schrieb:Yes, certainly, but often with restrictions that should not be underestimated concerning communication and stability compared to wired options. Nevertheless, KNX supports powerline and wireless as well.
A wireless or powerline solution should technically be no problem,
AleXSR700 schrieb:But only if your electrical system is going back to the way it was done in grandpa’s days—simple if-then tasks like basic automation of lights, outlets, and shading. Everything else requires a different approach—that is, more planning and extra work.
requires much less planning and hardly any extra work for the electrician.
AleXSR700 schrieb:That’s a misconception. In a smart home, minimizing standby power consumption is important. Ideally, each component is powered only as long as necessary.
Every component to be controlled is powered anyway.
AleXSR700 schrieb:Here lies a flawed assumption. Saving in one area usually means spending more in another. Otherwise, you’re left only with wireless and retrofit options. Why limit yourself? Especially with lighting, many mistakes can be made when following a cookie-cutter approach.
And if someone wants to save a little during construction, they can retrofit certain components like lighting later and operate them manually until then.
AleXSR700 schrieb:Of course, if it’s just a single fixture. With a wireless receiver, the lamp remains non-smart in 90% of cases—it simply gains a remote control option. It only becomes truly smart when everything works together holistically, not just when individual lamps are switchable or dimmable.
There are no extra costs for a non-smart installation of a lamp.
AleXSR700 schrieb:Yes, and KNX can handle all of these under one system.
- There are wireless solutions
- There are powerline solutions
Currently, KNX offers four types of communication (all bidirectional and integrated):
KNX-TP (Twisted Pair)
KNX-PL (Powerline)
KNX-RF (Wireless)
KNX-IP (Ethernet/IP)
More communication methods will follow. Via gateways, KNX commands can also control and utilize manufacturer-specific and other media, communication standards, and protocols such as Wi-Fi, EnOcean, ZigBee, Z-Wave, Bluetooth, DMX, RS-485, etc.
AleXSR700 schrieb:Yes, generally that is true. The “processing delay” is where most powerline solutions fail more or less. Also, powerline solutions are usually not cheaper than KNX.
- It is said that powerline solutions are slower
- It is said that powerline solutions are less reliable or simply "worse"
AleXSR700 schrieb:Price, speed, capabilities, installation conditions, reliability—there are many reasons. While powerline is fine for IT applications, it is only conditionally suitable for building automation. Beyond a certain size (number of devices), other solutions are simply better.
So why should powerline be slow or poor in home automation?
AleXSR700 schrieb:Yes, I addressed this above. Power consumption is one of the reasons twisted pair is simply better. With 15 devices you might overlook it—but what about 100 or 200 devices?
I would only consider higher power consumption with Wi-Fi, because connections usually stay active and consume more power than cabling.
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AleXSR7009 May 2020 17:15Okay, sure, if everything is directly wired, I definitely see the advantages. Ultimately, it is always the most stable and energy-efficient method.
For clarification:
Powerline is a concept, and KNX is a manufacturer. Or is Powerline a proprietary system by D-Link?
I was referring to the realization via the existing electrical network, not a D-Link solution. So the quality of the implementation would be independent of the Powerline principle itself. Because Powerline, if well implemented, should be just as good and fast as twisted pair (TP) wiring, or at least within the millisecond range.
Regarding lighting, I think automation needs two components: a lamp and a sensor. Both are powered. So both are connected to the electrical network. Therefore, there is already wiring that connects both to each other and to the control unit/server. So, during construction, you could just install a regular lamp, then later add a Powerline sensor and a Powerline lamp connector/outlet (for instance, from KNX) and define their locations via software.
It’s basically as if the Powerline electronics are simply integrated into the wall socket (the hardware). It doesn’t matter which end device is plugged in because you switch the power on or off at the outlet. For a lamp and many other consumers, this is actually a simple, binary principle. And for a lamp, very roughly simplified, it’s not much more complicated than a classic motion detector. A motion detector senses movement and then switches on the built-in lamp. With automation, it’s exactly the same, just that the lamp isn’t built-in, so a simple signal would have to go to the server, which then switches the “outlet” on, and that’s it.
Of course, this is complex in programming. But from a hardware perspective, these applications are quite straightforward to implement. And this would be done via Powerline.
I can’t think of an example where the communication itself would be complex. In sensor technology, yes, but in the message to the server and then to the actuator, not really.
Just as an example: a thermostat can be complex, but it’s basically just a simple temperature sensor (e.g., a bimetallic strip) that reports whether it is turned up or down—that is, the motor runs either left or right. This requires almost no bandwidth in communication. Millisecond response times are also easily sufficient here.
And an electrical network is inherently more stable than TP cable. The conductors are significantly thicker, with fewer points of failure.
As I said, I wonder whether the technology is the problem, or if more complex solutions are being pushed because they also generate more profit. Running an additional cable costs much more than just replacing the breaker panel with a control unit.
This is not an accusation; I’m just wondering why this more complicated and expensive route is chosen when there is such an elegant and universal solution as Powerline—with such low bandwidth requirements.
For clarification:
Powerline is a concept, and KNX is a manufacturer. Or is Powerline a proprietary system by D-Link?
I was referring to the realization via the existing electrical network, not a D-Link solution. So the quality of the implementation would be independent of the Powerline principle itself. Because Powerline, if well implemented, should be just as good and fast as twisted pair (TP) wiring, or at least within the millisecond range.
Regarding lighting, I think automation needs two components: a lamp and a sensor. Both are powered. So both are connected to the electrical network. Therefore, there is already wiring that connects both to each other and to the control unit/server. So, during construction, you could just install a regular lamp, then later add a Powerline sensor and a Powerline lamp connector/outlet (for instance, from KNX) and define their locations via software.
It’s basically as if the Powerline electronics are simply integrated into the wall socket (the hardware). It doesn’t matter which end device is plugged in because you switch the power on or off at the outlet. For a lamp and many other consumers, this is actually a simple, binary principle. And for a lamp, very roughly simplified, it’s not much more complicated than a classic motion detector. A motion detector senses movement and then switches on the built-in lamp. With automation, it’s exactly the same, just that the lamp isn’t built-in, so a simple signal would have to go to the server, which then switches the “outlet” on, and that’s it.
Of course, this is complex in programming. But from a hardware perspective, these applications are quite straightforward to implement. And this would be done via Powerline.
I can’t think of an example where the communication itself would be complex. In sensor technology, yes, but in the message to the server and then to the actuator, not really.
Just as an example: a thermostat can be complex, but it’s basically just a simple temperature sensor (e.g., a bimetallic strip) that reports whether it is turned up or down—that is, the motor runs either left or right. This requires almost no bandwidth in communication. Millisecond response times are also easily sufficient here.
And an electrical network is inherently more stable than TP cable. The conductors are significantly thicker, with fewer points of failure.
As I said, I wonder whether the technology is the problem, or if more complex solutions are being pushed because they also generate more profit. Running an additional cable costs much more than just replacing the breaker panel with a control unit.
This is not an accusation; I’m just wondering why this more complicated and expensive route is chosen when there is such an elegant and universal solution as Powerline—with such low bandwidth requirements.