Control Modbus devices without Loxone modbus gateway

[MihneaM]

Hello all,

I have learned quite a lot the last few weeks about home automation with Loxone and I love it! I started from the decentralized ventilation system I want for my apartment, which comes with optional Modbus control and by reading your conversations and advice here I realized I could put this Modbus to more work.

I think about adding a few split AC units in the house, and since Daikin seems to be one of the few manufacturers to supply a Modbus interface I looked up the price. And I was quite surprised to learn that Daikin modbus interfaces cost 350+ EUR per AC unit!

Then I got to the modbus-to-Ethernet gateways, like the ones from Intesis, which can control up to 32 modbus devices. Intesis seems to provide gateways for multiple split AC units from Daikin, so this would further reduce cost.

Does any one here managed to integrate such a gateway with Loxone? Can it fulfill the Modbus client / master role? 

(Just to mention that I live in Europe so advice can point to products on this market)

Thank you for advice!

Mihnea

[AaronP]

Checkout Airzone Aidoo - they integrate with pretty much every manufacturer. We have an Airzone Aidoo in our showroom over Modbus and an Airzone Aidoo Pro in the offices which we integrated over the network with local API

[MihneaM]

Thank you for the suggestion, but I forgot to mention I'd rather have everything wired, no wireless for smart home!

I am a bit confused about the difference between Modbus/TCP (I understand this needs to be supported by the controlled device) and Modbus RTU (this is the standard serial bus and needs to be supported by the dvice or through an add-on individual gateway) and the role of the Modbus/Ethernet bridge or gateway in all this. If you get the Modbus/Ethernet bridge you can see it from Loxone through the TCP/IP network and control all the devices on the Modbus bus connected to this gateway as if they were connected to a native Loxone modbus extension?

Thanks again for bearing with such dumb questions!

[Jonathan Dixon]

I think you're on the right track with your understanding. modbus is a communication protocol that can operate over TCP or RS485 as a transport. All devices wanting to communicate have to be on the same transport, hence the existence of gateways.

Loxone has good modbus TCP support (at least, as good as any modbus it supports). So long as the remote device supports modbus TCP and they're on the same LAN, it should be fine. For example, I integrate Loxone to SolarEdge inverter with no additional hardware. (mine has the ethernet connection already built in).

If the device you are integrating with does not have built in modbus TCP (e.g. a more basic device that does not have ethernet of any sort built in), then you need a gateway. If the device doesn't have any modbus of any sort (not TCP nor RTU) built in, as sounds the case here, then the gateway doesn't necessarily have to involve modbus at all.

e.g. maybe the aidoo KNX will give you a wired solution

https://www.airzonecontrol.com/aa/en/control-solutions/aidoo/knx/

it's a same the aidoo pro doesn't have a wired ethernet connection. looks a handy product otherwise

 

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[MihneaM]

Thank you for the recommendations!

It seems Modbus control is an expensive sport, there's no such interface to be found under 200+ EUR/device, but most are north of 300 EUR... It remains to be seen if it's really worth the cost if I end up with 6 modbus RTU devices.

[AaronP]

I may have missed something here but as far as I can see you only need one Aidoo per AC unit (circa 100 euros a pop) then one Loxone Modbus extension to control all of the Aidoos?

[MihneaM]

I already need to control 3 decentralized ventilation units on Modbus, then all the existing / new AC units. Adding another bus technology (like KNX) in addition to the Tree and Modbus RTU buses gets things a bit too complex for such a small installation.

Thanks again!

[Rob_in]

On Thursday, 24 November 2022 at 13:48:15 UTC+1 MihneaM wrote:

I already need to control 3 decentralized ventilation units on Modbus, then all the existing / new AC units. Adding another bus technology (like KNX) in addition to the Tree and Modbus RTU buses gets things a bit too complex for such a small installation.

FWIW, we have a Modbus extension on a Gen 1 Miniserver (which has KNX of course).

Initially I planned to use a Modbus interface to our Daikin heat pump but this didn't happen as the manufacturer who was promising to support that specific model didn't come through with that.

We now have a Zennio KNX interface connected to that Daikin unit. Works very well. I plan to get a second Zennio KNX device when we install a second heat pump for our upstairs rooms.

You said earlier that Modbus stuff seems expensive, but I find Modbus relays are very economic so we have a load of the KMTronic relay units too. I also recently did away with our 1-Wire gear and installed Modbus sensors on that bus wire instead which further simplified things.

Robin

[MihneaM]

Robin, you're right, there are other devices for Modbus which make using this bus sweeter! I have eyed the KMTronic relays as well after reading about them here. But certainly the gateway Modbus modules for each device you want to control are not cheap at all, and we're talking standard, mature industrial technology years and years old, which is odd to sell for that much (at least to me). 

Daikin sells this module for 350 EUR for each AC unit, Intesis the same. Intesis also sells an IR remote with wired Modbus RTU for many brands of ACs, but also for 300+ EUR/device. Considering the cost of let's say 1200-1500 EUR per the entire AC unit, the modbus interface adds 20-30% to the cost.

If you don't go for WiFi, you have to pay dearly. Oh well....

[Rob_in]

On Thursday, 24 November 2022 at 16:07:50 UTC+1 MihneaM wrote:

If you don't go for WiFi, you have to pay dearly. Oh well....

If you are slightly adventurous and don't like paying for overpriced gear...

You can add Modbus to a PC or SBC for practically nothing (easily found < $5). You can also add KNX for not much more (under $30) with a KNX Bus Coupler and a bit of DIY.

Then install your favourite automation software on PC/SBC and voila! I like ioBroker because you can read values from Loxone blocks directly (ie. read the state of lighting controllers, IRCs, etc, etc) but there are many other ways to interface a PC or SBC with Loxone.

TBH, I think the Zennio KNX gateways for A/C units are decently priced. If you don't have a Gen 1 Miniserver and don't want to home-brew a KNX interface you could add a proper IP KNX gateway for around $100. I have no idea how Loxone thinks they can charge over $500 for their KNX Extension when a generic IP Gateway is so much cheaper and obviously more flexible as it will work with things other than Loxone!

Robin