# Flexit Nordic S4 modbus communication

**URL:** <https://community.homey.app/t/flexit-nordic-s4-modbus-communication/29639>\
**Category:** Questions & Help\
**Created:** [May 10, 2020, 2:18pm UTC](https://community.homey.app/t/flexit-nordic-s4-modbus-communication/29639 "2020-05-10T14:18:50Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![Burlefot](https://sea1.discourse-cdn.com/flex025/user_avatar/community.homey.app/burlefot/32/17891_2.png) [@Burlefot](https://community.homey.app/u/Burlefot)\
**Post date:** [May 10, 2020, 2:18pm UTC](https://community.homey.app/t/flexit-nordic-s4-modbus-communication/29639/1 "2020-05-10T14:18:50Z")

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Hi

I am wondering if I could be able to control the ventilation system in my house through Homey.

It can be externally controlled through the modbus-protocol (english instructions starts at page 12): [https://www.flexit.no/globalassets/catalog/documents/111398\_fdv\_117989.pdf](https://www.flexit.no/globalassets/catalog/documents/111398_fdv_117989.pdf)

Here are the instructions that I would be able to use: [https://www.flexit.no/globalassets/catalog/documents/111400\_modbus\_nordic\_basic.xlsx](https://www.flexit.no/globalassets/catalog/documents/111400_modbus_nordic_basic.xlsx)

The question is, will I be able to use Modbus in Homey? What kind of Modbus RTU should I use? Assuming that TCP/IP is the way to go? Are there Modbus integrations vs homey that could be reused?

Assuming that I would have to write an app to support the RTU?

Grateful for all help and support.

Håvard

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**Author:** ![zeppen](https://sea1.discourse-cdn.com/flex025/user_avatar/community.homey.app/zeppen/32/16474_2.png) [@zeppen](https://community.homey.app/u/zeppen)\
**Post date:** [May 27, 2020, 8:49pm UTC](https://community.homey.app/t/flexit-nordic-s4-modbus-communication/29639/2 "2020-05-27T20:49:55Z")

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Hi there!

I’ve got the same wish to get an app to Flexit Nordic S4 via modbus communication.

I’ve asked the developer of [NibePi](https://github.com/bebben88/NibePi/blob/master/README.md) to look into this.  
I believe it can be done, but I have too little knowledge to help you out.

Since I have a Nibe S1255 that will fully support modbus TCP/IP anytime soon I think its possible.  
Probably by doing it over MQQT.

In other words, by using a Raspberry Pi (Zero or whaterver) and a RS485 HAT  
then install NodeRed and and configure it (or re-do) the NibePi to fit the needs of FlexIT S4 Nordic, then to send via MQQT to the Homey.  
Thats how the Nibe F-users do it (One can also use the User Interface of NodeRed in the Raspberry)

I’ve let my S1255 to be a guinea pig for the development of the upcoming version that has the option of TCP/IP, but the progress of development has been slow due to Covid-19. (The developer has been busy feeding his 3d-printers for hospital equipments, making more than 1000 visirs…)  
Hopefully the new version of NibePi (supporting nodered/modbus fully) will see the light within weeks (its in beta-version now)

if you get anymore info, please reply here or send me a PM. 🙂

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**Author:** ![cbjornerud](https://sea1.discourse-cdn.com/flex025/user_avatar/community.homey.app/cbjornerud/32/78899_2.png) [@cbjornerud](https://community.homey.app/u/cbjornerud)\
**Post date:** [March 17, 2024, 10:02am UTC](https://community.homey.app/t/flexit-nordic-s4-modbus-communication/29639/3 "2024-03-17T10:02:25Z")

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This is possible. Tom Heine has made an app to do this with a TCP-modbus konverter (webpage in Norwegian): [Flexit Nordic S4/S3 og Homey – tomheine.net](https://tomheine.net/flexit-nordic-s4-og-homey/)  
To use this app you need CLI access to Homey Pro. That prosess is explained here: [Getting Started | Homey Apps SDK](https://apps.developer.homey.app/the-basics/getting-started)  
Is it not an ease process if you are not a developer. You need a PC or Mac with admin rights to do this.