Best PLC with HA?

Hi there,

I’m starting to design a system for a small country house. The system will be quite simple: 8 electrovalves, around 10 sensors, 5 lights, cameras… As we’ll have to paint the house and so on, I’ve decided to have all the connections wired.
My first option was to use KNX as I wanted it to be secure and reliable, but due to the cost I changed my mind.
Now, I’m looking for a cheap PLC that works well with HomeAssistant, but I’m going crazy seeking for the right solution. I’ve seen machinon (nice but not very good connection with HA), unipi (quite expensive)…

What PLC do you recommend to me? Thanks in advance!


You might get more response if you don’t use such obscure acronyms.
KNX is an open standard for commercial and domestic building automation.
PLC is Power Line Communications.

I think you’re on your own.

In the years that I have been using Node-Red and Home Assistant to control my home, I have never heard of anyone attempting to connect devices over PLC.

I think my home is typical. I have a mix of devices connecting by MQTT over WiFi, some Z-Wave, and some, like my cameras, that are pure WiFi over the local LAN. I also have two ZigBee lights (Ikea Tradfri). Others have used Bluetooth as well. 433MHz devices work- sort of. I have even heard of one or two users using CAN bus, but that strikes me as overkill.

PLC also stands for “Programmable Logic Controller” (Source: I work in industrial automation using Siemens, Allen Bradley, and Modicon PLCs).


PLC in this instance refers to Programmable Logic Controller…


An alternative to KNX would be any PLC that can communicate via Modbus. HA has a Modbus integration, albeit not nearly as good as KNX with respect to supported device classes. Sorry I can’t recommend a specific PLC for your use case.

This setup uses the known Codesys IDE with ready to use MQTT function blocks to program your PLC and integrate with HA:

It’s however not cheap, most of the people using it have a Wago PFC200 which comes at a price. Nevertheless that price brings a very stable and robuust controller in your home to control you core home tasks (lights,covers, locks etc…) and will easily last 20 years… :slight_smile:

This might be of interest…

I did my whole house lighting and heating system using siemens LOGO plcs. I did integration via modbus. It works very well, there are a lot of information in this forum about this integration.

When you will do the wiring consider using 4 wire cables to connect the switch and the bulb as usual and for easy to change back to classics in case of samething fails.
If I had an opportunity to do it now I would not use plcs. For lightning I would rather use new sonoff modules

Hope that helps.

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But if you want to keep everything wired? Like me. Building new house. And want all sensors not via wifi, zigbee etc. Is the PLC the only option?

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I found these on aliexpress and wonder about their use for a diy Lighting Panel.

Leading Edge Dimmer
US $199.90 | 4 Channels Dimmable Module RS485 LED Lighting Dimmer Dimming Switch 86 APP Scene Control Suppports Android iOS Control4 Crestron

0-10V Dimmer
US $154.90 | 8 Channels Dimmable Module 0-10V for LED Lighting Dimmer Dimming Switch Control RS485 Supports CRESTRON Control4 Andriod iOS

US $89.99 | 8 Channels Intelligent Relay Switch RS485 for Lighting Curtains 86 APP Scene Control Supports Android iOS Control4 Crestron

I’m planning to use Unipi. Is anybody here using it? What’s your experience with Unipi? Thanks for answer

I am using Codesys running on raspberry pi. Maybe not the best choice, but it has pico ups (5V ups) and is powered from 24VDC buffer power supply (with battery). People say pi is unstable, well if it is well powered over pins, NOT usb plug and has some type of ups in my case it can run for 3 years without restart. Avoid connecting any hardware to your pi, as usually external hardware breaks pi stability.
My pi is communicating over ethernet with wago 750 series modbus IO island. So all the hardware part is wago/beckoff misture of second hand modules connected via modbus to my codesys controller.

I have modified raspian to mount /opt folder (where codesys works) to mount usb flash drive.
Internal pi flash is mounted as ReadOnly. When i make backup i dump both devices to file with compression. If usb disk crashes because of too many write operations then my pi will still boot and I will login remotely and recover codesys to new usb flash drive.

Why I choose this:

  1. Codesys like PLCs in standard for building automation.
  2. If my pi fails I can replace it with any wago 750 PLC controller (but it is more expensive so i keep my pi for now)
  3. Pi + codesys license was much cheaper when I was building my system in 2015.
  4. Codesys has simple VIsu web visualisation build in for free. I found it really usefull for testing. Actually 7 years later I still didn’t find time to make my Android app to control my home :smiley: and I am still using temporary visualisation to control heating, doors and power plugs, when I need to do it remotely. Also when I am adding new feature to my home I am using visu as debuging interface and temporary control panel.

So unipi, why not. It will work.
Second hand plc stuff, why not.
Whatever plc u like, why not, but check if it has:
modbus - usefull to read data from photovoltaic inverter, to connect remote IO, some other devices
opcua - quite universal protocol to connect any software that supports it
MTTQ - to connect home assistant for instance.

I know that most of low budged siemens plc does not support this protocols and is no use for home automation. Maybe this has changed right now. I am siemens programmer, but I have learnt codesys for my home and after 7 years I find it right choice.

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click plc, with MQTT try this

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Perhaps I am looking at the wrong rabbit hole, but you could build your end devices using the WT32-ETH01 board.