Hi all,
this is a post on how to integrate Home Assistant, via eBusd, to an Ariston Group (R) BusBridgenet (R) HVAC system, accessing the system bus via a custom/dedicated adapter, in READ and WRITE operations. You’ll be able read and change parameters as temperatures, modes etc.
This post is not a comprehensive HOWTO, but a more general “instruction” on how to do it, as there are many different ways to tap into the bus and many configuration possible for HA (HASSIO, local setup, docker etc).
This is a local and NOT a cloud based integration so it’s not depending on the Ariston cloud systems. A fair amount of space is given to hints on how to choose the right adapter and where to place it.
This system has been tested to work correctly on different models of Ariston Group appliances, the device compatible are the ones that have a device that has a bus port, in the owner/installer manual the port is identified by the “BUS” label and usually have the E-BUS 2 or B/T written nearby.
Ariston, Chaffoteaux and Elco are the primary brands, Ariston Nimbus HP and their Chaffoteaux and Elco corrispettives, Ariston Genus boiler and Chaffoteaux Mira etc can be accessed, please chech your applicance system, if in doubt reply here, I’ll try to help to understand if it’s feasible.
The codes I’ve been able to gather are mostly cross compatible, are thus common to many different appliances, but older or newer version of the FW can get different formats and/or meanings, so I cannot guarantee that it will alwais work 100%.
Link to the repo:
Pros are a a much faster response and total independence from (eventual) modifications done on Ariston cloud infrastructure. It works with a Boiler only configuration or with a more complex heatpump or hybrid system (like mine).
Cons are the need of an external adapter that must be wired to the HVAC system, some details on this are below in the post.
From now on I’ll use HVAC system as a general term for a single boiler, a single heatpump or a combination of both. My configuration is based on some assumptions:
- HA installed and working
- MQTT broker already in place, if using HASSIO and you miss MQTT you must install the MQTT add-on
- As said before, having an adapter to access the bus, here there are man possibilities:
- official ebusd adapter
- unofficial adapter (atm Im satisfied with this)
- other serial or ethernet adapter
- eBusd up&running, also here, if you’re using HASSIO there is an add-on for that
First of all the adapter, based on various variables you should choose the right adapter for you, eBus is a real time, latency sensistive protocol so low latency between the software (eBusd) and the hardware (the adapter) is required. If you have a good, shielded telephone cable you can place the adapter at a fairly good lenght from your appliance. A good wifi coverage is usually sufficient and thus you can choose the lesser impact device (wifi, bus powered).
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a wifi based adapter like mine (GitHub - danielkucera/ebus-adapter) is good if you have a fairly good wifi coverage where you intend to place the adapter itself, the adapter must be wired with a couple of cables to your HVAC bus port, in parallel with others equipment if you don’t have a free bus port on your HVAC system, it consumes few mW and is powered by the bus avoiding many hassles (EDIT: I’ve found that using only bus power may cause some problem in some HVAC system configuration, the problem is a random but periodical bus reconfiguration and discovery procedure that, in a way, reboots all your bus connected modules, if that kind of problem happens then check your wifi coverage, second add an external power supply to the adapter)
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the official eBusd adapter (https://adapter.ebusd.eu/index.en.html) has built-in wifi capabilities but also has the pro of having the possibility of being “mounted” as a shield on a raspberry, even the zero-w, this configuration can give you the ability of placing the ebusd daemon, installed on the raspberry, in direct contact with the adapter, in this way you can reduce almost to zero the ebusd<->bus latencies. The bus can be fairly busy so having al local decode and filtering can save you some problem if you need to write data on the bus. This config requires a good external power adapter, even if used in Wifi mode the adapter isn’t able (by choice) to use power from the bus port
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there are also serial and ethernet based adapters (eBus heating bus couplers and gateways)
or custom made (https://github.getafreenode.com/jkyprian/ebus2usb) these can help in situations in which you don’t want/cannot use wifi, in these scenario you need to place a wire from the HVAC system to the adapter and another one, being it USB, serial od ethernet, to he system running eBusd. You should take into account that this way can be more tricky to be accessible by a docker application, keep this in mind if you’re on an HASSIO configuration.
Having choosen the adapter and having it configured if needed (my adapter has a potentiometer that must be trimmed to get the right readings, on the github repos there are hints and link to docs) you can start to thinker with eBusd.
The adapter converts the electric signals traveling on the bus to digital “strings” and vice-versa for writing to the bus, eBusd is the software that decode the messages that came from the adapter and that, if correctly configured, translate these gibberish hex strings to meaningful MQTT messages.
In my github repo there are configuration files for eBusd that do 3 things:
- ariston.csv is the file mapping the various Bus messages to human-readable parameters and values
- mqtt-hassio.cfg is the file that helps eBusd to send those messages to HA via discovery protocol
- _templates.csv is a support file for translating the most used datatypes in the “master” csv
these files must be placed in the ebusd configuration folders, if using ebusd add-on you should check where… eBusd has been created mainly to access Vaillant systems and for this brand there is an almost automatic discovery process that downloads from the web the right config file, it does’t work with Ariston Group appliances because Ariston’s implementation of the protocol (namend BusBridgenet) have a good deal of differences from the standard.
Disclaimer:
This instructions are provided as-is, please consider the impementation to be at you own risk. Accessing the bus is a standard practice, it is done by Ariston own devices, so it is safe, but you need to take extra care when connecting something to the system that heat your entire home.
If you’ve come this far you have earned the rights to ask any question 
Disclaimer2: this integration is not really plug and play and probably never will be.
It seems that every Ariston/Chaffoteaux/Elco BusBridgenet combination of devices and FW version change some message, or it may be that we weren’t able to reverse engineer it correctly. Almost every installation needs adjustment and customizations.
This first leads to the need of more details in the help requests. A post that says “It doesn’t work” simply won’t lead you any nearer to the solution because at least I’ll need logs, message dumps etc. to be able to help .
Second, if you need something stable, that simply works “everytime” then the only way that I know is the native mobile app. That will be working as long as Ariston keeps it alive.
