eBUS network goes down when connecting eBUS Adapter Shield v5

[MatthiasValvekens]

Hello,

I have a heat pump installation at home consisting of a Vailliant aroTHERM VWL 35/5 AS, uniTOWER VWL 58 ... 128/5 IS and a VRC 700/6 control unit.

I got an eBUS Adapter Shield v5 to monitor/control the installation remotely. To figure out where to install it, I followed the eBUS wire from the uniTOWER's eBUS terminal to a point where it was plugged into a pair of 3-way Wago connectors (wired to the other devices in the eBUS network in parallel). I replaced those two Wagos with bigger ones and wired up my eBUS adapter similarly in parallel with the others; the cable run is less than 2m. For my tests, I connected the eBUS adapter to my network wirelessly, and powered it over USB. It's flashed with the latest firmware.

This is what I observe when the adapter is connected to the eBUS circuit:

• I can connect to the adapter with ebusd, but it doesn't get any messages. The LEDs on the board also don't really react (only blue led blinks).
• The adapter reports "no signal" as well
• The connection between the uniTOWER and the VRC 700 control unit breaks down (control unit screen blanks, uniTOWER displays a communication error) -- a bit like Steuerung "tot" bei Vaillant aroTHERM VRC 700/6 #967, except that in my case it happens consistently when the adapter is connected
• This is also what I see when I short out the two wires connected to the eBUS circuit, by the way (not surprising given that all the devices are connected in parallel)
• Whether the eBUS adapter is connected to power or not does not seem to matter, the effects on the rest of the eBUS network is the same.

For completeness, here's the output of ebusctl info:

version: ebusd 23.3.23.3
update check: OK
device: 10.6.0.6:9999, TCP, enhanced, firmware 1.1[460f].1[460f]
signal: no signal
reconnects: 0
masters: 1
messages: 11
conditional: 0
poll: 0
update: 4
address 31: master #8, ebusd
address 36: slave #8, ebusd

It's identical, whether the adapter is actually connected to the eBUS network or not.

As soon as I physically disconnect the eBUS terminal on the adapter, the other devices on the eBUS network immediately recover. What am I missing? Is it possible that I simply have a faulty unit, e.g. could there be a short in the eBUS terminal on the adapter, for example?

Happy to provide further details if needed.

Thanks!

[john30]

sounds pretty much like you got the wrong plug on the board as eBUS is never coming with a 3-way connector but always only 2. it also needs to say "eBUS" in the heater manual. everything else is simply wrong and using that could also damage your devices

[MatthiasValvekens]

Thanks for the reply!

So, perhaps I explained myself wrongly. The eBUS plug on the board takes two wires and is market "BUS"; the terminals are marked + and - (see first picture). I also cross-referenced with the schematics in the installer's manual to ensure that I got the correct plug, so I don't think that's it.

The + wire travels to a 3-way Wago, and the - wire travels to another 3-way Wago. From those Wagos there are similar wires travelling to the the other eBUS devices on the network (so they're connected in parallel); see 2nd picture (which is crappy due to the difficult angle). I replaced those two 3-ways with a 5-ways and plugged in my adapter in the same way as the other wires plugged into those connectors.

Does that make more sense, or am I still missing something obvious? :)

EDIT: picture of schematic from the manual, for completeness:

[john30]

oh dear, don't shortcut anything by intention - this might ruin your power source or do other damage.
anyway, you might be facing the seldom case of a device being dead on arrival. it is very rare as every adapter is tested on the eBUS side including communication before delivery (and I have proof of that). so if you're sure that you did't ruin the adapter already yourself (e.g. by creating a shortcut on the adapter itself somehow), ask for replacement (and best add me in cc)

EDIT: are you sure that you got the right cable as your picture shows several ones with identical green cable? you might just want to connect the adapter directly to the eBUS plug on the circuit just to be sure

[MatthiasValvekens]

Thanks again for your comments. I'm sure the cable is the right one; it's hard to tell from the pictures, but the Wago connectors are located in view of the eBus terminal on the board, so checking that was simple enough :).

Regarding replacing the adapter: even if the adapter is at fault, then all things considered chances are that I fried it doing something dumb. I'll eat the cost of replacing it (but thank you for offering). But that'll be something to deal with a couple weeks from now when I actually have time to work on this again.

Thanks once more!