How to manage a rotary switch 0-1-2 via openhab

Hi folks,

my new VMC is managed via rotary switch with 3 status:

0 - off
1 - standard mode
2 - turbo

I would like to connect this VMC to openhab, to maximise synergies (eg. when Netatmo see high level CO2, I can ask the VMC to go to mode 2).

My first idea is to use a zwave device to do so. I don’t know maybe a fan speed control like:

or a dimmer solution? maybe fibaro? but I don’t know if this should work or not.

Any suggestion guys?

Thank you very much


Although I’ve no idea what “VMC” is supposed to be, this is a common problem, and there’s no quick simple answer because it depends on the way your device is internally built.
Some of these use a 0-10V input. Those you could connect a PWM capable dimmer to such as the Fibaro FGRGBW (and a 12VDC external power supply).

But most of these internally actually use a binary logic. Quite often there’s binary input connectors on the mainboard of such devices that you can connect a binary zwave switch to.
The problem is you have to find out first. And you need to identify the proper connector and voltage to apply.
If you can’t get hold of a manual to explain the electrical internals, most of the time, the way to go is to open the case, wield a multi meter and spend some time on reverse engineering the main circuit board.

I think, “VMC” is “CAC” -> Central Air Conditioning.

It depends highly on what kind of Air Conditioning you own, and of course, if you want to build your own control or just “control the control”.
The simplest way would be to buy two relays, one for OFF/ON, the other for LEVEL 1/LEVEL 2. You would change the original switch to these relays ans switch the relays instead. The second step would be to build the interface for openHAB, maybe with an arduino or something similar.

But maybe there is already an interface that you could use, so it would be very helpful to know exactly what type of air conditioning system you own.

The product is “Vortice HR 200”

This is:

According to page 9 Fig. 23 you have two switches, one for ON/OFF (this one has two contacts for power and neutral) and another for switching between Level 1 and Level 2, so this would be easy to implement with two relays, you can do the level switching through a light switch (not dimmer!). For Power switch, i think you would have to modify a light switch, so that it switches of neutral, too (or add another switch to do this manually)

So I should use this?

or this

one for ON/OFF and one for fan control?

Either will do (FGS-222 is newer), but check out voltage ! I didn’t see that mentioned (admitted I might have overlooked it, just had a quick look).
I, too, am using a FGS-222 to control my own Vallox ventilation device. Just installed that a week ago.
It has 24VDC input and output ports, as used in probably most ventilation systems. Applying 230VAC would possibly blow it…

Damn … how can I check if this is compatible from voltage point of view?


Certainly you could use FGS-212 to switch between Level 1 and 2, and a second one could be used to switch off completely. But keep in mind, that the wiring in this case is different (poor drawings…):

             |     FGS-212
             V    ___________    _______
230V ~L1 ----/ --|-IN--/ --Q-|--|       |
             I   |___________|  |       |
       N ----/ -----------------|       |
                   __________   |       | Vortice HR 200
                  |  +-/ --Q-|--|       |
                  |  |       |  | J7    |
                  |  +----IN-|--|       |
                  |__________|  |_______|

So you will need an extra switch to completely isolate your Vortice from power supply, plus two FGS-212 to switch on/off automatically and to select the level.

No way from your perspective to use just one FGS-222?

One FGS-222 should be sufficient as it has two relays with an input each, unless the two switches use different voltage.
What you need is a reasonable wiring diagram. Vortice or your local dealer would need to provide it. Or, as I already suggested, go wield a multi meter.


Since the two relays have one common contact, you can’t connect the switches the right way! Be aware that wrong wiring can destroy the control of your CAC.

Of course, you may open the FGS-222 and disjoin the common contacts, which should suffice your needing.

Well you can still get along with a single FGS-222, eventually you need a DC power supply (a.k.a. voltage converter :slight_smile: ), but the solution and wiring depends on information we do not have.
You have to fully understand the electrical circuitry first. Either get a decent documentation from your vendor / installing electrician (a manual not even telling you the voltage that a connector has is crap) or do the reverse engineering (as I said, wield a multi meter. That’s what I did last week, too).

@Udo_Hartmann: Wir reden aneinander vorbei. Wenn der obere Eingang 230VAC hat, wird wahrscheinlich auch J7 an einem der Pins permanent 230VAC haben, dann kann man den Saft stattdessen auch von L1 bzw. Q1 nehmen. Auch wenn beide Eingänge 24VDC nutzen ginge das.
Nur wenn am einen Wechsel- und am anderen Gleichstrom anliegt, geht das nicht ohne weiteres, was ich aber auch schrieb (oder jedenfalls meinte). Aber selbst dann kommt man mit einem FGS aus, man muss dann einen Trafo einschleifen.

Oh, ich hab das schon verstanden :wink: Aber genau die Annahme, dass (selbst wenn eine der Klemmen an J7 Netzspannung führt) diese automatisch gefahrlos zum Umschalten verwendet werden kann, ist nun wirklich nicht richtig, sondern höchst gefährlich. Mit exakten Unterlagen über die interne Verschaltung kann man das herausfinden, aber die stehen nun mal nicht zur Verfügung, und da ist meine Beschreibung doch die ungefährlichere Variante. Da die Klemme komplett getrennt von der Netzspannung montiert ist, liegt übrigens die Vermutung nahe, dass hier eher eine Kleinspannung gesteuert wird - die Drehzahlen sind getrennt justierbar, die Umschaltung kann per Timer oder auch elektronisch erfolgen, und last-but-not-least das Gerät ist eigentlich gar nicht so gedacht, dass es jemals still steht. Man kann in der Originalkonfiguration lediglich zwischen Stufe 1 und Stufe 2 umschalten.

Einverstanden - ich hab ja eigentlich auch nichts anderes gemeint.
Aber es geht auch mit nur einem FGS, wenn man einen Trafo dahinterhängt. Hab ich gerade bei der Installation meiner eigenen Vallox Anlage so gemacht. Klar, Netz- und Kleinspannung sollte man trennen, aber mit ein bisschen Messen findet man schnell raus, dass das alles recht simple, robuste Technik ist, da kommt es auf ein paar Volt nicht an.
Meine Anlage hatte allerdings wenigstens ein vernünftiges Schaltbild. Seines hier ist ja Grütze.