KNX/EIB S0 connection between ABB US/U2.2 and AquaMetro AquaPuls

[caligula]

Hello,

I have a problem connecting a counter my water consumption to an ABB US/U 2.2 through an S0 connection. I've read many of the posts in this forum but can't find my answer.

The counter is an AquaMetro AquaPuls. Data on this one is here and here. The module doesn't have an external electrical plug i.e. it is only operated by a coin-size battery that needs to be changed every 15 years based on its documentation.

The ABB US/U 2.2 info is here.

To start with, I've tried simply wiring my US/U2.2 grey+brown (pins 2+3) to my AquaMetro S0 port, but it doesn't detect any pulse at all.

So I've started looking into it more closely and I simply don't understand how this could actually work at all! If I read the S0 "quick specification" here, it says that the bus works between 18-27V DC, that a OFF-signal is between 0-2mA and a ON-signal between 10-27mA. Fine.

Now, if I look at the US/U2.2 specification, it says its input works at 20V DC (fine, within S0 range) but with an input current of 0.5mA (!). Consequently, how can this setup, with an Aquametro just containing a coin-size battery (and not external power plug) and an US/U2.2 operating at 0.5mA can create-then-detect a signal within the 10-27mA range? Am I missing anything? Do I need to use another wire than just #2 and 3 above?

I am not an electrician so probably missing something obvious.

Thanks for your help!

[caligula]

Auf Deutsch jetzt!

Meisten Fragen here werden beantwortet aber ich habe kein Glück mit meine So vielleicht is die Sprache meine Frage das Problem. Also, if versuche auf Deutsch! Viel Glück ...

Hat jemand schon gelungen, ein Messgerät auf eine US/U2.2 ABB Aquametro AquaPuls zu verbinden? Ich verstehe nicht, wie es funktionieren kann.

Die "S0"-bus Spezifikation zeigt dass der Bus muss zwischen 18-27V DC und das AUS-Signale funktionieren zwischen 0-2mA und das EIN-Signal zwischen 10-27mA.

Der US/U2.2 hat ein 20V DC (gut) about nur 0.5mA! Und der AquaPuls is nur ein "passive" gerät der mit einer Batterie funktioniert. With ein 0.5mA und ein passiv Gerät ein correct 10-27mA signal senden?

Es gibt etwas ich verstehe night! (Ich bin kein Elektriker)

Ich have schön versucht einfach die US/U2.2 grau + braun (Pins 2 +3) auf die Aquametro S0-Anschluss, aber es erkennt keinen Puls.

Danke für ihre Hilfe!

[lobo]

Dear Caligula,

the language shouldn't be the problem. As a matter of fact, I assume that the system you use is not very common.

I looked at the docs and the aquapuls doesn't look like an S0 to me - it seems to be a potential free contact. This is better for you

Did you see that the different volumes will cause different lengths of contact closures (50 ms, 500 ms, 5000 ms)? Isn't there another documentation apart from the installation guide telling you what different pulses will be generated by your device?

Grey and brown should be fine for your aquapuls. Your device has a minimum impulse time (1 l) of 50 ms. Which debounce time did you choose with the US/U? You should be careful to make the debounce time shorter.

Best regards,

Stefan

[caligula]

Namur or not Namur, that is the question

Lobo,

Thanks for your reply!

You actually helped understand something strange about my counter. I've attached two pictures:

• Top of the counter
• Side of the counter

The top of the counter says this is a "80115", which, according to this documentation means I should have the one at the bottom LEFT i.e. the battery, and NOT the "Namur". The one with the battery indicates "max 220mA/48V DC" (i.e. *not* S0) while the Namur *is* the one with the S0 bus (i.e. DIN 19234). So, from that standpoint, I can reach the conclusion this si NOT a S0 device.

Now, if I look at the second picture, taken on the side of the device, it says: "Namur DIN 19234 ISO DIN 43864 Umax 27VDC, Imax 27mA" - which *is* a S0 device!

So there seems a bug here

BTW, I've tried plugging the grey+brown cables and set the debounce time to 30ms (since the pulse is supposed to last 50ms), but it doesn't count anything. If I try to cable the +/- in reverse, then the counter gets crazy and keeps counting in a infinite loop.

My suspicion at this point is that this device is really a Namur one, not a 80115. Consequently, I am trying to receive a contact-free signal with my US/U2.2 but the device is actually an S0 and so it can't work.

What do you think? Can you make sense of this?

Thanks. Cheers!

[lobo]

Hi,

your description that the counter conts endlessly after turning the polarity at least gives a clear indication that there seems to be a semiconductor switch (which may be according to the S0 definition).

In one of the pictures, I saw that it tells something like 100 L. Please check if your device really gives an impulse every litre - and not every 100 l (just to be sure) ....

As a matter of fact, I am not very familiar with S0, so everything I could do now is really guesswork (and not a too educated guess though) ;( , but I think I remeber to have read something that S0 should be working with the US/U, as well.

Sorry, but I don't have time to take a closer look.

Cheers,

Stefan

[caligula]

Thanks Lobo. The problem is that I cannot even detect a signal, so couldn't figure out if it is really a 100L or 1L device. I am stuck it seems

Thanks anyway!