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Hi members,

I saw a new RFXPulse module becoming available soon.

I was wondering, is it possible to connect a KWh-meter with S0-output to this new RFXpulse-module? I read the docs and know it's possible to connect a relay, but S0 is not quite the same i guess (i am a complete nono in electronics...). But still, if it's possible, or with some extra electronics in between, i would really like to know, because that would mean i can dispose of a bunch of Wires in the near future, even if it's just "1"

Regards,
Robert.

Hi Robert,
Right!
You can connect directly a relay, pulse signal, photo diode, photo transistor or CNY70 and need no extra hardware. So you it will clean up a lot!
For Bwired I use a photodiode for power, CNY70 for gas and a pulse signal for water. Plug 3 RFXpulse circuits on the RFXmeter connect the sensors that you need and you are set to go! Again a great product from www.RFXcom.com


Pieter Knuvers
www.bwired.nl Online House in the netherlands. Domotica, Home Automation.

Pieter,

Great News. I think..., but i'm not completely sure, and before i start selling my 1-Wire stuff... This is what the manual of my Eltako KWh-meter has to say about the S0-output: (dutch, sorry)

"Potentiaalvrije S0 uitgang conform DIN 43864, d.m.v. optocoupler
voor aansluiting op energiemanagement systemen,
externe voedingspanning min. 18V DC tot max. 27V DC, bij max.
27mA, al naar gelang de afstand tussen de meter en de logger"

Is this ok for the RFXPulse module? I'm sorry if i'm asking "naar de bekende weg", but this external 18-27 V DC external power supply thing is still bothering me...the RFXCOM manual states:

"Warning: the relay contact must be free from any voltage!"

Those 2 things are confusing me...

Regards,
Robert.

Robert,

You can't connect the S0 interface directly to the RFXPulse.
The Eltako S0 interface is a current interface that needs at least 18V. The RFXPulse current interface for the use of a reed contact delivers 0.1mA at 5V level.

1. You can use the RFXPulse with a phototransistor to read the LED blinks of your Eltako.
2. Connect a reflective-optical sensor to a second RFXPulse in the RFXMeter and you can also measure gas usage. Note: The gas meter must have a small mirror in the least significant 6 digit. This is valid for all NL meters.
3. Connect a water meter with reed contact output to the 3rd RFXPulse and you have the water usage available too.

Bert

Thanks Bert

Bert makes live easy, now i dont have to use a solder irong and make all kinds of crazy things myself (besides that i dont want to, i rather pay)

// Erik (binkey.nl)

Bert,

Thanks for clearing things up for me. Too bad the S0 won't work, i'll work something out with a photo-transistor, no problem.

And Erik is absolutely right, your beautiful 'inventions' make our lives a whole lot easier! I just can't wait till these modules become available...[:D]

I found a schematic of the S0 interface in the Eltako and it seems to be a standard opto-coupler. You can test to connect the RFXPulse directly to the S0 interface.
If it doesn't work you can connect a phototransistor to read the LED pulses.
For both solutions you have to disable the debouncing in the RFXPulse.

Bert

i have the S0 output of a kWh meter directly connected to an EDS GP1 counter, works like a charm.

I had a 25A KWh meter with S0 connected to a Hobby Boards Dual Counter, also DS2423-based as the EDS GP1 is. Supply was 5V and it worked too. But my current KWh-meter is 65A, and the datasheet explicitly mentions the 18-27V range with this model.

Assuming we are talking about the WSZ12B-65A

Pulse interface S0 according to DIN EN 62053-31, potential free by opto-coupler,
max.30VDC/2OmA and min.5V DC, impedance 100ohms,pulse length 50ms,1000Imp/kWh

I'm confused now .... here is the link with details.

Very close... it's the WSZ12E-65A.
Specs:http://www.eltako.com/dwl/zaehler_e_typ ... ternet.pdf
Page 2 mentions the S0 details.

Now you tell me wat's right...[?]

Strange there seems to be a contradiction in the specifications. Assuming (again It is conform DIN 43864, like other kWh meters which seem to do the job, my best guess is it is most likely going to work. Well we will know for sure when either one of us installed the device .....

Robert,

The RFXPulse is available now. http://www.rfxcom.com/sensors.htm#70095

If you like to do a test with the RFXPulse connected to your S0 interface you can have an RFXMeter, RFXPulse and open-end cable for try&buy.
You can pick up the unit in Veenendaal and if it doesn't work bring it back. If you blow up the RFXPulse it is for my risk. (this offer is only valid to Robert)

Bert

Hi Bert,

I just looked at the RFXCOM site and indeed, the RFXPulse is now listed. But there's no mention of the Ethernet transmitter/receiver interface yet. (Even the anouncement that used to be on the homepage has disappeared.) So I was wondering: how imminent is the release of the Ethernet interface? I'd prefer to combine the order to save on postage costs if it doesn't take that long anymore.

Thanks,

Lennart