watermeter Elster V200 PR6P:1

[alfred_j_kwak]

@Keptenkurk
Your installation hardware is quite creative. Very nice.

-Jussi-

[Keptenkurk]

@mbliek
While testing continues (ofcourse) i added some notes to the PiFace document in the Wiki. Find it here. Just let me know any remaining questions and they will be clarified in this document.
/paul

[cwavontuur]

Paul,

A very big thank you to you for figuring this one out and sharing it with us.

Season's greetings
Joep

[mbliek]

Thanks Paul. Going to try this very shortly.

[Keptenkurk]

Hi,
Please note: I changed the schematic. Somehow i managed to destroy the Mosfet and had no replacement available. So i changed it to a reed relay which switches the PiFace input. Maybe a less complex solution also... Now see if the watermeter and Domoticz will stay in sync.

EDIT: Over the past 2 days and 258 liters of water consumption the analog meter and pulse counter are perfectly in sync.
/paul

[Slorf]

I bought one of those sensors on ebay for 2 euro's, it arrived yesterday, but I cannot get it to work

I used a BS170 mosfet,and hooked it up to 12 volt's, connected it to input 0 and the 0 volt input ( the first and last ), and I changed the piface config file ( as described in the wiki )

When using 12 volts the led on the sensor is allways on, when it detects metal it will light up bright. ( it should not be on all the time ? )
When using 6 volts the led on the sensor is off, it will only light up when it detects metal

When I measure the resistance between the 2 wires going to the piface I see the following:

- When no metal is detected there is a resistance ( not remember how much )
- When metal is ddetected the resistance is 0

Above looks like right to me,but still domoticz does not detect anything.

Also I don't understand the piface conf file:

piface.0.input.3.enabled=false ( why is it not enabled ?? )
piface.0.input.3.pin_type=level
piface.0.input.3.count_enabled=true
piface.0.input.3.count_update_interval_sec=60

Thanks for the help

Alex

[Keptenkurk]

Hi Slorf,
Nice to hear you're trying to get this working!
Could you post a link to the exact proximity sensor you got? On ebay i found the LJ12A3-4-Z/BX device (which should be the same as the one i use).
The BS170 is okay. Measuring 0 Ohm from black to blue when metal is near sounds good.
I don't like that the led is already on without metal at 12V. That's not what i saw! In my case the only difference between 6V and 12V supply was the LED being dim at 6V but detection worked fine either way.
Do you see the input in your device list? Like this:

DeviceList.JPG (85.38 KiB) Viewed 9389 times

Did you restart Domoticz after changing the piface.conf? What does the log show you?
You can test the input and counter by pushing the button 4 a couple of times. This should show up a number of counts after a minute (in the picture you can see i used 1132 liter since the start).
For the config: The input is disabled as a plain input (Lighting 1 type) but only enabled as a counter (RFXmeter type).
/paul

[Slorf]

Hi Paul,

I bought this one: http://cgi.ebay.de/ws/eBayISAPI.dll?Vie ... 0634549454 this is the same as you mention

When it's on 12 volts the led is on ( dimmed ) allways, and lights up bright when near to metal
When it's on 6 volts the led is off allways and lights up bright when near to metal

I measured the resistance between the wires going to the piface ( without connecting it to the piface ), when it detects metal the resistance is zero, when no metal is detected there is resistance.

I only enabled one input I the piface config file, it looks exactly like yours, but when I move the sensor near to a metal object nothing is registrated,

Right now I am at work, will test again this afternoon.

Btw, in your new layout you use a reed relay, can you use this also for a S0 counter ?

Thanks for your help

Alex

[Keptenkurk]

Hi Slorf,
If its really the LJ12A3-4-Z/BY you have it has a PNP output. This means the black wire will be switched to + (brown) when active. So the load is put between black and blue.
The LJ12A3-4-Z/BX is of the NPN type.

PNP vs NPN.jpg (21.15 KiB) Viewed 9381 times

In your case the diagram with the FET should then be changed a bit.
A S0 output could, if powerfull enough to drive the reed relay coil, be used with a reed relay. They are fast and last long. But i'll try to see if a transistor can switch the PiFace input. If so, an opto coupler would be the better way...
/paul

[Slorf]

Hi Paul

You are right !!!

I will change the layout this afternoon and test it again.

Regards

Alex

[Slorf]

Just looked at it, but i cannot find a way to connect it using the bs170 fet i have

Would you please be able to make a little drawing on how you meant it ?

Happy new year

Alex

[Keptenkurk]

Alex,
You could try it like this:

Proximity-Sensor-2.png (27.7 KiB) Viewed 9403 times

The idea is that if there is no metal detected the voltage on the gate is 0V therefore no current through the FET and thus a 3.3V at the input (through its internal 330 ohm pull-up resistor) = not active. When metal is detected the black wire will carry 6V which is divided by the two resistors to 3V at the gate. Enough to put the FET in conducting state and pulling the input to ground = active. If you decide to use 12V supply R2 should be increased to 3K3.
Hope that helps.
/paul

[mobisat]

I've ordered a couple of sensors from China to hopefully work with my gas meter as it looks the same kind of dial as your water meter. Nothing to lose it this price, LOL.

http://www.ebay.co.uk/itm/LJ12A3-4-Z-BY ... 46166e63a4

[Slorf]

It works build it on a breadboard.

Although i noticed something " strange" on testing

When testing i was holding the sensor to a piece of metal and checked if domoticz would give the correct numbers, then i made a list of these numbers:

Sensor against metal Domoticz count

10 5
15 16
30 56
17 73

From there on Domoticz counts correctly.

You can see that Domoticz has a kind of a "lag", the first 2 counts of incorrect, only after the third count Domoticz catches up.


HAPPY NEW YEAR !!!

Alex

[Keptenkurk]

Congrats! Good to hear.
I'm not sure if i understand the table, but could it have something to do with the count_update_interval_sec setting in piface.conf for this counter?
If set to 60 the piface count value will be updated to Domoticz only once a minute, but counts will not be lost. You can see updates in the log like my watermeter:
Wed Jan 1 12:27:34 2014 (PIFACE1) RFXMeter (Water)

EDIT: Now i see.. one is the incremental as seen in Domoticz.. (sorry-still a bit early ). I'm still checking my real meter against Domoticz. The sensor has somehow counted 2 liters more on a total of 800 liters... not that bad!

/paul

[Slorf]

I also got the S0 pulse counter to work ( although my solarpanels do not too much these days ).

Is there way to give the counter a start value ?, right now my watermeter is on 67.000 something, would be nice if I could start counting from the real value in Domoticz.

Regards

Alex

[Keptenkurk]

To change the start value you would have to change the count value manually in the database. I wasn't brave enough to do so
And when i'm convinced it works reliable i will be only interested in the use, not the absolute value...
So don't know what side effects that has to the reports etc. Upon restart of Domoticz the previous count value is read as reported here.
/paul

[Slorf]

Hi Paul,

This Raspberry is not production yet, so I can try and change the database, if it fails I will just reinstall

/Alex

[Slorf]

So i made backup of the domoticz.db, copied it to my pc

Then used SQLLite Expert Personal, opened the DB.

Select "DeviceStatus" in the left colum, then on the right you see your devices, the is a colum named "sValue", this holds the last measured value for this devices.

Change this value, go to file, "close database", then copy the database back to Domoticz, start Domoticz.

On my Raspberry the values where changed , i tested the devices and they seem to work correctly, also after a reboot the new values where kept.

Regards

Alex

[Keptenkurk]

Just to report: In January the watermeter sensor counted 7281 pulses where the real meter reports a usage of 7283,7 liter. To me enough proof to say that this way of measuring water consumption is accurate. Which of course doesn't prove the meter is accurate.
/paul