Calculating the voltage drop of a copper wire of 0.5 square millimeters with a length of 70 meters (35 to, 35 from the FLM) at a current of 20mA you get a wire resistance of 2.5Ohms and a voltage drop of 0.05V - so this should be no issue at all; try for yourself http://www.electronicdeveloper.de/WiderstandSpannungsverlustKabel.aspx - it's in German, but should be self-explaining. (at 0.2 square millimeters and 5mA it is 0.03V) - this applies also if the switch (as in the FLM case) pulls to ground.
bazzle |
Yes I'm familiar with electrical constants etc. I suppose I was wondering if the impedance and other influences in for example a length of cat 5 run down the garden path to the meter would still give a proper pulse at the FLM using the probe for sale on this site?
I have ordered a probe to play with.
Cheers Baz
bazzle |
Arrh the probes are 8.00 Euro.
The shipping is 48 Euro :(
Bart please send me a paypal request with a more sensible shipping cost.
These things wshould fit in an envelope.
Baz
gebhardm |
BTW - just buy yourself a (couple of) reed switch(s) (these little glass tubes with contact tongues in it); they should cost you just a few cents and encourage your soldering experience...
bazzle |
Ill have a look , thanks. Soldering is easy for me so no probs there.
Didn't realise they were just reeds.
bazzle |
Ebay :)
When they turn up Ill post re the success of 35 metres.
petur |
I would worry more about the long line picking up noise and spikes, resulting in false triggers? Although I assume the inputs are properly debounced as the whole thing is supposed to operate near electrical cabinets.
gebhardm |
@bazzle: just try it out with an attached reed switch; there is a 100nF capacitor in parallel to the pulse input, thus debouncing shouldn't be an issue. I wonder why certain Europeans always see arguments that something may (sic) not work - grmph; this is what finally will make us descend.
petur |
It's called experience? :P
petur |
@GEBHARDM, was that grmph directed at me?
Since my electronics knowledge dates back from quite some time, I had a specialist at work do the simulation for me, he came up with 3 ohm wire resistance and 60mH for the induction (the long wire will act as a coil).
Combined with the 100nF cap this gave a nice graph in the sim that shows quite a bit of ringing at the edges of the pulse (like oscillation), and it will indeed be prone to picking up noise.
*IF* it doesn't work, the suggestion is to use properly shielded cable and add a small RC filter.
adamcowin |
Ive got my water probe wired up to the water main (its a grenade style, almost identical to the one on the flukso water probe page)
As the crow flies the meter is about 10 meters away from the flukso.
But by the time you take into account the length of the cable going from the inside of the house, up the wall into the roof, across the roof and then back down the wall to ground level, around the edge of the garden beds (as I didnt want to dig up the lawn to run it diagonally across the lawn) and then to the probe.... i'd say i've gotto be getting close to 20-25 maybe 30 meters. NB the cable exits the house via a hole in the wall covered by a junction box, which is connected to conduit that i've run around the edge of the garden beds (at approx 300mm deep) to the water meter.
I'm not having any problems getting readings from the probe - understanding it on the flukso dash though is another story... (though thats most likely due to my lack of understanding on reading the dash)
At the moment i'm trying to find a way to get that sensor into pvoutput.org's dash (along with the gas probe) to be able to read it a bit easier
So all in all, I don't see why 35 meters length wouldnt work either but keep us updated on how you go :)
Good luck Baz!
gebhardm |
For noise and oscillation on a wire: There is something called twisted pair; if you are not sure, just try it out or use the opportunity to get a longwave receiver for free ;-)
petur |
For the noise part yes, for the oscillation no.
bazzle |
FYI my background 45 years ago was as a Telephone Technician. Twisted pair was my forte :) Changed a lot since then though.
Ill let you know how it works out.
Good to see you've got a long one too Adam ;)
adamcowin |
LOL!
Let me know how you go, once you get it working if you can interpret the results in the dash's graph.
I'm slowly getting the hang of reading it and also toying with getting the water and gas readings into pvoutput on a separate graph
bazzle |
I cant find a way to get readings from my Gas meter ..yet. That will be a new post and project.
This mine
[URL=http://s8.photobucket.com/user/bazzslk230/media/Gasmeter1_zps06c03505.jpg.html][IMG]http://i8.photobucket.com/albums/a19/bazzslk230/Gasmeter1_zps06c03505.jpg[/IMG][/URL]
If anyone has a way to read them Ill be interested.
If you do Ill start a new post.
adamcowin |
hard to see exactly - the photo is quite blurry are you able to get a better pic?
Looking at it quickly, the plastic/glass display, Look up and under the words cubic meter or the middle clock dial. You may be able to see a gap and the dials from under there?
i'll post a picture of my gas meter tomorrow if i can find the picture
Calculating the voltage drop of a copper wire of 0.5 square millimeters with a length of 70 meters (35 to, 35 from the FLM) at a current of 20mA you get a wire resistance of 2.5Ohms and a voltage drop of 0.05V - so this should be no issue at all; try for yourself http://www.electronicdeveloper.de/WiderstandSpannungsverlustKabel.aspx - it's in German, but should be self-explaining. (at 0.2 square millimeters and 5mA it is 0.03V) - this applies also if the switch (as in the FLM case) pulls to ground.
Yes I'm familiar with electrical constants etc. I suppose I was wondering if the impedance and other influences in for example a length of cat 5 run down the garden path to the meter would still give a proper pulse at the FLM using the probe for sale on this site?
I have ordered a probe to play with.
Cheers Baz
Arrh the probes are 8.00 Euro.
The shipping is 48 Euro :(
Bart please send me a paypal request with a more sensible shipping cost.
These things wshould fit in an envelope.
Baz
BTW - just buy yourself a (couple of) reed switch(s) (these little glass tubes with contact tongues in it); they should cost you just a few cents and encourage your soldering experience...
Ill have a look , thanks. Soldering is easy for me so no probs there.
Didn't realise they were just reeds.
Ebay :)
When they turn up Ill post re the success of 35 metres.
I would worry more about the long line picking up noise and spikes, resulting in false triggers? Although I assume the inputs are properly debounced as the whole thing is supposed to operate near electrical cabinets.
@bazzle: just try it out with an attached reed switch; there is a 100nF capacitor in parallel to the pulse input, thus debouncing shouldn't be an issue. I wonder why certain Europeans always see arguments that something may (sic) not work - grmph; this is what finally will make us descend.
It's called experience? :P
@GEBHARDM, was that grmph directed at me?
Since my electronics knowledge dates back from quite some time, I had a specialist at work do the simulation for me, he came up with 3 ohm wire resistance and 60mH for the induction (the long wire will act as a coil).
Combined with the 100nF cap this gave a nice graph in the sim that shows quite a bit of ringing at the edges of the pulse (like oscillation), and it will indeed be prone to picking up noise.
*IF* it doesn't work, the suggestion is to use properly shielded cable and add a small RC filter.
Ive got my water probe wired up to the water main (its a grenade style, almost identical to the one on the flukso water probe page)
As the crow flies the meter is about 10 meters away from the flukso.
But by the time you take into account the length of the cable going from the inside of the house, up the wall into the roof, across the roof and then back down the wall to ground level, around the edge of the garden beds (as I didnt want to dig up the lawn to run it diagonally across the lawn) and then to the probe.... i'd say i've gotto be getting close to 20-25 maybe 30 meters. NB the cable exits the house via a hole in the wall covered by a junction box, which is connected to conduit that i've run around the edge of the garden beds (at approx 300mm deep) to the water meter.
I'm not having any problems getting readings from the probe - understanding it on the flukso dash though is another story... (though thats most likely due to my lack of understanding on reading the dash)
At the moment i'm trying to find a way to get that sensor into pvoutput.org's dash (along with the gas probe) to be able to read it a bit easier
So all in all, I don't see why 35 meters length wouldnt work either but keep us updated on how you go :)
Good luck Baz!
For noise and oscillation on a wire: There is something called twisted pair; if you are not sure, just try it out or use the opportunity to get a longwave receiver for free ;-)
For the noise part yes, for the oscillation no.
FYI my background 45 years ago was as a Telephone Technician. Twisted pair was my forte :) Changed a lot since then though.
Ill let you know how it works out.
Good to see you've got a long one too Adam ;)
LOL!
Let me know how you go, once you get it working if you can interpret the results in the dash's graph.
I'm slowly getting the hang of reading it and also toying with getting the water and gas readings into pvoutput on a separate graph
I cant find a way to get readings from my Gas meter ..yet. That will be a new post and project.
This mine
[URL=http://s8.photobucket.com/user/bazzslk230/media/Gasmeter1_zps06c03505.jpg.html][IMG]http://i8.photobucket.com/albums/a19/bazzslk230/Gasmeter1_zps06c03505.jpg[/IMG][/URL]
If anyone has a way to read them Ill be interested.
If you do Ill start a new post.
hard to see exactly - the photo is quite blurry are you able to get a better pic?
Looking at it quickly, the plastic/glass display, Look up and under the words cubic meter or the middle clock dial. You may be able to see a gap and the dials from under there?
i'll post a picture of my gas meter tomorrow if i can find the picture
Is there a magnet in that you can detect with a compass or some smartphone ?
Or maybe detecting the movement of one clock dial with an optical sensor like i use for detecting my gasmeter or watermeter...
http://userbase.be/forum/viewtopic.php?f=88&t=39962#p526881
http://userbase.be/forum/viewtopic.php?f=88&t=39962&start=60#p531867
Its raining for the next few days. Ill have a look again on the coming weekend.
Baz