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Latest Cumulus MX V3 release 3.28.6 (build 3283) - 21 March 2024
Cumulus MX V4 beta test release 4.0.0 (build 4018) - 28 March 2024
Legacy Cumulus 1 release v1.9.4 (build 1099) - 28 November 2014 (a patch is available for 1.9.4 build 1099 that extends the date range of drop-down menus to 2030)
Download the Software (Cumulus MX / Cumulus 1 and other related items) from the Wiki
Lost Sensor Contact!!
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- Posts: 20
- Joined: Mon 24 Aug 2009 7:45 am
- Weather Station: wh1081
- Location: Qld Australia
Re: Lost Sensor Contact!!
Hi Gina
It is is difficult to tell from your photographs, but is your mast effectively earthed? Even dry wind over the mast can build up a static charge, and when it reaches a critical level discharges to earth causing a spike of RF interference if the mast is not effectively earthed.
This adventure will rival days of our lives when it is eventually solved.
gordonwh40
It is is difficult to tell from your photographs, but is your mast effectively earthed? Even dry wind over the mast can build up a static charge, and when it reaches a critical level discharges to earth causing a spike of RF interference if the mast is not effectively earthed.
This adventure will rival days of our lives when it is eventually solved.
gordonwh40
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- Location: NE7 7QE Newcastle upon Tyne UK
Re: Lost Sensor Contact!!
I think I'd have put the capacitors on the other side of the choke, on the grounds that you would be connecting the RF pulse to ground BEFORE any of it was conducted through the choke. However, I was only ever a hobby electronics dabler, whereas you seem to have a proper engineering background.Gina wrote:I'm thinking of the following, from Maplin :-
Does this sound sensible, EvilV? (or anyone else au fait with this subject)
Actually Gordonwh40's suggestion about static is quite persuasive. You'd better know whether the spikes only take place in low humidity. I don't suppose that DEvon gets that much dry wind, poking out into the Atlantic as it does, but earthing the mast might be a good test before you make your circuit.
Another thing I would do, is uncouple the signal wire from the mast, roll it up and lay it on the ground to see if the spikes go away. There might be an occasional glitch in the socket on the sensor unit, caused by wobbling in the wind or maybe even thermal expansion / contraction. You could simulate movement by manually wobbling the cable.
This thread is turning into a compelling epic. It reminds me of Apollo 13, where brave and resourceful engineers struggle to identify and solve the problems, while a massive team wait with baited breath for the next instalment.
My weather data page on WU:
http://www.wunderground.com/weatherstat ... =INEWCAST6
http://www.wunderground.com/weatherstat ... =INEWCAST6
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- Posts: 1885
- Joined: Sat 21 Feb 2009 12:41 pm
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- Operating System: OS X, Linux Mint, Win7 & XP
- Location: Devon UK
Re: Lost Sensor Contact!!
Hi Gordon, thanks for your inputgordonwh40 wrote:Hi Gina
It is is difficult to tell from your photographs, but is your mast effectively earthed? Even dry wind over the mast can build up a static charge, and when it reaches a critical level discharges to earth causing a spike of RF interference if the mast is not effectively earthed.
This adventure will rival days of our lives when it is eventually solved.
gordonwh40
Like EvilV, I think you have a very good thought there. The bottom of the mast sits on the ground but isn't buried. This allows me to put it up and take it down by pivoting at the bottom. We have had a fortnight without measurable rain though there has been some dew. It could be that the base is not earthed well enough. There was a period with no wind but there were spikes. OTOH last night there was no wind and no spikes, much to my surprise.
Gina
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Sorry, no banner - weather station out of action. Hoping to be up and running with a new home-made one soon.
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- Joined: Sat 21 Feb 2009 12:41 pm
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- Location: Devon UK
Re: Lost Sensor Contact!!
Yes, I do have an engineering background, particularly electrical and electronics. Mains RF filters usually have a capacitor across line and neutral then a choke in each followed by capacitors to earth. I could easily add capacitors at the input too. The output capacitors do the main work though. The chokes provide a high impedance (resistance) at high frequencies while being virtually short-circuit at DC and low frequencies. Capacitors are the opposite - no affect on DC or very low frequencies etc. Thus the choke (inductance) and capacitor provide a high attenuation at radio frequencies while passing DC and LF untouched.EvilV wrote:I think I'd have put the capacitors on the other side of the choke, on the grounds that you would be connecting the RF pulse to ground BEFORE any of it was conducted through the choke. However, I was only ever a hobby electronics dabler, whereas you seem to have a proper engineering background.
Agreed! As I said to Gordon, we have had a spell of dry weather for the last couple of weeks. A proper earth is easy enough to implement. I'll do that.Actually Gordonwh40's suggestion about static is quite persuasive. You'd better know whether the spikes only take place in low humidity. I don't suppose that DEvon gets that much dry wind, poking out into the Atlantic as it does, but earthing the mast might be a good test before you make your circuit.
I've tried wobbling the connector by hand - nothing.Another thing I would do, is uncouple the signal wire from the mast, roll it up and lay it on the ground to see if the spikes go away. There might be an occasional glitch in the socket on the sensor unit, caused by wobbling in the wind or maybe even thermal expansion / contraction. You could simulate movement by manually wobbling the cable.
Yes, it is rather I hope I'm quite resourceful but I don't know about brave I enjoy a challenge and I enjoy a puzzle. I like to keep my mind active I do the testing but provide ideas as part of the team, of course I'm grateful to others for the useful suggestionsThis thread is turning into a compelling epic. It reminds me of Apollo 13, where brave and resourceful engineers struggle to identify and solve the problems, while a massive team wait with baited breath for the next instalment.
Gina
Sorry, no banner - weather station out of action. Hoping to be up and running with a new home-made one soon.
Sorry, no banner - weather station out of action. Hoping to be up and running with a new home-made one soon.
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Re: Lost Sensor Contact!!
10:50 18 Apr 2010 Connected wind sensors again to check for interference. Once the spikes come back I'll earth the mast. I want to be sure things are still the same. If I were to earth the mast and got no more spikes I wouldn't know if I'd fixed it or just that the interference had stopped.
With the last test - separate cable from TX unit wrapped round sensor cable and mast - we had two spikes then nothing.
With the last test - separate cable from TX unit wrapped round sensor cable and mast - we had two spikes then nothing.
Gina
Sorry, no banner - weather station out of action. Hoping to be up and running with a new home-made one soon.
Sorry, no banner - weather station out of action. Hoping to be up and running with a new home-made one soon.
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Re: Lost Sensor Contact!!
No spikes yet!
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Gina
Sorry, no banner - weather station out of action. Hoping to be up and running with a new home-made one soon.
Sorry, no banner - weather station out of action. Hoping to be up and running with a new home-made one soon.
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- Location: Whitehorse, Yukon Territory, Canada
Re: Lost Sensor Contact!!
Hi Gina,
If you do decide to build the filter, you could likely increase either L or C by an order of magnitude for better filtering and still only have unmeasurable negative effect on switching times of the counter relays. What were you thinking of using as a ground reference to route the offending currents to?
I might be tempted to try common mode chokes if there is still some spiking once the filter is tried. It's a pity that a spike couldn't be captured on a storage scope - it's a lot easier if you know exactly what you're dealing with.
If you do decide to build the filter, you could likely increase either L or C by an order of magnitude for better filtering and still only have unmeasurable negative effect on switching times of the counter relays. What were you thinking of using as a ground reference to route the offending currents to?
I might be tempted to try common mode chokes if there is still some spiking once the filter is tried. It's a pity that a spike couldn't be captured on a storage scope - it's a lot easier if you know exactly what you're dealing with.
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- Posts: 1885
- Joined: Sat 21 Feb 2009 12:41 pm
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Re: Lost Sensor Contact!!
I can certainly increase C but 1mH is the largest value of choke sold by Maplins. For the ground for the Cs I was thinking of using a piece of copper pipe driven into the ground near the base of the post holding the Stevenson screen and TX unit etc. Then wiring that to the junction of the Cs.Charlie wrote:Hi Gina,
If you do decide to build the filter, you could likely increase either L or C by an order of magnitude for better filtering and still only have unmeasurable negative effect on switching times of the counter relays. What were you thinking of using as a ground reference to route the offending currents to?
I might be tempted to try common mode chokes if there is still some spiking once the filter is tried. It's a pity that a spike couldn't be captured on a storage scope - it's a lot easier if you know exactly what you're dealing with.
I do have a hand-held digital storage oscilloscope but the problem is setting it up to catch the interference. The frequency of occurrence is rather low! Also, the LCD screen is difficult to see outdoors.
Current situation is that in spite of re-connecting the wind sensors there are no spikes. Well, not as yet. So I have just re-connected the rain gauge and fan. It rather looks as if the cause of the spikes has ceased. Many might say "that's good" but I want to find the problem. Intermittent problems that just "go away" I can't stand!!! There is always the feeling that they'll come back!
Gina
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Sorry, no banner - weather station out of action. Hoping to be up and running with a new home-made one soon.
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Re: Lost Sensor Contact!!
EDITED I thought I had magic with the rain plot but it was the way I was plotting the data. All the same the rain gauge or it's cable appeared to be picking up interference and reading feet of virtual rain.
Now had two spikes on the temperature plot.You do not have the required permissions to view the files attached to this post.
Last edited by Gina on Sun 18 Apr 2010 6:02 pm, edited 2 times in total.
Gina
Sorry, no banner - weather station out of action. Hoping to be up and running with a new home-made one soon.
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Re: Lost Sensor Contact!!
18:00 18 Apr 2010 Earthed mast. Just wind sensors connected - no rain gauge, no fan
EDIT The earth wasn't good enough - got a spike. On checking the conductivity from mast to earth with a multimeter I got <2Mohm (off the scale). So did it properly...
19:55 18 Apr 2010 Re-did mast earth. 9" copper pipe hammered into ground and connected to mast.
Resistance using just 3/4" tip of MM probe in soil to mast showed 1.2Mohm. The resistance mast to earth is probably a lot lower but, in any case should prevent any build-up of static charge.
Temp plot showing spikes without mast properly earthed :-
EDIT The earth wasn't good enough - got a spike. On checking the conductivity from mast to earth with a multimeter I got <2Mohm (off the scale). So did it properly...
19:55 18 Apr 2010 Re-did mast earth. 9" copper pipe hammered into ground and connected to mast.
Resistance using just 3/4" tip of MM probe in soil to mast showed 1.2Mohm. The resistance mast to earth is probably a lot lower but, in any case should prevent any build-up of static charge.
Temp plot showing spikes without mast properly earthed :-
You do not have the required permissions to view the files attached to this post.
Gina
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Re: Lost Sensor Contact!!
Here is a live plot of temperature only. This will be no more than 10 mins out of date as the data is uploaded every 10 mins.
At time of posting we have one spike, just before 21:00. Wind sensors are connected, rain gauge and fan are not. The mast was earthed as from about 20:00 on 18 April. This would appear to indicate that earthing the mast has not cured the problem.
At time of posting we have one spike, just before 21:00. Wind sensors are connected, rain gauge and fan are not. The mast was earthed as from about 20:00 on 18 April. This would appear to indicate that earthing the mast has not cured the problem.
Gina
Sorry, no banner - weather station out of action. Hoping to be up and running with a new home-made one soon.
Sorry, no banner - weather station out of action. Hoping to be up and running with a new home-made one soon.
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Re: Lost Sensor Contact!!
Plenty of data spikes overnight so earthing the mast has not helped. Next stage will be to lower the mast, remove the sensors and replace the sensor cable with another cable to the mast top, then stick the mast back up again. Can then see if it's RF pick-up by cable or mast. While I've got the anemometer and vane units down I may take them apart and see if there are any dry joints or suchlike. I'd like to see how they're made, anyway. I'll take photos.
Gina
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Sorry, no banner - weather station out of action. Hoping to be up and running with a new home-made one soon.
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- Location: Devon UK
Re: Lost Sensor Contact!!
10:45 19 Apr 2010 Lowered mast, removed wind sensors (unplugged from coupler half way up mast), extended cable to TX unit and taped it to the mast. Excess cable length fed down inside the mast. See above (top of page) for live temperature plot.
Gina
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- Posts: 127
- Joined: Wed 27 Jan 2010 11:28 am
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- Operating System: XP
- Location: NE7 7QE Newcastle upon Tyne UK
Re: Lost Sensor Contact!!
I've opened the 24 hour temp chart in a new window and saved the url into my bookmarks bar so I can open it any time irrespective of whether I am on this forum.
At the time of posting, there seem to be no spikes. Looks like its the wind gadgets.
Wish we had 15C. It's 7.5 here!
LATER EDIT:
This is getting a bit weird because I was under the impression that you had previously isolated the wind apparatus and were getting spikes with a new extension cable plugged into nothing but strung up the mast. Now it seems you have a new cable plugged into nothing but no spikes. You already ruled out the static build up theory (except that I wouldn't count a 9" copper pipe as a good earth myself. In my Radio Ham days I used at least a one metre copper rod hammered down into the ground and watered it regularly in dry weather) so why have the spikes gone now? Is it because you are now shielding the cable by running it up the inside of an earthed tube, perhaps? And what will happen when you re-connect your wind gear at the top?
I may have missed something here in your current arrangements.... It si getting complicated to keep up for an 'auld git'.
At the time of posting, there seem to be no spikes. Looks like its the wind gadgets.
Wish we had 15C. It's 7.5 here!
LATER EDIT:
This is getting a bit weird because I was under the impression that you had previously isolated the wind apparatus and were getting spikes with a new extension cable plugged into nothing but strung up the mast. Now it seems you have a new cable plugged into nothing but no spikes. You already ruled out the static build up theory (except that I wouldn't count a 9" copper pipe as a good earth myself. In my Radio Ham days I used at least a one metre copper rod hammered down into the ground and watered it regularly in dry weather) so why have the spikes gone now? Is it because you are now shielding the cable by running it up the inside of an earthed tube, perhaps? And what will happen when you re-connect your wind gear at the top?
I may have missed something here in your current arrangements.... It si getting complicated to keep up for an 'auld git'.
My weather data page on WU:
http://www.wunderground.com/weatherstat ... =INEWCAST6
http://www.wunderground.com/weatherstat ... =INEWCAST6
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- Posts: 1885
- Joined: Sat 21 Feb 2009 12:41 pm
- Weather Station: Nothing working ATM - making one
- Operating System: OS X, Linux Mint, Win7 & XP
- Location: Devon UK
Re: Lost Sensor Contact!!
Good ideaEvilV wrote:I've opened the 24 hour temp chart in a new window and saved the url into my bookmarks bar so I can open it any time irrespective of whether I am on this forum.
Looks like it. I shall be leaving things as they are for a few hours, so we'll see.At the time of posting, there seem to be no spikes. Looks like its the wind gadgets.
Yes, lovely day here, continuous hazy sunshine and warm. Unfortunately, I have indoor jobs I have to get done! Sorry you haven't got the same weather.Wish we had 15C. It's 7.5 here!
Gina
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