Topic: Davis Vantage Vue - Extreme Temperature Fluctuations and Errors

[wjourdain]

I have a new Davis Vantage Vue that has been installed for about 8 days.  It has the wireless ISS and the serial data logger.  I have been using the station with the Cumulus software.  Everything has been perfect for the first 8 days.  This afternoon at 5:01 p.m, my station suddenly went from reporting the correct temp (about 62 degrees F) to reporting -90 F (minus).  Then, at 5:02 p.m, it reported a temp of 164 degrees F.  Since that time, it has fluctuated all over the place, but often either displays -90 or 164.  While I have been typing this post, I have seen -90 and 164.  I don't see where the other sensors are reporting these wild fluctuations.  I have not moved the ISS since the initial installation 8 days ago, nor has anything changed around it.  It has just suddenly started displaying these extreme outside temps.  I looked at the statistical diagnostic and reception diagnostic screens and everything reported there appeared to be within the normal parameters.  I have also reset the console a couple of times to no avail.  I have also unplugged the data logger from the cable and this did not solve the problem.

The ISS in on the roof and I have not climbed up there at this point to try to reset it or remove the battery, hoping that there is a better solution.  I would appreciate any helpful advice or assistance anyone on the forum can provide that will help me solve this problem.

Thanks.

[LittletonCOwx]

A few questions for clarification.  When you plugged the data logger in (and unplugged it), were you sure to power down the console (both AC power AND batteries)?  You can fry things if you don't power the console down while doing this.  Also, you don't tell us if the odd values displayed were on the console display itself, or in Cumulus, or both.  Are you uploading data anywhere on the web?  If so, can you link us to those feeds.  They might help provide insight to the problem.

Having said that, it might well be the ISS battery.  From what you describe, to me that sounds like the most likely thing, and would be one of the first things I would check.

[wjourdain]

A few questions for clarification.  When you plugged the data logger in (and unplugged it), were you sure to power down the console (both AC power AND batteries)?  You can fry things if you don't power the console down while doing this.  Also, you don't tell us if the odd values displayed were on the console display itself, or in Cumulus, or both.  Are you uploading data anywhere on the web?  If so, can you link us to those feeds.  They might help provide insight to the problem.

Having said that, it might well be the ISS battery.  From what you describe, to me that sounds like the most likely thing, and would be one of the first things I would check.

Thanks for the reply.  Before I plugged in the data logger I had unplugged the AC power and removed the batteries.  The console was completely powered down.  The readings are showing up in Cumulus and on the console.  I am uploading the data to the web, but I stopped uploading when I found this problem as I didn't want those temps uploaded.  My weather site is http://www.calhounweather.net.

I probably won't have a chance to deal with the battery until this coming weekend if that is the problem, but I hope with a brand new unit that's not it.  That would be an easy fix, though.

Thanks again for your response. 

[LittletonCOwx]

Well if the bad data is showing up everywhere, there's a good chance of it being the battery.  The 123 lithium batteries that Davis sends with the units are pretty good quality, but that doesn't necessarily mean there isn't a bad one here and there.  You don't have to spend $8 - $10 per battery either; If you buy them online, they're much cheaper (Battery Station is a good one).  I use theirs in my good flashlights (and have for about 10 years, buying 50 at a time), and their house brand is every bit as good as the Duracell or Energizer.  IMO, only the Surefire 123's are better.

Otherwise, it could be a board (hopefully not).  I'd bet that Davis tech support would have you change the battery before doing anything else.

[wjourdain]

I've got an email in to Davis tech support, but I may go ahead and change out the battery just to see if that fixes the problem.  I've read several posts on this forum and others about short battery life on these units (I've also read that others have received very good battery life).  I hope that's not the problem.  I have a friend with this same unit and he has gotten 3 years out of his original battery and is about to change it.  I've had mine for 8 days, so I hope this is not a trend!

[LittletonCOwx]

No, you definitely shouldn't be having to change the battery every 8 days, especially if the ISS is getting sun.     I think the ISS will run for months on nothing but the battery, so I don't think the problem is the solar panel either.

[jerryg]

I dont own a vue but i saw on your web site the humidity was 1 percent and that is not normal to be that low, so it looks to me like you have a bad temp/humidity sensor giving those bad readings.

[PaulMy]

I've got an email in to Davis tech support

I suggest you telephone Davis support to get the best/quickest support.  They are generally easily reached and helpful.
Paul

[dalecoy]

OK, let's review

.... Everything has been perfect for the first 8 days. 

....This afternoon at 5:01 p.m, my station suddenly went from reporting the correct temp (about 62 degrees F) to reporting -90 F (minus).  Then, at 5:02 p.m, it reported a temp of 164 degrees F.  Since that time, it has fluctuated all over the place, but often either displays -90 or 164. 

....  I don't see where the other sensors are reporting these wild fluctuations.  I have not moved the ISS since the initial installation 8 days ago, nor has anything changed around it.  It has just suddenly started displaying these extreme outside temps. 

....I looked at the statistical diagnostic and reception diagnostic screens and everything reported there appeared to be within the normal parameters. 

Worked fine for several days, now wild temperature measurements with no other measurement errors, and the reception diagnostics are nominal.  This occurred during the daytime.

I don't see how that's a battery problem (although replacing the battery would be a good diagnostic).  I would suspect a temperature sensor failure (or perhaps some contamination or spiders or whatever around the temperature sensor).  Look for things to clean up, and replace the battery (but keep the old one, and measure the voltage if you have a meter). 

Be prepared to obtain an in-warranty replacement.

[ValentineWeather]

I doubt its the battery. The solar panel charges a capacitor on the sensor interface module (SIM) which normally runs the instruments and transmitter. Battery in the ISS is rarely used except maybe on the longest nights just before sunrise, that's why you can go 2 plus years easily without replacing them. The battery is just a backup power supply is my understanding. You need to call Davis instruments they can help out there.

[johnd]

I concur too - very unlikely to be the battery. It will likely be something to do with the T/H sensor.

Talking to Davis is your only option AFAICS. Sounds to me like you're going to need a new ISS harness (since it's a recent Vue, there will be no separate T/H sensor board). Probably Davis will need you to send the ISS in to them.

That said, there's just a tiny chance that it could be a console fault but there's no way of telling for sure until you've swapped out the harness. But I'd put 10-1 on it being an ISS fault.

This is really quite an unusual fault - it's extremely rare that there are T/H faults pretty much out of the box. You've definitely been unlucky here.

[wjourdain]

I put in a call to Davis tech support this morning, but unfortunately they are closed for the President's Day holiday.  I will try them again tomorrow.  I looked at the console this morning before leaving for work and it was reading -90.   I will keep the group posted with what I find out.

[Beaudog]

It easy to put that battery in backwards. I did the first time. Been too long for me to remember what the results were.

[dalecoy]

It easy to put that battery in backwards. I did the first time. Been too long for me to remember what the results were.

......would not match the symptoms reported in this thread.

[wjourdain]

As a follow up to my previous posts about this problem, I returned home about 45 minutes ago after being gone all day.  Unexpectedly, the temperature and humidity are now being reported accurately and have been so for most of the afternoon.  I'm not sure why this happened, but I assume this means it is not a battery problem.  I'm still going to call Davis and discuss this situation, as I imagine it is likely to happen again.  For now, I have reactivated uploading of the weather data to the site.  I did this after editing the previously reported highs and lows from the erroneous data.  I'll post here if there are any further developments.  Very strange, indeed.

[dalecoy]

If you are comfortable doing it, inspecting the sensors for cleanliness, bugs, etc. might be useful.

[LittletonCOwx]

Certainly interested to see what Davis decided to do in this case.  Have you spoken with them again?

Typically, when sensors report 0 or full scale values, it means that they're not being powered properly.  However, now that you are definitely seeing some kind of intermittant problem, my thoughts are with the others in that there is likely something else going wrong with the ISS.

[wjourdain]

Davis finally responded to me and suggested changing the radio channel for the ISS to talk to the console.  I have not done this as the station has been working properly since my last post.  If it repeats this strange activity I will try their advice.