Cumulus mis-handling VP2 temperature sensor failure?

[freddie]

The temperature sensor on my Davis VP2 appears to have given up the ghost. My Cumulus (latest beta version) doesn't appear to be handling this very well. Firstly: when the sensor failed and the VP2 started to report missing values (---), Cumulus responded by continuing to log and display current data for all working sensors, but used the last available temperature and dew point and reported them (instead of marking them as missing). I noticed this after about three hours. I then restarted Cumulus. It is now logging and displaying current data for all working sensors (as previously) but is now reporting 0 for temperature and dew point!

It's obviously going to be a while before I can install a replacement sensor. In the mean time, how can I indicate to Cumulus that the temperature data is missing and hence shouldn't be used?

Thanks in anticipation.

[steve]

I have the same situation myself at the moment as my temperature sensor has failed yet again. Cumulus has no concept of a missing value, so the only thing it can do is re-use the last good value when it gets a data failure reported by the Davis DLL which communicates with the console. At start up, the initial value is zero, so that's the value it keeps using. I realise this is a deficiency, but there's no easy solution, sorry.

[freddie]

Thanks for the reply, Steve.

No worries - I will just edit the data when I can.

I also notice that I no longer appear to be sending data to PWS, WOW and Twitter - but Wunderground is receiving OK.

Just out of curiosity - who do you use as a supplier for Davis parts?

[steve]

I also notice that I no longer appear to be sending data to PWS, WOW and Twitter - but Wunderground is receiving OK.

Most timer-based activity in Cumulus doesn't start until it's had a good temperature reading and a wind reading. You can over-ride this in 1.9.3, see http://wiki.sandaysoft.com/a/FAQ#Cumulu ... eb_uploads

Just out of curiosity - who do you use as a supplier for Davis parts?

It varies. John Dann (Prodata) at weatherstations.co.uk is good. Often I have bought from Archer Trading in the US, as even after shipping and import duty some parts are around half UK price that way. The temperature sensor doesn't seem to be worth importing as the saving isn't great, for some reason.

On this occasion, as I'm already on my third temperature sensor, and this one is only 18 months old, I contacted Davis but didn't get a very helpful reply (their suggestion was that I buy a new one and wrap the radiation shield in cling film). I then contacted McMurdo, the UK distributor, who have given me an RMA number and asked me to send it to them. I don't know how much they intend to charge me, if anything.

[freddie]

I also notice that I no longer appear to be sending data to PWS, WOW and Twitter - but Wunderground is receiving OK.

Most timer-based activity in Cumulus doesn't start until it's had a good temperature reading and a wind reading. You can over-ride this in 1.9.3, see http://wiki.sandaysoft.com/a/FAQ#Cumulu ... eb_uploads

Thanks for pointing this handy feature out. Data is now flowing again

Thank you for the supplier names too.

[mcrossley]

On this occasion, as I'm already on my third temperature sensor, and this one is only 18 months old, I contacted Davis but didn't get a very helpful reply (their suggestion was that I buy a new one and wrap the radiation shield in cling film).

Steve, I don't know what the internal cct board(s) are like, but have you considered giving it a good spray with a PCB lacquer? (such as this http://www.maplin.co.uk/pcb-lacquer-25345)

[steve]

I don't know what the internal cct board(s) are like, but have you considered giving it a good spray with a PCB lacquer? (such as this http://www.maplin.co.uk/pcb-lacquer-25345)

The problem is that there's a humidity sensor in there too, so it would be a bit tricky.

[mcrossley]

Yep, that would have to masked off before spraying.

[yv1hx]

I don't know what the internal cct board(s) are like, but have you considered giving it a good spray with a PCB lacquer? (such as this http://www.maplin.co.uk/pcb-lacquer-25345)

The problem is that there's a humidity sensor in there too, so it would be a bit tricky.

We found a cheaper and quickly solution, but can lead to problems with your wife or daughters:

Paint both sides of the PCB board with two or more layers of transparent nail lacquer, be sure to dry and clean completely the board before painting.

The new generation sensors board are very protected from the elements, below some pictures of some of our stations, received from the dealer some weeks ago.

BTW: I was dissembling the sensors to paint'em with the nail lacquer prior his definite station deploying, but leave aside the issue when I saw the rubber protection.

[steve]

That's interesting; I can't remember what mine looks like (I do remember it was a 'newer' type at the time, which mounted 'upside down' as some form of protection), I'll see when I dismantle it.

[yv1hx]

That's interesting; I can't remember what mine looks like (I do remember it was a 'newer' type at the time, which mounted 'upside down' as some form of protection), I'll see when I dismantle it.

Maybe your sensor board look like this:

P3280349.JPG

This picture is from another Davis station http://www.wunderground.com/weatherstat ... =IMIRANDA8

Please note some of the copper traces are exposed, those traces are attacked by the humidity then misleading the data communication between the sensor itself and the SIM board.

[steve]

Yes, that looks familiar. I'll upload a photo tomorrow when I take it apart. So hopefully if I get a replacement now, it will be like yours and I won't have this problem again.

[steve]

Here's what mine looks like. Apart from being out of focus, it does seem to have all the tracks covered.

[mcrossley]

Hard to see how anything could get in there other than around the sensor chip itself. Presumably only the slot needs to be exposed for humidity, covering the rest of the chip in thick rubber would slow down it's response to temperature changes, but I hope all its edges are at least covered in a thinner lacquer?

[steve]

There isn't really anywhere that needs lacquer, the whole thing seems to be sealed in rubber, apart from the very small area on the sensor.