Broken pressure sensor?

[jim-easterbrook]

My station lost contact with the outside sensors overnight, so I decided to change the outside sensors' batteries. Hence I had to take the batteries out of the base station to re-establish contact with the outside sensors.

Since then I've been getting crazy pressure readings. I've set the display to show absolute pressure, and that's currently 1440.3 hPa. It was 1013.6 an hour ago, just before I removed the batteries. Now it's reading 1444.6. Another half a minute and it's 1448.9. (Interesting - it's going up by 4.3 each time.)

Has anyone seen anything like this before and, more importantly, does anyone have any ideas on how to fix it?

[mcrossley]

Jim, I had my pressure jump up when I removed the batteries, but it has remained stable at the new high value, the base station and Cumulus calibrate back to the real value OK.

BUT it does cause me one problem, I can no longer change the base station logging interval (stuck at default) because EasyWeather does some range checking on the pressure values and will not let you submit the settings dialog to make the change (the pressure field is read-only and populated by EW).

I guess that the base station has some factory calibration offset for reading the pressure gauge stored in NVM somewhere, but I cannot find any means of resetting the base station.

[jim-easterbrook]

If only it were stable. In the last 24 hours it's varied from 0.8hPa to 1793.1hPa, sometimes jumping by 1500hPa in as little as 5 minutes. I suppose I've nothing to lose by getting the back off and having a look around - something I've resisted doing up to now.

[jim-easterbrook]

My base station lost contact with the sensors many times today, despite new batteries in both, so I took an executive decision and visited Maplin on the way home from work.

I now have a spare system to play with and test software on. The new unit is on a different frequency, so I can't have two base stations receiving the same data. I don't know what the neighbours will think if I put up another set of sensors.

[jim-easterbrook]

And now my replacement turns out to be kaput. The console - computer connection hangs once there is more than a couple of days worth of data logged. The console memory 'button' also stops working.

Anyone know if Maplin will replace just the console, or do I have to lug the entire kit back to them?

[daj]

Is it still under warranty? A warranty replacement is usually all the kit, not a part of it

[mcrossley]

BUT it does cause me one problem, I can no longer change the base station logging interval (stuck at default) because EasyWeather does some range checking on the pressure values and will not let you submit the settings dialog to make the change (the pressure field is read-only and populated by EW)

I'm glad to say that using Jims pywws Python scripts I have been able to reset my station logging period from the default 30 mins to 10 mins. Jim's scripts also allow you to dump the 256 byte fixed memory area, I knocked up a spreadsheet to decode the known values. Just paste the text of the dump into cells B2-B9...

[mcrossley]

Oops, I posted an older version of the spreadsheet, this one has the monthly/yearly rainfall totals spread over the 3 bytes defined in the AmbientWeather protocol document...

PS: I ran Jim's scripts from a Linux VM, and after a bit of tweaking that solution worked fine.

PS: moved the spread sheet to it's own thread