Fine Offset Dew Point/Temp Identical?

[LTCSZ]

i am using the AW-1090 station with Cumulus...The humidity today went very low (4% according to the NWS)...The fine offset apparently stops reading/recording humidity at below 10%...Could this be the reason it began showing the Temp and the Dew Point to be the same? Or am I doing something wrong in the settings of Cumulus? Thanks for the assistance...

Steve

[steve]

The station apparently sends '255' when the humidity gets below 10%. Cumulus checks for this value and ignores it (so it should stick at 10%). If the station wasn't sending 255 but was instead a value of 100% or more but less than 255, then Cumulus would set the dew point to the same value as the temperature.

What was the humidity reading in Cumulus?

[wmayfield]

Do you know if there have been any further developments on this? My Fine Offset station has been reading humidity less than 10% for the last couple of days when it get really hot. When it does the display unit shows two dashes in the humidity and Cumulus seems to be reading that as 99% humidity.

As a result Cumulus is currently displaying a temp of 109.4F, dew point of 109.5, heat index of 271.1, and apparent temp of 151.9.

I'm running the beta of 1.9.2 build 1007 on 32-bit windows xp.

[steve]

I haven't progressed this; I was waiting for answer to my question from the OP. But now you've answered it - thanks. The next time the humidity goes to dashes on the console and Cumulus displays 99%, could you please turn on the debug log and leave it for 10 minutes, then upload it here. Please also zip up the diags folder and attach that.

[wmayfield]

Here you go -- I already had the debug log turned on.

[steve]

Thanks; the problem is that the humidity was already showing FF (the underflow value) when Cumulus started, and it didn't have chance to get a previous good reading. I'll change it so that it uses 10% instead of the last known good reading when the underflow situation occurs.

[wmayfield]

This situation has sort of returned for me now.

I fixed this problem by switching to the beta release and have been running Cumulus 1.9.2 build 1008. The RH has gotten down to the 'underflow' setting several times and Cumulus displays it as 10% so the heat index and apparent temperatures are normal.

Now my Fine Offset base unit is displaying 99% humidity when I know the actual humidity is about 15-20%. This is making me have crazy apparent temperature and heat index values since the current temp is around 108F.

Any idea what I can do to fix this? I have tried resetting the sensor unit and the base unit and neither one of those changed the 99% humidity reading.

I have attached a debug log in case that might help.

[wmayfield]

A few minutes after I posted this the base unit switched to the underflow display of "--" and Cumulus started displaying 10% humidity. So I'm guessing the 99% humidity is related to the low/underflow humidity issue.

[steve]

Sounds like a faulty humidity sensor; I don't know of anyone else who has very low humidity seeing 99% on the console just before it displayed the dashes. You could see what it does the next time, perhaps.

[wmayfield]

OK, thanks. I have a feeling it's a case of "You get what you pay for" when it comes to weather station equipment.

[WoodburyMan]

OK, thanks. I have a feeling it's a case of "You get what you pay for" when it comes to weather station equipment.

Check out my thread
https://cumulus.hosiene.co.uk/viewtopic.php?f=13&t=5969

I had the same issue 3 times after replacing the battery. It took a bit of waving the unit around and luck till it started reporting correct values for me, other than 99%.