THSW index from Davis Vantage Pro 2

[pcmwn]

Hi,

Just wondering if there is a way to get the THSW index from a Vantage Pro 2 as a sensor that can be added to my Web Cam image?

Peter.

[Mattk]

As far as I am aware THSW is a computed value (after the event) requiring a Solar radiation sensor + Humidity, Temp & Wind sensors etc. Davis provide a THW tag but not aware of a THSW tag so would be something you would have to compute yourself?

[milehighweather]

Hi,

My apologies for resurrecting a 4yo thread, but I am trying not to generate new discussions on existing topics. I have been a meteobridge user for years, and have recently ordered a meteobridge Pro, which I am waiting on as we speak! This is my first forum post, and I apologize in advance for the length. I am trying to ensure I include all relevant info.

What am I asking for?

I am wondering if there was ever any resolution around the threads requesting the THSW value provided by Davis Vantage Pro 2 console (where the user has a solar radiation sensor)? In my brief research, it appears the current THSW index is now included in the LOOP 2 packet (https://www.davisinstruments.com/suppor ... s_v261.pdf), as offset 39, with additional THSW information at offsets 95,97,99, and 101. This may not have been the case back in 2014. This *seems* like it would be an easy addition, but I'm well out of my depth here, in terms of knowing what would be required to include this. I have not been able to find a good way to access this data, and the calculation is highly-complex and beyond my skillset to implement on my own. It does not appear meteobridge offers a 'tag' to access this data via a template. Is there any way to include this data, calculated by the Davis Vantage Pro 2 console, where the user has solar radiation sensors?

Why does it matter?

Even while acknowledging all of the inherent flaws in highly-subjective 'apparently temp / feels like / real feel' metrics, the THSW index is quite useful in my location. To address a different thread on the same topic, the Davis unit DOES seem to calculate THSW in all temperatures (personally witnessed from -10C to ~20C). The climate here in Denver, Colorado, US (high-elevation, semi-arid) makes standard windchill and heat-index values highly problematic, mostly due to the perpetually low humidity. Solar energy has a huge impact on the 'feel' of our climate, perhaps more so than many other places, and having tracked the THSW index on my Vantage Pro 2 console for some time it seems that Davis' THSW calc does a nice job of capturing how the climate 'feels.' In the shade, temperatures tend to feel somewhat colder than the actual air temperature year-round, which is captured nicely by existing wind chill and heat index metrics. During the day, however, it is almost always sunny and we have little shade and the climate frequently feels far warmer than the temperature would indicate due to our high-altitude sunshine and low humidity. Existing 'apparent temperature' metrics which don't include solar radiation universally show our 'feel' as much lower than the actual temperature, which is misleading.

Any guidance on how to access this metric would be highly appreciated.

Thank you!
Josh

[agallardo1980]

Hi,

I agree with @milehighweather. In my case (I have solar and uv sensor). I think it would be very useful to have the variable THSW available in meteobridge and be able to use it in templates.

Boris: Is there any chance of implementing this? It would be very complicated?

I would appreciate it very much

[Ag2000CO]

If you can capture the value it sounds like a use for the new "data21"

Not having a console I'm looking for how to cal THSW.

There is of course the thread viewtopic.php?f=18&t=7507

[agallardo1980]

data21num sensor requires you have a driver to access to this data in the console/weatherlink and later to call a shell script to output this data to sensor. But the problem is that I have no access to this driver, and I understand that this driver to access to Console data for Davis VP is included and compiled in Meteobridge code. Is it correct?

[Ag2000CO]

Yes I think that is all true. There would seem to be two approaches to using THSW in a MB:
1. wait for Boris to program the capture of this Davis console unique computed value into the MB, making it available IF you have a Davis Console and IF you have a Solar sensor, etc. There would also need to be coding to handle all the permutations of having/not having a Davis console and necessary sensors and valid readings.
2. What I was addressing was, doing it yourself and using the new data21 as a way to display the data. Off the top of my head it looked like there were two approaches to the DIY approach; A) Figure out how to capture the THWS value from your Davis console pushing that value to the data21 tag, or B) For us without a console, use the available data (temp, humidity, wind, solar...) calculate a thws value to display again using data21.

In the THSW thread I linked to, someone who lives in Denver, CO, USA, a high/dry climate, said "How it feels" has more to do with the sun/uv than the temp. I too live at 9,318 feet in a dry climate so was interested enough to put THSW somewhere on my look-in-to-this list, and the data21 tag looked like a way to access the calculated value.