THSW index

[EmjayNet]

I prefer the THSW index given on the VP2 console as the feels-like temperature.

Is there any way for MH to extract this value out of the console?

[Hathor27]

Me too...

...how could we get THSW index out of Vantage Pro2?

Is it somehow covered in meteohub, or is it not yet implemented?

[Hathor27]

...
Calling to admin : Is there any chance to get this THSW index out of Davis Vantage ??

[EmjayNet]

Yep would love to see this added to the list a things to add!

I know there are less vantage users but i would be nice to have 1 thing I requested added to software if it at all possible, please boris!

[d_l]

The THSW index is re-calculated by the WeatherLink software and not simply output by the Davis hardware in the LOOP data to the WL software. Note that there is even an option in the WeatherLink software to re-calculate the THSW index after some of its input data values have been altered. The HI/LOW data does output the Day High THSW and the
Time of Day High THSW, but this isn't what you would want. Therefore, any implementation of the the index would have to be re-calculated by the Meteohub from the component data.

The formula for the THSW can be found in this Davis application note

[skyewright]

Yep would love to see this added to the list a things to add!

THSW is what I have my VP2 console set to show as "feels like" too. It would be nice to be able to log it...

[EmjayNet]

Normally everything on the console is availiable in the LOOP, it would seem odd if this console output was not in the LOOP but who knows with Davis.

Unless someone here has the output of the LOOP, then I guess only Boris can answer this!

[YJB]

Normally everything on the console is availiable in the LOOP, it would seem odd if this console output was not in the LOOP but who knows with Davis.

Unless someone here has the output of the LOOP, then I guess only Boris can answer this!

From the Davis interface manual:

Code: Select all

Only values read directly from sensors are included in the LOOP packet

From the Davis App note 28 document:

Code: Select all

The following parameters do not have any sensors or circuitry. They are calculated from measured variables.
<SNIP>
THSW INDEX
Parameters Used: Temperature, Humidity, Solar Radiation, Wind Speed, Latitude & Longitude, Time and Date
<SNIP>

THSW is available in the HIGHLOW packet, but since that will only list extremes it will not be suitable to satisfy the requirement listed above:

Code: Select all

Day High THSW 95 2
Time of Day High THSW 97 2
Month High THSW 99 2
Year High THSW 101 2

Ysbrand

[EmjayNet]

I stand corrected. What a pity!

It so nice to visit such a friendly place every now and then.

Have a good year all.

[Hathor27]

The formula for the THSW can be found in this Davis application note

If there's no direct output within the LOOP, couldn't we rebuild THSW manually ? The application just talks about series of formulas used to.

Does anybody know how we could calculate it as a virtual sensor from its based values?

[d_l]

Does anybody know how we could calculate it (THSW) as a virtual sensor from its based values?

I have more details on the THSW calculation from a Davis VP Tech manual than is offered in App Note 28. Unfortunately it is in PDF format and is over a megabyte in size. I'll try to condense the size or format some how and post it here when I get the time -- the next day or so.

Suffice it to say that calculating it as a virtual sensor with AWK will be tricky as the wind factor is from several look up tables and the solar factor is a sum of four complicated equations with If/Then complicating limits on the raw data and not just simple "terms" as AN 28 states.

[Hathor27]

I'll try to condense the size or format some how and post it here when I get the time -- the next day or so.

Would you mind sending me the original file as private message (email) or posting just a link here?

[YJB]

I'll try to condense the size or format some how and post it here when I get the time -- the next day or so.

Would you mind sending me the original file as private message (email) or posting just a link here?

Here you go (directly from the source):

http://davisnet.com/product_documents/w ... iables.pdf

THSW starts at page 28-7

Also, one needs to be very careful when starting to make calculations on the fly, especially when using a virtual sensor. Think about the cpu resources needed every time the "trigger" sensor is being updated. One will be forced to use something like "C", otherwise this is not going to fly.

Ysbrand

[Hathor27]

http://davisnet.com/product_documents/w ... iables.pdf
THSW starts at page 28-7

Thank you, Ysbrand, I know about that application note - but d_l wrote about Davis VP Tech manual and over a megabyte. I think that would be something more precise - the application note doesn't describe the exact formula.

Also, one needs to be very careful when starting to make calculations on the fly, especially when using a virtual sensor. Think about the cpu resources needed every time the "trigger" sensor is being updated. One will be forced to use something like "C", otherwise this is not going to fly.

If we know more details about the formula, we can probably estimate the required recources...

[d_l]

AFAIK, there is no public link to this VP tech manual. The entire manual is over 5 megabytes. I tried extracting just the THSW section and ended up with a one megabyte PDF file. I tried taking images of the section but they had to be pixel huge on each side to be legible. Extraction to txt or RTF formats really scrambled the text. So I upgraded my program (it isn't Acrobat), and tried again. I had to break it down and zip it to be under the permitted size limit and in an allowable format.