DAVIS #06372 Temp Station 'integer' only?

[Old Tele man]

Help!

I have (another, duh) question about DAVIS system 'idiosynchracies' -- apparently WeatherLink software only handles "integer" values from second-stations, like the #06372 TEMP station!

Seems (per DAVIS tech support) that the VP2 console can receive signals from just ONE ISS station at a time, so when a second-station is connected it is relegated to 2nd-class status (or something) and it's data, although actually 0.1ºF resolution, is truncated to an integer-value by the WL software! The ONLY way to get it's data in 0.1ºF format is to assign the #06372 Temp Station as ISS, which, of course, then loses the actual VP2 ISS temp/rh/anemometer data.

So, has anyone found a way to get around this problem? I need to access the 0.1ºF resolution data that's actually coming from the #06372 Temp station and archive it to my computer. The integer-value numbers I'm currently getting are WAY too granular/coarse in resolution!

Any ideas, suggestions, condolences...or, help?

[d_l]

The only solution is to buy an additional Envoy and logger and set the temp station to be an ISS. It would only be a partial station in that the other normal ISS data would not (could not) be sent.

The Envoy could be an 8X version, but you run into software complications and the lack of real-time update with that hardware.

[DaculaWeather]

Is it just a WL issue?

[Bushman]

Nope!  The loop packet has a 7 byte field for each of the 7 possible stations you can add. 

Davis:

"This field supports seven extra temperature stations. Each byte is one extra temperature value in whole degrees F with
an offset of 90 degrees.  For example, a value of 0 = -90°F ; a value of 100 = 10°F ; and a value of 169 = 79°F."

[Bushman]

BTW, same thing for soil and leaf temps.  Bad design IMHO

[dalecoy]

The specification for the 6372 says:

Sensor Output
Temperature
Outside Temperature (Air)
Resolution and Units . . . . . . . . . . . . . . . . . . . . . . . . 1°F or 1°C. Celsius is converted from Fahrenheit and rounded to the
nearest 1°C
Range . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -40° to +150°F (-40° to +65° C)
Sensor Accuracy . . . . . . . . . . . . . . . . . . . . . . . . . . . ±1°F (±0.5°C) typical (See Chart)

This would imply that the 6372 does resolution limiting.  Perhaps you should ask Davis about that.  Clearly if the resolution and accuracy are 1 degree, trying to achieve a precision of 0.1 degree is .....

Just out of curiosity, what unusual application are you using this for, that requires a precision of 0.1 degree?  And why this precision, when accuracy of the same magnitude is not required?

[moehoward4]

The console, when you set a second or third or whatever station on any thing other than ISS, is going to show whole numbers. Period. I use 3 or 4 different programs, and each one shows 'other' stations this way. So it is not WeatherLink doing this....it is the console.

[dalecoy]

...per tech support reply:

• "The only VP2 transmitter that can provide you with 1/10th of a degree resolution is the ISS."
• "You could tell your console that your Temp station is an ISS, then it would also give you 1/10th of a degree resolution."
• "The problem...is that your console is only allowed to listen to one ISS."
• "These [SIM] transmitters are really all identical."

...per #2 and #4 above, that says the RTD-sensor and SIM transmitter are capable of outputing 0.1ºF resolution data but that it gets truncated somewhere along the line (ie: WL software); hence, my question.

OK, so the Davis specification sheet is incorrect, and it would be appropriate for you to tell them that, since they explained it to you.

And I'm still curious:
"Just out of curiosity, what unusual application are you using this for, that requires a precision of 0.1 degree?  And why this precision, when accuracy of the same magnitude is not required?"

[Bushman]

I use a remote sensor for water temps where  .1 degree IS important.  Stupid design decision on Davis' part.  And it is NOT WL's fault - this is the Loop packet that all software uses.

[johnd]

In short, the 6372 measures and transmits to 0.1degF resolution (accuracy is something totally different of course - no assurance at all that accuracy is any better than 1degF). What happens at the console then determines the downstream resolution. The VP2 consoles (excluding 8X) can only receive one transmitter at a time that retains the 0.1degF resolution and that transmitter type has to be assigned as 'ISS'

[Faceng Ret]

The only solution is to buy an additional Envoy and logger and set the temp station to be an ISS. It would only be a partial station in that the other normal ISS data would not (could not) be sent.

The Envoy could be an 8X version, but you run into software complications and the lack of real-time update with that hardware.

The Envoy8x does have a real time update with the WDTU running by clicking view/current readings. I have two stations connected to my 8X and there is an update every ten seconds for both ISS's. Of course, there is no other software that uses this data as yet.

[d_l]

...I have sent an e-mail back to DAVIS Technical Support stating that this "integer-only" limitation is NOT specified in ANY of their catalogs/brochures/data sheets and SHOULD BE.

Of course it is!

http://www.davisnet.com/product_documents/weather/spec_sheets/6372_Spec_Rev_C.pdf

or see Page 32-4: http://www.davisnet.com/product_documents/weather/app_notes/AN_32-sensor-configurations.pdf

[d_l]

The Envoy8x does have a real time update with the WDTU running by clicking view/current readings. I have two stations connected to my 8X and there is an update every ten seconds for both ISS's. Of course, there is no other software that uses this data as yet.

The current lack of software that would integrate the 8X data collection into the the framework of WL or other third -party WL replacements is discouraging.

[johnd]

The Envoy8x does have a real time update with the WDTU running by clicking view/current readings.

The trouble is that this all depends on your definition of 'real-time'. Personally I can't call an update frequency of 10 seconds real-time for the following reason:

In weather monitoring, most weather parameters don't change much from one minute to the next and so typically updates every 5 or 10 minutes are often enough to give a good  'current conditions' record of what the weather is doing. But there's one obvious exception to this statement, which is wind data. By the WMO definition, a wind gust is the mean wind speed over a a 2-3 second interval, so you need wind speed updates every 2-3 seconds (eg as supplied by a Vue or VP2 non-8X console) in order really to monitor the wind conditions in real time. Updates every 10 seconds are only going to reflect 20-30% of wind gusts and so miss the majority of them. So I can't call 10 second updates 'real-time'.

Why Davis chose to use 10 seconds for the 8X is a bit of a mystery (from the outside at least). I do wonder whether whatever processor they chose to put in the 8X isn't man enough to handle updates every 2 seconds (ie as per the standard VP2 loop records) when you consider everything else that it might have  to do (eg monitor 8 ISS units simultaneously). But that's total speculation and very possibly completely wrong. But there has to be some reason why 10 seconds was chosen rather than the traditional 2 seconds. Maybe all will be revealed when the 8X API is eventually published. It's a shame this is so delayed  - can't help feeling that 8X sales would be a lot better if the third-party software writers could experiment with the 8X API.

[dalecoy]

...as for *why* the 0.1ºF resolution, well my understanding is that NOAA/CWOP wants that resolution for data being sent to them, with the only exception being relative humidity, which should be interger.

OK, but I'm still curious why you need that resolution from a 6372, rather than from your ISS. 

That's not a big-deal-question, of course, but your initial question seemed to imply some "different" application, which initiated my curiosity.

Of course, your question also has resulted in an addition to the collective knowledge here.  Thanks.

[dalecoy]

... I need to simultaneously monitor HVAC 'inlet' and 'outlet' temperatures inside the house, but those locations are nowhere near where the Console is located...it's the typical "real estate" problem: "...location, location, location!"

Remember, I tend to use my "weather" stations for applications not typically thought about, such as: monitoring & analysis of evaporative cooler operation (past) and monitoring & analysis of HVAC efficiency and cycle-times (present).

Yes, I remembered that.  But you really confused me when you said:

...as for *why* the 0.1ºF resolution, well my understanding is that NOAA/CWOP wants that resolution for data being sent to them, with the only exception being relative humidity, which should be interger.

I'm fairly certain that you aren't reporting those HVAC 'inlet' and 'outlet' temperatures inside the house to NOAA/CWOP. 

So, I'm still curious why you want a precision of 0.1 degree, when accuracy of the same magnitude is not required?  Perhaps you're going to calibrate the sensors against each other, and it's really the temperature difference inlet-to-outlet that you're needing to a relative accuracy of 0.1 degree, and you don't actually care much about the actual accuracy of the measurement?

How were you doing this "before Davis"?

[Bushman]

For my app, water temps relate to fish.  Feeding/spawning and catching them (hopefully).  My 5 buck RatShack thermo shows tenths of a degree.

[dalecoy]

...aren't reporting...to NOAA/CWOP:  Am I the only person in the world who's NOT sending DAVIS #06372 Temp Station data to NOAA/CWOP? I don't think so. DAVIS sells this unit as part of their "professional" weather equipment, so it SHOULD at least MEET the minimum data requirements that NOAA/CWOP expects to receive from such stations.

I said "I'm fairly certain that you aren't reporting those HVAC 'inlet' and 'outlet' temperatures inside the house to NOAA/CWOP. "

And I sincerely hope that nobody else is doing that, either. 

Of course, I certainly agree that it would be nice if the Davis 6372 and other similar equipment would report with a resolution of 0.1 degrees.