Davis Agrar Station

[Thunderstorm]

I have seen a PeetBros weatherstation which looks like the Davis Weatherstation but the Anemometer and the Rain gauge(pro) seem to be better!
Has anyone tryed a peetBros weatherstation or does someone know why the Mounting tripod and the (strahlungschutz) which protect the anemometer from the sun, I don't know the English word for this, are looking to be the same?
In the forum wetterfreaks.de someone is going to test this station!

Anonther question, is there a shop where i can by PeetBros stations very cheap?

What do you think about the leaf/soil station that there is no higher resolution than 1F?
Can Davis change that in the next firmware
Julian
www.wetter-haltern.de
(sry for my English)

[Thunderstorm]

No answer 

[Weather Display]

any URL to this new Davis look alike Peet Bros station?

[dalecoy]

No answer 

You're asking about PeetBros stations in a forum for people who like Davis stations.  It is likely that nobody here has direct knowledge to answer your question.  Opinions might be biased or suspect, if given at all.

http://www.peetbros.com/shop/item.aspx?itemid=2

"What do you think about the leaf/soil station that there is no higher resolution than 1F?"
That's OK with me.

"Can Davis change that in the next firmware"
Yes.

[Thunderstorm]

No answer 

"Can Davis change that in the next firmware"
Yes.

Are you sure?
Why aren't they going to do ist

[Bushman]

...
"What do you think about the leaf/soil station that there is no higher resolution than 1F?"
That's OK with me.

"Can Davis change that in the next firmware"
Yes.

I don't think is the case. The thermistor used is low res and they'd have to go to diff hardware.  Sure, you can interpolate, but that is not really increasing resolution.  Besides, high res themometers cost as much as a vantage Vue!

[dalecoy]

No answer  

"Can Davis change that in the next firmware"
Yes.

Are you sure?

Yes.  They can change the indicated reading. 

Why aren't they going to do ist

I'm not Davis, so I don't know why.  

History says they don't often do changes that are suggested by customers.  

In addition, the sensor accuracy is only +/- one degree F.  Therefore, having an indicated "precision" of 0.1 degree would not make sense.  That's what Bushman said.

But I'm not Davis, so I can't speak for them.

[SLOweather]

My take on it is that so much of the existing hardware/firmware is built around the 1 degree resolution, I think it would be a major project to redo it.

1) The ADC in the remote station reads to 1 degree F

2) The data  transmission is in 1 degree F.

3) The displays in the console are 1 degree resolution.

4) The WeatherLink hardware and commands are in 1 degree resolution.

All of those things need to be changed to increase the resolution. And, it affects every remote temperature station, not just the leaf/soil station.

I would have liked higher resolution. The 1 degree resolution pretty much made my wet bulb/dry bulb hygrometer project a bust.

...
"What do you think about the leaf/soil station that there is no higher resolution than 1F?"
That's OK with me.

"Can Davis change that in the next firmware"
Yes.

I don't think is the case. The thermistor used is low res and they'd have to go to diff hardware.  Sure, you can interpolate, but that is not really increasing resolution.  Besides, high res themometers cost as much as a vantage Vue!

[johnd]

The thermistor used is low res and they'd have to go to diff hardware. 

I don't believe this is the case. The issue AFAIK is that the temperature from supplementary temp sensors is held in a 1-byte field and hence there's no resolution available for 0.1degF. I suspect that it might be possible to rewrite the firmware, but there might be a number of major implications (eg the processing of all such temp values would need to go from integer arithmetic to floating point) and so probably won't happen without a major firmware update, eg perhaps a complete firmware rewrite.

But why would you want 0.1degF resolution? The accuracy of all VP2 temp sensors is 1degF and so even if 0.1degF resolution were available it wouldn't give any greater information than the current 1degF resolution. (OK OK I know that the main air temp sensor has 0.1degF resolution but in reality the same 1degF limitation in interpreting any air temp value applies.)

[Bushman]

While the 1-byte (how many bits??) thing might be an issue, they may have designed the storage to match the HW.  You only have to look at Digikey.com to see that there are all sorts of resolutions for thermistors. And they get spendy real fast if you want super high res (some are platinum based for instance)

[wxtech]

The soil temperature sensors are analog RTD (resistance temperature detectors).  Therefore every conductor and connection in the circuit affects the accuracy. 
The resistance of the RTD is high so that the conductors low resistance and the connections resistance will usually be negible. 
Notice that here Davis doesn't use RJ connections which are not low resistance connectors.
If someone is seeking lab accuracy; suggest digital temperature sensors such as the 1-wire devices from Maxim.  Other than lab requirements, why is greater than 1 degree accuracy needed.  Move the sensor a few feet and the temperature will change by that amount anyway.

[johnd]

...they may have designed the storage to match the HW.

If you look at Davis App Note 32 under 'Temperature only' alternate configurations you'll find that you can, for example, set a 6372 Temp station to be received as ISS data type and - assuming that it's the only ISS configured on that console - it will then 'display and log data in tenths of a degree'. The 6372 station uses the 6470 temp sensor (albeit fitted with an RJ11). So this piece of information about enhanced resolution is generally applicable to 6470 temp sensors.

The point is that the 6470 temp sensor element is perfectly capable of generating a signal that can be interpreted to 0.1degF resolution, but it's the processing in the console that otherwise limits the resolution reported by supplementary temp sensors - this is where the 1-byte (I'm assuming 8-bit, as used eg in the loop record, but ICBW) limitation bites.

[Thunderstorm]

the sensors are able to have 0.1f i think and the ground temp is always the same 1f and it would be nicheif there would be a resolution of 0,1

[Bushman]

The soil temperature sensors are analog RTD (resistance temperature detectors).  Therefore every conductor and connection in the circuit affects the accuracy. 
The resistance of the RTD is high so that the conductors low resistance and the connections resistance will usually be negible. 
Notice that here Davis doesn't use RJ connections which are not low resistance connectors.
If someone is seeking lab accuracy; suggest digital temperature sensors such as the 1-wire devices from Maxim.  Other than lab requirements, why is greater than 1 degree accuracy needed.  Move the sensor a few feet and the temperature will change by that amount anyway.

I have several 1-wire devices.  They are only good to .5 degree C 

[wxtech]

From the DS18B20 data sheet.  "The resolution of the temperature sensor is user-configurable to 9, 10, 11, or 12 bits, corresponding to increments of 0.5°C, 0.25°C, 0.125°C, and 0.0625°C, respectively."

[Bushman]

I stand corrected. 

[dalecoy]

Going back to the basic question:

What do you think about the leaf/soil station that there is no higher resolution than 1F?

Julian
www.wetter-haltern.de
(sry for my English)

Why would you need resolution better than that?

Along with that question, what accuracy and precision do you need?

Most measurement needs are defined by accuracy, precision, and resolution. 

[wxtech]

From the DS18B20 data sheet.  "The resolution of the temperature sensor is user-configurable to 9, 10, 11, or 12 bits, corresponding to increments of 0.5°C, 0.25°C, 0.125°C, and 0.0625°C, respectively."

Bushman; sorry that I was so coarse.  I recently received IC samples from Maxim and had just read that temperature resolution data.  I haven't used 1-wire sensors for several years but have an idea in the works.

[Bushman]

No worries Al.  I have lots of 1=wire and have used it for years and think it is pretty neat.  I was aware of the # of bits resolution and simply did nto check.  My bad. 

I'm going to investigate using 1-wire for external temp sensors for my Weatherlink