Davis PRO2 and Daytime FARS

[prodata]

Thanks John. I'm no expert on these things so happy to accept your explanation.

But please remember that my speculation is nothing more than that - an informed guess if you will. It's a slight frustration for us as UK dealers that while we have excellent contacts with Davis sales and support services in Hayward (California), the way that Davis is structured means that the design engineers and programmers seem to live in a more walled-off part of the company and we rarely get the chance to interact with them. So we're pretty clued up on virtually 100% of the information that is publicly available from Davis, but digging further below the surface of that can be much more of a challenge.

I did wonder back in 2009 that as soon as I bought the VP2 a VP3 would soon become available. It didn't of course and 7 years later there is still no new version. Might be down to expense in research plus the fact that the VP2 does a pretty good job albeit with a few irritations.

Re the VP2 design: The other thing to remember is that the design does continually evolve. So while the VP2 may look about the same as the original model, virtually all of the detailed sensor design has changed over the past several years. For instance, we're now starting to see the latest models coming through fitted with the new SHT31 sensor element, which promises still greater intrinsic accuracy.

I think you're right in that the VP2 ISS does a respectable job anyway, so less urgent need of a VP3. There are only so many ways you can measure wind data, temp/hum, rainfall etc and it's not very obvious how you would improve the standard sensor set while keeping the same price point. It would be nice to see eg an ultrasonic anemometer in the VP2 range and maybe that will happen one day, but I suspect that price will be a challenge.

But as we've said before in these speculations, it's the VP2 console that could usefully benefit from a more radical update, but of course that could well come in a form that remains compatible with the existing VP2 ISS. But that said, there's no rumours on the dealer grapevine of any such introduction and we typically hear hints about such things at least a year in advance of actual availability, though occasionally there are surprises.

What is reasonably clear is that in the past 2-3 years Davis have been putting their VP2-related development effort into two aspects. One is improving sensor design, as above with the latest T/H and the revised anemometer.

The other is in enhanced data handling with the Connect remote data link and the continued expansion of the weatherlink.com cloud service. I know this is less relevant to users in this Cumulus forum, but both Connect and wl.com are strong growth points for Davis with Connect+wl.com offering a package for remote data collection that is relatively unchallenged by other manufacturers at similar price points and of great interest to eg farmers. And the wl.com network is continuing to grow, with some 23,000 active uploaders currently and a software update apparently waiting in the wings.

[RayProudfoot]

Chris,

She clearly didn't want to draw attention to her handle!

[RayProudfoot]

Hi John,

Interesting post, thanks. Your points about enhancing the sensors are interesting as I'm reading The Weather Observer's Handbook presently and in the Wind chapter there is a table showing sensitivities of several designs.

Most sensitive is the Gill Windsonic (0.02kn). Next is the Vector Instruments A100 at 0.4kn. The Davis does pretty well at 1.4kn but what surprised me was the Met Office's Mk 4a cup anemometer at 6kn. If Davis could develop a sonic anemometer that would undoubtedly appeal providing the cost wasn't prohibitive.

My only complaint about my VP2 is that the pressure will sometimes drift away from nearby stations quite significantly for no reason. Maybe up to 0.5 - 1.0 hPa over several hours. I adjust it to match Mark's Wilmslow reading and it will then be fine for many weeks. It's been happening for a few years now and I can't fathom out why. Replacing the sensor appears to be difficult if not impossible. Any views on this?

[Mapantz]

There is an Ultrasonic anemometer available for the Davis: https://www.darrera.com/en/detalle-prod ... d=1&id=229

I can't say what it would be like for that price (£1700) but the Netatmo ultrasonic anemometer i've got, is susceptible to strange wind spikes when it is raining.

[RayProudfoot]

There is an Ultrasonic anemometer available for the Davis: https://www.darrera.com/en/detalle-prod ... d=1&id=229

I can't say what it would be like for that price (£1700) but the Netatmo ultrasonic anemometer i've got, is susceptible to strange wind spikes when it is raining.

Only £1700? I'll have two! Notice how they have it mounted. At ground level! And if the resolution is no better than the VP2 what's the point?

When my anemometer cups broke in a storm I bought the new improved Davis anemometer from ProData and it will last me many years hopefully.

When I recorded weather manually back in the 70s I had a grass thermometer. Odd in this day and age there is no digital equivalent that can 'speak' to an ISS.

[prodata]

There is an Ultrasonic anemometer available for the Davis: https://www.darrera.com/en/detalle-prod ... d=1&id=229

There are other substantially cheaper Davis-compatible options available too like the LCJ ones - as it happens there's one my office desk right now awaiting installation for long-term evaluation. But powering these ultrasonic anemometers remains something of an issue to make them suitable for use at the majority of well-exposed positions where typically there will be no mains-derived power available. But a self-powered LCJ unit is apparently almost ready for production and should be available for sale sometime soon after the Madrid AWS trade show in late September.

So it is a technology that's moving forwards and coming down in cost but when the point is reached at which Davis might consider it feasible to include it in a VP2 product line-up, even as an extra-cost option, is open to question. I'd like to think that it might be within 1-2 years but that's just a guess.

It all goes to show why weather stations at particular price points reach a certain level of maturity with their sensors, beyond which it's not easy to improve further. The current Davis 6410 anemometer, for instance, needs no external power (beyond what is briefly provided by the ISS SIM) and is a relatively robust and accurate unit for its price point, especially now that it has a Hall Effect speed sensor.

[colinpb]

I too have an anemometer transmitter but due design limitations its a no go for solar sensors. I would be happy to extend the cable for the solar sensor except there’s a drop in solar readings. As Davis are fully aware of the consequences of cable extensions, I'm surprised they haven’t updated the console software to include a solar calibration. Obviously it’s not as easy to do as to say.

Colin


hemelhempsteadweather.me.uk

[Mapantz]

I have a similar setup, with a separate transmitter for the anemometer. What I really, really wish though was that Davis would support the Solar & UV being attached to the wind transmitter so I could get them up on the chimney mounted pole with a clear view of the sky.

I just wanted to come back to this..

Today, I have received the solar-powered anemometer transmitter kit, so i can move it to my chimney. I've noticed that the inside of transmitter is exactly the same as the one on the ISS; 5 jacks for UV, Solar, Rain, Wind, Temperature & humidity. Surely then, I could plug the solar sensor in, and have that on the chimney as well?

[mcrossley]

Tina, the restriction is in the console. it can only be configured to listen to one ISS, your wind transmitter has to be designated as a wind transmitter in the console. So you could plug the solar sensor into into the wind transmitter, and the transmitter will send the solar (and wind) data, but the console will ignore everything but the wind data.

[Mapantz]

Tina, the restriction is in the console. it can only be configured to listen to one ISS, your wind transmitter has to be designated as a wind transmitter in the console. So you could plug the solar sensor into into the wind transmitter, and the transmitter will send the solar (and wind) data, but the console will ignore everything but the wind data.

Ahh - I see! Thank you for the clarification.

That does seem like a design flaw in the console (firmware?) then? That is such a shame, I thought my luck was in!

[RayProudfoot]

I took this up with Davis years ago saying it was a gross under use of the second transmitter. They muttered something about looking at it but as you can see it's come to nothing. Probably the weakest aspect of an otherwise excellent product.

[mcrossley]

I think the problem is that they have run out of memory in the console, so adding any new features to the code is next to impossible.

One road they probably don't want to go do would be provide alternative firmware streams. One for multiple ISS (and remove say soil temperatures or some other 'lesser used' feature(s)) and the standard firmware.

[Mapantz]

Interesting information, thanks for the replies!

Not to worry, i'm just happy to be putting my anemometer 11m up on the chimney. The other houses nearby aren't as tall as this one, so wind data will be much better. I got a good deal on the transmitter too, so it has all worked out nicely.