Topic: different wind readings between vantage vue and vp2 consoles

[sheldon]

Hi guys,
I am doing a test comparing a vantage vue and a vp2 consoles placed side by side and synchronized with the same VP2 ISS on channel 1. I noticed something very strange: on high speeds the wind speed reading is different. In fact, when the wind speed goes over 8 km/h, I observe a small difference on the two consoles: the vp2 one reads 1-2 km/h more. For example, I read 10 km/h on vue and 11 km/h on vp2. The higher the speed is, the bigger the difference seems to be: sometimes I read 24 km/h on vue and 27 km/h on vp2, for example. This is not always happening, but it is very frequent. It is paradoxal that the high reading tomorrow is 45 km/h for the vp2 and 47 for the vue 
Obviously, I checked that they are receiving the same data packets, and it seems to be so (they change the wind readings at the same time), and on the diagnostic page I read 100% on vp2 console and 99% on vue console. The wind cup size is set as "large" on both consoles.
I am observing this phenomenon also using another vp2 console, reading still a little bit higher speed.
Does someone have any ideas? 

[johnd]

The consoles apply a secondary correction to the raw wind speed to compensate for eg effects of the anemometer structure on the measured wind speed as the wind blows from different directions. It sounds like the Vue and VP2 consoles are using slightly different lookup tables (LUT) to make this correction, maybe because the console firmware versions are not using exactly the same LUT. I'm not sure anyone outside of Davis knows which LUT version is in which firmware or even if there are exactly comparable firmware versions across different console types.

[ValentineWeather]

Make sure the Vue console has the latest firmware update. Firmware version 4.18 This fixed my Vue consoles from reading low when using VP2 anemometers.  Correction Rev 4.30

[sheldon]

Make sure the Vue console has the latest firmware update. Firmware version 4.18 This fixed my Vue consoles from reading low when using VP2 anemometers.

I updated the firmware to the latest version but the problem is still there

[ValentineWeather]

Correction you need 4.30 firmware. I had started a thread similar posting on youtube the discrepancy and sent a copy to Davis Instruments. They never admitted there was an issue as usual, just that they would look into it and get back which they never did after a few emails.  When Rev. 4.30 came out it was corrected.  Side by side now both show the same wind speeds.   

[sheldon]

Correction you need 4.30 firmware. I had started a thread similar posting on youtube the discrepancy and sent a copy to Davis Instruments. They never admitted there was an issue as usual, just that they would look into it and get back which they never did after a few emails.  When Rev. 4.30 came out it was corrected.  Side by side now both show the same wind speeds.

ok, now with rev 4.30 I have the same readings with a vp2 console having rev 3.15. But I still have differences with a vp2 console having the old 2004 firmware (which unfortunately can't be updated). However, now I trust that the readings are correct, and I think that in 2004 rev there is a different way of interpreting data packets (maybe wrong because not updated).

[ValentineWeather]

Can't help with the older 2004 vp2 console if firmware won't update. Least you have the Vue and newer VP2 working together.

[CW2274]

Just as an FYI, I just bought a new Vue console this week, it has 4.33 on it, but Davis's download site doesn't have it available and I have no idea what the difference is from 4.30

[Mattk]

Not sure why you think the firmware in a 2004 VP2 can't be updated? What's the current FW? Should be able to get to at least 1.9? May not be the latest but they can be updated.   

[johnd]

Not sure why you think the firmware in a 2004 VP2 can't be updated?

Well, strictly speaking, a VP2 with firmware earlier than Nov 2005 (IIRC) can be updated, but only with the VP2 updater device. Direct from PC updating does not work. The updaters are no longer sold or loaned so you'd need to try and find one on eg eBay (and it does need to be the VP2-specific updater, ie 6311VP2 from memory rather than plain 6311 (which was the VP1 version)). There was a thread in the past about trying to do it without an updater but only if you're an electronics hobbyist too:

https://www.wxforum.net/index.php?topic=14145.0

Not clear whether it was ever successful.