Author Topic: VP2 tipping spoon raingauge?  (Read 18937 times)

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Offline galfert

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Re: VP2 tipping spoon raingauge?
« Reply #350 on: July 19, 2019, 02:59:13 PM »
Okay this idea may not be the best but I just thought I'd share it anyway and let you all poke holes and criticize it. What if you take a Stratus CoCoRaHS gauge and fill up just the internal cylinder to 1.00 inches. Then you slowly pour it into the VP2 gauge.....sloooooowly! Like maybe you don't pour it straight out of the cylinder and instead you use a piece of nylon cloth as a barrier or something like that which won't absorb water but let it pass slowly. They are both the same diameter...right?

UPDATE:
They are both the same diameter...right?
No, 4" vs 6.5".

Oh well. I guess I could do this with my Ambient since both are 4 inches.
« Last Edit: July 19, 2019, 03:37:23 PM by galfert »
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Offline CW2274

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Re: VP2 tipping spoon raingauge?
« Reply #351 on: July 19, 2019, 03:17:53 PM »
They are both the same diameter...right?
No, 4" vs 6.5".

Offline CW2274

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Re: VP2 tipping spoon raingauge?
« Reply #352 on: July 19, 2019, 03:25:53 PM »
Like I've said in previous threads, I used a gallon milk jug, a scale accurate to a gram, and a syringe to precisely add or remove water from said milk jug to calibrated my RW111 with. It ain't rocket surgery, just time consuming.

Offline rwilhour

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Re: VP2 tipping spoon raingauge?
« Reply #353 on: July 19, 2019, 06:46:05 PM »
John you may be right (you usually are) but when I buy a product with the Davis name on it, I expect the new or revised product to have been properly field tested.

Well, yes. But my point is that as far as I'm aware the TS VP2 gauge has not been officially released by Davis as yet and so one can't assume that testing is complete. If Ryan sees this then maybe he can clarify the status in the US for example. But I'm not aware of any official launch or promotion more generally for the TS part, which I would expect to see with a new product release.

If I had to guess, it would be that Davis are reasonably advanced in their plans to announce the TS part with part numbers etc assigned and have manufactured a substantial pre-production batch, a few of which inadvertently made it to Australia last year with some more released into the US spares market, but without being part of the full official launch. This is just a guess and ICBW but it has echoes of the launch of the SHT15 T/H sensor (the .174 sensor part) a couple of years back which was available in EU VP2 stations but only for a short while and also as a spare in the US, but was then superseded by SHT31 before ever making it into full production.

Yes John is correct there has not been an official release of of the actual parts 7345.147 and 7345.425 HOWEVER they ARE currently being integrated into 6163s at this moment because I have some in stock.  There was an official announcement that went out on March 8, 2019. here is the text of the release:

"At Davis Instruments, we pride ourselves on designing and manufacturing the most accurate, durable, and affordable weather instrumentation on the market. To achieve that goal we are continuously evaluating how to improve our products. One of our R&D projects has been focused on the Vantage Pro2 rain collector. After rigorous testing and evaluation of many prototypes, we are excited to announce that we have started to manufacture and ship Vantage Pro2 Plus weather stations (Item# 6162C, 6162, and 6163) with a new and improved tipping spoon mechanism. The tipping spoon is an incremental improvement for both accuracy and durability of the Vantage Pro2 rain collector. We will continue to phase in the tipping spoon for all of our Vantage Pro2 products over the next few months. Of course, the tipping spoon assembly is 100% backward compatible with previous versions of Vantage Pro2 rain collectors. Please note that all new Vantage Pro2 rain collectors with a tipping spoon will be factory calibrated to either 0.01 or 0.2 mm per tip and will no longer include an adapter that allows owners to convert from inches to millimeters or vice versa. 
 
There will not be any change to part numbers for Vantage Pro2 weather stations. However, stand-alone Vantage Pro2 rain collectors will have new part numbers once we begin to manufacture these items with the tipping spoon. We will send a follow-up email with a revised 2019 price list when the stand-alone rain collectors are ready to ship."

So how the heck did I end up with the assemblies so soon?  After getting the message above the question for me was to ask my account manager was what was the new part numbers for equivalent of the 7345.444 and 7345.147 and she gave me the part numbers (the ones with 40' cables are models 7345.439 mm and 7345.440 inch but I never ordered any of those).  My next wholesale order I order about 20 units of each (can't remember how many to be exact), and they were shipped to me with my freight.  I looked at the invoice price and wow I was getting a good deal on them, they were cheap so I put them on my website for a good price.  When I started running out I ordered a bunch more.  This time my invoice price was much higher so I was forced to raise my prices on the units (some of you may have remembered that).  I still have that stock and have not run out yet.

About 2 weeks ago my account manager told me that she got in a bit of trouble releasing all these units to me in two separate shipments.  She said that they were not planning on selling these until they were all phased into all the pro2 units.  So at this point I don't know if they will sell me more.   Apparently the units were all boxed up and sitting on the shelf ready to go and the stock pickers saw my order and pulled the parts and shipped without consideration that corporate wanted to hold that stock.  It appears as the new TP is in full production and has been since the March 8th 2019 announcement. 

Offline Mattk

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Re: VP2 tipping spoon raingauge?
« Reply #354 on: July 19, 2019, 09:51:35 PM »
I would ask what problem? Being a tipping spoon or tipping buckets there will ALWAYS be a discrepancy and difference, can be over, can be under (depending on the way or what the gauge has been calibrated for/too) to something else as different rate rates will produce different rain amounts relative to the "real" rain amount and one reason why real tipping bucket assemblies store the rain going through the tippers so as to actually measure and confirm actual rainfall if required at a later time. This type of gear is going to cost a lot more than a garden variety PWS tipper and I think too many users are being overly expectant of the garden varieties they are using.   

Offline drew1021

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Re: VP2 tipping spoon raingauge?
« Reply #355 on: July 23, 2019, 09:36:24 AM »
We had a heavy rain shower with wind during the night with the following results

Stratus.        1.18
Vp2.            1.27

This is with the new tipping spoon (uncalibrated)
VP2 with 24 hour FARS. WU: KNCLEWIS2. CWOP/APRS: DW4712, COCORAHS: NC-FR-7

Offline miraculon

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Re: VP2 tipping spoon raingauge?
« Reply #356 on: July 23, 2019, 01:32:52 PM »
I noticed when I received the tipping spoon that it didn't have the metalized plating like the older tipping buckets.

Perhaps this was a cost-down measure, but did the metallic surface of the tipping buckets offer any advantage? Davis must have decided that it wasn't needed for the tipping spoon.

Greg H.


Blitzortung Stations #706 and #1682
CoCoRaHS: MI-PI-1
CWOP: CW4114 and KE8DAF-13
WU: KMIROGER7
Amateur Radio Callsign: KE8DAF

Offline bahuga

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Re: VP2 tipping spoon raingauge?
« Reply #357 on: July 23, 2019, 03:31:17 PM »
Here are my statistics of the last few months, in millimeters.  I have compared the values obtained with the "classic" VP2 tipping buckets, the new tipping spoon (metric version) and with the reference rain gauge (SPIEA)  used in France. 

From April 24 to April 30, 2019 (5 measurements) : SPIEA 33.6 mm, VP2 tipping spoon: 34.4 mm (+2.4%), VP2 tipping buckets : 32.6 mm (-3%)
May 2019 (12 measurements) : SPIEA 77.5 mm, VP2 tipping spoon: 80.2 mm (+3.5%), VP2 tipping buckets :76.4 mm (-1.4%)
June 2019 (8 measurements) : SPIEA 129.3 mm, VP2 tipping spoon: 134.6 mm (+4.1%), VP2 tipping buckets :134.2 mm (+3.8%)
From July 1 to July 21, 2019 (4 measurements) : SPIEA 10.6 mm, VP2 tipping spoon: 11.2 mm (+5.7%), VP2 tipping buckets :10.8 mm (+1.9%)

My VP2 new tipping spoon is over reporting rainfall, as already observed in this forum, but it seems this  is going worst with time : + 2.4% in April and now +5.7%. 

I will continue the comparison, without changing any calibration, to know how will evolve the measurements of the tipping spoon, and if it will stabilize at a certain point.
« Last Edit: July 24, 2019, 11:26:30 AM by bahuga »

Offline mike88ag

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Re: VP2 tipping spoon raingauge?
« Reply #358 on: July 25, 2019, 08:48:00 AM »
I'm considering ordering the tipping spoon when I finally order the Sensiron SHT31 T/H sensor today, but I'm a little hesitant because of the results reported here. I have my tipping bucket dialed in to within 1-2% of the Stratus gauge mounted only inches away, so I can't say I'm not happy with it. Is it possible to calibrate the tipping spoons?

To calibrate the tipping bucket, I built a constant-head calibration tool similar to the one from R.M. Young. I use a triple beam balance accurate to 1/100th of a gram to measure a known volume of water (density corrected for temperature), and I calculate the rainfall total that volume of water should translate to based on the 6.5" diameter of the rain collector. I use different orifice sizes to simulate a wide range of rainfall rates, with the rate derived from the measured total and the time required to empty the container.

Offline CW2274

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Re: VP2 tipping spoon raingauge?
« Reply #359 on: July 25, 2019, 02:47:25 PM »
I have my tipping bucket dialed in to within 1-2% of the Stratus gauge mounted only inches away, so I can't say I'm not happy with it.
If you're consistently getting that kind of accuracy from a Davis tipper, I wouldn't even look at it crossed eyed let alone buy a new one. They're only spec'd to 4% as is, and that's on a good day...

Offline mike88ag

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Re: VP2 tipping spoon raingauge?
« Reply #360 on: July 25, 2019, 07:18:00 PM »
I have my tipping bucket dialed in to within 1-2% of the Stratus gauge mounted only inches away, so I can't say I'm not happy with it.
If you're consistently getting that kind of accuracy from a Davis tipper, I wouldn't even look at it crossed eyed let alone buy a new one. They're only spec'd to 4% as is, and that's on a good day...

That's the conclusion I reached. I bought the new T/H sensor and a few other spare parts, but decided against the spoon. Almost bought the replacement ISS PCBA that goes w/ the new sensor, but decided the 0.9 deg F calibration adjustment would be just fine for now.

Offline miraculon

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Re: VP2 tipping spoon raingauge?
« Reply #361 on: July 27, 2019, 08:31:32 AM »
Last few observations:
=====================================
Update on another one:
CoCoRaHS=0.88"; VP2=0.93"; Novalynx=0.92"
=====================================


Coco: 0.05"; VP2=0.04"; Novalynx=0.05"
Coco: 0.04"; VP2=0.04"; Novalynx=0.04"
Coco: 0.29"; VP2=0.31"; Novalynx=0.31"

Coco is CoCoRaHS manual gauge, VP2 has Aerocone and Tipping Spoon. Last entry was from this morning and we had fairly heavy rain between 5-6AM when thunderstorms passed through. Winds were very light < 1 MPH during the rainfall. I have some suspicions that the CoCo has trouble with splash-out during heavy rain.

Greg H.

« Last Edit: August 06, 2019, 08:21:54 AM by miraculon »


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CoCoRaHS: MI-PI-1
CWOP: CW4114 and KE8DAF-13
WU: KMIROGER7
Amateur Radio Callsign: KE8DAF

Offline ecobuild

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Re: VP2 tipping spoon raingauge?
« Reply #362 on: February 03, 2020, 07:21:44 AM »
Old topic, new question! Has anyone got tips/pictures for removing old tipping spoon assembly from VP2? I would like to remove it cleanly without breaking any bits. I tried levering it off with a flat screwdriver but it did not come willingly and I was afraid something was going to break. (Curiously I am getting very close results at present between my VP2 and my manual gauge ever since my VP2 developed a slight tilt - accidental calibration!)

Offline miraculon

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Re: VP2 tipping spoon raingauge?
« Reply #363 on: February 03, 2020, 08:32:53 AM »
Old topic, new question! Has anyone got tips/pictures for removing old tipping spoon assembly from VP2? I would like to remove it cleanly without breaking any bits. I tried levering it off with a flat screwdriver but it did not come willingly and I was afraid something was going to break. (Curiously I am getting very close results at present between my VP2 and my manual gauge ever since my VP2 developed a slight tilt - accidental calibration!)

The latches that hold the original tipping bucket were difficult to release and I had the same concerns about breaking them. They were tougher than expected and I didn't break mine. After the old "bucket" assembly is out, the installation of the spoon was relatively easy.

My only suggestion is to wait for warmer weather so the plastic isn't brittle.

I used a small screwdriver at the time, but I have recently ordered a spudger set from Amazon. (I don't have it yet, so I cannot vouch for the tools)

Greg H.


Blitzortung Stations #706 and #1682
CoCoRaHS: MI-PI-1
CWOP: CW4114 and KE8DAF-13
WU: KMIROGER7
Amateur Radio Callsign: KE8DAF

Offline johnd

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Re: VP2 tipping spoon raingauge?
« Reply #364 on: February 03, 2020, 08:55:38 AM »
My only suggestion is to wait for warmer weather so the plastic isn't brittle.

Or maybe bring it into a warm room for some hours before attempting the 'operation'?
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Offline CW2274

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Re: VP2 tipping spoon raingauge?
« Reply #365 on: February 03, 2020, 02:37:04 PM »
Yes, it's a b***h to remove. I believe someone here used a lube like WD40 or vegetable oil to help slide things along. I got mine out without breaking it, but I thought for sure I was going to...but I also didn't care either as it wasn't going to be reused so it'll take some pressure without breaking. YMMV.

Offline ecobuild

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Re: VP2 tipping spoon raingauge?
« Reply #366 on: February 04, 2020, 01:34:26 PM »
Thanks all for suggestions. It was 10oC (50oF) this afternoon and I had a go again after seeing this guide: https://www.youtube.com/watch?v=TD2hIu_WnUI and it worked. It is necessary to press quite hard with one hand against the tabs (in sequence) that hold the base in place while the other hand levers the screwdriver in the slot under the base. Relieved to get it done without breaking anything!