Rainfall Conversion Error

  • 2
  • Problem
  • Updated 3 weeks ago
Rainfall from my Davis Vantage Pro2 Plus with metric rain adaptor gives in 0.20 mm increments per bucket tip,  yet magically WU converts it to 0.25mm giving an accumulated error. I assume some sort of  metric conversion error.
Be great if this can be fixed.

Photo of Mike Bloodworth

Mike Bloodworth

  • 28 Posts
  • 4 Reply Likes

Posted 3 weeks ago

  • 2
Photo of John Renyard

John Renyard

  • 3 Posts
  • 0 Reply Likes
Mike, that is right, but not only that inaccuracy, if you run a check physical rain gauge, you will find that the Davis Vantage Pro2 under provides by 30% and more. I use a multiplier in the software to get close
Photo of Mike Bloodworth

Mike Bloodworth

  • 28 Posts
  • 4 Reply Likes
I have not experienced your issue of -30% but read the following and it may solve your problem.  There are 2 versions of the Davis Vantage Pro2+ rain bucket assy and there was an upgrade to the funnel assy too which I have installed.  The Bucket assy for the US that is the system default on delivery here in Australia  does 0.01" tips (0.254mm) and a kit to install for metric countries that does 0.20 mm tip.  If you have US bucket assy and set Console to Metric for 0.2mm  the error will be 27% under what it should be.   I have the metric kit and new funnel installed and measured mine on the bench after installing the metric converter and it tips on exactly 0.2mm.  When installed it is important to make sure the filter does not get blocked by leaves, spider webs and that fine sediment does not partly fill the buckets.  I clean mine every 3 months.
This could account for your 30% under reporting error.
My system uploads to Weathlink.com and rainfall is accurate in 0.2mm increments, it is then forwarded every 5 min to WU where the .rainfall figure is made higher as explained in orig post.
Cheers Mike
(Edited)
Photo of John Renyard

John Renyard

  • 3 Posts
  • 0 Reply Likes
Mike, my gauge has the 0.2 conversion alright and is set to metric. I am aware of dust, spider webs and the like, though leaves haven’t been a problem. My gauge is up a tower so I have to access it by ladder. I use Meteohub software on a Raspberry Pi.
I do have variations up and down from the physical gauge.
I will look out for the metric kit and converter but am away from home for another week or so

Cheers,John
Photo of Paul Grace

Paul Grace

  • 23 Posts
  • 5 Reply Likes
Agreed.  30% error is some mechanical defect, and Davis can repair it.
An automated multiplier is a poor solution for mechanical defects.

Photo of Mike Bloodworth

Mike Bloodworth

  • 28 Posts
  • 4 Reply Likes
Paul, You didn't read my response to John.  When I bought my Davis in Australia there was a conversion kit to fit to make the buckets tip at 0.2mm.  Then just set the console to metric 0.2mm giving  Zero Error.  The error I refer to in my initial post is when I transmit 0.2mm to WU, it is magically made into 0.25mm within WU software not the Davis software and WU needs to fix it when Metric is selected in WU PWS profile.
(Edited)
Photo of Paul

Paul

  • 3 Posts
  • 1 Reply Like
Don't worry about that guy "Paul".
He is a certified expert on every subject material known to man.
He is always right. He can never be incorrect.
We use him here to educate the ignorant masses like you and me.

It's best to not respond to him, he will immediately show you how intelligent he is.
Photo of Paul Grace

Paul Grace

  • 23 Posts
  • 5 Reply Likes
Ah-  Makes sense, Mike.  Yes I missed it.
Photo of Paul Grace

Paul Grace

  • 23 Posts
  • 5 Reply Likes
Cheers, Paul.  Great name!