Author Topic: Wildly Inaccurate Rain Readings  (Read 328 times)

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Offline melmerby

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Wildly Inaccurate Rain Readings
« on: February 14, 2020, 08:47:43 AM »
Hi all
This is my first post.
I'm located in Worcestershire in the UK

I have had a VP2 wireless since May 2011, without a problem except a failed rechargeable battery in the ISS.

Over the Christmas period just gone the Rainfall readings showing on the console became totally erratic and unpredictable.
e.g. I would get a rainfall reading of 281mm/hr when it is not raining at all and at other times when it was raining - nothing.
The ISS reading on the data stream is always 100 and no other parameter is affected.

I checked the buckets and cleaned the connectors in the ISS and checked the battery, which was fine.
This made no difference to the erroneous readings.

I contacted Davis support and the reply suggested I change the station ID
This is the reply:
"Change the station ID


1. Put your unit is setup mode. Press DONE & MINUS at the same time. Let it sit here for hour.
2. Make a note of the station number(s) listed on the screen. Note: If a Vantage Pro2 or Vantage Vue ISS has been installed in your area, its ID number may also be displayed.
3. We want to avoid these numbers. Choose a number that does NOT show up on the screen.
4. Press DONE to move to the next screen
5. Press the < and > keys to select the transmitter ID. Step through ALL stations and set ot OFF (use the minus key to turn a station off). When you select a transmitter ID, the ID number is displayed on the screen as well as the current configuration.  Turn ON the station you want. Press the + and - keys to toggle console reception of signals from transmitters using that ID on and off.
6. Press GRAPH to change the type of station assigned to each transmitter. Scroll through the station types - ISS, TEMP, HUM, TEMP HUM, WIND, RAIN, LEAF, SOIL, and LEAF/SOIL - until the correct type appears.
7. Press DONE to move to the next screen.
Press DONE for 2 seconds to Exit
"

I sent a reply to that e-mail, asking whether they thought it likely that the station was being affected by interference, I got no reply.

However by the time the original reply had been received the station had reverted to normal, so I did nothing.
Today it has started doing the same thing, again all other readings are fine and the ISS reads 100.

Any suggestions?
Sorry for the long first post! :oops:
Cheers

Keith
Wireless Vantage Pro 2
Weatherlink 6.0.5
Win 10

Offline racer3

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Re: Wildly Inaccurate Rain Readings
« Reply #1 on: February 14, 2020, 08:53:57 AM »
Most likely the reed switch under the tipping buckets.

Offline johnd

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Prodata Weather Systems
Prodata's dedicated Davis EnviroMonitor website
UK Davis Premier Dealer - All Davis stations, accessories and spares
Littleport, Ely, Cambs UK

Offline melmerby

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Re: Wildly Inaccurate Rain Readings
« Reply #3 on: February 14, 2020, 11:20:34 AM »
Hi Guys, thanks for the replies.

Having worked with reed switches as part of my employment (now retired [tup]) I would not expect to get such a consistent error.
See this snip just taken:

 [ You are not allowed to view attachments ]

Cheers
Wireless Vantage Pro 2
Weatherlink 6.0.5
Win 10

Offline johnd

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Re: Wildly Inaccurate Rain Readings
« Reply #4 on: February 14, 2020, 01:30:35 PM »
Having worked with reed switches as part of my employment (now retired [tup]) I would not expect to get such a consistent error.

Well until you do some checks as suggested you won't know. There are ways that a reasonably consistent rate could be generated artefactually, eg 24mm/5mins is 120 tips/interval (assuming a 0.2mm tip) or about one tip per wind message on channel #1. I'm not sure exactly how that might come about but just saying that there could be explanations for certain numbers popping up. It could also reflect a SIM board fault - probably not but without more clues it's impossible to say. How old is the ISS?
« Last Edit: February 14, 2020, 01:40:01 PM by johnd »
Prodata Weather Systems
Prodata's dedicated Davis EnviroMonitor website
UK Davis Premier Dealer - All Davis stations, accessories and spares
Littleport, Ely, Cambs UK

Offline melmerby

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Re: Wildly Inaccurate Rain Readings
« Reply #5 on: February 14, 2020, 06:26:33 PM »
Hi John
It's 9 years old, apart from the ISS battery failure about 3 years ago no problems with the ISS.

Today the odd readings suddenly started but it wasn't raining at all at the time.
They started at 1220 until 1425 and again at 1525 and stopped at 1715. (then a few more this evening.)

This is what the expanded strip chart from that period looks like:
 [ You are not allowed to view attachments ]

Re reed switches:
I would expect contact bounce to give extra readings when rain is being recorded, not when it's dry.
I wonder what would a stuck reed do to the readings? (A common failing of reeds.) But it would still need to operate before it could stick.

Cheers

Keith
« Last Edit: February 14, 2020, 06:29:28 PM by melmerby »
Wireless Vantage Pro 2
Weatherlink 6.0.5
Win 10

Offline Waimarie

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Re: Wildly Inaccurate Rain Readings
« Reply #6 on: February 15, 2020, 03:53:27 PM »
I had a similar problem with an older  FineOffset station.  Turned out to be a combination of wind and the gauge "wobbling" on its mount. slightly.  My fix was a simple move to a more sheltered spot and securing the mount to an immovable object.  It lasted until the station died last year.
Fine Offset WH3081 (Deceased)
Mi.Sol  WH2900C
Ecowitt GW 1000 915MHz
Ecowitt GW 1000 433MHz
Ecowitt WH 31
Ecowitt WH51
WU: IFEATH6
WOW: 910486001
Weathercloud: d4523488549

Offline melmerby

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Re: Wildly Inaccurate Rain Readings
« Reply #7 on: February 15, 2020, 06:28:49 PM »
Hi there
I don't think wind is a problem as it has done it sometimes when it is still.
It's also fixed to a 100mm/4" square concrete post, which doesn't deflect when I lean a ladder against to inspect the ISS.

Cheers

Keith
Wireless Vantage Pro 2
Weatherlink 6.0.5
Win 10

 

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