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Huge nonlinearity on 200P wind vanes


Antoine

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Dear members,

I recently decided to test some NRG #200P wind vanes i've had since 2007 (and which have not been used a lot) before resetting them in one of our wind farms.

Maybe they are too old and already out of service, I don't know exactly the reason, but I observed a huge nonlinearity on three of those sensors : indeed, the first 10 degrees it goes quickly from 0 to around 200 degrees, then it goes on to more than 300 (and I did not even reach a quarter turn) and after that it slowly goes to 360 once the round is completed.

I really don't understand why. Is it possible to test the resistance/potentiometer, and how ? Are they definitely out of service ?!

Thanks for helping.

Regards,

Antoine

 N.B. : I use a Campbell CR1000 datalogger with an excitation channel set to 2,5V (I also tried 5V but the problem remains)

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 OK I don't have a DVM for the moment but I'll post my measurement as soon as I get one.

 

I really don't understand, I've been reading Campbell manuals for a week now and I didn't find anything about my problem.

Even better, the software provided with the datalogger is able to generate code automatically in order to make measurements with several widely known sensors, including the NRG #200 ; this is the code I used ! I tried to change some parameters, the range of the values, the excitation channel, but it's still the same...

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Maybe it could be due to a poor connector or partial shorting between leads? If I connect a 5K resistor in parallel to a windvane, between the "+" and "sig" leads, I get a similar response to what you report using a Symphonie datalogger. Good luck! :-)

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Thank you Matt, that can help me identifying the problem.

But it is weird, I think Campbell at least made sur that the excitation and measurement channels were correctly isolated before selling their devices...

I sent them an e-mail yesterday I hope I'll get an answer soon.

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