Testing Vanes

[Fred T]

Hi,

 Does anyone know of a good way to test if my 200p wind vanes are still good?  I have a couple that were installed for a while, and I want to be sure they'll work before I  put them on another tower.

 

Thanks,

FT 

[David Carlson]

Fred,

 You're right, it's generally a good idea to test your vanes before reinstalling them.  The 200P is a potentiometer based wind vane - 10k nominal.  You can find instructions on testing them in our KnowledgeBase:

http://www.nrgsystems.com/TechSupport/KnowledgeBase.aspx?id=205&category=15

 Here's what that entry says:

Testing a 200P wind vane




Instructions:

 

• Disconnect the vane from the logger.

• Set your DVM to the 20K OHM scale and measure from the first
  terminal to the last terminal (skipping the center terminal). The
  reading should be around 10K ohms nominal (minimum 8K ohms, maximum 12K
  ohms).

• Measure from each end terminal to the center terminal. You should
  see a reading that varies between 0 and 10K ohms (depending on the
  position of the tail of the vane relative to the body of the vane) in
  each of these two cases.

• Notes: 
  
  • There is a "deadband" of 8 degrees centered around north which will measure as an open circuit (infinite resistance). 
  • When the notch on the head and body align, the vane is pointing towards "electrical" north.
    

Example 1:

• Vane tail is fixed pointing south
• End to end resistance = 10500 ohms
• Either end to center will equal about 5250 ohms

Example 2:

• Vane tail is fixed pointing east
• End to end resistance = 10500 ohms
• One end to center will equal about 2625 ohms
• The other end to center will equal about 7875 ohms