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The direction readings from the Davis 6410 sensor are not accurate

Please follow the steps of this guide only, if the following conditions are true:
  • your weather station has a Davis 6410 or 7911 mechanical wind sensor
  • the wind direction readings are not accurate
  • the black plastic vane is still properly mounted on the shaft at the top of the wind sensor
  • the wind vane is not stuck by e.g. an ice layer or snow, which could also disturb its free rotation

Theory: The Davis wind sensor's direction sensor is mainly a 20kOhm potentiometer. Between the RED and YELLOW wires you should measure constant ~20kOhm. Between the RED and GREEN X kOhm and between the GREEN and YELLOW 20-X kOhm. X changes in the function of the wind vane's position. When the vane is pointing to South (paralel with the mounting arm, pointing towards the pole), you should measure 10-10kOhm.
Tools required:
  1. Cross/Phillips (+) screwdriver
  2. Mini flat-head (-) screwdriver (maximum 2mm wide head) for the green wire terminal of the main board.
  3. Multi meter to measure resistance (0-50kOhm), and voltage (DC 0-5V)

Possible causes of the problem:
  1. The potentiometer in the Davis wind sensor has been worn out, due to the heavy long-term wear.
  2. The Davis wind sensor's internal electronic parts could damage as well (e.g. because of a lightning strike).
  3. The wire of the sensor is broken or went loose from the screw wire terminal of the main board. If you found a disconnected wire please connect it back to the right position. You find the pinout guide at the end of the manual.
  4. The main board is defected.

Testing steps:
  1. Open the station's enclosure.
  2. Check the wire connections of the Davis direction sensor, RED wire should be at PIN 1, GREEN at PIN 3 and YELLOW at PIN14 or PIN15.
  3. Restart your station: Turn off -> press the button for a moment -> turn it back on.
  4. For about 20 seconds after reset you should measure 3.3V between PIN 1 and PIN 14 on the Holfuy main board.
  5. Between PIN 1 and PIN 3 you can measure a voltage between 0 and 3.3V in the function of the position of the wind vane.
    Please note that this voltage is active only for about 20-40 seconds after startup!
  6. If you can't measure 3.3V between PIN 1 and PIN 14 after startup then the main board is probably defected.
  7. Disconnect the RED and GREEN and YELLOW wires of the wind sensor from the main board.
  8. Check the wind direction sensor's potentiometer if it is working as the theory says (above).
  9. If the measurements show that the potentiometer is not working properly then the Davis sensor is defected.
  10. Please send us the result of your tests and measurements by email!

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