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:
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.
- 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:
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Cross/Phillips (+) screwdriver
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Mini flat-head (-) screwdriver (maximum 2mm wide head) for the green wire terminal of the main board.
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Multi meter to measure resistance (0-50kOhm), and voltage (DC 0-5V)
Possible causes of the problem:
- The potentiometer in the Davis wind sensor has been worn out, due to the heavy long-term wear.
- The Davis wind sensor's internal electronic parts could damage as well (e.g. because of a lightning strike).
- 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.
- The main board is defected.
Testing steps:
- Open the station's enclosure.
- 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.
- Restart your station: Turn off -> press the button for a moment -> turn it back on.
- For about 20 seconds after reset you should measure 3.3V between PIN 1 and PIN 14 on the Holfuy main board.
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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!
- If you can't measure 3.3V between PIN 1 and PIN 14 after startup then the main board is probably defected.
- Disconnect the RED and GREEN and YELLOW wires of the wind sensor from the main board.
- Check the wind direction sensor's potentiometer if it is working as the theory says (above).
- If the measurements show that the potentiometer is not working properly then the Davis sensor is defected.
- Please send us the result of your tests and measurements by email!
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