Cumulus Support

I have been suffering massive and continuous external temperature spikes of some 10 degrees.

This turned out to be a faulty cable to the WIND direction sensor!!!

Interestingly it appears that problems with either the wind sensors, or rain bucket can effect the external temperature measurement.

Hi,

Yes, the temperature sensor thermistor and wind vane share the same Analogue-Digital converter and both are permanently connected to the A-D input. The resistance being measured is determined by switching a voltage onto the other end of the resistance. So any leakage current in the wind cable/connectors can ruin the temperature measurement.

It's less obvious why the rain or windspeed sensors (which both use reed switches) should upset the temperature measurement, but the A-D converter actually converts current to a time delay, so if a pulse occurs close to the "detection window" then an error may occur.

Cheers, Alan.