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.
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Massive temperature spikes
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goldrush
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Massive temperature spikes
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AllyCat
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Re: Massive temperature spikes
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.
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.