We have been seeing CHTs and O/T doing funny things on the Dynon for a few weeks (after having done some work that affected the battery connections). Since all other ground-related functions were fine and there were no tell-tale problems with the radio or other senders we suspected a dynon internal problem.
After way too much thinking and analysis it all turned out to be slightly loose connections to the battery ground and from battery to the first ship's ground near the battery.
We found this by turning on all the avionics and measuring the voltage between battery GROUND (-) and the dynon cage ground. It was about 6 millivolts (mV). That doesn't sound like much but it indicated there was a faulty ground path to the panel. After tightening things up properly we were down to 1.2 mV. The CHT/OT spiking and strange excursions went away.
NOTE: the dynon does some input smoothing to the sensor data so we saw rapid, but not always drastic, changes. This fooled us for a bit.
Hope this helps someone avoid tearing all their hair out.![Smile :) :)](data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)
-Neil
After way too much thinking and analysis it all turned out to be slightly loose connections to the battery ground and from battery to the first ship's ground near the battery.
We found this by turning on all the avionics and measuring the voltage between battery GROUND (-) and the dynon cage ground. It was about 6 millivolts (mV). That doesn't sound like much but it indicated there was a faulty ground path to the panel. After tightening things up properly we were down to 1.2 mV. The CHT/OT spiking and strange excursions went away.
NOTE: the dynon does some input smoothing to the sensor data so we saw rapid, but not always drastic, changes. This fooled us for a bit.
Hope this helps someone avoid tearing all their hair out.
-Neil