- Tue Jan 05, 2021 11:49 pm
Ah, OK. Then your VR sensor is wired backwards. The trailing edge of the tooth leading into the gap should be fully negative-going, then rising voltage across the gap, as in the first 'scope image. That means the VR sensor voltage swings high as a ferrous object (tooth) approaches, and swings low as it departs. There are a number of reasons the polarity should be this way for almost all setups.
So, reverse the VR wiring into Speeduino, and then select the correct Trigger Edge for Speeduino to see the trailing (falling) VR voltage. This setting would be Rising for inverting conditioners such as the MAX992x, LM1813, etc, and Falling for non-inverting conditioners such as the DSC, LM358, etc. That should make the signal and output coordinated, trigger a proper gap width, and prevent timing drift. Note that using reverse VR polarity and reversed edge would seem to be OK, but does not solve some of the issues.
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