Alternative to digital rotary encoder

[DaveX]

@backflip

I guess, that it would be possible, but it do not seam easy like just reading the voltage from a DC tacho generator as shown above. I do not think, that the specific time between each edge of the two digital outputs from the encoder would be the same. So each of the four transitions timing would need to be calibrated individually.

Per this DC tachogenerator?

@backflip

This is how a steady state situation at 123rpm looks like, with about one revolution shown:

In order to keep a low speed reasonable constant, the controller needs to work with a quite fast sample sample rate of the feedback and control. For each dot in this curve, the PWM output was corrected 20 times.

550ms at 123RPM is 0.55/(123/60)=0.26 revolutions, I'd doubt that the device under test/physical rotor speed/red trace/input is changing speeds by +/-20% in 20ms. The variation in the speed signal looks like an artifact of the geometry of the coils versus the magnets. I would think that 5000Hz(20 corrections/dot?) adjustments in a control system with an input like this are mostly chasing noise.

How fast does the motor speed change versus a step change in input voltage?