Thanks to all who replied for the very good information.
To summarise:
- Adding encoders to steppers can be done, and HAL has all the components
needed. using encoder-PID-freqgen creates basically a "servo system with
steppers". Freqgen has parameters for capping velocity and acceleration.
- But this means tuning PID loops, which is not a trivial task, especially
with the non-linear characteristics of steppers (mid-band resonance...)
- The index pulse of the encoder can be used as a precise home switch.
- But because of the torque/speed curve of steppers (different from
servomotors), the behaviour of the system when pulses are missed is
*difficult* to master at best...
So it seems that the benefits are not worth the trouble and price of adding
encoders, and so I will stick with my bare steppers which work *very* well.
Thanks again for all the information and your kind replies,
Michel
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