Comment by GabeIsko
5 days ago
Absolute encoders can be really good for position critical applications that you don't want to re-home all the time. Linear stages, winches - if you don't want to re home it and it needs accurate position control you start looking at an absolute encoder.
Even for speed control, hall effect sensors are kind of a poor way to track position. What is nice about hall effect sensors is that you can use them as a signal to perform brushless commutation in your motor controller, and then also use them as a poor-man's encoder. Very useful if you don't need that much accuracy in your application, but you do need brushless motors for some reason. But one of the first things I would go to as a application engineer was recommend customers get an encoder mounted.
It seems like an absolute encoder would immediately lose its advantages if a reduction gear were used though? Then you would still need to rehome the number of revolutions.
Wouldn't you mount the encoder after the reductor then, where the position actually matters?
Yes, we are discussing servos packaged with an absolute encoder
You can get multi-turn absolute encoders for these applications.
Yeah, we have one application like that, a big gantry that would be a pain to home. Interestingly, the high res absolute encoder is also used to commutate the servo (it's sine) but the teaching of the commutation is a little nerve wracking. Maybe I'm getting old but the whole setup stresses me out