Re: Closed loop Stepper


Here you go. This is the "Type 1". It is not hidden in this picture, the magnet is between the washers and screws. While it is physically the same as a disk magnet it is polarized as in the previous postings.  The calibration routine "trains" the encoder to the magnetic flux lines of the particular magnet.
Seems the cal is for temp comp, not magnet mis-alignment.
This implies that there is a shaft centering recess in the magnet.
I dont see any recess in the magnet to help center it?
I don't think it needs to be very accurate - the motor has a calibration procedure, which I think is implemented in order to compensate for the inaccuracy of the magnet installation.
Quickly skimming the datasheet
The calibration is for temp change, not magnet misalignment.

As can be seen in the table, typical error can be 0.6 degree (max 1.0 degree), see notes in table. Also "Max. 1.0° angle error over lifetime and temperature-range with activated auto-calibration".
Seems Howard's test shows much better. Would be interesting to purposely mis-align the magnet and retest, maybe it dont matter much.

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