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Stepper Stall Detection Without a Physical Stopper

Question asked by Subash R on Jul 20, 2015

Hi ,

My Stepper motor can rotate upto 300 degree, but my requirement is just 180 degree. So I will be rotating the motor only 180 degree. Also we cannot assume the physical zero degree of the motor and electrical zero degree of my application will always be same. Hence I need to ensure the zero position of the stepper motor at every initialization.

 

The controller has an SSD module which drives the stepper motor in full steps and the back emf generated during each step is integrated and available in a register. The application note suggests to have a threshold value for the integrated value and once the motor hits a stopper and is unable to move, the emf generated will be less than the threshold and this point can be used to detect the motor stall (or in my case the upper and lower set points for the stepper). But for this, I am assuming I need a physical stopper to block the stepper movement.

 

Could we do the zero position detection without a stopper in the board to block the stepper movement.

 

Note: The board doesn't have a stall current feedback to the controller.

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