While the stepper is powered, the position can be queried but it is relative to the power on position, once the power is off that is lost.
So after a power off of the stepper motor what is the best way for the tic/microcontroller to know the absolute position of the stepper?
You can record the last know position in ROM or file, but even recording it will not guarantee that the position is correct, in case of misstep or sudden power supply interruption while moving.
Hello.
The Tic does not have any special support for absolute position control using feedback. One solution might be to use a separate microcontroller to keep track of that using some kind of feedback sensor (such as a potentiometer or absolute encoder).
Depending on your application, you might be able to get away with just using a homing switch, which the Tic does support. The Tic can use the homing switch whenever it does not know the relative position of the stepper motor (such as on startup or after de-energizing the motor) to recalibrate. You can find more information about this in the “Homing” section of the Tic user’s guide. However, please note that the Tic has no way to tell if the stepper motor has missed steps while operating, but you can command it to run its homing procedure if you think this has happened.
Brandon
