Posted on January 17, 2018 at 10:23The controller might zero to the nearest 'zero' electrical position, meaning the closest full step position, when switching to step clock mode. Its like when giving the hard stop command for the first time when the bridge was in high impedance mode, the motor switch to hold and the shaft makes a slight move as it locks to the nearest zero electrical position. To confirm this, try the following:
1 - Give the motor a move command in micro steps equal to the step mode to land on a full step position. So if your step mode is 1/8 micro steps per step then give a move command in multiples of 8, say 800. Now switch to step clock mode, it should not move or at least minimal. Read back the absolute position counter also to see if this is zeroed too!
2 - Give the motor a move command in micro steps in multiple of your step mode plus 1/3 of that, so if your step mode is 1/8 micro steps per step than give it a move command of say 802. Now switch to step clock mode. The motor will make a slight move in one direction, lets assume for now it is counter clock wise.
3 - Give the same move command as in step 2 but this time with 2/3 of the step clock mode, lets say 806 micro steps. Switch to step clock mode. If my theory holds, the motor should also make a slight move but this time in the opposite direction.
