Hi Mohamed,

Your iterations show decreasing position numbers for both forward and reverse, the delta's.
Is each set of measurements made with a different filter or just different focus runs?
Looking at the numbers
8910 - 6328 = 2582/4 = 645.5 *degrees/step(0.067) = 43.2485 degrees output shaft movement
8651 - 6119 = 2532/4 = 633 *degrees/step(0.067) = 42.411

Where the /4 is your 1/4 stepping and 0.067 from your 27:1 motor/gearbox reduction

Gene

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