I’m using the below stepper motor with the Tic 36v4 controller and need it to only move at a constant speed of 22.22 RPM or 289.8466 steps/sec. I’ve got the speed dialed in but I’m unsure how to set the parameters in yellow? Changing these makes a big difference in how smooth the motor runs but I’m unsure of the ideal setting for this motor, micro steps, current, and speed. Is there a way to calculate this? Rule-of-thumb?
I referenced Pololu - 6. Setting reference and the TI documents but wasn’t able to apply the knowledge to my settings.
Thanks, Joel
Hello.
I do not have a general rule of thumb to suggest for optimal settings since it depends on the specifics of your setup such as the stepper motor and supply voltage, but if the default values are not good enough for your application, the best approach for tuning them is probably to look at the coil current with an oscilloscope current probe and try to adjust the values to get as close to a smooth sinusoidal waveform like the DRV8711 Decay Mode Setting Optimization app note demonstrates.
If you don’t have access to an oscilloscope with a current probe, it probably doesn’t hurt to try to adjust them based on the perceived smoothness of the motor that you were observing.
Brandon
Brandon-
Thanks. My battery ranges from 12.3 - 8.5V and looks like the Tic is supplying 4.792V.
Playing with the settings will be fine but I’m wondering if there’s a limit to the fixed off time where the motor would loose torque?
Hello.
It sounds like you might be misunderstanding the “Input before scaling” variable. To clarify, the “Input before scaling” variable is the reading that the Tic is taking from your analog or RC input; it is not a representation of the Tic’s output to the stepper motor.
I generally wouldn’t expect the off time setting to have a significant effect on the motor’s torque.
Brandon
