Help needed to understand Stepper and Smoothie

smoothie-forum
(cdndave_SW) #1

Hello all

I have been using my Smoothie for a while now, and have been suffering from step loss. I have been looking at the stepper wiring and current being used by the stepper.

I have a #23-305-DS8A (425oz-in bipolar rating, 305oz-unipolar rating, 4.2v, 3A, 200 S/R, 3.2mH, Size #23) and some smaller #23-205-DS8A (3V 3A) - they are 8 wire steppers and are wired for serial and have the current set to 2.0 amps (ie all set to alpha_current 2.0)

Is this the optimal setting? Some reading I’ve done would indicate the when wired in serial I should be using Current rating / 1.4 - so X-current set to 1.7

Would their be benefit of configuring my steppers for parallel at setting X_current to 2.0?

I could run some experiments, but I would like to start from a position of basic understanding before messing with my setup.

Thanks,

Dave

Imported from wikidot

(Arthur Wolf) #2

Hey there !

The maximum current Smoothie can provide is 2A. If you run steppers that are rated for 3A, at 2A, you won’t be getting their full torque/speed.

I strongly suspect that’s why you are getting skipped steps : your motors do not get enough power to do the job.

If you can wire the steppers to be 1.7A instead of 3A, then you really should do that ( and set the current to 1.7A in config ).

Also, at 2A, depending on ambient temperature, your Smoothieboard could be overheating, causing skipped steps. So I advise you point a fan at the board.

Cheers.