SoliForum - 3D Printing Community — Stepper Driver VREF Chart

Re: Stepper Driver VREF Chart

null@example.com (carl_m1968) — Wed, 17 Feb 2016 19:03:49 +0000

I also believe it should be the same for all 8825's regardless of the carrier they are on. The current limits are dictated by the chip.

Re: Stepper Driver VREF Chart

null@example.com (axjurado) — Wed, 17 Feb 2016 13:59:55 +0000

wouldn't be:

cooldrv 8825 I = Vref/4...... or 0.25Vref/A
polulu 8825 I=Vref/2..... or 0.5Vref/A
polulu 4988 I = Vref/2.5 .... or 0.4Vref/A

Thinking you might have some multiplication/divisions off on the table.

Re: Stepper Driver VREF Chart

null@example.com (adrian) — Sat, 07 Dec 2013 22:01:42 +0000

Updated the table above. Yes some of the formulas are the same but shortened, but I've listed both as various vendors tend to list one or the other in their datasheet/wikis...

If you fit a new motor to any axis, an additional handy formula to use as a rough guide for the current to tune to when using microstepping is:

TripCurrent * sqrt(2)/2 ;

e.g, a 1.8 amp stepper should be initially tuned to (1.8 * sqrt(2)/2 1.27A . This is a good ballpark for low heat, max torque/speed...

Stepper Driver VREF Chart

null@example.com (adrian) — Sat, 15 Jun 2013 13:16:01 +0000

I made this up for use in my RAMPS how-to, but thought it might be handy in its own little thread too.

Maybe if people can add what RSense values the various Stepper Drivers used have, that'd be of value.

The standard Pololu's are 0.05
G3D Drivers from Gadgets3D are 0.1
DRV8825 md20a and md20b from Pololu are 0.1
StepStick from Botronicz are 0.05, but most others are 0.02 .