1 Topic by adrian (edited by adrian 2013-12-07 22:01:31)

  • adrian
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Topic: Stepper Driver VREF Chart

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 .

http://www.soliforum.com/misc.php?action=pun_attachment&item=4107&download=0

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2 Reply by adrian (edited by adrian 2013-12-07 22:14:45)

  • adrian
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Re: Stepper Driver VREF Chart

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 smile 1.27A . This is a good ballpark for low heat, max torque/speed...

3 Reply by axjurado

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Re: Stepper Driver VREF Chart

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.

4 Reply by carl_m1968

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Re: Stepper Driver VREF Chart

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.

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