How to calculate resistor needed for gecko drives

[Richards]

For the G201, G203, or the G203v stepper drivers, the formula is:

47 X Amps / ( 7 - Amps) = Resistor.

So, for your motor:

47 X 5.6A / ( 7 - 5.6A) = 188K resistor.

A 180K or a 200K 1/4 Watt resistor would work fine ( or any other resistor that is +/- 5% of 188K).

[Red_boards]

What a timely post. I was looking at this earlier.
For the MK 9801's:
(47 * 4.1)/(7-4.1) = 66.5 kOhm
Fantastic - this is 4x what I got earlier using the same calculation! A lot to be said for re-reading and re-calculating (and thinner fingers).

[Kobus_Joubert]

Buy the UIM drivers. Amps are set with a onboard potentiometer...no more looking for resistors.;)

[Richards]

The Geckodrive G201X uses an internal dip switch for selecting current limiting resistor values. It has most of the features of the G203v but costs less, $114 plus shipping.

[litemover]

Hey Mike,

I was reading the manual and it actually states 47*I/ (7-I). That would be inductance no? Just confirming because on the G203V manual, it specified Inductance as part of the formula, not amps. Any ideas why?

Thanks,
chris

[Gerald D]

From http://en.wikipedia.org/wiki/Electric_current:

The conventional symbol for current is http://upload.wikimedia.org/math/d/d/7/dd7536794b63bf90eccfd37f9b147d7f.png, which originates from the French phrase intensité de courant, or in English current intensity.[3] (http://en.wikipedia.org/wiki/Electric_current#cite_note-3)[4] (http://en.wikipedia.org/wiki/Electric_current#cite_note-4) This phrase is frequently used when discussing the value of an electric current, but modern practice often shortens this to simply current. The http://upload.wikimedia.org/math/d/d/7/dd7536794b63bf90eccfd37f9b147d7f.png symbol was used by André-Marie Ampère (http://en.wikipedia.org/wiki/Andr%C3%A9-Marie_Amp%C3%A8re), after whom the unit of electric current is named, in formulating the eponymous Ampère's force law (http://en.wikipedia.org/wiki/Amp%C3%A8re%27s_force_law) which he discovered in 1820.[5] (http://en.wikipedia.org/wiki/Electric_current#cite_note-5) The notation travelled from France to Britain, where it became standard, although at least one journal did not change from using http://upload.wikimedia.org/math/0/d/6/0d61f8370cad1d412f80b84d143e1257.png to http://upload.wikimedia.org/math/d/d/7/dd7536794b63bf90eccfd37f9b147d7f.png until 1896.[6] (http://en.wikipedia.org/wiki/Electric_current#cite_note-6)

[litemover]

Awesome explanation Gerald. Thanks for that! Very educational! :D

[Tom Ayres]

Gerald, I don't know if you or wiki contains more knowledge.:D

[smreish]

...Gerald.