"Tachus 42" board builders?

[buellguy]

Anyone familiar with the "Tachus 42" designed board?
I'm a bit of a newb, and I would like to build this board. The problem that I'm having is understanding the accompanying chopper board plans.
The values of the so called "current setting resistors" are not listed. There are 3 sets of 5 resistors in paralell. I presume this must be taylored to the motors being used? But how?

Also printed is " R5+R4 (supply-10) /0.05". This refers to a pair of resistors in series that presumably limit the voltage to the steppers. There are two other pairs of resistors in the same configuration, R18 and R17, R31 and R30. Are these to be the same values as R5 and R4?

http://pminmo.com/3axis/3chprschematic.pdf

Is there a better board that I should be considering?

[David Flowers]

Im in the same boat as you, have blank cb and fecl to etch it just trying to get to a lazer jet to print. The chopper is next on my list and i am also a bit confused.

[jam5295]

Suggest you look at PMinMO's bulletin board. http://pminmo.com/phpBB2/ there is a section for the tachus42 board. http://pminmo.com/phpBB2/viewforum.php?f=2 PMinMO has answered a lot of questions there.

[Konstantin]

Well. The R4,R5 and the other that are in the same position for the other 2 axises are calculated by the given formula.

The 5 resistors in parallel are setting the current, individually for each axis.

I have built that board and it is working nice.

Current limiting resistor formula is in the top left corner, fist column is the ideal resistance (calculated parallel) and the 2nd column is the current output. For currents above 3A u must use 5 watt resistors, ircc.

[David Flowers]

I have alot to learn, but it is nice to know there are people out there willing to help, Thank You all. And PMinMO, nice web site, the best I have found.

[David Flowers]

Ok I etched my board and have the jumper and IC sockets soldered on, just waiting on some parts now. First time etching a pcb for me. I have to say that was pretty cool much easier than i thought it would be. I would like to run the kelinginc steppers p/n kl340h280-48-8a 3.2v 4.5a Will this board hold up ok to them?

[David Flowers]

ok I have the driver board done now i just need to get started on the chopper