# Re: [Machinekit] Stepper motor configuration

```Dear Charles,Schooner, Bas de Bruijin,

Due to time lag and working, sorry for late reply.```
```
could it be that instead of 4 rev/mm you have a reduction of 4 mm/rev ?
> that would mean 100 full steps/mm and might make more sense.
>

First of all, I make mistake that is should be 4 rev/mm. So I change scale
to 100.

As Charles comment:
"Almost certainly.  With a scale of 1600, and a maximum velocity of
200, your maximum step pulse rate would be 320,000 KHz, and with your
acceleration of 3000 mm/s/s, you'll get there pretty quick.  The
default PRU settings result in a maximum pulse speed of about 50 KHz,
so you need to either reduce the maximum allowed velocity or decrease
the PRU cycle time (or both). "

May I guess in this comment 320,000 KHz should be 320KHZ, is it?
If PRU maximum pulse speed is 50KHZ, the max speed is 500? Because scale
100* 500=50KHZ.

I am not very sure about Schooner said "Try increasing dirhold / dirlen to
1us and steplen / stepspace to 5us
If that cures it, try reducing the figures towards the chip specs until you
hit problems"

Anyhow I tried to change ini file, i am not sure. But it seems no affect.
# these are in nanoseconds
DIRSETUP   =              1000
DIRHOLD    =              1000
STEPLEN    =              5000
STEPSPACE  =              5000

About speed, yes, i shift one decimal left as follow:

TYPE =              LINEAR
MAX_VELOCITY =       20.0
MAX_ACCELERATION =   300.0
# Set Stepgen max 20% higher than the axis
STEPGEN_MAX_VEL =    24.0
STEPGEN_MAX_ACC =    360.0

>     SCALE =  -100
>

It works much better than before, but motor still stall when execute G00.
Speed still too high? where to set G00 speed? 20.0 is only stand for feed
speed?
Then when motor change rotate direction, speed decrease to zero, around
Zero motor start move step by step, make vibration and noise. It seems it
doesn't work well at low speed.

It will be much clear if i can post video here.

Thanks for anymore tuning methods!

-chengxi

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