# Machsupport Forum

## Mach Discussion => General Mach Discussion => Topic started by: writerson on May 16, 2014, 04:51:19 AM

Title: Mach3 cant reach desired position .00x
Post by: writerson on May 16, 2014, 04:51:19 AM
I have a rotary axis as x. normally i use steps per unit as 200 and velocity as 120. I have calculated a full rotation on x axis exact value of x12.6 and my 90 degree rotation is x3.15,
On another machine i was able to make a different reduction.
Steps per: 195.4 and velocity: 36
Then i calculated an absolute rotation as X6.407,
after that when i try to send x axis to 6.407 i saw that is going somewhere else like x6.38,
I tried to change values like making steps per:1.954 and velocity:3600
In this calculation my full rotation was x640.7
i can get x640.7 on full rotation but my 90 degree rotation was x160.175 and i could'nt get exact value. it went x160.08 and measurements were wrong on table.
Any suggestions for this situation ?
Title: Re: Mach3 cant reach desired position .00x
Post by: RICH on May 16, 2014, 07:28:42 AM
Rotary axis is A,B,C about the associated X,Y,Z axis.
A rotary axis can be linear or degrees.
You need  required axis resolution for positional accuracy.

Not sure what your trying to accomplish by setting the rotary axis to X.

RICH
Title: Re: Mach3 cant reach desired position .00x
Post by: writerson on May 16, 2014, 07:31:16 AM
It seemed easier to me set it as a linear axis and measure.. how can i set it as a rotary "A" and tune it to 360 degrees ?
Title: Re: Mach3 cant reach desired position .00x
Post by: Fastest1 on May 16, 2014, 08:49:11 AM
On the general config page, check A axis is angular.

In the motor tuning section use a value of 200 x your micro stepping value to obtain the degrees (IIRC)