Re: rotary axis

[Paul <paul.corner-at-tesco.net>]

Hi Nasir

A couple of notes first on the naming conventions for lathe axis - The cross 
slide is usually labelled X, the carriage, Z, and the spindle is referred to 
as C. Therefor, the [TRAJ] COORDINATES would be X Z C.

Defining the C axis in the ini file will cause a number of problems - 
Assuming a start up position with C =0, when the spindle is turned on, EMC 
will attempt to provide feedback to maintain C at zero. But because C is 
being driven by an external motor that EMC has no control over, a following 
error will be generated. This following error is probably being generated 
before the spindle has completed half a turn, so I wouldn't expect the 
display to change - I dare say EMC is going in to E-Stop as soon as the 
spindle is switched on because of this.
The answer is to only define the X and Z axes in your ini file. If you must 
have a positional readout for the spindle, emcmot.c will need to be modified 
so that no feedback is applied to the C axis.

Finally, G33 is not available with EMC - There has been discussions in the 
past on the subject of implimenting threading, but it is not a trivial task 
(at the programming level).

Regards, Paul.



On Friday 09 Aug 2002 1:18 pm, nasir2ahmed-at-yahoo.com wrote:
> The axis for the spindle which we have selected is "Z" or "axis-2".
> as we made changes in the ini file for z-axis in the option TYPE
> ANGULAR AND UNITS "1.0" and start rotating the spindle, no changes
> were observed in the encoder readings as it should have.
> The reading was in the form of linear type, not in the angular form
> ( 0-360-0 degrees).