Re: ini questions

[Chris Stratton <stratton-at-mdc.net>]

> > The other question also has to do with the ini file. I want to know what to
> > set so the sliding table moves the distance I want and the display also
> > reflects the distance. From reading the manual, it seems the input_scale is
> > the variable to adjust. When I adjust this it does not always make sense. I
> > tried calculating the number as it is shown and it causes tkemc to be a bit
> > jumpy as the mouse moves around, and the distance of the move is not
> > correct. If I set it at "1,000   0" everything moves smoothly but when I am
> > in mdi mode and tell it to move 1 inch, the reading says 1.000 but the
> > actual move is about 1/10". If I set input_scale to "10,000  0" and tell it
> > to move 1 inch, the readout is 1.000 and the actual move is about 2.5/10".
> > I get that jumpy mouse move as well. It also seems to change the speed at
> > which the motor turns. What is happening, what am I doing wrong?
> 
> What number did you calculate to be correct?
> 
> I really don't understand what is happening here.  Tkemc with a jumpy
> mouse pointer almost sounds like a freqmod period type problem but it
> shouldn't vary with the number of steps per unit.   Are you using freqmod? 
 
I've seen similar behaviour with steppermod.o if any of the maximum
velocity parameters are set too high.  It seems some part of the task
runs at the maximum step rate all the time, and really slows the
machine down.  Looking at the source I thought it only ran at the step
rate needed, but maybe that isn't the case, or maybe it isn't working.

Anyway, try lowering the maximum velocity parameters, both in the
trajectory section and the axis sections.  Start by reducing them by a
factor of ten, and see if that makes input scale = 10000 run smoothly.

Also, make sure the stepper isn't missing steps by being driven too
fast.  Try using something like G1F1 for one inch/minute feed for this
kind of test initially.  

Chris


-- 
Christopher C. Stratton, stratton-at-mdc.net
Instrument Maker, Horn Player & Engineer
22 Adrian Street, Somerville, MA 02143
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