Re: No Parallel Port

[Ray <rehenry-at-up.net>]

Phil

I'll mix my comments into your post.

On Sun, 27 May 2001, you wrote:
> Ray,
> 
> I've wired myself a little gender bender to get the wiring on my Camtronics
> controller compatible with EMC and I can now jog the axis!

There had been some talk about writing a steppermod that would output the
same pin definitions as the camtronics.  Your solution works as well.  I've
seen several that used the radioshack jumper box for this.
  
> I'm looking for documentation for the INI file so I can setup the motors
> correctly. Forgive me if  I've missed something but looking through the
> handbook and the EMC site I can't find a comprehensive description of the
> INI file parameters. Is there one available ?

Not really.  Most of os get so tired of learning the ini the hard way that
we have refused to write up what we are supposed to know about it.  I'm
still looking for someone who can take charge of this.  I'm sure that many
would contribute but someone has to take the point.
 
> In particular I'm trying to setup my steps per inch. I beleive that I use
> the Input Scale and Output Scale parameters to do this but I've increased
> these and yet I don't see any difference in the output.
> 
> At the moment if I enter a command to move an axis 1 inch I get an output on
> the motors that looks like 1/4 of an inch. This suggests that I need to
> increase the Input & Output scale to 4000. I've changed the ini file but I
> don't see and change in behavour.

First, make sure that the ini file that you are editing is the one that you
are really using.  The run file defines which ini to read on startup.

-----snippet of run file-----
# Set the name of the .ini file, using emc.ini as default. Change this to
# your .ini file, if you don't use emc.ini.

INIFILE=emc.ini
-----eos-----

This last line is the ini that that run will read on startup.  Once you
have this done, then look at the input and output scale.  With steppermod,
only the input scale is used.  With freqmod, both input and output must be
the same.  With smdromod.o, input scale is the number of steps per inch and
output scale is the number of return pulses per inch from the Kulaga/Mauch
board.

I would first test the distance commanded and distance traveled using the
manual jog commands from the gui.  This will ignore inch/metric
considerations.  

Then I'd figure out how many pulses it should take to move an axis one
inch.  On my Grizzly, I have 200 steps per rev motors, half step mode on my
gecko drives, 3 to one belt ratio, and 5 turrns per inch ball screws.  So
my guess is

200 x 2 x 3 x 5 = 6000 pulses per inch.

So I enter that number for each axis on the Input scale line and save the
file.  Then I set up an indicator and see that I really get an inch of
travel.  I did.
 
> The other issue I have yet to tackle is Backlash compensation. Do I just
> enter my values into the ini file as inches or steps ?

Inches.  My thompson nuts give about 4 thou lash so I enter 0.004 on the
backlash line.  You can see this happen on an axis if you command a circle
and watch each axis as it nears zero speed at the quadrant.  As the axis
crosses the quadrant, the motor will jump back the backlash distance you
set and then gradually begin to speed up.

You're doing great.  Keep asking as you need help.

Ray