INI Setup Issue

[rmacster]

Below is the stepper_inch.ini setup for my X axis. Currently it is exactly the same for the Y and Z axis.

My Problem is this: I setup the input scale to 8000. When I jog the X axis (jog increment set to .1) it moves the X axis exactly 1 tenth of on inch. But if I give it a .ngc file with the command G01 X+2 it actually moves almost 3 inches. I'm sure I'm missing something simple but I just can't find it.

Thanks for all the help.

Rick McNeely
[AXIS_0]

TYPE = LINEAR
HOME = 0.000
MAX_VELOCITY = 1.2
MAX_ACCELERATION = 20.0
STEPGEN_MAXVEL = 1.4
STEPGEN_MAXACCEL = 21.0
BACKLASH = 0.000
INPUT_SCALE = 8000
OUTPUT_SCALE = 1.000
MIN_LIMIT = -10.0
MAX_LIMIT = 10.0
FERROR = 0.050
MIN_FERROR = 0.010
HOME_OFFSET = 0.0
HOME_SEARCH_VEL = 0.0
HOME_LATCH_VEL = 0.0
HOME_USE_INDEX = NO
HOME_IGNORE_LIMITS = NO

==========Test .ngc File Below===========
F 2
G01 X+2
M2

[/FONT]

[acondit]

Rick,

My first question would what was X's position to start?
If X was at -1 and you told it to go to +2 that would be a three inch move.
Try this and see if it moves back to your starting position (or not).
F 2
G01 X+2
X0.0
M2


Alan

[cyclestart]

Originally Posted by rmacster INPUT_SCALE= 8000

Is your table moving to the left when jogging X+ ? Just curious as my .ini reads minus, ie -8000 on that line.

I'm going to take a guess at the problem. Remember my specialty is misreading posts.

This is difficult to put into words, so please excuse the explanation by example. I'm assuming you're using the axis interface.

Look in the file stepper.var and note the numbers on lines;
5220 -> this determines the active offset. Should be 1.0000 at this point.
5221 -> the x offset
5222 -> the y offset
5223 -> the z offset

Try this. Before opening axis, change the values associated with 5221 and 5222 to zero. Now start axis and move the table to the position you would like to call HOME. I like that position to be the table moved to the far right and near the column.

Now click Machine -> Homing -> home y axis. If this worked as intended the actual and relative positions of y will both read zero.

In MDI enter

 G01  Y.1  F10

The expected result is the table moving 0.1" towards you.

To play a bit more with this idea, move the machine to Y 1.0. Now "touch off" Y and accept a relative co-ordinate of zero. Open the stepper.var table and line 5222 should now read 1.00000. Toggle between the relative and and machine position views to get a feel for what has happened.

If you look at the active gcodes on the MDI window, G54 should be listed.

In MDI

 G00 Y0

no movement should take place.

 G00  Y.25

and notice the difference between the machine and relative positions.

Keep playing with this and the concept will become second nature.

Wow, I do rattle on. The axis developers explanation might be more clear and covers some additional possibilities.
http://www.mail-archive.com/emc-user.../msg03400.html

[rmacster]

I guess my beginner status really shines! You're both correct of course. Thanks for the extended answer cyclestart, it's beginning to make sense to me. CNC is really a different animal. But all in all quite nifty.

Rick McNeely

[rmacster]

Also, my my table moves to the left. I had to add the line:

setp parport.0.pin-03-out-invert 1

to my xylotex_pinout.hal to reverse the direction of x travel. I never thought of using -8000 instead of 8000.

[stustev]

This is a little off topic but your table should move to the left when you move in the X positive direction. The program should move the 'tool' relative to the work. If the tool doesn't move but the table moves then the table must move left (if you are looking in the Y positive direction).

[cyclestart]

Originally Posted by stustev This is a little off topic but your table should move to the left when you move in the X positive direction.

Yep, and both myself and rmacster have machines working this way. We just used slightly different methods to make this happen.

Rereading this post, there is something I forgot to mention. A command of G91 will result in an incremental move. Axis defaults to G90 (absolute) when opened.