Lathe conversion from stock to CNC

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04 May 2013 23:37 #33604 by Soundreflections
I have now gone through wiki.linuxcnc.org/cgi-bin/wiki.pl?Simple_Remote_Pendant and applied config as they suggest. I include my joypad file, showing my findings and the buttons I found using halmeter (I can see those signals true when pressed), though the machine does not move for anything. I can move with the on screen buttons & mouse, though the pad would be great.

I would also like to use the analogue "click" (press-switch?) to trigger movement if possible.

Any ideas how to accomplish this, or where to get more info?
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05 May 2013 01:06 #33612 by BigJohnT
I don't see the part that actually jogs the axis in your postgui hal file.

John

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05 May 2013 02:34 #33618 by Soundreflections
Thanks John, can you point me to where I can see how to set that up? Looking through the wiki I could not figure the specific control out, just it seemed to set speed somewhere. If you can post a pointer I will try further tomorrow morning.

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05 May 2013 05:27 #33627 by BigJohnT
Step 6 in the tutorial is what actually moves the axis, it looks like you stopped at step 5.

John

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07 May 2013 20:44 #33725 by Soundreflections
Thanks John,
I had indeed stopped before step 6! I am not sure how as I thought I had followed all instructions.

I had to invert X and Y axis's, but it works great. Any idea how I can add a 4th speed (My joystick has 4 number buttons and I prefer using all resources) to the entry, I tried just adding after 3 but axis would not start, so I think I need to define the 4 somewhere?

I would like to assign other buttons to functions (ie. put Estop and power on back buttons) where can I see a list of active inputs, I presume I can then just add entries from the joystick to that value?

I would also like to (once set up) start spindle and set speed, I was wondering about the digital direction pad, maybe up and down for FWD/REV, left and right for speed, maybe one of the back buttons as an enable button. Any suggestion how I can do that, and perhaps other handy functions?

Where can I put the config so stepconf does not overwrite it? I re-calibrated my Z axis, trying 20th mictostepping, to try get better performance / speed out of it, though I am obviously doing something wrong. I put 20 as the mictostepping value, but had to have a ratio of about 20:10 for any scale accuracy, where my actual ratio is 10:21.

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08 May 2013 04:35 #33746 by BigJohnT
You would have to use a mux8 (I assume there is one) to have more than 3 speeds. Sounds like it is time for you to study HAL a bit. Look at the Basic HAL Tutorial in the manual for guidance. Take one step at a time so you can correct your mistakes as you go.

I would never put an e stop on any pendant unless it was hard wired to the e stop loop.

Sounds like you have outgrown the Stepconf Wizard, if not each file that has "this will not be over written" is safe from Stepconf.

The numbers you put in Stepconf to get your scale number don't matter a twit, they are all just calculated to get the final scale value and that number is the only one used.

Typically you arrive at the scale like so:

Stepper steps per rev = 200
Stepper Drive Micro Steps per step = 10 (just depends on your drive)
At this point you know that it takes a scale number of 2000 to turn the stepper one revolution.

Say for example your stepper it connected to the lead screw directly and 5 turns equals 1" then 5 x 2000 = 10,000 step pulses to move the axis 1". If you have a reduction between the stepper and the leadscrew they you also have to figure that in.

John

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08 May 2013 18:23 #33766 by Rick G

I would also like to (once set up) start spindle and set speed, I was wondering about the digital direction pad, maybe up and down for FWD/REV, left and right for speed, maybe one of the back buttons as an enable button. Any suggestion how I can do that, and perhaps other handy functions?


There are several examples of adding more functions with a pendant in the wiki, you may want to look there for ideas.
It can be as simple as connecting a pendant hal pin to another hal pin.
You can use hal show machine configuration and hal watch to see what pins are available on the pendant and hitting a button to see the effect.

As John for said for safety an e stop should be hard wired to the e stop loop.

Rick G

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09 May 2013 17:18 #33817 by Soundreflections
OK, Noted E-stop to stay hardware! (Currently I do not have enough inputs, so E-stop is mouse or F1 only) I will put power on Joystick, as hitting a limit switch is the most common error I have run into.

Found the extra functions in the wiki - will look there and adapt.

Now to figure out how to draw and convert models for CNC!

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21 May 2013 17:29 #34490 by Soundreflections
I have been finding it useful to have the joypad to control, it makes for easier work most of the time, though the motors do not have enough torque for deeper cuts.
I have had the pad stop responding a few times, then un-plugging / re-plugging and restarting LinuxCNC is required. Then it hung whilst moving! I was closing in on the workpiece, so high speed both axis's and they kept going. Fortunately I killed the motor quite quick, so some scratches on the chuck and my tool survived, but I did not run CNC again, finishing the project manually.
Any idea if it could have been the joypad / Linux, or CNC causing the problem?
I am thinking of uprating the pad's cable, soldering some smoothing caps in likely places and trying to screen the circuit board, to see if things improve.
I will also start experimenting with CAD and conversions, to run full auto.

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21 May 2013 18:08 #34492 by andypugh

I have had the pad stop responding a few times, then un-plugging / re-plugging and restarting LinuxCNC is required. Then it hung whilst moving!


I think you have found the problem with USB and userspace components in general. They stop if/when the UI freezes.

The realtime system carries on.

If you want to actually do machining under motor-control but twiddling knobs by hand, then I think that a couple of encoders (one for each axis) wired to HAL with all-realtime components will be a lot more reliable (should be 100% reliable).

However, might I suggest that something like my lathe routines might be more convenient for the sort of ad-hoc work you seem to be describing?
www.linuxcnc.org/index.php/english/forum...0-lathe-macros#34357
But note the caveats about it not actually working correctly yet.

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