Advertisements

MPCNC: GRBL Configuration

This collection of GRBL settings gets the MPCNC hardware up and running:

Conveniently, the $$ command (in the first line) produces output in exactly the format it will accept as input, so just pour the captured file into GRBL’s snout. I used ascii-xfr with a 250 ms line delay:

ascii-xfr -s -v -l 250 MPCNC-GRBL.cfg > /dev/ttyACM0

Now, to be fair, the MPCNC hasn’t yet done any useful work, but it moves.

Notes:

Setting $22=1 requires home switches to be installed and working, with $23=7 putting them on the negative end of the axes, which may not work well in practice. In particular, having the Z axis homing downward is just plain dumb.

The step/mm values in $10[012] require 1/16 microstepping with 2 mm belts on 16 tooth motor pulleys. The MPCNC’s Marlin config uses 1/32 microstepping, which doubles the step frequencies and (IMO) doesn’t provide any tangible benefit.

The speeds in $11[012]=6000 seem aggressive, although they actually work so far.

The accelerations in $12[012] may push the motors too hard with anything installed in the toolholder.

The travel limits in $13[012] depend on the rail lengths you used.

Advertisements

, ,

  1. #1 by madbodger on 2017-11-23 - 12:32

    As Galileo said: “E pur si muove”!

    • #2 by Ed on 2017-11-25 - 09:49

      Along those lines, I’ll put in another plug for Galileo’s Daughter by Dava Sobel.

  1. MPCNC: 12 V Supply vs. Stepper Current vs. Axis Speed | The Smell of Molten Projects in the Morning
  2. MPCNC: A4988 Driver Microstep Waveforms | The Smell of Molten Projects in the Morning

Spam comments vanish. Comment moderation may cause a delay.

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s