I’ve got the cnc shield an uni installed, including my relays to control 2 additional outlets. I’m also trying out Lightburn. So far I like it, now that I’ve understood why origin and homing location aren’t the same thing.
Steps per mm are dialed in at 158. X and Y travel in correct directions, and I’ve edited the grbl source code for 2 axis homing (X then Y), enabled PWM spindle control and successfully uploaded to the Arduino Uno. I then discovered that my K40 mechanical limit switches.are NC, so I am using $5=1. $23 is adjusted to back off switches by 2 mm which does get the axis off the switch lever.
The problem is that the homing behavior is inconsistent. One click of the homing button may result in 60mm X movement and backing off before the switch is hit then the same for Y. A second click may do the same, or the x may home as expected then the Y does a “short run” or may home normally. Or it may take 4 or 5 tries to get to the top left corner.
Any thoughts on how to improve this? It looks like the switches have an additional contact so I can probably change them to NO, although I do prefer the logic behind using NC home/limit switches. I also notice that the motor and limit wiring runs together for a significant distance, so noise may be a factor, but the original nano board never showed any homing problems.
Homing is working now. I rerouted the endstop cable to get some separation from the stepper cables, but that didn’t seem to make any difference, so I went ahead and changed them over to NO instead of NC, and then everything started to work as expected (once I reset $5-0). I figured since I’ve chosen to go GRBL, I may as well adopt it’s defaults if I hit a snag.
$0 is set to 10.
From my reading of GRBL options, setting $1=255 will keep the steppers enabled all the time, even when not being sent a move command. Do I really need that?
@Tom_Traband $1 set to 255 ensures that all lines do align. Without it, belt tension or not level machine gantries can cause the gantry to wander a bit with as end result as less accurate cut. With engravings, I have not seen any impact since the steppers are driven continuously hence no wandering.