Positive coordinate space after homing

[classbproject]

Hello. I have a couple of questions around homing and some issues that I've been facing. I have two NC limit switches wired in series on each axis. I'm currently using only X and Y axis since this is a laser engraver. After some trial and error with $23, $5 and motor wiring flips, the machine homes to the top right corner [as shown here]. I read in the Wiki that homing sets the machine in the negative coordinate space. This means that in the current location, a movement to the left would be -X and towards the bottom would be -Y. However, if I issue a command such as G0 X100 Y100, the machine moves correctly in the X-axis (which it should not since this is -X, but it does) but in the Y direction it tried to move further to the top and triggers one of the limit switches.

How do I make the left and bottom of my workspace positive in both directions after homing? This would mean that left movement would be +X and bottom movement would be +Y.

Also on startup, I see this:

Grbl 1.1f ['$' for help]
[MSG:Check Limits]
[MSG:'$H'|'$X' to unlock]

even though #define HOMING_INIT_LOCK is disabled.

Here are my changes to the config.h file: #define HOMING_INIT_LOCK is commented out. #define HOMING_CYCLE_0 (1<<Z_AXIS) is commented out. #define HOMING_CYCLE_0 ((1<<X_AXIS)|(1<<Y_AXIS)) is enabled. #define HOMING_FORCE_SET_ORIGIN is commented out (though I had enabled this earlier it didn't help with my issue. Hence I reverted it to its default state).

Current settings are:

$0=10
$1=25
$2=0
$3=0
$4=0
$5=1
$6=0
$10=1
$11=0.010
$12=0.002
$13=0
$20=0
$21=1
$22=1
$23=1
$24=100.000
$25=1000.000
$26=250
$27=5.000
$30=255
$31=0
$32=1
$100=80.000
$101=80.000
$102=80.000
$110=3000.000
$111=3000.000
$112=3000.000
$120=500.000
$121=500.000
$122=500.000
$130=300.000
$131=300.000
$132=20.000

[luben111]

Hi, GRBL works only with negative coordinates (X, Y and Z are negative digits) when homing enabled. You can't make it to work with positive coordinates until you have limit switches and homing. This is how GRBL for CNC machines work, there are many threads in this forum discussing the positive coordinates.

[chamnit]

@luben111 : Not quite. HOMING_FORCE_SET_ORIGIN will place the origin anywhere homing ends. So if you home to the front-left-bottom, all of the machine coordinates will be in positive space.

@classbproject : Please see this wiki FAQ.

[classbproject]

I did read that but I still find it confusing. I did uncomment HOMING_FORCE_SET_ORIGIN in config.h and then homed the machine to front-left-bottom corner. Now the Y-axis seems to be in positive space but the X-axis is reversed. So when I enter G0 X-10 THEN the axis moves in the +X direction.

[chamnit]

@classbproject : You need to invert the direction pin of your X-axis.

[classbproject]

Ok did that but it homed the X-axis on the opposite side. I then inverted the X and Y directions for homing and now it seems to be in the positive coordinate space. Thank you for helping me sort this out.