Homing not working despite functioning limit switches

LightBurn Hardware Compatibility
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1

Hi There,
My DIY 5watt diode GRBL table has hard wired limit switches back to the controller. The controller is a Woodpecker CNC CAMXTOOL V1 windows 10 laptop.
If I push any of the limit switches why the head is in motion the switch with trigger a stop. Yet when I hit the either of the home buttons in the software screen the head does not move. The machine will manual jog and burns OK, just cant get it to home. I have tried it with the home at startup set to on and also with it set to off.
I’m getting the Alarm 9 code. See the message code below and my settings.
The Alarm 1 that occurred twice is me pushing the limit switches.

Homing
ALARM:9
Homing fail. Could not find limit switch within search distance. Defined as 1.5 * max_travel on search and 5 * pulloff on locate phases.
ok
Grbl 1.1f [‘$’ for help]
[MSG:‘$H’|‘$X’ to unlock]
[MSG:Caution: Unlocked]
ok
ALARM:1
Hard limit triggered. Machine position is likely lost due to sudden and immediate halt. Re-homing is highly recommended.
[MSG:Reset to continue]
Grbl 1.1f [‘$’ for help]
[MSG:‘$H’|‘$X’ to unlock]
[MSG:Caution: Unlocked]
ok
ALARM:1
Hard limit triggered. Machine position is likely lost due to sudden and immediate halt. Re-homing is highly recommended.
[MSG:Reset to continue]
Grbl 1.1f [‘$’ for help]
[MSG:‘$H’|‘$X’ to unlock]
[MSG:Caution: Unlocked]
ok
<Idle|MPos:0.000,0.000,300.000|FS:0,0|WCO:0.000,0.000,0.000>
ok
$0=10
$1=25
$2=0
$3=2
$4=0
$5=0
$6=0
$10=1
$11=0.010
$12=0.002
$13=0
$20=0
$21=1
$22=1
$23=0
$24=25.000
$25=500.000
$26=250
$27=5.000
$30=255
$31=0
$32=1
$100=80.000
$101=80.000
$102=80.000
$110=5000.000
$111=5000.000
$112=4000.000
$120=50.000
$121=50.000
$122=50.000
$130=475.000
$131=475.000
$132=200.000

2

Check the switches first. Activate a switch, and while it is activated, send the ‘?’ command via console. Report the output. Then do the same with the other switch activated. Look for the ‘Pn:’ section, if the correct letters appear.

1 Like
3

The limit switches work fine!
The problem I’m having as stated is when I push the homing button on the screen the laser head does NOT move at all. There is no movement to home.

4

Looks like I may have found the answer to my problem.
His is what I found online search:

Primary Causes and Solutions

  • Incorrect Z-axis Homing Configuration: Many laser machines do not have a Z-axis limit switch or motor. The GRBL firmware, if compiled with Z-axis homing active, will try to home Z first and stop all movement when it fails to find the switch, resulting in no X or Y movement.
    • Solution: You need to flash a version of GRBL firmware that does not include Z-axis homing or disable Z-axis homing in the controller settings if your board allows this.
1 Like
5

What I meant was to check if the limit switches are wired to the correct axis. This can cause a similar behavior. Electrically, we knew they worked.

Great, you sorted it out. Firmware would have been the next step after checking physical connections. :slight_smile: