Hello all,
I have made my own desktop CNC machine, with grbl controller, and using the universal gcode sender.
while setting it up using the setup wizard, I was confused to configure the limit switches, I have 2 for X-axis (X+ and X-), 2 for Y-axis(Y+ and Y-), and 1 for Z-axis (Z+), I dont know how to configure them to home my machine.
this is my firmware setting:
$0
10
Step pulse time
$1
25
Step idle delay
$2
0
Step pulse invert
$3
3
Step direction invert
$4
0
Invert step enable pin
$5
0
Invert limit pins
$6
0
Invert probe pin
$10
1
Status report options
$11
0.010
Junction deviation
$12
0.002
Arc tolerance
$13
0
Report in inches
$20
0
Soft limits enable
$21
0
Hard limits enable
$22
1
Homing cycle enable
$23
3
Homing direction invert
$24
25.000
Homing locate feed rate
$25
100.000
Homing search seek rate
$26
25
Homing switch debounce delay
$27
1.000
Homing switch pull-off distance
$30
1000
Maximum spindle speed
$31
0
Minimum spindle speed
$32
0
Laser-mode enable
$100
100.000
X-axis travel resolution
$101
100.000
Y-axis travel resolution
$102
100.000
Z-axis travel resolution
$110
100.000
X-axis maximum rate
$111
100.000
Y-axis maximum rate
$112
100.000
Z-axis maximum rate
$120
10.000
X-axis acceleration
$121
10.000
Y-axis acceleration
$122
10.000
Z-axis acceleration
$130
200.000
X-axis maximum travel
$131
10.000
Y-axis maximum travel
$132
10.000
Z-axis maximum travel
I dont know what to change, or either by changing the settings or from the hardware
Are you wiring the +/-axis limit switches in Series? grbl assumes that if it's moving +X and Xlimit trips, it's hit Xmax, and if moving -X and Xlimit trips, it's hit Xmin, so it's expected to double up the the X+ and X- switches on the Xlimit pin.
I connected the NC terminals of the limit switches to the CNC shield.
for example for x-axis:
1 NC to the positive pin on the shield and the other to the negative
The default grbl+shield setup is for normally open switches in parallel. It is better to use NC in series, so it fails-safe, but then you need to invert the limit pins ($5) and wire the switches in series.
If you invert the limit pins and leave the NC switches connected in parallel, one or the other of the limit switches will be closed and always will inhibit detection of the other limit by shorting Limit ?-Axis.
It does not matter which of the +/- pairs you use. For each axis, the pins on the endstop headers are connected together on the CNC shield before they hook into the 3 Uno pins:
One column is grounds, and the other column is signals:
That is:
Z+ is connected internally to Z- in its silkscreened box. As is Y+ to Y-. And X+ to X-. So you need Z+ and its ground. I'll edit my wrong line above to:
the x and y axis are working properly, disconnected one i press the limit and connected when released.
however, the z axis still not working, the limit switch is normal and functional.
i connected directly the Z to the ground and the Z still didnt seem to be connected.
i tested the Z pins, the positive and negative pins of the Z are working as ground.
Is the CNC shield damaged? Or any recommended solution??
Oh, depending the shield version/clone version/grbl version/grbl configuration, the Z-stop might be on a different pin, like SpindleEnable/pin 11/pin12:
