Homing switch’s

[rob75uk]

Hi folks my machine is all together and all motors are working and going in the right direction when I manually move machine with gcode platform v2 , I now could do with advice on how to set my homing switch’s within the program ?

[Derek the Admin]

I think you might misunderstand there use a bit.

Here is a comprehensive video that will cover these concepts:
www.youtube.com/watch?v=61FNml8M3i0

[rowiac]

Under the Common Actions tab in UGS, you can hit Home and the machine should move toward each of the limit switches--Z first, then X and Y simultaneously. The firmware is set up to sneak up on the switches and then back off about 4mm.

[Bruce]

By default, the homing cycle goes through the following steps:

The GRBL settings are shown with the settings for the Power Route.

Z axis:
Z Axis will move up (positive) with Fast Rate ($25=800.00)
When Z home switch triggered, Z stop for a short time ($26=200) and back off a distance ($27=4.00)
Z Axis will move up slowly util it touches the Z home switch again ($24=35.00)
Z Axis backs off a small distance ($27=4.00)

X and Y axis:
X, Y Axis move both to Homing direction at fast rate ($25=800.00)
The first Axis triggers the switch will stop and wait for the second axis to trigger
When second axis triggers the switch, both axis back off a distance ($27=4.00)
Both X and Y axis will move toward switches again slowly, until both switches triggered again ($24=35.00)
Both X and Y axis will back off a small distance ($27=4.00)

Homing speed:
As described above, homing is done in two distinct phases per axis: feed and seek. The feed speed is controlled by setting ($25=800.00). In this phase, GRBL is just trying to find the limit switch within a reasonable amount of time.

After the feed phase, the seek phase does exactly the same thing, but at a low speed, controlled by setting ($24=35.00). This phase is all about accurately finding the trigger point for the limit switch.

Homing travel:
GRBL will give up searching for a limit switch after 1.5x the max travel distance. The max travel distance is controlled by $130=632.00, (for x), $131=626.00 (for y) and $132=128.00 (for z). These numbers are also used for soft-limits, and should be set slightly below the length of your axes.

After the feed phase, the axis moves back a little, to un-trigger the switch. This distance is controlled by setting $27. Set this number high enough so the limit switch is cleared, even when the feed phase overshoots.