Ross_Hendrickson
Mon, 19 Jun 2017 01:32:11 +0000
CNC Routers

Hey, maybe someone can help me here. I have ‘slowly’ been converting a Proxxon MF70 to CNC and have a V3.0.0 GRBL Shield. I built a shapeoko v1 a long time ago and I’m a little rusty at this point but I can’t for the life of me figure out how to get my limit switches to work for homing. I’ve read the docs here (https://github.com/grbl/grbl/wiki/Configuring-Grbl-v0.9) and a few other tutorials other places.

I assumed my homing switches needed to be on the Axis + end stop lines but if I do that then Homing fails and no Hard Limit’s get triggered. (Marlin makes it much easier to see if switches are working). I have three NO switches as I thought that is what I should be using with this shield (I have NC wired ones too, if I need them).

This is the version of GRBL I am using (I will upgrade if I have to, just didn’t want to risk changing too much too quickly).

Grbl 0.9i [’$’ for help]

I have these settings set
$21=1 (hard limits, bool)
$22=1 (homing cycle, bool)

When I have the NO end stops wired into the Y-, X-, Z- places on the shield then I can trigger this.

ALARM: Hard limit
[Reset to continue]

But in either Z- or Z+ I cannot get home to work. I always end up with the below when I manually ‘pretend’ to hit Z, then hit XY by physically triggering the end stops.

ALARM: Homing fail

I am assuming there is something dead simple that I have wrong. The shield works (I can move my motors) but is not wired up to 12v or the steppers right now as I want to ensure the switches are working correctly before I try to ‘home’ the real machine. I have been using USG though I have used Chillipepper w/ this same board in the past.

Any help would be appreciated. Thanks!