Dual End Stops Not Stopping Machine

First of all, thank you so much for this great project. I just jumped into 3D printing back in December and the MPCNC parts is one of the first things I printed. I saved up for the kit and I’m putting it together this week. the MPCNC is an awesome project and I’m excited to get it running!

So I have everything assembled and wired up. It is working well. I haven’t cut any wood yet but I just did some pen/marker tests last night. The crown test came out pretty good. Dimensions and everything seem good so far but I’m going to run some more tests later.

However, my question pertains to my end stops.

  • My work area is about 24"x48" (yes I know this is a little bigger than recommended but that's okay). It looks sort of messy in the photo - the kit wiring isn't quite long enough for my build so I had to order another set to extend it (should be here tomorrow).
  • I purchased the MOSTLY PRINTED CNC PARTS BUNDLE with the full size RAMBO and duel end stop kit from Ryan.
  • I'm operating it with a Raspberry Pi B3+ over WiFi, using v1Pi & CncJs and I am able to control the movement with no problems.
  • I followed the directions here (https://www.v1engineering.com/auto-square-dual-endstops/) to wire up the end stops.
  • I can poll the status of my end stops using M119 and everything reports correctly. They are wired normally closed as they should be, and if I activate one of the limit switches and check the status again, it will report correctly as triggered. I tested them all and they report as expected.
The problem I'm having is that if I activate a limit switch while my gantry is moving, it doesn't do anything to stop the movement. What am I missing here? Shouldn't opening one of the limit switches on the X axis make the X axis stop moving? Or did I miss a step? They seem to be reporting status correctly but not actually affecting the movement of the machine.

Let me know if I’m not making sense, and if any other photos would help. I appreciate any help anyone can offer!

NOTE: The overall view photo of my machine was taken before I mounted the end stops. They have since been mounted as seen in the close up photo (I realize they are on the outside of the bracket, vs. the inside like Ryan had in his example, but that is because I wanted to still use the quick connect wires and they wouldn’t fit next to the bearing. This isn’t causing the issue I’m having).

No they are not limit switches they are set only as active for homing, if you want them to always be active you can set that in the firmware but you risk ruining a lot of projects as they can pretty easily get mistakenly triggered.

Thank you for your reply! You’re right, I got them working with homing XY and I’m happy with that. I thought I was doing something wrong but I guess not - thanks!

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Wouldn’t mounting the switches to the frame/rails mitigate this as then the switches are not moving with the cutting head?

Nope, Spindle, vac, refrigerator line noise can trigger it as well as curious/ panicked hands trying to stop a cutout from breaking a bit.

You should always be watching the router, there is no need for this kind of limit switch.

Fair point :slight_smile: