Dual Z endstop behavior: Firmware 507 Dual LR

LowRider CNC Troubleshooting
1

Problem
I have been struggling with an issue with dual Z not aligning consistently. When starting at the Z resting position, the issue is not apparent since the maxes begin at equal height. However, if the machine is reset and doesn’t quickly settle to an equal resting Z position on both sides, problems are quickly made apparent during homing.

Investigation
As can be seen below, both endstops are connected and reporting correctly when triggered.

Only Z1 triggered:
image

Only Z2 triggered:
image

However, the homing process (G28.3 Z0) is only responding to the status of the Z1 endstop:

  • The Z1 endstop halts both Z motors, regardless of Z2 position.
  • The Z2 endstop has zero effect.

I have looked through the firmware and have been unable to locate anything that appears it would address this issue, so I’m currently at a loss. Any help or insight will be greatly appreciated.

I’m tagging @jeffeb3 since he’s involved with firmware development.

2

What if you just do G28 Z? I’m not sure what the .3 does on a G28. Or the Z0.

Which ports do you have the Z2 wired into? It should be the E1 port, not the second Z port.

And which board?

1 Like
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Same result with any G28 commands. Rambo 1.4.

Oooh… Nope, I’ve been using the second Z port. I will make the change and test shortly. It’s currently in the middle of a job. I never suspected anything was wrong with that since it’s working perfectly otherwise.

4

You are the man. I assume the dual Z ports are wired as one? I guess I should have seen that coming since they conveniently placed them more closely together than the other ports. Much appreciated! I’m finally wrapping up my Lowrider 2 rebuild.

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5

Yes. On the rambo they are in parallel. In the skr, they are in serial.