Trouble with the Z endstop, crashes controller

Quick question (I hope). I got my primo machine up and running thanks to all the detailed docs and help in this forum. I used the full rambo board and bought everything from V1 so it’s all ‘standard’. I’m using the simple series wiring so no endstops on x or y as of yet…

I have the z probe and it is plugged into the Rambo but when I short the two wires to test it (connected to - and ground, not positive) it works in stopping the z axis but then it crashes the Rambo. I’ve linked an image. Does this make sense to anyone? Is the Rambo flashed with the correct firmware to work with the z probe as it is shipped from V1 or do I need to reflash it with something else?

Google Photos

Are you positive you have the probe plugged into the right two pins? It needs to be signal and ground, and not plugging into the positive pin. And the pins are offset/reversed between the two rows.

I wonder if it is trying to back off, but the connection isn’t opening, so it thinks something is broken.

You can test with M119.

Thank you both for your input. I am aware of the different orientation of the pins for zmin and zmax and I think I have it plugged in correctly. I also tested M119 and included the results in the screenshot. It reports triggered when I short the wires which (I assume) is the same as having the bit with the negative terminal attached touch the plate connected to the signal wire. I only briefly touch them together (I don’t hold them) to simulate the bit touching and then retracting so it’s not like it is remaining in the triggered state for more than a second.

Does the console show you any more details to the error? Homing failed? Probing failed? Reset?

I can only think of goofy reasons why this would happen. With the exact text, we might be able to narrow it down.

There shouldn’t be any damaging effect to holding the switch closed (or leaving the wires connected) while testing. M119 is an instantaneous command showing the current state of the limit switch, it doesn’t have any memory of how recently the switch was hit. I believe that the log in Repetier should only show “Triggered” when the wires/probe elements are actually touching. If the wires in the foreground are the test leads, I think your firmware may be set to invert the Z_min signal, as if it were expecting a Normally Closed switch. The probe functions as a Normally Open switch.

Well, I got back to the machine after work and tried it again to see if there was anymore details in the console and I could not reproduce the issue. z homing worked exactly like it should with no crashes! I’m not sure if I was doing anything different before or if it was just gremlins but I appreciate everyone’s suggestions!

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Glad to hear its now behaving itself.