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Endstops problem

This is my first post so - Hi everyone. I am Lukas

I have a K40 with ribbon cable and opto endstops. I connected everything according to the instructions but I have no reaction to endstops. In the lightburn console I do not have "Pn: XY" status. I tried to change the 24V power supply because I suspect groundloop. No effect. I checked if the voltage is transmitted to the endstops and is 5V. I read the Troubleshooting Guide but it also did not help me. M2 nano works correctly.

any ideas?


sorry for my English 😉

Hi, If you have opto limit switches, please ensure that they receive their 5V power supply.

The connections on the break out pins are from left to right: GND, Y limit, X limit, GND, +5V.

Manually set the Gantry in the zero positions and measure with a multi meter (in Volt-measure setting) on the breakout pins if you get a signal. Maybe post some photo's too?

Cheers, Paul awesome.tech

I used a multimeter and I measured Y and X endstop pins. 5V voltage is on endstops. The voltage in the zero positions on the X and Y pins is 0.15V. With open endstops on the pins is 0.05V.

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Hi Lukas,

Just to confirm the measurement process - the attached diagram shows you should be measuring limit switch voltages between ground and X, and ground and Y pins on the Mini Gerbil connector J5.

For a K40, the limit switches are Normally Closed (NC), so when the gantry is away from home position, the X and Y pins should each measure around 5V relative to ground.

When the gantry is in home position, the X and Y pins measure approximately 0V.

Can you confirm the above please ?

I can see you're doing some work on your laser: just wonder if any of the following basic issues could apply:

a  If your voltages are the other way around to the above description, make sure the limit switches are connected by their NC and common contacts, instead of NO and common.

b  Check that you haven't mis-wired X and Y to eachother.

c  With Mini Gerbil turned off, use a multimeter to check continuity (no break in your wiring) between Mini Gerbil pin X, and the end of the wire connecting to your X limit switch.  Then repeat for Y.  You should temporarily remove the connection to the limit switch when checking continuity so we can be 100% sure it's not backfeeding through the switch.

Once you confirm the above, we'll go from there !


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