Problem with x not stopping when homing

The endstop issue was/is a hardware issue with the SKR Pro boards, it should not require a change in firmware. the announcement there is that the boards purchased after 10/2023 would have updated hardware and the weak end stop problem should not be happening to those any more, but it would not affect boards older than that.

That said, the actual circuit design that allowed the weak end stops to happen is unchanged, and it is possible that some issues could cause it to present again.

There were some issues with the TFT firmware, but AFAIK, the 03/2023 addressed this and it is working well.

Thanks for information. I will try TFT firmware update. I observed issue with endstop only while working with Merlin firmware (which I started to use because of other issues with TFT). If endstop issue will occure while using updated TFT, I will use external resistor solution.
Thanks for your response. Happy Easter!

Does it mean that picture by @robertbu is wrong?

No, that diagram.is correct.

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Thank you for your answer.

I performed the soldering of the resistors to my endstop pins hack. Was it kind of a pain? Yep. Did I still have issues? Nope! Jumpered Vcc to Signal on all the endstop connections.

The other thing that I did was pulled off the jst connectors plastic on the board. It appears that the connection is so much better (not loose in my case) when I plug in the endstop wires. This also probably was a reason I was having the motors not stopping when homing.

Howdy!

I just received my SKR Pro V1.2 last week. I am having this issue on all axis. The light on the board indicates that the endstop is closed but the axis keeps moving. Should I do the wire solder ?

Also, when I “home” the machine X moves in the positive direction for half a second and stops, then Y moves in the positive direction for half a second and stops, then Z moves in negative to reach zero. But as above, the endstop does nothing to stop it.

Please help :weary:

I can reply with videos if needed.

I do not have the touch sensor (touch plate, touch pad, whatever that thing is) installed

Might be better starting a new thread for your case.

With the switch entirely unplugged, the SKR Pro will think that the switches are triggered. This will result in the behaviour you describe when homing. The board logic is:

  • Move towards the axis min until the switch reads triggered. (It already is, so no motion)
  • Back off a few mm towards axis positive
  • go back more slowly towards the axis minimum until.the switch is triggered. (Again, it already is.)

The X and Y switches for all V1 machines require a normally closed switch, that is, a switch that shorts the signal to ground unless triggered. Z on a Primo requires a normally open switch, which shorts signal to ground on contact.

Another oddity of the SKR Pro 1.2 is that if you do not bend or clip the “Diag” pin on the TMC2209 drivers, the end stop switches will not work at all.

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Thank you. The pins are bent. So I should do the resistor on the wire ?

@ak47ok47 - Welcome to the Forum. As mentioned by @SupraGuy , it is always better to start a new thread (they’re free and easy to do), rather than resurrecting a months old thread. Even if symptoms seem the same, your issue may be somewhat different than is discussed in the older thread.

I’ll try to assist here

Note that the switches only work during a Homing operation. They do not prevent Move operations.

More info required:

  • Can you move all three axis correctly using the Move commands?
  • Where is the gantry/core when you start the homing? (Middle of the travel, or near the switches ?)
  • What are the LEDs showing before you press the Home button?
  • What happens to the LEDs after you press the Home button (when the axis “moves for a second”)
  • Are you testing homing on each axis individually, or are you pressing the Home button to test all three at once? (Better to try to home each axis individually)
  • Try testing each endstop individually using M119 commands. Run the command before pressing the switch, and then again while pressing and holding the switch. Ensure that the correct switch is asserted (for example, when you press X, make sure that Z1 isn’t asserted) What are the results?

The behavior that you describe (X moves first, then Y, then Z) seems odd - I don’t have my machine set up right now to test, but I thought that it would do Z first, then X, then Y. Again, do a manual Move command first (from the middle of the travel position) to verify that all axis are wired correctly .

When you say that the X and Y axis move positive for a few mm after a Home command, then stop, that sounds like what would happen if the endstops are always asserted. The controller thinks that the gantry/core is already at the home position, so it “backs off” and then it still thinks it is at the home position, so doesn’t move closer.

All in all, I think that you may have some of the endstops miswired, rather than the resistor issue described below.

That would be helpful. Please include the status of the LEDs and the results of the M119 commands.

There is an issue where some SKR boards do not properly respond to the endstop being asserted. Search the forum using combinations of SKR M119 endstop (or end stop) resistor pigtail

The issue may be intermittent, but to test, assert the endstops (one at a time) and do a M119 command. If the corresponding LED comes on, but the M119 command does not show triggered, then you probably need to add resistors (solder to board, or add a pigtail - the latter is better IMO).

If the LED is on all the time, and M119 shows triggered all the time, then you have an open circuit (check wiring).

But let’s get the issue diagnosed a bit better before you go down that road…

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No. The resistor used on the SKR Pro is used when the lights come on and the stop does not trigger. Your stops are triggering, so thst is not the problem.

The stops will trigger if you have wired the switches wrong. They should be normally closed, that is they should conduct to short ground to signal unless the switch is pressed. In this state, the light for the end stop should be dark.

They will also trigger if there is a break in the wire, or something is unplugged.

To test that the board is reading the signal properly, you can use a jumper cap between signal and ground on the SKR Pro. Do not put the jumper on the +V pin or you will damage the board.

With the jumper in place, the light should go out and M119 should report the stop “Open.” Remove the jumper, and M119 should report the stop “Triggered.”

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Thank you all, apologies for making a mountain out of a mole hill. My firmware had endstops reversed.

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Are you sure that you didn’t just have the switch wired NO instead of NC?

Howdy, I plugged it the way they came. It was easier to reverse it in the firmware than swapping the wires on the plug.

This is true, and if the machine works for you that’s the most important part.

Consider, though, that there are very good reasons to go with NC endstops instead of NO, most importantly that with NC a broken wire is immediately obvious, where with NO you are blind to it until the machine misbehaves further.