Wiring optical endstops with an Fysetc E4

after successfully building my MPCNC I have begun to build my ZenXY. Everything is going perfectly so far

My Table is working but I don’t know how to wire the 3pin optical end stop with my Fystetc E4.

I would be happy about some help


Welcome Timo!

I don’t have any advice for you but I wanted to hello!

Thank you Dusty.

I’ve got it wired up and working.
But still two problems.
First is the very jerky stuttering motion, no matter whether slow or fast.

But the bigger problem is, that my build looses its position suddenly resulting in a wrong track and overshooting the limits of the machine.

I really don’t know what the problem could be.

The jerky motion probably has something to do with the magnet, the ball, or the sand. Have you tried baking soda as the medium? Can you post a video somewhere and drop a link in here? What is the distance from the ball to the magnet?

The losing position could be a couple of things. The first thing I would check is the grub screws holding the pulleys on the motors. There really shouldn’t be much resistance at all in a ZXY. So it shouldn’t be skipping steps like that. Even at low motor current.

Hi Jeff

I’m using backing soda. I bought Natron (Natriumhydrogencarbonat) because Baking Soda in Germany is often Baking Powder which has more than one ingredient.
I have uploaded a video of the movements.
The distance from the ball to the magnet is about 3,5mm.

The loosing position.
The pulleys aren’t loose.
Maybe it is the tension of the belt. It is very tight.
The other idea I had is maybe this screw?

The screw cannot be tightened so the belt can probably move.

Just a moment ago I laid under the table and watched the movement from there, after loosening some screws and the belt a little bit.

I noticed a gentle “bang” which ist reproducable.
It’s the same movement from a slow to a faster part of the pattern.
I can’t find the source of the noise but this could be the problem. I assume it comes from the X Power Corner when only Y is moving and then X starts again moving.

I found this thread which sounds like a similar problem.

Any ideas how to troubleshoot?


I had a second closer look and can see a strange movement after a few minutes where everything worked fine.

Then suddenly where a 90degree angle should be there are two 45degree movements resulting in a shifted pattern.

Here is the video

Baking soda in the US is “Sodium Bicarbonate”. I am assuming that is the same thing, although it looks a little different. I prefer a lot less medium. I like the ball to be driving over the sand like a bike tire would climb a curb:

CoreXY moves both motors to make a movement that is only in X or only in Y. If one motor stops, then it can only move in a 45 degree direction. I think that is related, but I can’t figure out exactly how. Something definitely seems like it is binding, which is causing that corner to get cut short, and once it skips (the hard click you heard), it won’t find it’s way back. The skipping steps isn’t bad on the steppers, it is just the magnets aligning with the next magnets in the motor. But it sounds like a skipping gear.

The first thing I would try is to just set the min/max work area to something smaller. Instead of 0,500 and 0,500, try using 10,490 and 10,490. If you can run a full pattern without any problems after just removing the border, then you have a working machine and the binding is an optimization. Next, I would try making manual movements in that corner. First by just unplugging the machine and manualy moving it in that corner to see if you can feel what is binding. You can also try jogging the machine under its own power. Be on the lookout for loose wires too, although the motors don’t move on the ZXY, so I don’t know how the wiring could get loose.

Thank you for your reply.

Yesterday evening I laid under the table and watched the movements for half an hour
I noticed during X movements that one side of the gantry moves slightly earlier than the other side.
This could cause jamming the truck on this side for a short moment.

It looks the same when I push or pull only one truck manual and the other would move because of the gantry connection.

So I try to tighten up the belts much more.
I don’t know how tight the belt has to be but now the belt is making a sound like a guitar string.

Now both trucks move together immediately during an X movement. It seems that this eliminates the problem because I could draw a small pattern without problems but I will have to test it more today.

So how tight should the belt be?