Ruida 644XG Homing Issue

Hi so I’ve searched through a lot of old threads to answer my questions but haven’t found one specific to my issue. I bought a used 90w Omtech and long story short its had tons of issues. I’ve got a lot of them fixed but one is way over my head.

So when I turn the laser on it moves to the upper left corner. The Y limit switch lights up and works. The X limit switch lights up but then makes a couple grinding sounds (not really loud like a crash) and then the laser head moves to the middle of the bed (I think it goes to the position of my last job in Lightburn). Anyway this hasn’t been a issue for months because everything seems to work fine when I cut and engrave, etc. But now I want to install a camera and I see there is going to be an issue. I did a few tests: I cut a rectangle to the perimeter of my bed size and a little square in the middle. Then I turned off the laser, turned it back on and did the same cut. So the result was that the buttom and top line (controlled by Y gantry) cut on the exact same spot, but my left and right lines moved to the right by a quarter inch. So my guess is that my X limit switch is not working so the positions it gives as home is different every time I turn the laser on. Obviously this will be an issue if I try to install a camera because X coordinates would change every time I start up. What can I do to fix this problem? The limit switches are PL-05N and I have Ruida 644XG

Thanks for the help!

You can check the switch on the controller very simply.

The machine needs to be powered up. You can do that by power on, then keep pressing the ‘esc’ key on the console, it will abort the home operation. I have the same sensors.

Any ferrous metal will trigger the hall sensors, like a metal screwdriver. When the sensor goes active, it will pull it’s output low (sinks current.) It’s probably pin 4 of CN4 on your Ruida.

Screenshot from 2021-10-27 18-32-17

The output of the X limit pulls the LmtX- pin low when it becomes active. I’m guessing that you have a broken sensor or wire. Of course it’s the one that goes through the drag chain :sob:

That should give you a good idea of what’s happening.


According to your description, you used a faulty proximity switch on the X-axis hill, which caused the device to make a sound when you went back further
I have a video here for you to check if your X-axis mountain proximity switch is good
Processing: 830a89029c44fb6617fa32e7b61e2938.mp4…

Thanks for the help. For some reason your video link says “Processing” and wont allow me to click on it. Do you think you could send me that again please? Thanks

Do you have a voltmeter?

You will have to power it up to check that sensor.


The video file may be too big, I have sent it to you by email

Do you have anything like ‘google drive’?

You can put it there.

Right click, set access to ‘anyone with the link’ and copy link.

Post the link here…


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