Machine limit issues

Before installing the Ruida 6442 and LightBurn if my machine hit a side rail or physical limit it would rattle a couple of times and stop. Now is persistent it will keep going until I hit the E-stop. Any ideas of what I could change to help?


fix the limit switch? or disable the reset of the limits on start up

+1 on fixing the mechanical problems instead of trying to solve them with software.
Do you even use limit switches?

I don’t really use them. When I first started my machine up it kept wanting to go home, so I thought I would hook them up.
I’m still not sure how they work. My home position is in the top left corner. There is a limit switch in the top right corner for the X axis. The machine goes all the to the top of the machine and triggers this switch. There is a limit switch in the top left hand corner of my machine. This is the Y axis limit switch. When the gantry goes all the way to the top left corner it stops and is home.
What happens when the gantry is in the middle of my laser and goes to the physical limit of my machine either left or right?

I’m still not sure how they work.

What do you mean? They help your machine to identify it’s position (homing). When homing the machine touches both the X and Y limit switch and then knows it’s zero. After homing they prevent the machine from destroying itself as soon as you actually hit the limit switches (controller will stop the motors and trigger an error message).

What happens when the gantry is in the middle of my laser and goes to the fisical limit of my machine either left or right?

As long as both min and max travel have a limit switch, the limit switch will be touched and this will trigger the controller which will then in turn stop driving the motors and popup a error message notifying you that it hit the limit switch.

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A hah, I only have a limit switch hooked up to x- and y-. I will have to look at my old controller and see if I can find the other 4 wires. This is what you mean by min and max travel correct?

Yes, that is what I mean. You have a max and min travel limit (also referenced as + and -).

It is always good to have these in place. Of course Lightburn will take machine size into account when defining machine limits so you should never hit them. There is a catch though. For instance if the machine loses steps it could be that you bump into a mechanical limit and might damage something.

The limit switches prevent that as an extra safety - a hardware limit before actually hitting the machine hardware limit. This also means that you should not mount them on the exact hardware limit, but a little before that. Keep some slack.

Better safe than sorry :blush:

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if your home is set correct and the size aswell (and steps) you should not need the other two limits

Don’t rely on software only.

For example when working near the side where there is no limit switch. Say you move away from the side with no limit switch and miss steps for what ever reason. When moving back to the side with no limit switches your machine can hit mechanical limits. This can happen easily when engraving with a lot of x-axis movement and something breaks or does not run smoothly.

Always use the limit switches as a backup. They are there for a reason…

Can I just jumper the wire from the - connection to the + connection?

Also should list the bed size a little smaller? Mine is 1200 x 900. Maybe go 1190 x 890.

Not sure what you mean by that?

Depends on your machine. If you have mechanical limits at 1200 x 900 then it is wise to make it a little smaller, yes.

Can I put a jumper from the X- connection to the X+ connection and the Y- connection to the Y+ connection. I think that is the way it was on the Leetro board.
Thanks for the help,

That means you are using the negative limit switch also as the positive limit switch? Why would you want to do that? If you do this, reaching the - switch will also trigger the + switch, probably resulting in the machine not being able to move anymore since both limit switches will be activated at the same time.

Maybe we should get back to the start. What are you trying to solve now? You spoke about the machine missing steps when hitting mechanical limits and in the old situation stopping because of losing steps and now we are at the point where you want to bridge limit switches, trying to solve which problem?

I’m not sure. I haven’t had a chance to go fool with the laser for a week now. I just don’t want the laser to accidentally run into a side rail and sit there and rattle while try to hurry up and hit the estop. I just have not seen any wires for other than the white and orange wire.
I am going to try and home the laser and also go through the settings tomorrow.
Thanks for all your help!

JP, I have most everything working pretty good except for my limit switches. I will try and explain where I am with pictures and some text and see if you can figure it out. I hope you have some patience with me. Here goes… the first picture is the pin out of my Leetro board

Ok. I am having trouble how to post pictures

This is a picture of my Leetro board before I moved andy wires.

Here is a picture of my Ruida control with some wires hooked up to the limit switches.The X and Y limit switches work some what.