I got my hands on an old FS Laser with a broken controller. I am replacing it with a Ruida RDC6445GT5.
The laser has two mechanical limit switches on X+ and Y+, putting the home position in the top-right. They are currently wired as NO (normnally open) and the polarity is set such that they trigger as expected. Through testing I have discovered that the ruida controller only recognizes the X- and Y- switches for the homing/reset operation, so that is where I have them wired. When I turn the machine on, or do a reset the axes move towards the top-right and stop at each limit switch as expected. The homing operation works. The controller button direction polarity is also set to manually move the head as expected. So far, so good.
However, when the homing operation completes, my position is at (0,0). That is fine, but the controller seems to think I am working in the first quadrant (positive X and Y). I cannot move the position of the laser below zero (so I am stuck in the top-right corner). Either the controller needs to set the position to max for each axis when homed, or I need to be able to move negative (or something needs to be inverted?). In any case, I am struggling to use the laser after it is homed.
Summary of relevent vendor settings (same for both X and Y):
Enable Homing: True
Limit Trigger: False
Invert Keypad: True
Limiter Polarity: True (NO switches)
Direction Polarity: False (homes towards switches)
So, contrary to your (and my) burned-in knowledge, jogging the laser head toward positive coordinates like (+100,+100) moves it to a point diagonally left-and-front of the origin up there in the corner.
I am okay with that coordinate system. However with my config (direction polarity = false), positive X and Y are to the right and back. If I change the direction polarity to true, the coordinate system is as you describe, but the machine tries to home to the bottom left (away from the switches).
In my current config, the head is stuck in the top-right. The controller wont allow the head to move towards the front or left because this would be negative. Moving in the positive direction crashes the machine.
As far as I am aware, direction polarity is the only setting that controls which direction the machine will move durig the home operation. That’s why I am wondering if I am missing something.
AFAICT, that’s correct: you must set the Direction Polarity so it homes toward the switches.
The next piece of the puzzle is the Invert Keypad Direction setting, which changes which way is “positive” for both the controller’s keypad and LightBurn. You want it the other way from whichever way it is now, so that “positive” motion goes the correct way.
I worked through that mess a while ago and wrote it up so I could find it again:
I think you’re pretty close to having it work …
Oops, I didn’t properly read your initial post. For some reason I thought you were dealing with a converted CNC Machine. Carry on and follow ednisley"s direction.
I tricked myself! I got the limit switch polarity mixed up, but I had also drastically reduced the max speed of each axis for testing. The limit switches were already triggered when the homing op starts, so they start moving backwards very slowly until they physically trigger the switch to “finish” the homing op.
Long story short I had the limit polarity backwards and I tricked myself into setting the direction polarity incorrectly.
That’s controlled by the Home Offset value for each axis, which should be just enough ensure the switches are inactive when the homing operation stops.
