I have a Omtech Polar laser cutter that uses the RDC6442S (panel added to it). I’ve been attempting to add an autofocus switch. I was able to wire up the switch to a z-axis limit, set the polarity, and get it to work as expected when I press run the ‘Autofocus’ command from the panel.
However, now, when I turn on the device, it autofocuses the z-axis down instead of homing the z-axis upwards. If I disable homing (via lightburn machine settings) for z-axis, the whole axis is disabled (including autofocus).
Does autofocus always just run the z-axis homing or can the two work in different directions with different limit switches? Or is it possible to disable startup homing but still keep the z-axis & autofocus on?
As far as I can tell, for Ruida systems, autofocus does exactly the same as auto-home does, which is to search for a Z- limit switch by moving in a Z negative direction and then set Z=0, the only difference is that autofocus is like a home followed by a secondary move to the ‘Focus Distance’.
If you changed the direction polarity then your Z movement will be in the opposite direction but from the controller’s perspective - homing and autofocussing will still be in a Z negative direction and searching for the same Z- limit switch. I’m guessing that you piggy-backed your new focus switch off the Z- limit switch wiring which would have been at the top if that’s the direction it was previously homing towards.
I don’t have that machine, but I’m guessing that if you now manually jog the head upwards (you may have to use the down-jog button to do this) it will hard-crash? since the controller will be will be now be waiting for and not finding a Z+ limit switch signal. If that is the case, I would recommend that you switch the wiring inputs for Limit Z+ with Limit Z- and this will mean you will have to piggyback your new autofocus switch off the bottom switch instead, which could remain in place as a backup to stop you from bottoming out if the autofocus switch failed.
You should be able to do this, I did test this on a Ruida RDC6442G controller I have and if you leave ‘Enable Homing’ enabled in LightBurn machine settings, but then use RDWorksV8 software to access User>Auxillary settings and set ‘Auto home z’ to ‘No’, that should stop the Z-homing on startup/reset.