Endstops and touch plate

Running skr pro controller. Just updated all the latest firmware.

My x/y endstops work when I click auto home but if I manually move the router around it does not stop it when triggered. Is this normal? I have read about the resistor deal on the skr pro and that seems out of my league.but I wasn’t sure if that’s even the problem since they seem to work for auto homing.

As far as the touch plate. How does this thing work. The led lights up when contact is not made which means it’s always on. Shouldn’t it be triggering when that circuit is completed?


Yes, by default, End stops are only read during the homing operation.

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Alteady answered, but yes. 100%.

Homing is the only time when the end stops are read. You could enable soft stops, which will prevent the machine from going outside of it’s work area, but this has other problems that need to be addressed if you do that. For example, Estlcam (and I’m sure many others) define X=0 and Y=0 as the lower left of the pbject to be cut, by default, but the tool must move into negative space by at least the tool radius in order to cut out the piece. If it doesn’t then it takes a chunk 1/2 the tool width out of the bottom left.

You can technically enable/disable reading the end stops at all times with M120/121 or in the firmware, but it’s probably better to not mess with that, and just make sure your job is going to stay within the bounds of the machine.

Last thing you want is some EMI or something to send a false signal or accidentally touch an endstop
and ruin a job.

You can configure Marlin to allow movement beyond the “zero” point by specifying a negative value for the location of the endstop switch. On my home-built Prusa clone, my X endstop is at -5 mm and my Y endstop is at -7. When I home the machine, then move to 0,0 it puts the nozzle perfectly at the front left corner of my build plate. I use this to allow my “prime line” to be outside my normal build envelope.

You wouldn’t need as much spare space as I’ve got, that’s just how the mechanics of my machine worked out. You just need enough “overrun” for half the diameter of your largest tool.

Of course, but it still won’t work if you use G92 codes to re-define the zero point, and if you (for example) did your CAM with the origin at the center of a big circle, it will still cause you problems when you try to go to a large negative value. Sometimes there are good reasons to do your CAM with the origin in places that are not the lower left corner. So basically it means that soft stops aren’t the answer, you must take care to place your job such that the machine does not TRY to go beyond it’s physical envelope.

Of course using workspace coordinates, soft stops will work and prevent the machine from trying, and by so doing might (but probably not) save a work piece.