Just received 6 of these form Open Builds, thank you. A few question on the wiring (again) and mounting. I have a home made plasma table with an Arduino computer interface. The usual stepper drivers for NEMA 23 motors. The labeling on the connections for the switch is GND V+ and SIG. From what I'm reading the GND is for your DC ground. In my case that would come off of my Arduino board. V+ also from the Arduino and the sig to the appropriate pin for what ever axis I'm using them for. I believe without looking are pins 12, 10 and 9. What I noticed is the plated mounting hole on the switch and therefore the metallic mounting bolt is also connected to that same GND connector on the switch. That would mean that by mounting the switch, my DC ground and my frame ground become connected together. I'd rather not do that. I've gone to great lengths to keep my control box isolated from my frame including all the shielded cabling. I'm not sure about tying the to two together by the mounting of the Xtension Limit switch. The only thing I can think of is to use a nylon mounting bolt for the switch and the included plastic spacer. Has anyone else had the same concern? Anyone have better solution for mounting the switch? The nylon screws, especially a 5mm one, is not that strong. Anyone make a small plastic box for these switches?
Did you measure? The pad surface on older revision switches (v1.1s from before 2022) was Grounded (option needed for some machines) but note the inside edges of the hole was not (it's never been a plated via). For that generation of switch you had both options: 1) Fit the switch "right-way-up" with the rubber spacer provided = isolated (Screw head touching disconnected top plate, passes through unplated hole in bottom board cannot touch GND pad, rubber spacer isolates the pad front surface from machine body) 2) Flip the switch upside down. Metal screw head can contact pad = Earthed for severe EMI situations or other use cases As of 2022 (production date, not sure when those started shipping) we did disconnect the Pad though so its always been isolated in the newer rev
Thanks for the reply. I think I ended up with option 1. For the left hand switch, I split the circuit boards apart. Placed my mounting screw thought the hole on the board without the components. Reassembled the circuits boards and tightened the screw through to hole of the other board. See the 1st picture. For the right hand side. I wanted the switches in the same orientation but flipped, obviously. Yes the mounting holes are not through plated but too close to the screw to be comfortable with. I took a Dremel tool and scrapped away part of the trace around the mounting screw hole on both sides of the component board. 2nd picture. Used the provided spacer to mount the switch on the linear rail and that worked. 3rd and 4th picture. I might take some silicone and put it on the exposed parts of the circuit board to keep the trash off them. Oh by the way, I put my oscilloscope on the SIG line to test the bounce and it was too small to measure, good job there. These switches are ver 1.6 if you were wondering.
