I've been using my Sphinx (rails) with water cooled spindle, Blackbox & Probe for a few months. Everything worked great, always had perfect probe functionality and never any electrical problems. Then, yesterday I finally decided to add limit switches to the machine (even though it worked fine without them, I have accidentally "crashed" when jogging a couple times due to not being able to set soft limits without the ability to home). Unfortunately, this is when the trouble started... When I plug in the probe, the green lights turn on immediately indicating the probe has made contact with the spindle. To me, this means 24v GND is getting to the ground of the machine. After scratching my head with an ohmmeter for an hour or two, I have realized that the entire chassis of the machine is connected to 110v earth ground (as it should be for safety reasons with the 220v spindle wiring). But because the limit switches are also mounted to the chassis, this connects the 24v GND and the 110v earth ground, which I have read over and over in these forums is a BAD IDEA. So, why are the limit switches designed so that the screw terminal is conductive and has to be mounted to metal on the machine chassis? As soon as I remove the limit switches from the machine (keeping them connected, just not screwed to the frame) then everything goes back to working as intended. Not sure what's going on, but I'd like to be able to use the probe AND limit switches, but I'm not having any luck so far. Thanks!!
Make sure to install the included rubber spacer Also, although in some videos it shows switches installed "upside down" refrain from doing that as the bottom pad is connected to DC GND (screw head touches GND pad, and then the chassis). If installed correctly (pins down, rubber spacer on bottom, screw in from the top) it doesn't make contact
That's exactly what I just did, and it works great! I was just hoping to confirm that I wasn't bypassing a safety feature or using them in a way they weren't designed. Thanks for the quick support!
