This should clear it up. http://gnipsel.com/linuxcnc/configs/7i77.html
JT On 4/7/2017 3:47 PM, Todd Zuercher wrote: > I was going to start working on putting a tool touch probe on a machine with > a Mesa 7i77 setup. > (I was just going to try a wire clipped to the tool and a touch plate for a > start.) > I pulled out the multi-meter and started poking around to try to figure out > what exactly I wanted to do and noticed something odd. I checked the V+ to > ground and it read 0v and V- showed -12v. > My field power is suppied by a simple 12v switching power supply (wall wart). > I don't see any obvious place where the 12v power is referenced to ground > (positive or negative.) Might this be normal? Would It cause a problem if I > tried to connect the V- to ground (such as short out the 12v power supply)? > Is this a symptom of another wiring problem somewhere (a short to ground > hidden somewhere.) > Which side should I use for the spindle/tool wire clamp the field power or > the input pin? (the spindle does show a little resistance to ground) > Should I put any resistors in line to help protect from short circuits? ------------------------------------------------------------------------------ Check out the vibrant tech community on one of the world's most engaging tech sites, Slashdot.org! http://sdm.link/slashdot _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
