I have converted an old NC mill to full CNC by adding a quill drive. I am using gecko drivers and an 72VDC power supply. I am having a problem with the home and limit switch wires picking up noise, i can't put a wire any longer than about 6 inches even if i connect that wire directly to 5VDC.
I have the breakout board jumpered to use pullups.
I do not have any problems with any of the drives
all work perfectly at 120 IPM and the geckos send 10,000 pulses per inch.
There are three home inputs. Initially I thought the pullup from the breakout board would be enough but when I add a wire and leave the other side unconnected it is triggering the switch with a low signal, sometimes you can see the led light up on the mach3 screen so I know it's noise. Two of the motors are 7AMPS and one is a 3amp.
I was able to get it to work by adding a bypass capacitor ( .10 UF) at the input line to the breakout board.
The switches will pull the line to ground through a 2n7000 mosfet. So the wire will be free floating at the switch side perhaps that needs a pullup as well? Wires will be 8 feet maximum. Using 18ga 5 wire shielded alarm system wire.
What suggestions to you have for capacitor size or other filtering methods to look at.
My first CNC I used a totally separate mega48 to read the signals from the home and limit switches (9 of them) and feed one short wire to the gecko driver.
1/2 inch aluminum plate is grounded from the AC line plug.
I ran a ground from the breakout board to the AC ground line as well. The 5VDC power supply is a wall wart that powers the breakout board.