Hi all,

After reading many posts about how to ground (0vdc) and earth correctly I discovered that my CNC has something estrange so I would like to ask a question. to prof

My PC has the parallel port "jacket" connected to 0vdc from the power supply (there is only earth connection into the ATX power supply).
The CNC controller has the parallel port "jacket" connected to earth and some pins connected to his own 0v.

Obviously when I connect the PC and CNC controller with parallel cable I'm connecting the ground (0v) and earth together and I have read that it is not good practice (some power supplies have an internal resistor to "rise" the ground (0v) level over earth to make it cleaner from noise).

THE PROBLEM: I discovered I was losing steps in Z axis when I was milling and checked that this happens when the spindle goes close to the z stepper. Only loses few steps normally but for long works it is notable due to the total z distance lost.

Does someone know if the ground+earth could be the problem?


Thanks al ot in advance.