7151
General Mach Discussion / Re: System grounding questions
« on: April 12, 2011, 03:14:25 AM »
Ideally the Earth and Ground should be treated as two separate circuits.
For obvious reasons all exposed metal parts must be bonded to Earth and this circuit must be regularly tested under health and safety regulations in industry so it makes sense to regularly test the circuit in home shop installations as well.
The Ground (GND) is the signal common return and as there are many signals then the associated GND's should ideally be connected a at one common point at the controller end only. It is important to avoid GND loops and if you are using the PC parallel port then the LPT screen should only be connected at the PC end and the internal wires 18-20 connected via the breakout board to the common GND point. It may also be prudent to use screened / shielded cable for all external wiring runs just to avoid the possibility of future problems.
In the real world this is not always possible but Earth loops and Ground loops are often the source of unwanted electrical noise so avoid them if you can.
Tweakie.
For obvious reasons all exposed metal parts must be bonded to Earth and this circuit must be regularly tested under health and safety regulations in industry so it makes sense to regularly test the circuit in home shop installations as well.
The Ground (GND) is the signal common return and as there are many signals then the associated GND's should ideally be connected a at one common point at the controller end only. It is important to avoid GND loops and if you are using the PC parallel port then the LPT screen should only be connected at the PC end and the internal wires 18-20 connected via the breakout board to the common GND point. It may also be prudent to use screened / shielded cable for all external wiring runs just to avoid the possibility of future problems.
In the real world this is not always possible but Earth loops and Ground loops are often the source of unwanted electrical noise so avoid them if you can.
Tweakie.