Signal ground system
Frame ground system
System ground system
Machine toolOperator’s panel
Notes on connecting the ground systems
Connect the signal ground with the frame ground (FG) at
only one place in the CNC control unit.
The grounding resistance of the system ground shall be 100
ohms or less (class 3 grounding).
The system ground cable must have enough
cross–sectional area to safely carry the accidental current
flow into the system ground when an accident such as a
short circuit occurs.
(Generally, it must have the cross–sectional area of the AC
power cable or more.)
Use the cable containing the AC power wire and the system
ground wire so that power is supplied with the ground wire