
3.INSTALLATION B-63943EN/02
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3.5.3 Connecting the Signal Ground (SG) of the Control Unit
Connecting the 0 V output in the CNC to a protective circuit (ground)
The IEC 204-1 and JIS B 6015 standards specify the following:
- Protection against malfunctions due to ground faults
“To make the control circuit prevent malfunctions of a machine tool
due to a ground fault and not to prevent the machine tool from
stopping, either of the ground and electronic circuits shall be
connected to a protective circuit.”
Note that for each FANUC CNC, the 0V output in the CNC is
connected to a protective circuit (ground).
Machine
24 VDC power
supply
Relay
Power
magnetics
cabinet
Output
signal
NC ground terminal
Machine protective circuit (ground) network
Connection to the ground in the user factory
This bold line indicates grounding for the control unit described in the connection manual.
s shown in this figure, by just connecting the ground terminal of the control unit to the machine ground,
the 0 V output of the relay circuit in the power magnetics cabinet is connected to the ground (protective
circuit).