Series 16/18/160/180-Model C Maintenance Manual, GFZ-62755EN ...

B–62755EN/012. HARDWARE GroundThe following ground systems are provided for the CNC machined tool:1. Signal ground system (SG)The signal ground (SG) supplies the reference voltage (0V ) of theelectrical signal system to the machine.2. Frame ground system (FG)The frame ground system (FG) is used for safety, and suppressingexternal and internal noises. In the frame ground system, the framesand cases of the units, panels, and shields for the interface cablesbetween the units are connected.3. System ground systemThe system ground system is used to connect the frame groundsystems connected between devices or units with the ground.PowermagneticsunitServoamplifierCNCcontrolunitSignal ground systemFrame ground systemSystem ground systemOperator’spanelPower magneticscabinetMachinetoolDistribution boardNotes on connecting theground systems⋅⋅⋅⋅Connect the signal gournd with the frame ground (FG) at only oneplace in the CNC control unit.The grounding resistance of the system gorund shall be 100 ohms orless (class 3 grounding).The system ground cable must have enough cross–sectional area tosafely carry the accidental current flow into the system gound whenan accident such as a short circuit occurs.(Generally, it must have the cross–sectional area of the AC powercable or more.)Use the cable containing the AC power wire and the system goundwire so that power is supplied with the ground wire connected.127