
B-65150E/04 4. SERVO FUNCTION DETAILS
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(4) Detailed operation
Suppose that there is a machine (with the FANUC CNC) having
horizontal and vertical axes of motion. When a servo alarm(*) occurs
on the horizontal axis but no error occurs on the vertical axis, the
MCCs of the amplifiers for all axes are turned off. When the
emergency stop button is pressed, the MCCs of the amplifiers for all
axes are turned off.
Standard machines have a mechanical brake that prevents the tool from
dropping vertically in such cases. The mechanical brake may actually
function according to the timing shown in Fig. 4.10 (d). If this occurs,
the tool will drop vertically, causing the tool or workpiece to be
damaged.
Fig. 4.10 (d)
Delay
The tool drops vertically.
(Td)
Alarm or emergency
stop signal
Mechanical brake
Servo amplifier
MCC off
*ESP signal to PSM (+24 V)