<Feed axes and spindles>
⋅ For a failure related to feed axis servo
1) Occurred at both low feedrate and high feedrate ?
2) Ocurred only for a certain axis ?
⋅ For a failure related to spindles
When did the failure occur ? (during power–on, acceleration,
deceleration, or constant rotation)
3 What failure occurred ?
⋅ Which alarm was displayed on the alarm display screen on the
(Check the axis along which an alarm has occurred for alarms 300
⋅ For alarm 350 : What does diagnostic display 202 indicate?
For alarm 351 : What does diagnostic display 203 indicate?
For alarm 414 : What does diagnostic display 200, 201, 204
⋅ For alarm 751 or 761 : Which spindle alarm is indicated ?
(indicated by AL–XX (XX is a number))
⋅ Is the screen correct ?
⋅ If machining dimensions are incorrect
1) How large is the error ?
2) Is the position display on the CRT correct ?
3) Are the offsets correct ?
4 Other information
⋅ Is there noise origin around machine?
If the failure has not occurred frequently, the cause may be external
noise to the power supply or inductive noise on machinery cables.
Operate other machines connected to the same power line and see
if noise come from the relays or compressors.
⋅ Is it taken any countermeasure for noise in machine side?
See Section 2.14.
⋅ Check the following for the input power supply voltage :
1) Is there variation in the voltage ?
2) Are the voltages different depending on the phase ?
3) Is the standard voltage supplied ?
(10% of 24 VDC, instantaneous voltage, and ripples are
⋅ What is the ambient temperature of the controller in the cabinet?
⋅ Has excessive vibration been applied to the control unit?
(0.5 G or less during operation)
5 When you contact our service center, specify the following items :
1) Name of the NC unit
2) Name of the machine tool builder and type of machine
3) Software series/version of the NC
4) Specifications of the servo amplifier and motor
(for a failure related to the servo)