
8. TROUBLESHOOTING
B–64115EN/01
476
An error occurred in the communication between the serial spindle
amplifier (SPM) and the CNC. The probable causes include:
D Contact failure of the connection cable
D Defective printed circuit board on the CNC
D Defective spindle amplifier
D Noise
Check that the cable connecting the serial spindle amplifier (SPM) to the
CNC is in contact.
Check that the cable is inserted firmly into the connectors and that it does
not have any conductors likely to be cut off.
Check that the cable used is a twisted–pair cable and that it is connected
as described in the connection manual.
A spindle control circuit for the CNC is installed on the main board. If
this alarm is issued, replace the main board.
When an error occurred on the spindle amplifier module (SPM) side, a
code of A, A1, or A2 is indicated on the SPM depending on the nature of
the error.
In this case, take appropriate actions in the Maintenance Manual of your
servo motor.
If any of the above actions does not solve the problem, examine the noise
environment of the connection cable.
See the section on the measures against noise, take appropriate actions
such as the reinforcement of the cable shield and the separation of the
cable from the power line.
8.21
ALARM 749
(SERIAL SPINDLE
COMMUNICATION
ERROR)
Causes and actions
D Connection cable
D Printed circuit boards on
the CNC
D Spindle amplifier module
(SPM)
D Noise environment