52 ALARM — ITP SIGNAL ERROR I

Turn off the machine power. Inspect the serial communication cable connecting the CNC to the Spindle Amplifier. Ensure the connectors are securely seated and check the cable for any physical damage or broken wires. If the cable is damaged, replace it.

Check the routing and shielding of the serial communication cable. Ensure it is not bundled together with high-voltage motor power cables and that the shield is properly clamped to the frame ground to prevent electrical noise from disrupting the ITP signal.

Turn the machine power back on. If the alarm is cleared, the error may have been caused by transient noise or a temporary communication glitch. Monitor the machine during operation to see if the alarm recurs.

If the alarm persists, the internal control printed-circuit board of the Spindle Amplifier is likely failing to receive or process the ITP synchronization signal. Replace the Spindle Amplifier control printed-circuit board.

If the control board replacement does not resolve the alarm, the Spindle Amplifier module itself may have a severe internal hardware failure affecting serial communication. Replace the complete Spindle Amplifier module.

If replacing the Spindle Amplifier does not resolve the alarm, the fault lies within the CNC side failing to send the ITP signal. Replace the CNC board or module related to the serial spindle communication.

If none of the above steps resolved the alarm, contact an authorized FANUC service representative.