When encountering the SP9019 SSPA:19 Excess Offset Current U error message indicating that there is an abnormality in a spindle amplifier component and that the initial value for the U phase current detection circuit is abnormal, it suggests an issue with the spindle amplifier’s ability to detect and manage current properly. Here’s how to address this issue:

Steps to Troubleshoot and Resolve the Issue

1. Power Cycle the Machine: Turn off the CNC machine completely, wait for a few minutes, and then turn it back on. This can sometimes reset temporary errors.
2. Check Connections: Inspect all electrical connections related to the spindle amplifier, especially those connected to the U phase. Ensure that all connectors are secure, clean, and free from corrosion.
3. Examine the Spindle Amplifier: Check the spindle amplifier for any visible signs of damage, such as burnt components or physical wear. If the amplifier is damaged, it may need to be replaced.
4. Measure Phase Currents: Use a multimeter to measure the actual current flowing through the U phase and compare it to the expected values. An abnormal reading could indicate a fault in the amplifier or motor.
5. Verify Settings and Parameters: Ensure that the machine’s parameters related to the spindle and current detection circuits are set correctly. Incorrect settings could lead to abnormal readings.
6. Inspect the Motor: Check the spindle motor for any issues, such as short circuits or open windings. An abnormal motor condition can affect current detection.
7. Replace the Spindle Amplifier: If all other checks are inconclusive and the error persists, replacing the spindle amplifier may be necessary to restore normal operation.
8. Consult Technical Documentation or Support: Refer to the Fanuc technical manuals for specific diagnostic procedures related to the SP9019 error, or contact Fanuc support for further assistance.