SP9052 (Alarm 52) ITP Signal Error (Synchronization) fault in Fanuc drive

SP9052 (Alarm 52) ITP Signal Error (Synchronization) fault in Fanuc drive

Description

SP9052 (Alarm 52) is a synchronization clock error between the CNC and the Spindle Amplifier. "ITP" stands for Interpolation Time Period. In high-speed contouring or C-axis mode, the CNC sends position commands at precise time intervals. If the Spindle Drive receives these packets out of sync with its own internal clock, Alarm 52 is generated. It implies the two CPUs (CNC and Drive) have drifted apart in time.

Cause

• I/O Link Cable: The serial cable carrying the data is picking up noise, delaying the packets.
• CNC CPU Load: The CNC main processor is overloaded (too many background scripts or complex look-ahead), causing jitter in the signal transmission.
• Drive Logic: The Spindle Drive control board's oscillator is drifting.

Solution

1. Shielding: Verify the ground clamp on the communication cable between CNC and Spindle.
2. Cable Routing: Separate the comms cable from the high-voltage motor cables.
3. Replace Drive Board: If the error is persistent and not noise-related, the Spindle Drive control card clock generator is faulty.