6693

Check the system log in Diagnostics > Machine Data > MD 18000 (NCK Messages) and review the timestamp of alarm 6693 to confirm it correlates with a power event or network disconnect.

Navigate to NCK > File System and verify file integrity using the file browser. Look for incomplete or zero-byte files with recent timestamps. Use HMI Diagnostics > File Management to list directory contents and identify the lost file referenced in %1 parameter.

Do not attempt to edit or re-open corrupted files; delete and retransfer instead.

Confirm UPS (Uninterruptible Power Supply) function by checking parameter MD 30240 (Backup Power Supply). If the system lacks battery backup, recommend UPS installation to prevent mid-transfer interruptions.

Retransfer the file from the external source (DNC, USB, or network drive) using a controlled transfer with checksum verification enabled (if supported by your SINUMERIK version and DNC software).

Power down the system safely and remove the CompactFlash card (if applicable). Inspect for physical damage, corrosion on contacts, or signs of repeated insertion wear.

Ensure the system is in STANDBY or OFF state before removing the CF card; do not remove during active file operations.

Reinsert the CF card firmly and restart the system. Monitor Diagnostics > System Status for any additional file system errors or alarm repetition. If alarm 6693 reoccurs immediately on startup, the FAT is likely corrupted.

If corruption is confirmed, back up critical data (MD, SD, and part programs) via DNC or USB export before attempting repair. Use NCK Diagnostics > File System > Check Disk (if available in your control version) or replace the CF card with a new one.

Data loss is possible if FAT repair fails; always maintain external backups of critical machine configurations.

After replacing the CF card or repairing the file system, reload all necessary part programs, MD parameters, and SD data from your backup source using controlled file transfers.

Check the Ethernet connection physical layer: inspect the RJ45 cable connector at the NCK Ethernet port (typically labeled X101 or similar on 840D systems) for loose seating, bent pins, or corrosion. Reseat the connector firmly or replace the cable.

Do not apply excessive force when inserting network cables; use proper RJ45 crimping and testing tools.

Verify network parameters in Machine Data: navigate to MD 10000–MD 10100 (Ethernet/Network Configuration) and confirm IP address, subnet mask, and gateway are correctly configured. Use Diagnostics > Network Status to ping the DNC server and confirm connectivity.

Review the DNC or file transfer software log on the external PC or server for any timeout, CRC, or transmission error messages corresponding to the time the alarm occurred. If available, enable verbose logging and retry the transfer with reduced block size or increased timeout values.