6620

Power down the machine and remove the NC card from the card slot on the 840D control module.

Ensure the machine is in a safe state with spindle stopped and axes secured before removing hardware.

Insert the NC card into a PC or external card reader and check the file system using Windows Disk Management or a third-party utility (HxD hex editor). Verify the boot sector and FAT table integrity.

Reformat the NC card using the Siemens-approved utility (if available) or a standard Windows format tool selecting FAT32 file system. Do NOT use quick format; perform a full format to repair corrupted sectors.

Reformatting will erase all data on the card. Backup any critical part programs or configuration files first.

Reinsert the formatted NC card into the 840D card slot and power cycle the control. Monitor the startup sequence in the Diagnostics menu (System → Storage Media) to confirm card recognition without alarm 6620.

Inspect the NC card gold contacts visually for oxidation, corrosion, or debris. Clean the contacts gently with a soft, dry, lint-free cloth. Do not use solvents that may damage the card.

Avoid touching the contact area with bare fingers; oils can cause corrosion and poor connectivity.

Test the NC card in a different SINUMERIK 840D control (if available) or in a PC card reader. If the card is not recognized on multiple devices, the card hardware is likely faulty and requires replacement.

If the card is not recognized on any device, contact Siemens Service to obtain a replacement NC card. Provide the original card's manufacturer and capacity (typically 128 MB to 2 GB CompactFlash for 840D systems).

Do not attempt to force the card into the slot or apply excessive pressure; this may cause permanent damage to the card slot connector.

Install the new NC card, power on the control, and verify in Diagnostics (System → Storage Media or Siemens Service menu) that the card is recognized and no alarm 6620 is triggered.

Access the SINUMERIK 840D Diagnostics menu (press Diagnostics on the operator panel) and navigate to System → Machine Data → MD 30200 (Card type setting). Verify the setting matches the installed NC card type (e.g., 'CompactFlash', 'CF Card', or 'Type A').

Do not modify machine data parameters without consulting Siemens documentation specific to your 840D software version.

If MD 30200 is incorrect, note the correct card type from the card label or packaging. Contact your Siemens service team to update the parameter through authorized maintenance access or restore the default configuration.

If MD 30200 is correct, perform a backup of current system data and request a firmware/card driver update from Siemens Service. Corrupted card driver files in the control's system memory may require a control module flash update.

Firmware updates must be performed by authorized Siemens service personnel to avoid system lockout.

After any configuration or firmware change, power cycle the control and monitor the startup log in the Diagnostics menu to confirm alarm 6620 is cleared and the NC card is properly initialized.