6650

Power off the CNC machine safely using the main disconnect switch.

Ensure spindle and all axes are at rest before powering down.

Locate the NC memory card in the 840D control cabinet. Identify the small physical write-protect switch (lock tab) on the side edge of the CompactFlash or SD card.

Do not force the switch; it should move freely with gentle pressure.

Slide the write-protect switch to the UNLOCKED position (typically away from the card edge). Consult the card manufacturer's documentation if labeling is unclear.

Reinsert the card firmly into the CF/SD slot on the 840D control and power on the system. Verify alarm 6650 is cleared and write operations to the card are now permitted.

Access the 840D control panel and navigate to Diagnostics menu (typically via HMI/keyboard: DIAG or Diagnostics softkey). Select 'Parameters' and search for write-protection related MD parameters (commonly in the 10xxx range for general machine data or 30xxx for memory management).

Look for parameters such as MD10500 (Card Access Rights) or equivalent memory protection settings. Check if the parameter value contains a lock flag or protection bit set to '1' (enabled). Document the current value before making changes.

Some systems may require a specific operator password or service-level access to modify protection parameters.

If a write-protection lock bit is found, set the parameter to '0' (disabled) or modify the access control value to permit write operations. Confirm the change and allow the control to update its configuration.

Do not blindly modify MD parameters without understanding their function; incorrect settings can cause machine malfunction.

Power-cycle the control or press 'Reset' on the operator panel to apply the parameter change. Verify alarm 6650 no longer appears when attempting to write to the NC card.

Back up all critical NC programs and machine data stored on the card to an external storage device or to the control's internal memory via HMI Program menu.

Reformatting the card will erase all data; ensure backups are complete and verified before proceeding.

Access the 840D HMI menu and navigate to System > Memory Management (or similar path depending on your control version). Select the option to Format or Initialize the NC card. Select 'Full Format' if available to clear all protection attributes.

Full format takes longer but ensures all file system protection flags are removed.

Confirm the format operation on the HMI. The control will rewrite the card's boot sector, file allocation table, and initialization parameters with default (unprotected) settings. Wait for the operation to complete.

Restore your backed-up NC programs and machine data to the newly formatted card. Test write operations by downloading a small test program to the card and verify alarm 6650 does not recur.