140-0002

Locate storage media

Open the TNC control cabinet or front panel to access the CompactFlash (CF) or SD card slot. On TNC 320/530 models, this is typically behind the front panel. On TNC 620/640 models, check the rear electronics compartment.

Check write-protection switch

Examine the CF/SD card for a physical write-protection slider switch. On CF cards, this is typically on the side. On SD cards, it is on the left edge. Ensure the switch is in the unlocked position (opposite of 'LOCK' marking).

Power down the control before removing or manipulating storage media to prevent file system corruption.

Verify write capability

After ensuring write-protection is disabled, power on the control and attempt the configuration save operation again. Navigate to MOD > System Files and try creating a test file to confirm write access.

Check available disk space

Press MOD key, select 'System Files' or 'File Manager'. Look at the partition overview (typically shows TNC:, SYS:, etc.) and check the free space displayed for each partition. Configuration files are typically stored on TNC: partition.

On iTNC 530 and later, you can also check space via Settings > General > System Information.

Identify large files consuming space

Navigate through directories looking for large NC programs in TNC:\NC_Programs\, old backups in TNC:\backup\, or excessive log files in TNC:\system\log\. Sort by file size to identify candidates for deletion.

SysLog files can grow to several hundred MB over time. These can be safely archived or deleted if older than your required retention period.

Free up disk space

Delete or archive unnecessary files to external media. For NC programs, use the 'Copy to network/USB' function. Ensure at least 50-100 MB free space remains for system operations and configuration files.

Never delete files from SYS: partition or files with .SYS, .DLL, or .EXE extensions unless directed by Heidenhain service.

Retry configuration save

After freeing sufficient space, attempt the original configuration write operation that triggered the alarm.

Check file system status

Navigate to MOD > System Information or view system messages during boot. Look for messages indicating 'read-only' file system or file system errors. On TNC 640, check the System Health display.

If you see 'mounted read-only' messages during startup, this confirms file system protection is active.

Perform controlled shutdown and reboot

Execute a proper shutdown via MOD > Shutdown or the power button menu. Do NOT use emergency stop or main power switch. After complete shutdown (display off), wait 10 seconds and power on normally. This may clear transient file system locks.

Boot into Service Mode

During power-up, press and hold the CE (Clear Entry) key and Z key simultaneously when the Heidenhain logo appears. This boots into service mode where file system utilities are available.

Service mode provides low-level access. Only proceed with file system checks if you are trained in Heidenhain service procedures.

Run file system check

In Service Mode, select 'File System Check' or 'Check Disk' utility. Allow the system to scan and repair file system errors. This process may take 5-20 minutes depending on disk size.

Document any errors reported during the file system check for Heidenhain service if repair fails.

Test normal operation

After file system check completes, reboot normally and attempt the configuration write operation again. Verify via MOD > System Files that you can create and delete test files.