8082

Perform a full Power ON cycle (disconnect 24VDC supply for 10 seconds minimum) to reset the NCK license key attempt counter. This clears the internal lockout flag and allows three new authentication attempts.

Do not use soft reset or emergency stop; a hard power cycle is mandatory.

Access the License Key entry screen via HMI: Navigate to Diagnostics > System Information > License Management (path varies by HMI version: SINUMERIK Operate, SINUMERIK Run Advance, or 840D classic panel).

Verify the license key format and characters against the official Siemens license documentation. SINUMERIK 840D license keys are typically 16-32 alphanumeric characters. Check for transposed characters, O/0 (letter O vs. zero), I/1 (capital I vs. one), or case-sensitivity errors.

License keys are case-sensitive in most SINUMERIK versions.

Re-enter the license key character-by-character carefully. If the alarm recurs three more times, contact Siemens support with the machine serial number and request a replacement or verification of the license key from the original order documentation.

After power cycle, check the NCK diagnostics to view the currently stored license key. Access via Diagnostics menu or use SINUMERIK parameter read: Query MD 18000 ff (License Key Status) in the Setup or Diagnostics screen to determine if the key is readable or corrupted.

Compare the stored license key displayed against the original documentation. If the key appears truncated, contains unusual characters, or shows as 'invalid,' the NVRAM entry is corrupted. Do NOT attempt re-entry; proceed to Step 3.

Do not power cycle repeatedly without clearing NVRAM; this will exhaust the attempt counter permanently until factory reset.

Clear the NVRAM license key area using Siemens service software (e.g., SINUMERIK Operate 'Clear Settings' or SINUMERIK HMI Backup/Restore function). This requires access credentials (typically service level password). Alternatively, contact Siemens Field Service for NVRAM restoration if the HMI does not provide a clear option.

After NVRAM clear, perform another full power cycle and re-enter the correct license key from official Siemens documentation, verifying the firmware version and machine ID match before entry.

Verify the current NCK firmware version and machine ID. Access Diagnostics > System Information and note the SINUMERIK version (e.g., 840D sl, 840D Plus) and NCK build number. Cross-reference against the license key documentation to confirm the key was issued for this version.

Check MD parameter group 10000 ff (Machine Identification Data) via Setup > Parameter > Machine Data (or SINUMERIK Operate settings view) to view the encoded machine ID, options code, and feature set. Compare against the license key specification sheet provided by Siemens.

Modifying Machine Data without proper authorization may void support contracts.

If the firmware version or machine configuration has been recently updated (new NC version, option modules added, or hardware upgraded), contact Siemens licensing to request a new license key tailored to the updated configuration. Provide machine serial number, current firmware version, and list of active options.