8040

Access HMI menu: Diagnostics > Machine Data > MD table. Identify which MD parameter was reset by checking the alarm message parameter %1 (e.g., MD20050 for axis assignment, MD32100 for kinematic options).

Cross-reference the reset MD with Siemens option requirements documentation. Common option-dependent MDs include MD20100 (AXIS_TYPE), MD32010 (KINA), MD33000 (FEED_ACTIVE_AXES) for 5-Axis functionality.

In Diagnostics > Service > Options, verify the installed option keys match the required feature set. Contact Siemens if the license key for the required option is missing or expired.

Do not manually force-set locked MDs; the NCK will reset them again on next startup.

If option is confirmed licensed, trigger a full NCK data reload: Power cycle the control and force a parameter refresh via HMI > Service > Reset Machine Data (if safe). This resets the alarm state and reloads option flags.

Check the NCK event log (Diagnostics > System Info > Event Log) to determine when the MD was last modified. Note the timestamp and compare against recent commissioning or parameter backup restoration activities.

Review the MD that triggered the alarm and check its dependency list in the SINUMERIK 840D/810D Parameter Manual. Verify if it requires a specific option (indicated by 'Option' column in MD reference table).

If the MD modification was intentional, acquire and install the corresponding software option license. If unintentional, revert the MD to its factory default by clearing the value or restoring from a known-good backup via Automation > Backup/Restore.

Backup current machine data before restore operations to avoid loss of other valid custom settings.

After correcting the option/MD mismatch, perform an NCK cold start: Diagnostics > Service > Reset Machine Data (if authorized) followed by power-cycle to clear alarm 8040.

In HMI > Automation > Backup/Restore, check the date and source machine of the last loaded machine data file. Verify it matches the current control's hardware and software version via Diagnostics > System Info > Software Versions.

Compare the option string from the source machine (noted in backup metadata) against the current machine's installed options in Diagnostics > Service > Options. If options differ, the backup contains incompatible MD values.

If the backup is outdated or from a different machine model, do not restore it. Instead, manually re-enter necessary custom MD values on the current machine after confirming they are compatible with the installed option set.

Never force-load a backup from a machine with different hardware generation (e.g., 840D to 840D SE) without Siemens validation.

Create a fresh, validated backup of the current machine after all custom MDs are correctly set and alarm 8040 is cleared. Label the backup with control model, software version, and installed options for future reference.