SINUMERIK 802D Alarm 1002 System Error 350010: MDA Mode Recovery

Overview: SINUMERIK 802D Alarm 1002 and System Error 350010

The SINUMERIK 802D power line is a Siemens compact CNC platform designed for entry-level turning and milling machines, pairing a numerical control unit (PCU) with a digital drive section. Under specific conditions, the controller raises Alarm 1002 "System error 350010" and refuses to accept operator input, save modified blocks, or delete part-program lines. The alarm is generated by the NCK (Numerical Control Kernel) when an internal consistency check fails in the channel-specific runtime data structures used for the MDA (Manual Data Automatic) interpreter buffer.

Alarm 1002 is a generic NCK system-error wrapper. The trailing 6-digit hexadecimal code (in this case 0x350010) is the precise fault signature that identifies the affected internal sub-system, in this instance the MDA save/load path between the NCK working memory and the persistent flash file system on the PCU. Because the same interpreter buffer is shared with program editing, the side effects cascade to block deletion, file save, and any write that touches the active MPF / SPF working set.

The good news is that the condition is recoverable in the field. JOG and AUTO modes continue to execute because they use the part-program interpreter that runs from already-committed NC memory. Only the MDA editor and its associated save path are affected. The fix path is to reload user-saved data from the commissioning backup set, perform a default-data reset if the user save is not clean, and, when the issue persists, reinstall the system software from a Siemens 8 MB PCMCIA card using the FFS / SinuCopy tooling.

System Identification and Affected Versions

Before applying any of the remediation steps below, capture the full version data block from the SINUMERIK 802D so you can request the correct software build from Siemens regional service. On a 802D power line the version data is read out as follows:

1. Press SYSTEM on the operator panel.
2. Press the horizontal softkey Version.
3. Press the vertical softkey Version data.
4. Capture the displayed block (use PRINT or transcribe manually).

The reference machine that triggered the original report returned the following identifying data:

The MLFB 6FC5610-0BA10-0AA1 decodes as a SINUMERIK 802D power line controller with two feed axes and one spindle. The BA10 segment in the MLFB identifies the controller class and the 0AA1 suffix indicates the regional / export variant. Any 802D power line running system software 02.04.03.00 build 70 is potentially exposed to this fault; the same fault has been observed on adjacent build numbers in the 02.04.xx branch when the FFS file system becomes inconsistent after an uncontrolled power-down or PCMCIA card removal.

Documented affected range, per field reports and Siemens service bulletins:

• System software 02.04.03.00 build 70 (reported)
• System software 02.04.04.00 (susceptible, same NCK build family)
• System software 02.04.02.00 (susceptible, same NCK build family)
• All hardware versions A through D shipped with FFS revision < 2.1

Root Cause Analysis

Alarm 1002 with the trailing code 350010 originates in the NCK task that owns the MDA buffer save manager. Three root causes account for nearly all field occurrences:

1. FFS metadata corruption in the persistent flash file system. The MDA save path commits new blocks to a journal file (mdajrnl.ffs) on the PCU FFS before the actual MPF / SPF file is updated. An uncontrolled power-loss or a PCMCIA card pulled while the journal is open leaves the journal pointer in a state the runtime cannot reconcile. The NCK surfaces this as code 350010 on the next MDA write attempt.
2. Memory card hot-swap during a write cycle. The 802D power line has a single PCMCIA slot used both for the system-software card and for user data cards. If the operator ejects the card while a save is pending, the FFS driver returns an I/O error that is mapped to code 350010.
3. CRC mismatch on a saved part program block. A bit error in the saved block table (caused by aging flash, ESD, or a borderline PCMCIA connector) causes the block-validation CRC to fail when the MDA editor re-loads the working set. The runtime refuses the write and raises 350010 instead of dropping the block silently.

Code 350010 is therefore a consistency-fault alarm, not a hardware fault. The PCU, NCK, drives, and operator panel are otherwise healthy. The condition is fully recoverable by re-establishing a clean FFS image and reloading a known-good part-program working set from a commissioning backup.

Symptoms and Observable Behavior

The reported symptom set is highly characteristic of the 350010 fault and is useful for distinguishing it from other 802D alarms (for example, 1002/350001 which is a different code with a different root cause). Operators and maintenance technicians should confirm the following behavior pattern before applying the remediation steps:

If the failure pattern does not match (for example, JOG is also blocked, or the drives drop ready), stop the remediation path described here and open a Siemens service ticket. The condition is then no longer a 350010 FFS fault and a different repair branch applies.

Pre-Remediation: Mandatory Data Backup

Before touching the FFS or reloading system software, take a full backup of every file currently on the PCU. The order is important: backup first, then remediate. The 802D power line supports two backup mechanisms, and both should be used in sequence.

Step 1 - Series startup backup via PCMCIA

1. Insert a Siemens 6FC5 347-1AA00-0AA0 (or equivalent 8 MB SRAM PCMCIA card) into the PCMCIA slot. The card must be fully charged if it is a battery-backed SRAM card; battery-backed cards must be replaced every 5 years.
2. Switch the controller to SYSTEM > Startup > Save data.
3. Select NC data, Tool data, Zero offsets, R parameters, Setting data, and Compile cycles.
4. Confirm with OK. The backup writes a dated folder /card/user/yyyymmdd_hhmmss/.
5. Press the vertical softkey Save data again to write the same data to the PCU internal flash (not just the card).

Step 2 - Part program backup via SinuCopy / FFS

For the part-program working set, use the FFS-based image tool on a service laptop:

1. Connect a service PC to the 802D via the RS-232 service port or the Ethernet service interface (depending on the build variant).
2. Run SinuCopy FFS (or pcimage.exe on the Siemens service toolbox) with administrator rights.
3. Set the source to the controller's NCK FFS volume.
4. Dump the entire FFS image to a local .img file with a timestamp name.
5. Verify the image by reading it back and comparing the directory listing with the source.

Remediation Path A: Reload User Saved Data

This is the lowest-impact remediation and should always be tried first. It restores the FFS working set from a previous clean save without touching the system software.

1. Switch the controller off at the main disconnect. Wait at least 30 seconds for the PCU to discharge.
2. Switch the controller back on. Watch the boot screen carefully.
3. When the prompt "Press SELECT to enter setup menu" appears, press SELECT.
4. From the setup menu select Reload user saved data.
5. Select the most recent dated backup folder from the PCMCIA card (or from the internal flash if no card is present).
6. Confirm the reload. The controller will boot into the normal operator screen using the restored FFS image.
7. Switch to MDA mode and try to enter a simple block, for example G91 G1 X10 F500 followed by RESET.
8. If the entry is accepted and "data cannot be saved" no longer appears, the fault is cleared. Proceed to Verification below.
9. If the alarm returns on the first MDA write, escalate to Remediation Path B.

Remediation Path B: Default Data Reset (NC-Reset)

If Reload User Saved Data does not clear the alarm, the FFS image is too damaged for the user save to be loaded cleanly. Perform a default-data reset to wipe the FFS to factory state, then reload the commissioning backup. The machine data, setting data, and tool data must be reloaded from a known-good backup; the default data reset itself destroys all of them.

1. Press and hold SHIFT on the operator panel.
2. While holding SHIFT, press SYSTEM. The machine configuration screen opens.
3. Press the horizontal softkey STARTUP.
4. Press the vertical softkey POWER WITH DEFAULT DATA.
5. Confirm the warning that all existing NC data, tool data, zero offsets, R parameters, setting data, and compile cycles will be lost.
6. Confirm with OK. The PCU performs a full FFS wipe and re-initializes with the factory default machine data set.
7. After the controller returns to the operator screen, switch to SYSTEM > Startup > Load data.
8. Load, in this order, from the most recent commissioning backup: machine data, setting data, tool data, zero offsets, R parameters, part programs, compile cycles.
9. Press SHIFT + SYSTEM, then press the vertical softkey SAVE DATA to commit the loaded set to the PCU internal flash.
10. Test MDA mode as in step 7 of Path A.

Remediation Path C: System Software Reinstallation (Last Resort)

If Paths A and B both fail to clear Alarm 1002 / 350010, the system software itself is corrupted and must be reinstalled. The 802D power line boots from a Siemens-supplied PCMCIA card, so reinstallation does not require opening the controller.

Prerequisites

Procedure

1. Image the system-software .img file onto the PCMCIA card using SinuCopy FFS. Verify the image by reading it back and comparing the directory listing against the source image.
2. Power off the controller at the main disconnect. Wait at least 30 seconds.
3. Insert the freshly imaged PCMCIA card into the PCMCIA slot.
4. Power on the controller. The PCU will detect the system-software card and prompt for a reload.
5. Select Reload system software from the boot menu.
6. Confirm the warning. The PCU formats its internal FFS, copies the new system software, and reboots.
7. After reboot, the controller returns to the operator screen with default machine data.
8. Re-apply the OEM license if the controller is a licensed variant.
9. Re-load the commissioning backup: machine data, setting data, tool data, zero offsets, R parameters, part programs, compile cycles.
10. Save the loaded set to the PCU internal flash with SHIFT + SYSTEM > SAVE DATA.
11. Test MDA mode as in Path A, step 7.

In the original field report, Path C executed by Siemens regional service cleared the alarm. After the reinstall, the operator's part programs, tool offsets, zero offsets, and R parameters were reloaded from a known-good commissioning backup with no further recurrence.

Preventing System Software Corruption on 802D power line

The 802D power line is robust in normal operation but has a small number of operating practices that, if violated, increase the probability of the 350010 FFS fault recurring. The following are the practices that field experience and the Siemens service bulletins list as the highest-impact prevention steps.

1. Controlled shutdown only. Use the operator-panel softkey SYSTEM > Shut down or the front-panel OFF button to bring the controller down cleanly. Never use the main disconnect while the PCU is in the middle of an FFS write. The journal file is the most exposed artifact.
2. No hot-swap of the PCMCIA card. Switch the controller to a state that does not perform FFS writes (typically JOG with no MDA / AUTO active) before inserting or removing the PCMCIA card. Wait for the on-screen confirmation that the card can be removed before pulling it.
3. Battery maintenance on SRAM cards. Replace the battery of any battery-backed SRAM PCMCIA card on a 5-year cycle regardless of operating hours. Log the replacement date on the card label.
4. UPS on the cabinet supply. Install at least a short-duration UPS (5-10 minutes) on the cabinet. The 802D power line PCU performs a clean FFS flush on a graceful power-down; a short-duration UPS gives the PCU enough time to complete the flush before the supply collapses.
5. Annual commissioning backup. Capture a full backup on the PCMCIA card at least annually, and after every NCK option-bit change, every PLC program change, and every drive-parameter change. Label the backup with the date, the MLFB, the hardware version, and the system software build.
6. ESD and connector hygiene. The PCMCIA connector is the most failure-prone electromechanical interface on the controller. Inspect the connector annually for oxidation, pin wear, and contamination. Clean with isopropyl alcohol and a non-abrasive swab; never use a fiber-tip pen or any abrasive tool inside the slot.
7. Firmware update discipline. Apply Siemens-released service packs to the NCK and to the drive section only after a verified clean backup. Do not run a service pack from a PCMCIA card that has not been re-imaged for the new build.

Verification: Post-Remediation Commissioning Checks

After any of the three remediation paths, run a structured verification pass before returning the machine to production. The pass confirms that Alarm 1002 / 350010 is cleared, that no other alarm has been raised by the remediation itself, and that the loaded data set is consistent with the pre-fault state.

1. Alarm queue: Switch to ALARM and confirm the queue is empty. If 1002 / 350010 is still present, repeat the active remediation path. If a different 1002 / 35xxxx code is present, look up the new code in the diagnosis guide and resolve that code separately.
2. MDA write test: Enter G91 G1 X1 F200 in MDA and execute. The block must run without raising any alarm. Repeat with a second block of the form G91 G1 Z-1 F200. Both must run.
3. MDA delete test: Enter a throwaway block, then highlight it and press DEL. The block must be removed and the alarm queue must remain empty.
4. Tool offset write test: Modify a tool length offset by a small value (for example, +0.01 mm). Save with SHIFT + SYSTEM > SAVE DATA. Reload from the menu and confirm the value persisted.
5. Zero offset write test: Modify G54 by a small value, save, reload, confirm.
6. R parameter write test: Write a non-zero value to R0, save, reload, confirm.
7. Part-program execution: Run a known-good MPF in AUTO mode end-to-end with a dry-run feed-rate override of 10 percent. Confirm correct execution and no alarms at end-of-block.
8. Drive section sanity: From the SYSTEM > Drive screen, confirm all axes report Ready and the spindle reports Ready at zero RPM.
9. Backup verification: Take a fresh backup and read it back with SinuCopy FFS to confirm the new FFS image is self-consistent.

Related Alarms and Error Code Mapping

Alarm 1002 is the system-error umbrella alarm and the trailing 6-digit code is the discriminator. The 35xxxx range covers FFS and NCK file-system faults; a small number of related codes are listed below for reference. The diagnosis guide for the controller is the authoritative source for codes outside the 350010 family.

Frequently Asked Questions