SINUMERIK 810M GA2 Alarm 11: Resolving Wrong ASM Identifier

Problem Description

On a SINUMERIK 810M controller in the GA2 (Grundausstattung 2) or GA3 (Grundausstattung 3) hardware level, an operator is hand-entering machine data (MD) and part-program (PP) data without a PC link to the control. After typing the values, the new data sits in the ASM (Anwender-Speicher-Modul / user-memory module) and must be transferred to the main MD memory via the URLÖSCHEN (clear user memory / AWS-FORMAT) procedure. The PLC side of the operation completes successfully, but the "MD AUS ASM LADEN" (load MD from ASM) tick box is no longer settable. The control raises:

• Alarm 11 – falsche ASM-Kennung (ASM leer?) – wrong ASM identifier, ASM appears empty
• PLC STOP – the integrated PLC drops to STOP and will not return to RUN/RUN-S
• Any combination of Alarms 3024 to 3046 when the operator attempts to use the WS 800 workshop software for project transfer

Even after fresh backup batteries are installed while the unit is energized, Alarm 11 persists, the MD values cannot be edited through the standard overwrite routine, and the printout of the original commissioning record shows a different MD 5015 value than what the controller currently reports.

Hardware Identification: 810M GA2 vs GA3

The Siemens SINUMERIK 810M family uses the Grundausstattung suffix to denote the basic-equipment hardware level installed at commissioning. The GA suffix is set by the position of a hardware jumper and by the contents of the option memory module.

The ASM module itself is a 32-Kbyte to 128-Kbyte battery-backed SRAM cartridge (CMOS SRAM with on-board lithium cells) that holds the user-side machine data, part programs, and PLC project. The hardware jumper for GA2/GA3 selection sits adjacent to the ASM socket; the same firmware recognizes both, but the address window and the WS 800 communication parameters differ.

Confirm the level by reading the type plate on the mainboard (6FX1 138-… order number) and the rated-voltage label on the power supply. For the exact part numbers of the ASM, the CPU, and the operator-panel backplane refer to the SINUMERIK 810M, GA2, Operating and Programming (Edition 08.1990) document on Siemens Industry Online Support.

ASM Module Architecture

The ASM is the only persistent user memory on a standalone 810M. The control boot sequence after power-on, NC-Reset, or URLÖSCHEN is:

1. Power supply ramps, +5V logic stabilizes, backup batteries (typically 2× 3.6 V lithium, type ER14505 or equivalent) hold the SRAM.
2. CPU reads the ASM header and verifies the Kennung (identifier) – a 4-byte magic value at the start of the cartridge that tags the cartridge as belonging to a specific 810M/GA level and firmware version.
3. If the identifier matches, the boot loader copies the EZS parameter set (MD 5 controls how many) and the Teileprogramme (part programs) into working RAM.
4. If the identifier does not match, the boot loader halts and the alarm handler raises Alarm 11.

The user-entered machine data flow is therefore:

1. Operator edits MD on the keyboard → values go to the ASM scratch area.
2. Operator triggers the softkey sequence CLEAR USER MEM. (AWS-FORMAT) and CLEAR PP-MEM. (TEILEPR. LÖSCHEN) → control formats the ASM, then loads MD from ASM into the working memory via the MD AUS ASM LADEN tick box in the startup menu.
3. On next NC-Reset the values are committed to the working MD area and made visible to the NCK and PLC.

Any break in this chain leaves the new MD values inside the ASM but invisible to the control – which is why the printout of the original commissioning record (e.g. MD 5015 = 0101 0111b) does not match the controller reading (e.g. 0100 0100b) when the chain is broken.

Machine Data Reference: MD 5 and MD 5015

The two machine-data words that govern the ASM boot behavior are MD 5 and MD 5015. They are not standard NCK axis-machine data; they are system-configuration machine data in the 800-series pre-840D architecture.

MD 5015 bit layout (operator-pane display order, MSB left):

Bit:  7    6    5    4    3    2    1    0
      │    │    │    │    │    │    │    │
      0    1    0    0    0    1    1    1   (printout example, 0x47 = 71 dec)
      │    │    │    │    │    │    │    └─ reserved
      │    │    │    │    │    │    └────── reserved
      │    │    │    │    │    └─────────── reserved
      │    │    │    │    └──────────────── reserved
      │    │    │    └───────────────────── reserved
      │    │    └────────────────────────── reserved
      │    └─────────────────────────────── ASM-Modul vorhanden (1 = yes)
      └─────────────────────────────────── reserved

When the operator reports that MD 5015 currently reads 0100 0100b (0x44) but the printout states 0101 0111b (0x47), the discrepancy is exactly one bit – bit 6. With bit 6 cleared, the boot loader assumes no ASM is present, never reads the cartridge header, never validates the identifier, and stays in the "no ASM" branch. From the alarm-handler perspective this is indistinguishable from "ASM plugged in but identifier wrong" – hence Alarm 11.

Alarm Catalog: 5, 10, 11, and 3024–3046

The 810M alarm bar is split into NC alarms (1 – 999) and PLC alarms (3000 – 3999). The four alarms relevant to this fault are:

Alarms 3024 – 3046 are WS 800 (Werkstatt-Software 800) project-transfer errors. WS 800 is the Siemens workshop programming tool used to load the STEP 5 PLC project from a PG (Programmier-Gerät) over the serial V.24 line. The exact alarm sub-number is documented in the operating manual linked above. When the PLC project download is interrupted, the 810M PLC stays in STOP and the MD AUS ASM LADEN tick box is rejected by the start-up logic, because the NCK cannot trust a control whose integrated PLC is not running.

Root Cause Analysis: Why Alarm 11 Locks MD Load

The 810M start-up state machine has three preconditions before it will honor the MD AUS ASM LADEN tick box:

The three preconditions are:

1. MD 5015 bit 6 = 1 – the control must be told an ASM is plugged in.
2. ASM identifier valid – the 4-byte magic value at the cartridge header must match the expected value for the installed firmware and GA level.
3. PLC in RUN or RUN-S – the integrated PLC must be executing the boot project; a STOP condition (caused by a bad project download, an empty EPROM, or Alarms 3024 – 3046) blocks the MD-load commit.

If any one precondition fails, the start-up sequence branches to the alarm path and the MD AUS ASM LADEN tick box becomes a no-op. The user therefore sees the visible symptom of "MD overwrite does not stick" and "tick box is greyed out" but the underlying defect is the failed preconditions, not the edit operation itself.

Step-by-Step Recovery Procedure

Follow this sequence in order. Do not skip PLC STOP recovery – the MD write path is locked while the PLC is stopped.

Prerequisites

• Operator access to the 810M keyboard (numeric + softkeys)
• Manufacturer password for the 810M (the four-digit code set at commissioning – default 1111 for early GA2, NEIMEI style codes on later GA3)
• Fresh lithium backup batteries (2× 3.6 V, type ER14505 / LS14500 or the original Varta-type cells), installed with the control powered on
• Original commissioning printout (Maschinendaten-Ausdruck) for the target MD values
• PG with WS 800 software and a working V.24 cable (X2 / COM1 of the 810M to COM of the PG) – only required for the PLC project reload

Procedure

1. Replace the backup batteries with the unit energized. The SRAM of the ASM is held across the battery swap. Wait 30 seconds after insertion for the cells to settle.
2. Acknowledge all active alarms with the RESET key and the CANCEL softkey. Note the remaining alarms; they should narrow to Alarm 11 only.
3. Enter the manufacturer password by pressing MENU SELECT > PASSWORD > 1111 > INPUT. The display should now show the Manufacturer level.
4. Edit MD 5015 by selecting SETUP > MACHINE DATA > 5015 > INPUT. Type the new value 01010111 (binary, MSB-left) or its decimal equivalent 71 if the display expects decimal. Press INPUT to commit, then SAVE.
5. Power-cycle the control – main switch OFF, wait 10 seconds, main switch ON. This is the equivalent of a cold restart on a 810M and forces a re-read of the ASM header.
6. Trigger the ASM load sequence: at power-on, the start-up menu shows the line MD AUS ASM LADEN with a tick box. With the cursor on the tick box press the SELECT softkey to set the check mark, then press NC-START to commit.
7. Run the user-memory clear: from the same start-up menu trigger the softkey CLEAR USER MEM. (AWS-FORMAT) first, then CLEAR PP-MEM. (TEILEPR. LÖSCHEN). The first formats the ASM scratch area; the second deletes the part-program area so a clean re-load is possible.
8. Re-load the PLC project with WS 800 from a known-good source. From the PG start WS800 > PLC > Transfer > 810M > send. The 810M will raise Alarms 3024 – 3046 if the transfer fails; if no further alarm is raised, the PLC leaves STOP within 5 – 10 seconds and enters RUN.
9. Hand-enter the remaining MD values from the commissioning printout. The MD editor now accepts writes because PLC is in RUN.
10. Save to ASM: from SETUP > MACHINE DATA > SAVE TO ASM. This commits the edited values back to the cartridge.
11. Final cold restart: power-cycle one more time and verify the start-up screen shows all MD values matching the printout and the alarm bar is empty.

Battery Replacement and SRAM Preservation

The 810M SRAM is held by two lithium cells that are normally rated for 5 – 10 years at room temperature. A dead battery drops the SRAM contents to random values on the next power-down – the visible symptom is a corrupted ASM header and Alarm 11. Always replace both cells at the same time, and always replace with the unit energized; hot-swap preserves the SRAM. If the unit must be powered down for any reason, fit a 24 V UPS or a 3.6 V external battery pack on the battery clips to bridge the outage.

The exact battery-holder part numbers and the backup-time spec are in the SINUMERIK 810M, GA2, Operating and Programming (Edition 08.1990) manual. The manual also covers the additional capacitor (1 F / 5.5 V) that bridges short power interruptions and which must be replaced on any unit older than 15 years to avoid spurious Alarm 11 events after a brief mains dip.

PLC STOP Recovery and Hand-Entering MD Values

The integrated PLC is a SIMATIC S5-100U-class CPU on the same backplane as the NCK. PLC STOP can be caused by:

• Empty EPROM or EEPROM on the PLC sub-module
• WS 800 transfer interrupted mid-block (raises 3024 – 3046)
• Operator password change that wiped the project slot
• Battery failure during a previous power-down

The standard recovery is to re-load the project from a clean WS 800 backup. Without a backup, the machine is effectively a write-off until a project can be reconstructed. Once the PLC is back in RUN, hand-entering MD values from the keyboard uses the following key sequence:

SETUP
 └── MACHINE DATA
      └── MD number      (e.g. 5015)
           └── INPUT
                └── new value
                     └── INPUT
                          └── SAVE
                               └── confirmation softkey "OK"

If the controller refuses the input, the cause is almost always one of:

1. PLC still in STOP – repeat the WS 800 reload.
2. Access level too low – re-enter the manufacturer password.
3. MD number is write-protected by the option bit MD 5015.0 – set the bit appropriately for the duration of the edit.
4. The display is showing the MD in binary but you are entering decimal – switch the display mode with the BIN/DEC softkey.

Verification Procedure

After the recovery, run the following verification steps to confirm Alarm 11 is resolved and will not return on the next power-cycle.

1. Read MD 5015 on the operator pane – value must be 01010111b (0x47) or whatever the commissioning printout specifies. Bit 6 must be 1.
2. Read MD 5 – confirm the EZS parameter count is below the maximum supported by the installed firmware (typically 32 for GA2, 64 for GA3). Reduce if Alarm 5 is also present.
3. Trigger SAVE TO ASM and read back MD 5015 from the operator pane – the value must persist across a power-cycle.
4. Trigger a cold restart (main switch OFF, 10 s, ON). Watch the start-up screen – the MD AUS ASM LADEN tick box should already be pre-set if the ASM is valid.
5. Verify the alarm bar is empty. A residual Alarm 11 after the recovery indicates either a still-corrupt ASM (replace) or a wrong firmware/GA combination (cross-check the order number).
6. Verify PLC is in RUN – the PLC-LED on the operator pane is green and the PLC-STATUS screen shows CYCLIC RUN.
7. Run a manual reference-point traverse (G74) on each axis to confirm the NCK reads the same MD values that were entered.

Troubleshooting Matrix

Field-Commissioning Checklist

Use this short list before signing off a 810M repair that involved an Alarm 11 recovery.

• ☐ MD 5015 bit 6 = 1 and value committed to ASM
• ☐ MD 5 ≤ firmware maximum and Alarm 5 not present
• ☐ PLC project reloaded and PLC in RUN
• ☐ Alarm bar empty after cold restart
• ☐ Reference-point traverse (G74) on all axes successful
• ☐ Test part program executed without NCK or PLC alarm
• ☐ Battery voltage measured > 3.4 V per cell under load
• ☐ Commissioning printout (MD-Ausdruck) reprinted and stored with the machine documentation

FAQ