Resolving Siemens 30006 Alarm After SIMODRIVE 611 Power Swap

Overview

Field reports describe a recurring failure pattern on SINUMERIK 840D and 840D sl systems where a SIMODRIVE 611 power module replacement from order number 6SN1123-1AA00-0LA2 to 6SN1123-1AA00-0LA3 produces SINUMERIK alarm 30006 "Module 6 not found" together with a steady red indicator on connector X34 of the SIMODRIVE 611 control card. The fault survives full rewiring of the control harness, drive-bus reseating, and module reset, which means the root cause is not the power section itself but the control card, the drive-bus configuration, or a defective replacement module. This article walks through the diagnostic sequence that isolates the failing component and the corrective procedure that brings slot 6 back online without an unnecessary control card replacement.

Affected Hardware Identification

The fault involves three Siemens SIMODRIVE 611 part numbers. Each must be positively identified before any swap, because the SIMODRIVE 611 family uses suffix codes that look similar but describe different rated outputs and hardware revisions.

The -0LA2 and -0LA3 suffixes on Siemens 6SN1 SIMODRIVE 611 power modules denote the hardware revision index. Revisions in the same suffix family are mechanically and electrically interchangeable on the SIMODRIVE 611 backplane bus; they share the same drive-bus interface, the same DC link, and the same enable/command signals. The control card above the power module is the device that actually configures the drive on the bus, so a swap between same-family revisions of the power module should never, by itself, produce a "drive not found" alarm. When it does, the fault is upstream of the power module.

SINUMERIK Alarm 30006 Definition

In the SINUMERIK 840D and 840D sl alarm catalog, alarm 30006 belongs to the "Axis monitoring" group and is raised by the NCK when it cannot establish communication with the configured drive slot. The standard alarm text reads:

Alarm 30006: Axis %1 drive %2 not found. The drive assigned to this axis in the machine data is not available on the drive bus.

Alarm 30006 is generated when the drive bus (the SIMODRIVE 611 internal bus, or the PROFIBUS-DP link to SINUMERIK drive units on 611D digital drives) does not respond to the NCK poll at the expected logical slot. Logical slot 6 in a 6-axis SINUMERIK configuration corresponds to physical drive #6 on the drive bus. The alarm is not a wiring alarm and is not a power-stage alarm; it is a bus-communication alarm raised at the NCK layer. That distinction matters for the diagnostic procedure, because it rules out the enable chain and the motor power cables as primary suspects.

Related Drive-Bus Alarms

Symptom Analysis: Connector X34 Red LED

Connector X34 on a SIMODRIVE 611 control card is the drive enable / status header on the front edge of the card. A red LED continuously illuminated on X34 indicates one of the following conditions:

• Control card is receiving 24 V logic power but has detected an internal fault and refused to enter the run state.
• Drive-bus communication has failed between the NCK/PLC and this drive slot.
• The two-digit seven-segment display on the control card (if populated) shows "6" or another fault code instead of the steady-state "8" or blank.
• The enable chain (terminal X122 on the power module, or terminals on the connector strip) is open or has bad wiring.

A flashing red LED versus a steady red LED carries different diagnostic meaning. A flashing red LED on SIMODRIVE 611 control cards typically indicates the card is in the "waiting for bus" or "boot" state, which clears after a successful enumeration. A steady red LED is the more severe condition and typically maps to a hard fault or a missing drive on the bus, which matches the 30006 fault exactly.

Root Cause Analysis

Replacing a SIMODRIVE 611 power module with a same-rating, same-form-factor replacement should not generate alarm 30006 if the wiring, enable chain, and bus address are intact. The fact that the alarm persists after the replacement, after rewiring the control harness, and after power cycling points to one of the following root causes, in order of probability:

1. Defective control card 6SN1118-0DG23-0AA1 on the drive slot in question. The cross-swap diagnostic described below will confirm this in most field cases.
2. Defective replacement power module: the -0LA3 unit is itself faulty from stock and fails to enumerate on the drive bus.
3. Drive-bus address conflict or lost EEPROM configuration on the control card, caused by electrostatic discharge or power loss during the swap.
4. Backplane bus connector damaged or not fully seated between the power module and control card.
5. Configuration mismatch in machine data MD30130, MD30220, or the drive-assignment MDs following a PLC or NCK reset.
6. Enable chain open at terminal X122 on the power module or on the I/RF connector strip.

Drive-Bus Topology

The SIMODRIVE 611 drive bus is a parallel backplane bus shared by all power modules in the line-up. The NCK communicates with each drive through the NCU's PROFIBUS-DP port or through the SIMODRIVE 611 internal bus on the backplane. The drive bus assigns slot addresses automatically based on the physical order of the cards in the line-up; an empty slot or a missing card breaks the address chain and can produce a "drive not found" alarm on all subsequent slots.

The slot order is rigid. If slot 5 is empty or has been removed, the NCK enumerates slot 5 as missing and pushes the slot 6 drive to slot 5 in the logical mapping, which is exactly the "drive 6 not found" symptom. After any drive swap, confirm that no slots have been left empty and that the backplane connector between the power module and the control card is fully seated.

Diagnostic Procedure

Run this sequence before replacing any further hardware. Each step rules out a layer of the fault tree and is non-destructive. Allow at least 30 seconds between power-off and reseating to allow the DC link capacitors to discharge.

1. Verify the replacement module 6SN1123-1AA00-0LA3 is the correct variant for the drive slot by cross-checking the machine data drive assignment list (printed in the circuit diagram and equipment manual).
2. Power off the drive bus. Reseat the control card 6SN1118-0DG23-0AA1 in its slot. Reseat the power module. Power on and observe the red LED on X34.
3. Read the seven-segment LED on the control card during power-on. Codes "1", "2", "5", "6", "8" are common drive-fault indicators for SIMODRIVE 611D; refer to the equipment manual for the exact mapping.
4. Cross-swap the suspect control card with an adjacent drive of the same part number. If alarm 30006 follows the card, the card is defective. If the alarm stays on slot 6, the bus or the power module is at fault.
5. Measure the 24 V logic supply on X34 pins 1 and 2 against the equipment manual tolerance (typically 20.4 V to 28.8 V).
6. Use SINUMERIK HMI menu Diagnostics > Drive System to view the actual drive-bus topology and confirm whether drive 6 reports "online" or "missing".
7. Check the enable chain on terminal X122 of the power module: pin 1 must be at +24 V relative to pin 2 for the drive to enter the run state.

Seven-Segment Status Code Reference

Step-by-Step Resolution

Step 1 — Isolate the Control Card

Cross-swap the control card 6SN1118-0DG23-0AA1 on drive slot 6 with the same part-number card from a known-good slot. Power on the system. If alarm 30006 follows the card to the new slot, the card is defective and must be replaced. If the alarm remains on slot 6, the power module or the wiring is the issue and the card can be reinserted into slot 6.

Step 2 — Verify the Power Module

Reinstall the original 6SN1123-1AA00-0LA2 power module as a known-good unit. If the alarm clears, the replacement 6SN1123-1AA00-0LA3 unit is defective and must be returned to stock. Bench-test the replacement on a 24 V logic supply and a known-good DC link source before returning it to the vendor.

Step 3 — Check the Drive-Bus Topology

On SINUMERIK 840D, navigate to Commissioning > Drive System > Drive Configuration. Confirm the drive list shows six drives and that slot 6 is enabled. If slot 6 shows "not configured", restore the configuration from the commissioning archive. If the topology view shows five drives instead of six, there is an empty or unpowered slot upstream that is consuming slot 6's address.

Step 4 — Restore Machine Data

If a commissioning backup is available, compare the current machine data for drive slot 6 against the last known-good archive. Pay specific attention to:

• MD30130 CTRLOUT_TYPE[n] — setpoint output type for axis n
• MD30220 ENC_RESOL[n] — encoder resolution for axis n
• MD30100 CTRLOUT_SEGMENT[n] — bus segment assignment
• MD13050 DRIVE_TYPE[n] — drive type assignment (must match installed hardware)

Step 5 — Replace the Control Card

Replace the control card with a new 6SN1118-0DG23-0AA1 if the cross-swap proves it defective. Load the drive firmware to the replacement card using the SIMODRIVE 611 Toolbox or the NCK commissioning procedure (Commissioning > Drive System > Firmware Update). The firmware version must match the version on the original card or the version specified in the equipment manual.

Control Card Swap Procedure

The cross-swap test is the single most diagnostic step on this failure pattern. Use it as the first action after the visual and voltage checks.

1. Power off the drive system. Verify zero voltage on the DC link with a multimeter at the DC link terminals.
2. Loosen the four retaining screws on the control card of the suspect drive (slot 6) and on the comparison drive (same 6SN1118-0DG23-0AA1 part number).
3. Withdraw both cards using the extraction levers. Do not bend the backplane connector pins. Do not touch the gold edge connector.
4. Swap the two cards. Insert each card firmly into the backplane of the other slot until the connector is fully seated.
5. Torque the retaining screws to the value specified in the equipment manual (typically 0.8 N·m).
6. Power on the drive system. Observe the red LED on X34 and the seven-segment status display on both cards.
7. If alarm 30006 is now reported on the previously-good drive slot, the swapped card is defective. Replace it.
8. If alarm 30006 remains on slot 6, restore both cards to their original slots and continue with the power-module swap procedure.

Enable Chain Verification

The enable chain on a SIMODRIVE 611 power module consists of terminal X122 (or the I/RF connector strip on later modules) and the connector on the control card. The drive enters the run state only when:

• 24 V is present on the enable input relative to the enable common.
• The NCK has issued the controller enable.
• The drive bus has enumerated the slot.
• The control card has passed its self-test.

If the enable chain is open, the seven-segment display shows "5" rather than "6" or "8", and the red LED on X34 is on. Check the enable chain first because it is the cheapest thing to fix.

Drive-Bus Enumeration Procedure

After any drive hardware swap, force the drive bus to re-enumerate by performing a full NCK reset. The procedure on SINUMERIK 840D sl is:

1. Set the key switch to "0" (operator).
2. Navigate to Commissioning > NCK > Reset.
3. Confirm the reset. The NCK will cold-start and re-enumerate the drive bus.
4. Wait at least 30 seconds for the drive bus to complete enumeration.
5. Read the topology from Diagnostics > Drive System > Topology.

Firmware Compatibility Check

The SIMODRIVE 611 firmware matrix must match between the control card, the power module, and the NCK version. Mismatched firmware can produce a 30006 alarm even when the hardware is intact. The compatibility table is in the SIMODRIVE 611 documentation under "Firmware Release Notes".

Bench Test for Replacement Power Modules

Before installing a 6SN1123-1AA00-0LA3 on a production machine, bench-test it on a 24 V logic supply with a known-good SIMODRIVE 611 control card and a 600 V DC link source. The bench test procedure is:

1. Connect the 24 V logic supply to X34 pins 1 and 2 of the control card.
2. Connect the 600 V DC link to the DC link terminals of the power module.
3. Power on the logic supply. Observe the seven-segment display: it should boot through "1", "2", and settle on "8" within 10 seconds.
4. Apply the enable signal to terminal X122. The seven-segment display should change to blank (run state).
5. Connect a known-good motor to the U/V/W terminals of the power module. Run the motor at low speed for 30 seconds. No alarm should appear.

If the bench test passes, the replacement power module is good. If it fails, return the module to stock.

Verification

The repair is verified when all of the following conditions are true after a cold start:

1. The red LED on X34 of slot 6 is extinguished or shows the normal heartbeat pattern.
2. SINUMERIK alarm 30006 is no longer present in the alarm log after 5 minutes of operation.
3. The seven-segment LED on the slot 6 control card shows "8" or blank (refer to equipment manual for the exact steady-state code).
4. The HMI menu Diagnostics > Drive System reports drive 6 as online and ready.
5. A reference traverse of the axis on slot 6 completes without follow-on alarms (30070, 30071, 25201).
6. The drive-bus topology view shows six drives, all in "ready" state.

Troubleshooting Matrix

Prevention Checklist

• Record the control card part number, firmware version, and slot number before any power module swap.
• Stock a known-good spare 6SN1118-0DG23-0AA1 control card per machine.
• Bench-test every replacement 6SN1123-1AA00-0LA3 before installing it on a production machine.
• Maintain a current commissioning backup including the drive configuration archive.
• After any drive hardware swap, perform a full NCK restart (NCK reset) to force re-enumeration of the drive bus.
• Use an ESD wrist strap when handling control cards and store them in anti-static bags.
• Verify that no slots are left empty between drive cards on the backplane bus.
• Check the enable chain on X122 before swapping the control card.

Spare Parts Recommendations

For the official Siemens commissioning, alarm list, and firmware release notes, search the Siemens Industry Online Support portal using the part numbers 6SN1118-0DG23-0AA1 and 6SN1123-1AA00-0LA3, or query "SIMODRIVE 611" for the full commissioning manual set.

Frequently Asked Questions