Siemens AS-i Link 6GK1415-2AA10 Replacement in S7-400 HW Config

Scope. Field-procedural reference for replacing a discontinued AS-i link module (currently configured as 6GK1 415-2AA01) with its current successor (6GK1 415-2AA10, firmware V3.0) inside an S7-400 PLC station. Covers the SIMATIC Manager HW Config swap, AS-i master addressing, AS-i slave addressing impact, firmware update guidance, and the verification/commissioning checks that determine whether the cutover was a clean swap or whether an AS-i addressing tool is required.

1. Overview and Cutover Context

The AS-i (Actuator Sensor Interface) link module connects the AS-i cable segment, on which the binary AS-i slaves live, to a higher-level fieldbus (PROFIBUS DP or PROFINET IO) that terminates on the S7-400 CPU. The replacement scenario here is the typical lifecycle case:

• Original module 6GK1 415-2AA01 is no longer manufactured.
• Successor module 6GK1 415-2AA10 (FW V3.0) is in stock.
• A planned downturn window is available for the swap.

The cutover must be evaluated against three independent risk axes:

1. Engineering data — does the new module occupy the same slot, GSD/GSDML revision, and diagnostic address space as the old one?
2. AS-i master address — is the new unit delivered with the same AS-i master node address, or does it boot as address 0?
3. AS-i slave configuration — are the slaves projected by their permanent AS-i addresses, and will the new master accept that projected configuration without complaint?

The questions that arise from the field ("do I just delete and grab the new one from the library?", "do I need an AS-i programmer?", "will the slave configuration change?") all trace back to those three axes.

2. Module Identification and Functional Comparison

The two modules are pin- and footprint-compatible successors. The delta is captured in firmware, integrated diagnostics, and GSD revision. Treat the module names as the contract — both ship as AS-i master/link modules for the same station class.

Decision path. If STEP 7 lists both order numbers side-by-side in the HW catalog, the GSDs are functionally compatible and the replacement is a slot-for-slot swap. If only the new order number appears, confirm in the project's hardware catalog (Options → Install HW Updates) that the GSD for the old module is still installed; otherwise STEP 7 cannot resolve the existing configuration when you open it.

3. Prerequisites Before the Cutover

Treat the replacement as a controlled commissioning job, not a hot swap. The following prerequisites reduce downtime and remove the "strange things happen" category that the discussion references.

Capture the live AS-i diagnostics before powering down. From the STEP 7 online view of the AS-i master, record:

• List of Configured Slaves (LCS)
• List of Detected Slaves (LDS)
• List of Activated Slaves (LAS)
• Per-slave flags: PF (peripheral fault), CF (configuration fault), AF (address fault)

If LCS ≠ LAS before the swap, the new master will boot into the same mismatch and the fault will be misattributed to the module change.

4. STEP 7 HW Config Replacement Procedure

The HW Config replacement has three acceptable mechanical paths. All three converge on the same SDB.

4.1 Method A — Replace Object (recommended)

1. Open the S7-400 station in HW Config (SIMATIC Manager → Station → Open HW Config).
2. Right-click the existing AS-i link module 6GK1 415-2AA01.
3. Select Replace Object....
4. Choose the new order number 6GK1 415-2AA10 from the HW catalog.
5. Confirm the slot, diagnostic address, and any submodules are preserved.
6. Save and compile (Station → Save and Compile).

4.2 Method B — Delete and Insert

1. Right-click the slot occupied by the old module → Delete.
2. Open the HW catalog and drag the new module 6GK1 415-2AA10 into the same slot.
3. Re-enter the diagnostic address and any DP/PN parameters you have configured (only if the catalog asks; otherwise they survive the slot assignment).
4. Save and compile.

4.3 Method C — Direct substitution via GSD

Use this only when the old GSD has been removed from the catalog and STEP 7 refuses to open the existing station. Open a blank station, drag the new module into the same slot, and copy the SDBs from a backed-up project. This is a recovery path, not a normal workflow.

4.4 Compilation and Download

1. Station → Save and Compile with consistency check enabled. Resolve any address-overlap or duplicate-station errors before continuing.
2. Connect to the target CPU (PLC → Download to Target → Selected or Complete). A consistent download of the System Data (SDB container) writes the new configuration to the CPU while the program blocks remain untouched.
3. After download, switch the CPU from STOP to RUN only after the physical module swap is complete. Power-cycling the AS-i link module before the CPU is in RUN forces a cold start of the AS-i master with empty configuration tables.

5. AS-i Master Addressing

The AS-i link module is a master on the AS-i subnet. Each AS-i master must hold a unique AS-i address in the range 1 ... 31 (default out of the box is typically address 0, which is the reserved "unassigned" value).

The discussion explicitly asks whether the master address alone is what matters, and the answer is: yes, for the master itself, no, for the slaves. The master's own address is set via the AS-i addressing tool (or via the master's web/display interface on V3.x firmware) and is independent of the GSD or HW Config object.

6. AS-i Slave Configuration — What Actually Changes

Slaves are projected in HW Config under the AS-i master slot. Each projected slave has:

• Permanent AS-i address (1–31, single slave per address)
• ID code (vendor code, e.g. 0x0 for AS-i standard, 0xA for some safety devices)
• I/O code (4-bit, describes input/output count)
• Profile (e.g. S-0.F.E for safety slaves, S-7.0 for standard I/O)

These parameters live in the SDBs generated from HW Config and downloaded to the CPU. The new master reads them at boot and compares against LDS (List of Detected Slaves) on the wire.

Why does configuration impact exist at all? The projected slave configuration is in the SDB. The physical slave identity is in non-volatile memory on the slave itself. Three things can break the comparison:

Theoretical outcome. When the cutover is a like-for-like module swap with no physical disturbance to the AS-i cable and the slaves have retained their permanent addresses, the new master reads the same SDB, finds the same LDS, and reports LAS = LCS. No AS-i programmer is needed.

Worst-case outcome. If the AS-i PSU is interrupted, the cable is shorted during the swap, or a slave has aged memory, one or more slaves may appear at address 0. The new master will reject address 0 as not configured and the slave will need its permanent address re-written via a handheld addressing tool (or via the master itself on V3.x firmware that supports "Address programming from the master").

7. Firmware Update Recommendation

The factory firmware on the new unit is V3.0. This is generally current, but the recommendation is to verify against the latest available version on the Siemens support portal before commissioning.

1. Identify the exact MLFB 6GK1 415-2AA10.
2. Open Siemens Industry Online Support and search the entry for the module.
3. Read the firmware release notes — confirm V3.0 or later is current.
4. If a newer firmware is listed, schedule a firmware update during the same downturn window.

Firmware update procedure on the AS-i link module is performed over the AS-i cable using the Siemens Field PG or a Web interface (if the new revision exposes one), or through STEP 7 HW Config → right-click module → Firmware Update. The CPU must be in STOP, or the slot must be unassigned for the duration of the update.

8. Commissioning and Verification

Execute this sequence inside the downturn window. Step ordering matters: do not power the new module until the new System Data has been downloaded to the CPU.

1. Confirm STEP 7 project is compiled and the SDB container is downloaded successfully.
2. Power down the AS-i link module slot.
3. Physically remove the old module, install the new module 6GK1 415-2AA10.
4. Verify the AS-i address selector / display shows the correct master address (write before power-on if the module ships at 0).
5. Apply power to the AS-i PSU first, then to the new module.
6. Observe the module LEDs: SF, BF, AS-i, READY / RUN. All fault indicators must extinguish within the AS-i master's startup window (typically < 5 s for V3.0 firmware).
7. From STEP 7 online: PLC → AS-i Master → Diagnostics (path depends on STEP 7 version; equivalent is the right-click menu on the master slot in HW Config → Object Properties → Diagnostics).
8. Read LCS, LDS, LAS. All three must match.
9. Force I/O in a controlled test: toggle one input on each AS-i slave and confirm the corresponding input bit in the CPU's process image changes state.
10. Toggle one output and confirm the corresponding slave output actuates (e.g. indicator lamp, valve).
11. Archive the project with a timestamped comment indicating "AS-i link module cutover complete, FW V3.0, all slaves LAS = LCS".

8.1 Verification Matrix

9. Troubleshooting Common Faults After the Swap

The discussion captures the intuition that "the swap looks easy but be prepared for worst cases." This matrix maps the diagnostic symptom to the underlying fault.

9.1 When to reach for the AS-i handheld programmer

The handheld programmer is required in exactly two scenarios:

1. A slave has lost its permanent address and now broadcasts as address 0. Use the handheld to write the correct address (1–31) into the slave's non-volatile memory.
2. The new master itself was delivered at address 0 and the project expects a non-zero address. Use the handheld to write the master address into the new module.

Outside these two cases, the cutover should not require a handheld. If the handheld is needed for more than a couple of slaves, the underlying fault is more likely an interrupted PSU during the swap than a defect in the new module.

10. Process and Safety Notes

• Power sequencing. Apply the AS-i PSU before the AS-i link module boots, or the master will boot with empty LDS and report a phantom LDS < LCS alarm. Wait for the PSU to stabilize > 28 V DC before powering the module.
• ESD. Both AS-i modules are ESD-sensitive. Use a wrist strap and the station's ESD bonding point when handling the modules outside the cabinet.
• Documentation. Record the new module's serial number and the FW version visible in STEP 7 (Module Information → Firmware) in the asset register. This avoids confusion during the next maintenance window.
• Safety slaves. If the segment carries AS-i Safety at Work slaves (profile S-7.x), the safety configuration is held in the safety monitor, not in the AS-i link. A link-module swap does not affect safety logic, but any safety-related diagnostic evaluation must use the new module's diagnostic bit layout.

FAQ