Replacing Siemens ET 200S IM151-1 PN: 6ES7151-1AA04 to 1AA05

Overview: ET 200S IM151-1 PN Interface Module Replacement

The SIMATIC ET 200S distributed I/O system uses the IM151-1 PN interface module to couple PROFIBUS or PROFINET segments back to a higher-level controller. Two hardware revisions of the PROFINET interface module are commonly encountered in field installations: order number 6ES7151-1AA04-0AB0 and its successor 6ES7151-1AA05-0AB0. When a spare-part failure forces a swap between these two revisions, the engineering workstation must reflect the new MLFB in the hardware configuration, even though both modules are mechanically and electrically pin-compatible within the same ET 200S terminal block family.

The most frequently reported symptom during this swap is the STEP 7 / SIMATIC Manager dialog "HW Config (1230:5053) There is no replacement for this object", raised when an engineer uses the Replace Object command on the existing IM151-1 PN station. The error does not mean that a replacement is impossible — it means STEP 7 cannot auto-resolve the part number from the catalog alone. The replacement must be performed by manually re-stamping the IM151 slot with the new order number and re-loading the station. This article documents the exact procedure, the HSP/GSD considerations, the in-operation swap rules, and the long-term migration path to ET 200SP.

Identifying the Two Interface Module Variants

The Siemens Support entry 109767411 confirms that the entire SIMATIC ET 200S system, including both 1AA04 and 1AA05 IM151-1 PN variants, has been moved to spare-part-only availability. New installations should target the scalable SIMATIC ET 200SP family (e.g., 6ES7155-6AUxx-0BN0 IM 155-6 PN). The MLFB-to-MLFB swap covered here is therefore a maintenance / spare-part activity, not a new deployment.

Prerequisites Before the Swap

1. STEP 7 / SIMATIC Manager version. Use a STEP 7 V5.x version that ships with an HSP newer than the 1AA05 release date, or install the latest available HSP via HW Config → Options → Install HW Updates. TIA Portal users must run V14 SP1 or later with HSPs updated through the TIA Updater (TIA Updater is reachable from the TIA Portal Help menu).
2. Latest GSD/GSDML for ET 200S. Although the ET 200S IM151-1 PN is configured natively in HW Config (no GSDML is strictly required for the head-end), PROFINET device descriptions may still be referenced for downstream diagnostics. Pull the current GSDML set from the Siemens Support PROFINET GSD files page.
3. Project backup. Archive the STEP 7 project (File → Archive) before any HW Config edit so the swap can be reverted if the new MLFB behaves unexpectedly.
4. Device naming and PROFINET name assignment. Note the existing PROFINET device name and IP address of the station. The 1AA05 ships with the factory default name "im151-1pn"; this must be re-assigned to match the station name already known to the IO controller.
5. Slot documentation. Export the current slot table (Power Module, DO, DI, AI, AO, technology modules, etc.) so each module can be reinserted in the correct slot after the IM is re-stamped.
6. Spare IM151-1 PN of the new revision. Confirm that the spare carries the 6ES7151-1AA05-0AB0 label on the front face; do not rely on the carton label alone.

Step-by-Step Replacement Procedure in STEP 7 HW Config

The Replace Object command will fail with HW Config error 1230:5053 because the catalog lookup does not bridge from 1AA04 to 1AA05 automatically. Perform the swap manually as follows.

1. Open the STEP 7 project and launch HW Config.
2. Locate the ET 200S station containing the IM151-1 PN slot (typically slot 0).
3. Right-click the IM151-1 PN icon and select Object Properties. Record the PROFINET device name, IP address, and any slot-level parameters you customized (e.g., port assignment, fast start-up settings).
4. Close Object Properties, right-click the IM151-1 PN slot, and select Delete. Confirm the deletion — STEP 7 will only delete the IM itself, not the downstream I/O modules.
5. Open the hardware catalog and navigate to PROFINET IO → I/O → ET 200S → IM151-1 PN.
6. Insert the 6ES7151-1AA05-0AB0 entry into slot 0 of the station.
7. Re-insert every I/O module previously placed behind the IM, in the same slots, from the catalog. STEP 7 retains the symbolic IO addresses that were previously assigned because they live in the symbol table, but the slot assignments must be re-asserted manually.
8. Open Object Properties on the new IM and re-enter the original PROFINET device name, IP address, and any port or topology settings you recorded in step 3.
9. Save and Compile the HW Config. STEP 7 will regenerate the system data blocks (SDBs) for the station.
10. Download the new HW Config to the IO controller, but do not download to the ET 200S yet — the device name is still at factory default on the physical module.

Bringing the New IM151-1 PN Online

1. Power down the ET 200S terminal block and remove the 1AA04 IM.
2. Insert the 1AA05 IM into slot 0. The module's Power and Link/Activity LEDs will indicate PROFINET link state.
3. Power the station back up.
4. In HW Config, select PLC → Ethernet → Assign PROFINET Device Name. Browse the accessible nodes, select the MAC address of the new IM, and assign the previously recorded PROFINET device name.
5. Download the HW Config (or only the changed station) to the controller.
6. Open the online diagnostics in Online → Accessible Nodes or Online & Diagnostics on the IM to verify:

• PROFINET device name and IP match the project.
• All I/O slots report OK (green check).
• No diagnostic buffer entries indicating slot mismatch or sub-module mismatch.
• Firmware version of the new IM is shown in Module Information → Firmware.

Resolving HW Config Error 1230:5053

Error code 1230:5053 with the message "There is no replacement for this object" appears in HW Config when an engineer tries the Replace Object shortcut on a catalog object whose successor is not registered in the current HSP. The remedy is twofold:

1. Update the HSP. In HW Config, select Options → Install HW Updates. Connect to the Siemens support site (or pre-stage the HSP via DVD/folder) and install every applicable ET 200S HSP. Restart HW Config. After the HSP update, the catalog will expose the new revision and the Replace Object shortcut will succeed.
2. Manual replacement (always works). If the HSP update path is not available, perform the manual swap procedure documented in the previous section. The manual path is the field-proven method and does not depend on catalog auto-substitution.

Both 1AA04 and 1AA05 must be present in the catalog simultaneously for STEP 7 to recognize the swap; if only 1AA04 is present, HW Config will not allow insertion of 1AA05 either, and an additional HSP import is required.

HSP vs GSD File Considerations

For the IM151-1 PN swap covered here, the HSP is the binding element. The GSDML is not required for the head-end itself, but ensure downstream PROFINET device GSDMLs remain consistent across the controller project.

Module Replacement During Operation

Siemens explicitly documents the "Replace modules during operation" function for distributed I/O. While the canonical reference is for ET 200M, the same principle applies to ET 200S: pulling or inserting an I/O module while the backplane bus is live requires that the station has been configured for the operation. For ET 200S, the relevant configuration is to ensure that the slot reassignment described above is supported and that no active process data is currently using the module being swapped.

Reference: TIA Portal V20 — Configuration of the "Module replacement during operation" function.

Migration Path: ET 200S → ET 200SP

Because the entire ET 200S family is in spare-part supply only (announcement 109767411), long-term planning should target ET 200SP. Key migration points:

• Head-end replacement. ET 200SP IM 155-6 PN (e.g., 6ES7155-6AU01-0BN0 or later) replaces the IM151-1 PN. The new head-end is a different mechanical form factor; the backplane/base unit must be replaced as well.
• I/O module migration. ET 200S I/O modules are not directly plug-compatible with ET 200SP. Each signal must be re-mapped to an equivalent ET 200SP module (e.g., 6ES7131-6BF01-0BA0 DI 8x24VDC BA vs the ET 200S 6ES7131-4BF00-0AA0).
• Terminal block strategy. ET 200SP uses push-in or screw-type BaseUnits. Plan the wiring migration carefully; in many cases the conductor length and labeling can be retained with minor re-termination.
• Project re-import. TIA Portal offers a migration assistant for porting STEP 7 V5.x projects forward. STEP 7 V5.x → TIA Portal → ET 200SP is the recommended migration sequence rather than direct ET 200S → ET 200SP in STEP 7 V5.x.

Troubleshooting Matrix

Verification and Commissioning Checklist

1. PROFINET device name of the physical IM matches the project entry exactly.
2. IP address of the IM matches the project entry exactly.
3. All I/O slots report OK in Online & Diagnostics.
4. No diagnostic buffer entries on the IO controller referencing the swapped station.
5. Firmware version of the new IM is shown and compatible with the controller's GSDML/HSP expectations.
6. Symbolic IO addresses in the user program continue to read the correct process image.
7. Process-side signal test (force a known input, read on HMI / SCADA; command a known output, verify actuator).
8. Update the plant's asset register to record the new MLFB, firmware, and date of swap.
9. Archive the updated STEP 7 project.

FAQ