Restoring PROFINET Name and IP After SINAMICS G120C Drive Swap

Replacing a SINAMICS G120C power stage in a SIMOTION-controlled machine is a textbook maintenance task: backup the parameters with the BOP-2, swap the drive, restore the parameter set, and the machine should run as before. The catch that trips up most field engineers is that the BOP-2 (and the SD card) do not copy the PROFINET device name or the IP address. A drive that powers up with default PROFINET identity will not be recognised by the SIMOTION IO controller, the cyclic telegrams stay down, and the entire axis goes into fault. This reference documents the exact root cause, the affected parameter numbers, and four field-proven recovery procedures.

1. Problem Scope and Field Scenario

The classic failure mode looks like this:

1. Machine has a SIMOTION D4x5 controller commanding 4–12 G120C drives over PROFINET.
2. One G120C power stage fails (over-current, short circuit, IGBT fault). The CU240E-2 PN control unit typically survives.
3. Maintenance replaces the drive with an identical article number from the spare-parts shelf.
4. Technician plugs the BOP-2 into the new drive, runs TO BOP on the broken drive, then FROM BOP on the new drive, then RAM to ROM.
5. Power-cycle. PROFINET LED on the CU stays red/orange. SIMOTION diagnostic buffer reports PROFINET IO: Device failure. Drive will not enter RUN.

The technician assumed that an "all-parameter" backup would include the network identity. It does not, and the resulting downtime is exactly the scenario the BOP-2 was supposed to prevent.

2. Affected Hardware, Article Numbers, and Firmware

Refer to the SINAMICS G120C Operating Instructions for the full frame-size map. The behaviour described in this article applies to firmware V4.4 through V5.2 SP3 (all G120C variants released to date). Confirm the firmware in r0018 or via the BOP-2 menu Extras → Drive identification before re-applying any backup.

3. Why BOP-2 and SD Card Backups Skip PROFINET Identity

PROFINET device name and IP are interface parameters handled by the PN stack on the CU240E-2 PN, not by the SINAMICS parameter system in the classical sense. The PROFINET stack stores them in a separate non-volatile region that is managed by the DCP (Discovery and Configuration Protocol) layer:

• The drive parameter system is the "application layer" of SINAMICS (motor data, ramps, control words, setpoint sources).
• The PROFINET stack is the "communication layer" and is provisioned by the IO supervisor (SIMOTION, S7-1200, S7-1500) using DCP.

The BOP-2 TO BOP function serialises only the application-layer parameter set (a few hundred to a few thousand parameters, depending on firmware). The PROFINET stack is intentionally excluded because the IO controller is the authoritative source for network identity. A backup that silently overwrote the device name would be a safety hazard: it could cause a "wrong" drive to appear online at an address the controller did not assign.

4. SINAMICS G120C PROFINET Identity Parameter Map

The following parameters constitute the PROFINET identity of the drive and are the only ones you need to re-apply after a swap:

Source: SINAMICS G120/G120C/G110M List Manual, section "Communication / PROFINET".

5. Drive Replacement Workflow Selection

Choose the method that matches the available tooling on site. Methods 1–3 are manual recovery; Method 4 is preventive design.

6. Method 1 — Restoring PROFINET Identity via TIA Portal / SCOUT

This is the canonical workflow for SIMOTION-based machines and for S7-1500 / S7-1200 systems.

Prerequisites

• TIA Portal V17 SP1 (or current) with the G120C HSP installed, or SIMOTION SCOUT TIA.
• Engineering laptop on the same PROFINET network (or directly connected to a switch port).
• Project file (.ap17) that contains the device configuration with the original device name and IP.

Procedure

1. Open the project, expand Devices & Networks, locate the G120C in the device table.
2. Right-click the device → Assign PROFINET device name.
3. In the dialog, set:
   • PROFINET device name: exact name from the project (e.g. g120c_axis3). Case-sensitive.
   • PN interface 1 / Port 1: MAC address of the new drive, or "All" if only one unmatched drive is on the network.
   • Click Assign name. The PROFINET LED on the new drive should change from flashing red to flashing green within 2 seconds.
4. Once the name is assigned, the SIMOTION IO controller will push the IP address automatically through DCP. Confirm via the drive's BOP-2 menu Extras → PROFINET diagnostics that r8931 shows the expected IP (e.g. 192.168.0.13).
5. Trigger a SIMOTION restart of the PROFINET interface (e.g. _activate_profinet_interface() or simply power-cycle the SIMOTION rack if practical). The drive should establish the AR and the cyclic telegrams will start within a few seconds.
6. Verify r8936[0] = "PN IO OK" (or equivalent PROFINET status word) and that the SIMOTION axis no longer reports PROFINET IO device failure.

For SIMOTION SCOUT (legacy), the same function is at HW Config → PN IO → Assign device name; the result is identical.

7. Method 2 — Restoring PROFINET Identity via PRONETA

PRONETA is a free-of-charge Siemens tool designed for exactly this kind of field service. It works without a TIA project and is ideal for technicians who only need to re-assign name and IP. Download from the PRONETA tool page.

Procedure

1. Install PRONETA V3.x on a Windows laptop. Connect the laptop to the same PROFINET subnet as the new drive (any spare switch port is fine).
2. Start PRONETA → Network analysis. The tool will discover all PROFINET devices on the subnet, including the new G120C (it will appear with name = "" and IP = 0.0.0.0, marked as "Unconfigured").
3. Switch to IO test mode. The unconfigured drive will be listed with its MAC address and the type "SINAMICS G120C".
4. Right-click the new drive → Assign station name. Enter the original PROFINET name (the value previously in p8920 / r8930) and confirm.
5. Re-run network analysis. The drive should now appear with the correct name. If the IP is still 0.0.0.0, set it manually:
   • Right-click → Set IP address → enter the original IP / subnet / gateway. This writes p8921–p8923 directly.
6. Power-cycle the drive to apply the new identity if the IO controller has already attempted to AR with the old (default) settings.

8. Method 3 — Restoring PROFINET Identity via STARTER or Startdrive

Use this when no TIA project is at hand and the engineer has direct access to the drive via PROFINET or the serial RS232 USB interface.

Via PROFINET online access (Startdrive in TIA Portal)

1. Open TIA Portal, switch to Online & diagnostics, browse the accessible nodes. The new G120C will appear with name "" and a temporary IP (e.g. 0.0.0.0 or a DHCP-assigned address).
2. Right-click → Online & diagnostics → Assign IP address if needed (so you can establish a routing connection).
3. Open the project view, expand the drive in the device tree, and use the Parameters editor to write:
   • p8920 = original device name
   • p8921 = original IP address
   • p8922 = original default gateway
   • p8923 = original subnet mask
   • p8925 = 1 (DCP-assigned, recommended for IO-controller-managed networks)
4. Perform Copy RAM to ROM in the same tool (right-click the drive → Online & diagnostics → RAM to ROM). This writes p8920–p8923 to the non-volatile store.
5. Power-cycle the drive. The IO controller will re-AR with the new identity.

Via STARTER (legacy, RS232 or PROFINET)

1. Connect via the drive's RS232 service port (X12) with a USB-RS232 adapter, or via PROFINET through the same switch as the SIMOTION.
2. STARTER → Online → Accessible nodes. Identify the new G120C.
3. Open the expert list, filter on p892x, and edit the four parameters as above.
4. RAM to ROM, then power cycle.

Note that STARTER is end-of-life since 2018; prefer Startdrive for new installations. See the Startdrive documentation.

9. Method 4 — SIMOTION Topology-Based Automatic Name Assignment

This is the "do it once, save time forever" approach. If the PROFINET topology (port-to-port neighbours) is configured in the SIMOTION project, the IO controller can recognise a "new device" at a previously-occupied port and re-assign the original name automatically on the next AR attempt. This is what some engineers refer to as "the PLC handles the names and IPs".

Prerequisites

• Topology editor configured in HW Config (SCOUT) or device view (TIA Portal) for every PROFINET port on every device.
• Spare drive is of the same type (same article number) so that the IO controller can match device identification.
• The replacement device has not been manually assigned a different name (i.e. it is a "blank" drive with name = "").

Field Procedure

1. Remove the broken drive, install the new G120C, connect the PROFINET cables to the same ports (port 1 typically).
2. Apply power. The PROFINET LED will flash rapidly (looking for name). Within 30–60 s, the SIMOTION controller detects the unmatched device, consults its topology, and assigns the original name via DCP. The LED switches to solid green or to the standard "PROFINET OK" pattern.
3. The IO controller then pushes the original IP. Cyclic telegrams start.
4. On the HMI / engineering station, verify that the axis is back online. No PC tool required at the machine.

10. SD Card vs BOP-2 vs IOP-2 Backup Coverage

This table is the single most important reference for a field engineer choosing a backup medium. The PROFINET identity gap is consistent across all three drive-local media.

11. Verification Checklist After Drive Replacement

1. Power stage OK: BOP-2 shows no active fault (F-class); r0019 shows operating state Ready or Run.
2. PROFINET identity: r8930 (active name) matches the project, r8931 (active IP) matches the project, p8926 bits 0 and 1 are 1.
3. AR established: PROFINET LED is solid green (not flashing). SIMOTION diagnostic buffer shows no PROFINET alarm for this station.
4. Cyclic telegrams: In Startdrive / STARTER online mode, expand the drive → Diagnostics → Telegram diagnostics and confirm counter increments on r2050[0] (receive) and r2053[0] (send).
5. Control word handshake: Force the axis to a known speed (via SIMOTION test mode) and verify r8991 (active speed setpoint) tracks the setpoint within the configured ramp time.
6. Encoder / actual value: r0021 (smoothed actual speed) follows r0022 (actual speed). For encoderless drives, check r0061 (rotor angle) for plausibility.
7. Safety (if PROFIsafe): Re-validate the F-CPU signature (PROFIsafe CRC1 / CRC2). The F-address (p9610) survives the BOP-2 backup but the F-host must re-acknowledge.
8. RAM to ROM: Confirm on the new drive that a power-cycle does not lose any of the restored parameters. If anything reverts, the RAM to ROM step was skipped.

12. PROFIsafe and Telegram Considerations

PROFIsafe address (p9610) and the associated F-parameters are part of the standard parameter set and are included in a BOP-2 / SD card backup. However, the safety commissioning procedure must still be repeated end-to-end:

• The F-CPU stores a CRC of the PROFIsafe configuration; after drive replacement, the F-CPU raises a "safety signature mismatch" until the new signature is accepted via the F-CPU's web server or TIA Portal Safety Administration.
• Test the STO / SS1 / SLS functions according to the machine's safety validation report. The parameters are restored, but the proof of function must be repeated.
• If the spare drive was previously used in a different safety configuration, perform a "Restore factory settings" on the safety functions (p0010 = 30 → p0970 = 1) before loading the project backup.

PROFINET telegram configuration (Standard Telegram 1, 2, 3, 5, 6, 7, 9, 110, or 111) is stored in p922 and p2079 and is included in the BOP-2 backup. The SIMOTION HW Config / TIA device configuration remains the source of truth, and any mismatch between the configured telegram in the project and the drive will be flagged as a PROFINET fault on AR startup.

13. Troubleshooting Matrix

14. Preventive Measures for the Next Drive Swap

1. Document PROFINET identity in the machine file: For every G120C, record its PROFINET name, IP, subnet, gateway, and the SIMOTION slot / IO device number. A one-page appendix per machine is enough.
2. Store a PRONETA "Settings backup" CSV on the engineering server. It is generated in seconds and recovers a swap in two clicks.
3. Configure topology in the SIMOTION / TIA project for every G120C port. This converts the swap from a 10-minute PC procedure into a 1-minute power-on procedure.
4. Keep at least one engineering laptop with TIA Portal and PRONETA on site, or stash a USB stick with both installers in the cabinet.
5. Standardise spare drives: Buy spares of the exact article number. Mixed-stock drives (different power, different firmware) complicate the topology match.
6. Pre-stage the spare drive with a generic identity ("spare_axis_1") if you must, but never with a name from another machine, or the topology-based assignment will refuse to overwrite it.
7. Update the BOP-2 firmware if Siemens has released a BOP-2 update that adds PROFINET identity to the backup. As of the latest SINAMICS release notes, this is a long-standing customer request and is the single most impactful improvement that would close the gap.

15. Flowchart: Decision Tree on Drive Swap

Use this inline diagram as a quick field reference:

16. Frequently Asked Questions