Connecting SINAMICS G110M to TIA Portal via PROFINET: BF Fault Resolution

The Siemens SINAMICS G110M is a distributed frequency inverter designed for asynchronous and synchronous motors in conveyor, pump, fan, and basic servo applications. The G110M is engineered as a PROFINET-native device, but it can also operate on EtherNet/IP depending on the firmware variant and parameterization. Field engineers frequently encounter a Bus Fault (BF) LED flashing red on first commissioning when the drive is wired to a PC or S7 controller with the wrong cable type, the wrong protocol selected, or an internal wiring defect.

This article documents a real commissioning fault where the BF LED flashed red and the drive was invisible to TIA Portal's "Accessible devices" view, then walks through the systematic diagnosis, including the root cause (a missing internal COM/shield wire) and the verification path.

1. SINAMICS G110M Hardware and Connector Overview

The G110M uses two M12 D-coded (4-pole) industrial Ethernet connectors on the front of the device for the PROFINET interface (X01 P1 and X01 P2 for line and daisy-chain). The 4-pole D-coded M12 connector is the standard PROFINET interconnection per IEC 61784-5-3 and carries two twisted pairs (100BASE-TX) plus shield.

Two common G110M connector variants exist in the field:

• 6GK1901-0DB20-6AA0 / 6XV1870-8A — pre-assembled PROFINET M12 D-coded patch cable (PUR), typically 1 m, 3 m, 5 m, 10 m, 15 m.
• 6GK1901-0DB10-6AA0 — M12 D-coded to RJ45 transition cable for connection to a standard Ethernet port (PC, switch, S7-1200/1500 CPU PROFINET port).

2. The BF LED — What the Red Flashing Actually Means

On the G110M the LED cluster is positioned on the front panel next to the M12 connectors. The relevant indicator is the BF (Bus Fault) LED:

The original incident reported BF red fast-flashing on the drive and no link LED on the PC network card. This combination is the fingerprint of a physical-layer problem (no electrical link is being established), not a configuration problem. TIA Portal's "Accessible devices" (Online → Accessible devices) only enumerates devices that have a valid Ethernet link, so the drive remained invisible.

3. Root Cause Analysis — Why the Drive Did Not Show Up

Three failure modes can produce the exact symptom seen in the field incident:

3.1 Cable assembly defect or wrong cable type

A "4-pole" cable in the hands of a non-PROFINET supplier can mean anything from a genuine M12 D-coded PROFINET patch to a 4-wire sensor cable. Confirm the cable is a PROFINET-certified M12 D-coded assembly (e.g., 6XV1870-8A family) with shield continuity end-to-end. Check the RJ45 wiring if you are using an M12-to-RJ45 adapter:

3.2 Protocol mismatch (PROFINET vs EtherNet/IP)

The SINAMICS G110M ships in a configuration that depends on the ordered firmware variant. The standard product is PROFINET-only. EtherNet/IP variants use the same M12 D-coded hardware but expect a different stack. If TIA Portal is being used to commission a unit that was loaded with EtherNet/IP firmware (or vice versa), the device will not respond to PROFINET DCP identification broadcasts and will appear invisible in "Accessible devices". Check the rating label: PROFINET units carry MLFB suffix -...PN and EtherNet/IP units carry suffix -...EI.

3.3 Internal COM / shield wire missing inside the drive (the actual fix)

The reported resolution — "There was a missing internal COM wire inside the drive" — is a documented G110M field failure. The internal functional earth / shield bonding from the M12 connector shell to the drive's internal ground reference is implemented with a short pigtail or contact spring inside the housing. If this bond is missing or the spring is not seated, the M12 connector shell does not make contact with chassis ground and the link LEDs will not light on either the drive or the partner (PC, switch, or CPU). Even a fully wired PROFINET cable can fail to link if the shield reference at the device is open. This is also why the PC network card showed no link LED: a 100BASE-TX PHY will refuse to bring up the link if it cannot establish a reliable common-mode reference through the cable shield.

4. SINAMICS G110M IP Address Configuration

Even after the physical layer is restored, the G110M requires an IP address. The drive supports three IP-assignment methods:

1. PROFINET DCP from the PROFINET controller (S7-1200/1500/ET200) — assigned during controller bring-up.
2. Star topology address assignment via the SINAMICS Startdrive commissioning tool or SINAMICS STARTER over the PROFINET interface, using the device's MAC address.
3. Service interface (USB) parameter download — the G110M has an internal mini-USB service port behind a captive screw. Use this to push an offline parameter set to the drive when the bus interface is unavailable.

USB-only IP modification will fail if the drive is in a non-PROFINET firmware state or if the parameter write is blocked by access level. Confirm:

• Parameter p0003 = 3 (Expert access) before writing p0924 (communication interface selection) or p8920..p8925 (PROFINET name-of-station) and p8930..p8939 (IP, subnet, default router).
• p2030 = 2 (PROFINET interface) — setting this to a value not supported by the firmware will silently fail to write.

5. TIA Portal Project Setup for the G110M

5.1 Add the G110M GSD

The G110M is integrated in TIA Portal V14 SP1 and later as part of the SINAMICS G device family. Install the GSDML package GSDML-V2.3-Siemens-Sinamics_G110M-... from the Siemens support download portal. After installation, the device appears in the hardware catalog under Other field devices → PROFINET IO → Drives → Siemens AG → SINAMICS → SINAMICS G110M.

5.2 Configure the PROFINET interface

1. Insert the G110M into the project view and connect its PROFINET port to the S7 CPU's PROFINET port.
2. Open the device properties → PROFINET interface → Ethernet addresses.
3. Set the IP address (e.g., 192.168.0.10), subnet mask (255.255.255.0), and PROFINET device name (e.g., g110m-001) to match the values loaded offline to the drive in Step 4.
4. Assign the controller as the PROFINET IO supervisor.

5.3 Slot assignment and Telegram

The G110M supports Standard Telegram 1, Standard Telegram 20, and the Siemens Telegram 350 (PZD 2/2 free mapping). For most conveyor/pump applications select Standard Telegram 1 (control word + setpoint in process data, status word + actual value back). The GSD exposes the following slot modules:

6. S7 Open User Communication — TCON Parameters for the G110M

If the application needs raw data exchange with the drive (e.g., acyclic parameter read/write via the PROFINET record interface), use the S7-1200/1500 TSEND_C, TRCV_C, and TCON instructions over Open User Communication. Per the SIMATIC S7-1200 manual collection, the TCON block requires a populated TCON_Param structure:

See the official Parameters for the PROFINET connection reference for full field semantics. The PROFINET device name must already be assigned to the G110M before any TCP connection succeeds, because the controller addresses the device by name during DCP discovery.

7. Verification — Bringing the Drive Online

1. Re-seat the M12 D-coded connector on the G110M until you hear a positive detent click. Apply 0.6–0.8 N·m if a torque spec is on the cable label.
2. Re-apply power to the drive.
3. Observe the G110M link LED (port 1 / port 2). A green steady link LED indicates the physical link is up.
4. Open TIA Portal → Online → Accessible devices. The G110M should appear with its PROFINET name and IP.
5. Go online with the device. Check parameter r8970 (PROFINET diagnostics) — it should report no active communication errors.
6. Force the controller into RUN. The BF LED should extinguish within 2–3 PROFINET update cycles (default 1 ms update). The drive's status word (ZSW1) bit 0 (ready to switch on) will toggle in the watch table.
7. Issue an ON command via STW1 = 047E hex (ready to switch on → operation enabled) and confirm the motor runs.

8. Symptom-to-Cause Diagnostic Matrix

9. Preventive Measures for the Field

• Use OEM-crimped PROFINET cables. Hand-crimped M12 D-coded assemblies are the single largest source of intermittent bus faults. Order pre-assembled cables from the Siemens 6XV1870-8A range with the required length and connector gender.
• Pre-stage the G110M offline. Use the USB service port to set p8920..p8939 (PROFINET name, IP, subnet) before machine installation. This way, the bus comes up cleanly the first time power is applied at the field site.
• Document the MLFB suffix. Maintain a label on every cabinet identifying each drive as -PN (PROFINET) or -EI (EtherNet/IP). Mixing protocols is the most common cause of "drive invisible to TIA Portal" reports after a re-order.
• Lock the IP against DHCP. The G110M defaults to DCP-assigned IP. If the network has a stray DHCP server, set p8924 = 2 (permanent IP) and commit with p8940 = 1.

10. Further Siemens Documentation

For protocol-level commissioning training using SIMATIC NET components and TIA Portal, see the Siemens training portal entry PROFINET with Industrial Ethernet in TIA Portal (IK-PNCOM). For the S7-1200 Open User Communication parameter structure referenced in this article, consult the official S7-1200 manual collection — Parameters for the PROFINET connection. The SINAMICS G110M operating instructions (Siemens document A5E31969960) contain the complete M12 pinout and the full parameter list for p0003, p0892, p0922, p2030, p8920..p8999 used in this commissioning flow.

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