SINAMICS S110 STARTER Connection Failure: CU305-PN V4.4 SSP Fix

Problem Description: SINAMICS S110 STARTER Cannot Go Online

During commissioning of a SINAMICS S110 single-axis servo drive equipped with a CU305-PN (PROFINET variant of the control unit) engineers frequently encounter a situation in which the STARTER commissioning tool's Accessible Nodes function discovers the drive on the PROFINET network but cannot establish an online connection. The drive appears in the discovered nodes table with its MAC address and (often) the default IP 0.0.0.0, yet clicking Connect produces a dialog that lists one of two conditions:

1. SSP is not installed — the device description does not match the connected drive firmware generation.
2. Connection can't be established — the S7ONLINE routing layer cannot reach the drive via the chosen PG/PC interface.

This reference documents the field-confirmed root cause on CU305-PN firmware version 4.40.45 (SINAMICS V4.4 platform) and the remediation path combining the SINAMICS Support Package V4.4 SP3 with a manually bound TCP/IP PG/PC interface. The same workflow applies to CU305-PN variants, CU305-DP variants configured for PROFINET over PN/PN couplers, and S110 firmware generations between V4.3 and V4.5 when the matching SSP is missing.

Affected Components and Versions

Component	Model / Variant	Firmware / Software	Status
SINAMICS S110	Single-axis servo drive	V4.4 (4.40.45)	Confirmed affected
Control Unit	CU305-PN (PROFINET, RT/IRT)	4.40.45	Confirmed affected
STARTER commissioning tool	V4.4 / V4.4 SP1 base	Pre-V4.4 SP3 SSP	Confirmed affected
SINAMICS Support Package	SSP SINAMICS V4.4 SP3	Build per SIOS 109476277	Resolution
Controller	SIMATIC S7-1200 (any CPU with PN interface)	Firmware V4.x	Independent of issue
PROFINET switch	Managed or unmanaged, LLDP-capable recommended	n/a	Independent

Root Cause Analysis

The cannot connect behavior has two independent, additive causes. Either one will produce the symptom; in many field cases both apply simultaneously.

Cause 1 — Missing or Mismatched SINAMICS Support Package

STARTER does not ship with device descriptions for every SINAMICS firmware generation. Instead, each firmware generation is delivered as a separately installable Support Package (SSP) that contains the device description files (DDT/DCF), GSD/GSDML files, parameter list updates, and alarm-text catalogs. Without an SSP matching the connected drive firmware, STARTER finds the node at the discovery layer (the drive responds to PROFINET DCP identification) but cannot decode the device or open a routed S7ONLINE connection because the object dictionary it expects does not exist on disk.

For SINAMICS V4.4 firmware, the matching SSP is SINAMICS V4.4 SP3, published under SIOS entry 109476277. Earlier Service Packs (SP1, SP2) cover V4.4.x firmware point releases but are not sufficient for the 4.40.45 build that ships on drives delivered in 2024 and later.

Cause 2 — PG/PC Interface Configured to AUTO

STARTER uses the SIMATIC S7ONLINE routing layer to reach PROFINET nodes. The Set PG/PC Interface dialog defaults to AUTO selection, which lets Windows pick the first active Ethernet adapter. On typical engineering laptops this resolves to a Wi-Fi adapter, a Hyper-V virtual switch, a VPN tunnel adapter, or a USB-Ethernet dongle — not the physical PROFINET port wired to the drive. STARTER therefore fails the connection even though the drive is reachable via the correct adapter.

Symptoms consistent with this cause:

• Accessible Nodes lists the S110 IP address correctly.
• ICMP ping to the drive IP succeeds when issued from the correct NIC.
• STARTER still fails the online connection within 10–30 seconds with no detailed error.
• Microsoft Network and Sharing Center shows another adapter (often the Wi-Fi) as the active default route.

Solution 1 — Install SINAMICS Support Package V4.4 SP3

The confirmed primary fix for CU305-PN V4.4 (4.40.45) firmware is the SINAMICS Support Package V4.4 SP3.

Obtaining the Package

Download from Siemens Industry Online Support:

• SINAMICS Support Package V4.4 SP3 — SIOS 109476277

Authentication requires a Siemens Industry account. The download is an executable installer that registers the new device descriptions in STARTER, in the TIA Portal hardware catalog (when Startdrive is installed), and in the SIMOTION SCOUT device library. The installer is version-stamped; verify that the package supports S110 explicitly in the release notes before installing in production.

Installation Procedure

1. Close all Siemens applications — STARTER, TIA Portal, Startdrive, SIMOTION SCOUT, SINUMERIK Operate, and the SINAMICS PC tools.
2. Right-click the SSP executable and select Run as administrator.
3. Accept the default installation path (typically C:\Program Files\Siemens\Automation\SINAMICS).
4. Wait for the installer to register device descriptions in the Windows registry and to copy the GSD/GSDML files to the SIMATIC installation tree.
5. Reboot the PC to clear cached device-description handles.

Verification Inside STARTER

1. Launch STARTER.
2. Navigate to Help → Installed Devices.
3. Confirm the entry SINAMICS S110 V4.4 SP3 appears with a build date matching the package release.

If the entry is missing or shows an older Service Pack (for example SP1), the SSP did not install correctly. Re-run the installer as administrator and check the Windows Event Viewer under Application for setup errors. A common cause is UAC interception of the device-description registration step when the installer is launched without elevation.

Solution 2 — Configure PG/PC Interface for a Specific TCP/IP Adapter

Bind STARTER to the correct Ethernet adapter to eliminate the AUTO-routing failure mode.

Set PG/PC Interface in STARTER

1. Open STARTER → Options → Set PG/PC Interface.
2. Select the access point S7ONLINE (STEP 7) (or the access point assigned to STARTER by the installer).
3. Under Interface Parameter Assignment Used, select the specific physical Ethernet adapter connected to the PROFINET subnet, e.g., TCP/IP → Intel I219-V Ethernet or TCP/IP → Realtek PCIe GbE Family Controller.
4. Do not leave the selection on AUTO.
5. Click OK to commit.

Assign a Static IP to the PC Adapter

Static IP assignment eliminates DHCP variability and prevents the PROFINET segment from being routed through a default gateway.

1. Open Windows Settings → Network & Internet → Ethernet or via the legacy Control Panel → Network and Sharing Center → Change Adapter Settings.
2. Right-click the PROFINET-connected adapter → Properties → Internet Protocol Version 4 (TCP/IPv4) → Properties.
3. Select Use the following IP address and enter an address on the same /24 subnet as the drive (e.g., 192.168.0.10 / 255.255.255.0 for a drive at 192.168.0.1).
4. Leave the Default gateway and Preferred/Alternate DNS server fields empty.
5. Click OK and close all dialogs.

Verify Layer-3 Reachability

ping 192.168.0.1

A successful reply confirms layer-3 connectivity between the engineering PC and the drive. If ping fails, verify cabling, switch port activity LEDs, and the PROFINET station name assigned to the CU305-PN.

STARTER Installation Best Practices

When installing STARTER for the first time or after a major version change, use the complete Siemens media set. Partial installations are the most common cause of missing-device-description failures during commissioning.

Required Media

Disk	Contents	Required For
STARTER CD1	Core commissioning tool, base platform, online help	All installations
STARTER CD2	GSD/GSDML files for SINAMICS V4.4 and older firmware generations	PROFINET integration into STEP 7 / TIA Portal
STARTER CD3	Firmware images, additional language packs, manuals	Firmware updates, localized HMI text
SSP V4.4 SP3	Device descriptions for V4.4 firmware	Online connection to S110 V4.4 drives

CD2 is the most frequently skipped disk. Missing GSD/GSDML files cause STARTER to fail silently when an engineer adds SINAMICS drives to a project offline or attempts to import PROFINET device descriptions into STEP 7 V5.x.

Clean Reinstall Procedure

1. Uninstall STARTER via Control Panel → Programs and Features.
2. Delete residual folders: C:\Program Files\Siemens\Automation\STARTER, %APPDATA%\Siemens\STARTER, %LOCALAPPDATA%\Siemens\STARTER.
3. Reboot the PC.
4. Install CD1 as administrator.
5. Install CD2 and CD3 in sequence.
6. Install the matching SSP for each firmware generation in use.
7. Reboot and verify via Help → Installed Devices.

PROFINET Network Configuration Requirements

Connection troubleshooting requires verification across the full TCP/IP and DCP layer stack before assuming an SSP fault.

Layer 1 / Layer 2 Checks

• Confirm green link LEDs on both the switch port and the S110 X150 P1 or X150 P2 PROFINET ports.
• Use CAT5e or higher rated cabling. Maximum segment length per PROFINET specification is 100 m.
• For copper-based PROFINET, use shielded twisted pair designed for industrial Ethernet (e.g., Siemens IE FC TP Standard Cable).
• If the managed switch supports QoS, prioritize PROFINET frames (DSCP class 6 / VLAN priority 6) on the affected ports.

Layer 3 / DCP Checks

The CU305-PN ships with a default IP of 0.0.0.0 and no PROFINET station name. The drive is invisible to TCP/IP until the PROFINET controller assigns a name. Once a name is written, the controller (S7-1200) downloads the IP address from its IO device configuration.

• Use the S7-1200 TIA Portal Devices & Networks view to assign the PROFINET device name.
• Alternatively, use the free Siemens PRONETA tool to scan, name, and analyze PROFINET nodes.
• After naming, restart the drive or power-cycle it. The new IP and name become active after the next PROFINET AR (Application Relationship) establishment.

Firewall Considerations

Windows Firewall and corporate endpoint protection can block the UDP/TCP ports used by S7ONLINE and PROFINET DCP. Required ports:

Protocol	Port	Used By
UDP	34964	PROFINET DCP (Discovery and Configuration Protocol)
TCP	102	ISO-on-TCP / S7ONLINE for STARTER routing
UDP	161	SNMP (optional, for diagnostic tools)
UDP	162	SNMP traps (optional)
UDP	67/68	DHCP (only when used for IP assignment)

Create inbound and outbound firewall rules that scope the STARTER executables (STARTER.exe, S7WEBS.exe) to the specific Ethernet adapter's subnet. Avoid blanket allow rules across all profiles.

Verification Procedure After Remediation

1. Open STARTER and create or open the project containing the S110.
2. Right-click the S110 in the project tree and select Connect to Target System, or click the lightning-bolt online button in the toolbar.
3. Confirm STARTER reads the drive parameters online. First connection can take 5–15 seconds as STARTER uploads the project tree and parameter values.
4. Navigate to Drive → Configuration → Parameter list and verify live parameter values appear (especially r0002 drive state and r0019 current operating display).
5. Open the diagnostic buffer (Drive → Diagnostics → Diagnostic buffer) and verify that events with timestamps are listed.
6. Test write access by changing a non-critical parameter (for example p0010 commissioning filter) and confirming the change persists across online/offline toggles.

Troubleshooting Matrix

Symptom	Likely Cause	Corrective Action
Accessible Nodes shows drive IP, no device name	PROFINET station name not assigned	Assign name from TIA Portal or PRONETA, restart drive
Accessible Nodes shows drive, “Connection can't be established”	Wrong PG/PC interface selected	Bind TCP/IP to the specific NIC, not AUTO
Accessible Nodes empty after search	Wrong subnet, firewall, cabling, or PROFINET switch VLAN	Verify NIC IP, ping drive, check firewall rules and VLAN membership
Accessible Nodes shows drive but STARTER does not list V4.4 in Installed Devices	SSP V4.4 SP3 missing	Install SSP V4.4 SP3, restart PC
“Firmware version not supported” error on connect	STARTER base version predates drive firmware	Upgrade STARTER base or install matching SSP
Ping succeeds, STARTER fails to go online	S7DOS / S7ONLINE service not started	Start the “S7DOS Help Service” via services.msc, set startup to Automatic
Connection succeeds but parameter list is empty	Offline project mismatch with drive firmware	Run “Load to PG” to upload actual drive configuration
Connection succeeds, parameter list correct, but writes are rejected	Commissioning filter (p0010) blocks parameterization	Set p0010 = 0 to leave commissioning mode, then retry
Drive cycles online connection every 30–60 seconds	PROFINET watchdog timeout — update time too short	Increase send clock / update time in the S7-1200 PROFINET IO device configuration
STARTER shows S110 with red fault icon	Active drive fault (F-code) or alarm (A-code)	Read diagnostic buffer, resolve per fault code, acknowledge with p3981

Alternative Path — TIA Portal with Startdrive

For new projects Siemens recommends Startdrive (integrated into TIA Portal) over legacy STARTER. Startdrive V15 and later natively support the SINAMICS S110 including the CU305-PN and benefit from a unified project model with the SIMATIC S7-1200 or S7-1500 controller.

Startdrive Advantages Over STARTER

• Single-tool integration — drive and PLC commissioning in one TIA Portal project.
• Automatic GSDML handling via the Hardware Support Package (HSP) workflow.
• Integrated Safety Acceptance Test workflow for SINAMICS drives with Safety Integrated.
• Online parameter comparison between offline project and live drive using delta highlighting.

Migrating STARTER Projects

Existing STARTER projects can be migrated to TIA Portal using the TIA Portal project converter. The conversion preserves the drive topology and parameter values; however, references to GSD-based third-party IO need manual review.

SINAMICS S110 Operating Instructions — SIOS contains the canonical commissioning procedure and lists all SSP / HSP compatibility matrices per firmware generation.

Diagnostic Buffer Interpretation

After restoring the online connection, always read the diagnostic buffer before continuing commissioning. It records the last 64 drive-side events with timestamps and provides the only definitive evidence that a fault is historical or active.

Common Diagnostic Events

Code / Number	Meaning	Resolution
F08501 — PROFINET communication failure	AR (Application Relationship) lost	Check cabling, station name, controller state
F08502 — Sign-of-life monitoring failure	Watchdog timeout on PROFINET	Increase update time / reduce bus load
F08505 — PROFINET IP address conflict	Duplicate IP on subnet	Assign unique IP, verify with ARP scan
A08502 — PROFINET sign-of-life warning	Brief watchdog trip, not a fault	Monitor for recurrence, typically benign on first connection
F30001 — Power unit overcurrent	Hardware fault or motor short	Inspect motor, wiring, and DC-link voltage
F07802 — Drive commissioning incomplete	Required parameters not entered	Run STARTER commissioning wizard for motor ID

Acknowledge faults after resolution using the STARTER toolbar (or set p3981 = 0 to clear the fault buffer). The drive will not enter Ready state (r0002 = 0) until all active faults are cleared.

Parameter Backup and Restore

Always perform a parameter backup before firmware updates, SSP changes, or major parameter modifications. STARTER provides two backup paths.

Upload to PG (Recommended for Service Work)

1. Connect online to the drive.
2. Right-click the S110 in the project tree → Load to PG.
3. Save the resulting .dnc archive to a versioned project folder.

Backup to Memory Card

The CU305-PN ships with an optional SIMATIC Memory Card slot that supports the SINAMICS CF card (6SL3054-0AA00-1BA0 or successor part numbers). The CF card stores a complete drive image including firmware and parameters, allowing field replacement without STARTER.

1. Insert a blank or compatible CF card into the CU305-PN slot.
2. Set p0802 = 1 to start the backup from drive to card.
3. Wait for p0802 to revert to 0 automatically, indicating completion.
4. Remove the card and label it with the drive serial number and date.

Firmware Update Procedure

If the drive is on firmware older than 4.40.45 and STARTER reports the version as unsupported after the SSP update, perform a firmware update via STARTER or via the CF card.

Update via STARTER (Online)

1. Connect online to the drive.
2. Right-click the S110 → Load Firmware to Target System.
3. Select the firmware file matching the SSP version (typically SINAMICS S110 V4.4 HF8 or higher).
4. Accept the warning that parameters will be reset to factory defaults.
5. Wait for the update to complete (3–8 minutes depending on file size) and the drive to restart.

Update via CF Card

1. Copy the firmware file to the root of a compatible CF card.
2. Insert the card into the CU305-PN.
3. Power up the drive. The CU305-PN detects the firmware file and begins the update automatically.
4. Wait for the RDY LED to transition from flashing at 2 Hz to solid green.

Web Server Alternative Access

When STARTER commissioning is unavailable, the SINAMICS S110 ships with an integrated web server that provides read access to parameters and the diagnostic buffer via a standard browser. This is invaluable for remote support when an engineer cannot install STARTER on-site.

Enabling the Web Server

1. Set p8985 = 1 via STARTER, BOP-20, or the S7-1200 PROFINET write.
2. Set p8986 = 80 for HTTP or 443 for HTTPS.
3. Save parameters (p0977 = 1) and restart the drive.

Open a browser to http://<drive-ip> and log in with the configured user credentials. The web interface exposes parameter read-only access, alarm history, and firmware version information. Write access requires the appropriate user role (default roles are SINAMICS, Siemens, and Anonymous).

CU305-PN LED Diagnostics

LED	State	Meaning
RDY (Ready)	Solid green	Drive ready, no faults
RDY	Flashing green 0.5 Hz	Commissioning mode (p0010 <> 0)
RDY	Flashing red 2 Hz	Active fault, drive not ready
RDY	Solid red	Boot error or firmware corrupt — CF card recovery required
LINK (Port 1 / Port 2)	Solid green	Ethernet link established
Activity (Port 1 / Port 2)	Flashing yellow	Ethernet traffic present
BF (Bus Fault)	Solid red	No PROFINET communication with controller
BF	Flashing red 0.5 Hz	PROFINET station name missing or wrong
SF (System Fault)	Solid red	Group fault present, check diagnostic buffer

A solid red RDY LED combined with a failed STARTER connection almost always indicates firmware corruption. Recover by inserting a CF card containing a known-good firmware image and power-cycling the drive. The CU305-PN will detect the image and reload automatically.

Field-Proven Engineering Notes

• The default drive IP of 0.0.0.0 is a valid DCP response — STARTER will still list the device. Do not interpret a non-zero IP in the discovery table as a connectivity confirmation.
• STARTER V4.4 base install only ships SSP for the firmware that was active at the time of the media release. Drive firmware released later requires an updated SSP even when the STARTER base version is unchanged.
• Running STARTER in a Windows virtual machine is not officially supported by Siemens. If VM use is unavoidable, bridge the PROFINET adapter directly to the VM and disable the host's TCP/IP stack on that adapter to prevent the host's AUTO selection from intercepting PROFINET traffic.
• CU305-PN ports P1 and P2 are switched internally; either can be used for the controller connection. Daisy-chaining additional PROFINET devices is supported, but the ring should not exceed the PROFINET update-time and topology budget configured in the controller.
• When the S110 is integrated with an S7-1200, the controller's PROFINET IO device configuration determines the IP address, device name, and update time. STARTER cannot push these values; it can only read them after the controller has assigned them.
• Antivirus software with deep-packet inspection can drop UDP 34964 DCP frames, making the drive invisible to Accessible Nodes. Add STARTER executables to the antivirus exclusion list or switch the policy to scan on write only.

FAQ