Resolving SCALANCE XC208 PROFINET Name Errors in S7-1500R Systems

Problem Overview

When integrating a SCALANCE XC208 managed switch into an S7-1500R redundant PLC system with ET 200SP distributed I/O and a TP1200 Comfort HMI, two symptoms typically appear together: the SCALANCE XC208 reports a steady red Fault LED on its status row and the primary and backup S7-1500R CPUs show a flashing red SF (Group Fault) LED on the front face. Both indicators point to the same underlying defect: the PROFINET IO device name programmed into the SCALANCE XC208 at commissioning does not match the PROFINET station name configured inside the TIA Portal V16 project.

On a PROFINET network, every IO device must carry a unique device name. The IO controller uses the name to address the device, exchange AR (Application Relationship) and CR (Communication Relationship) parameters, and download the expected slot configuration. If the controller's name table does not match the actual name stored in the device, the AR is rejected, the device drops out of cyclic data exchange, and both the controller and the device raise diagnostic alarms that surface as the LEDs described in this article.

Affected Hardware and Firmware

Verify the SCALANCE firmware load via the Web-Based Management (WBM) page Information > Versions, or through the TIA Portal online > Diagnostic > Firmware view. TIA V16 supports SCALANCE XC208 firmware up to V4.3 only. If the switch ships at V5.0 or higher, the device can still be discovered by PRONETA 3.x, but TIA V16 will not load its GSD; in that case upgrade the project to TIA V17 or downgrade the switch firmware using the Siemens SCALANCE XC208 operating instructions and the SIMATIC Automation Tool firmware loader.

SCALANCE XC208 LED Diagnostic Reference

The XC208 front panel carries one row of port LEDs (1 through 8) and a top status row. The most important status indicators for the fault described in this article are summarized below.

A steady red Fault LED on the XC208 combined with a flashing red SF LED on the CPU's front face is the classic PROFINET name mismatch signature. The same combination can also be triggered by an IP address conflict, but that condition is rarer because Siemens ships all PROFINET devices with IP 0.0.0.0 and no IP is assigned until the device name is successfully resolved. Refer to the official SCALANCE XC208 manual for the full LED truth table.

Root Cause: PROFINET Device Name Mismatch

PROFINET IO discovery relies on the DCP (Discovery and Configuration Protocol) Get-Name and Set-Name services. When the IO controller powers up, it broadcasts an Identification request using the configured device name. If a device on the network answers with a different name, the controller will not associate that physical device with the expected slot configuration. Four situations typically lead to a name mismatch on the SCALANCE XC208:

1. The project was downloaded to the CPU but the PLC programmer forgot to use Assign PROFINET device name against the switch. The switch retains its factory name (empty string) or a name from a previous project.
2. The switch was pulled from a previous line that used a different name, and the new project assigned a new name in the device view but the assign-name step was skipped or the target MAC was wrong.
3. The PROFINET device name was typed differently (case-sensitive) in the TIA project versus what was assigned to the device. PROFINET device names are case-sensitive and limited to 240 characters; the first character must be a letter.
4. A topology editor port assignment points to a port that is not where the cable is physically connected, and the TIA Portal name-assignment utility targets the wrong device on the network.

The IO controller will log a diagnostic event similar to "PROFINET IO: Station failure on IO device [name]" with event ID 0x013C or 0x0192. The SCALANCE Web-Based Management under Information > PROFINET IO will show "AR status: No AR" or "AR rejected by controller". Detailed reasons are listed in the PROFINET commissioning guideline.

TIA Portal V16 Diagnostic Procedure

Follow the sequence below to confirm the name mismatch and isolate any other contributors before applying the fix.

1. Open the TIA Portal project and go online with the S7-1500R primary CPU (Online > Go online > CPU 1515R-1 PN > Online & diagnostics).
2. Open Project tree > Devices & networks and double-click the SCALANCE XC208 icon. The status indicator at the top of the device view should display the device as "Not reachable" if the AR cannot be established.
3. Open Online & diagnostics on the SCALANCE XC208. Select the Diagnostic buffer tab. Look for entries of type "PROFINET IO AR rejected" or "DCP: name not found".
4. Right-click the CPU in the project tree and select Online & diagnostics > Diagnostics buffer. Typical entries on the CPU side include:
   • Event ID 0x013C: "IO device failure"
   • Event ID 0x0192: "IO device: station failure"
   • Event ID 0x001B: "PROFINET interface: name resolution error"
   • Event ID 0xE002: "PROFINET IO port error" (cable/wrong port)
5. Open Online > Accessible nodes in the project tree. The empty node list is itself a clue. If the SCALANCE XC208 is not listed, DCP discovery is failing and the device is not reachable on Layer 2. If it is listed but with a different name, the mismatch is confirmed.
6. Cross-check the topology editor: Topology > Online view will show the cable that connects the I/O module to the XC208 in red with a "Port mismatch" warning if the physical connection does not match the planned topology. Although the topology editor is optional for plain RT, configuring it surfaces cable mis-wires during engineering and is required for IRT (Isochronous Real Time) and for explicit MRP ring-port assignments in the XC208.

Topology Editor Configuration for XC208

Even when MRP is the only redundancy mechanism used, a populated topology helps during commissioning and during the diagnostic step above. The topology editor in TIA Portal V16 is reached from Devices & networks > Topology view. Right-click each port and select Add port connection or use the Interconnections pane to draw the planned links. A typical S7-1500R line with one SCALANCE XC208 follows the table below.

When the topology is loaded and online, the Online topology view paints each connection in the same color used in the offline topology. A red line means the planned port is not the actually used port (different physical port number, or no cable at all). This is the easiest way to discover that the SCALANCE XC208 was patched to a different port than the project planned, which is the second most common cause of "device not reachable" alarms even after the name has been corrected.

Step-by-Step Resolution: Assigning the PROFINET Device Name

1. In the TIA Portal project tree, expand Devices & networks and right-click the SCALANCE XC208 device icon. Choose Assign PROFINET device name (German: PROFINET-Gerätenamen zuweisen).
2. The dialog shows the configured PROFINET name from the project (e.g. xc208-line1), the configured IP (e.g. 192.168.0.30 with subnet 255.255.255.0), and a list of devices found on the network with their MAC addresses.
3. Select the SCALANCE XC208 by checking the row whose MAC address matches the label on the physical switch. Click Assign name. Confirm the success message.
4. Repeat the same step for every ET 200SP IM 155-6 PN, the TP1200 Comfort panel, and any other PROFINET IO device in the project. The HMI and IM modules are likewise PROFINET IO devices and must receive their assigned names.
5. Compile the project (Ctrl+B) and download the hardware configuration to the primary CPU only. The S7-1500R pair will synchronise the new configuration to the backup automatically via the redundancy connection.
6. Cycle power on the SCALANCE XC208 if the F LED does not clear within 10 seconds. PROFINET AR re-establishment happens automatically after a power-cycle and typically completes inside 5 s.

MRP Manager and MRP Client Configuration in TIA V16

The S7-1500R pair takes the role of MRP manager in auto mode. The SCALANCE XC208, the ET 200SP heads, and the TP1200 Comfort are MRP clients. Confirm the configuration as follows.

1. Open Devices & networks, click the PROFINET subnet, and select the Topology tab at the bottom of the work area.
2. Click any PROFINET port of the primary CPU and look in the inspector window under PROFINET interface > MRP. The role should be "Manager (auto)" and "Ring port 1 / Ring port 2" must be assigned to the two physical PROFINET ports of the S7-1500R that close the ring.
3. Open the SCALANCE XC208 properties, PROFINET interface > MRP. Select "Client" as the role. Optionally select a fixed ring port pair (default: any two PROFINET-enabled ports).
4. Open the ET 200SP IM 155-6 PN properties, MRP tab, and select "Client". Repeat for the TP1200 Comfort PROFINET node.
5. Confirm the ring is closed physically. A common commissioning mistake is leaving the second MRP ring port on the SCALANCE XC208 unpatched. The SCALANCE F LED will flash red to signal an open ring even when the AR is healthy.

The S7-1500R redundancy works in parallel with MRP. The CPUs use the System Redundancy S2 protocol on top of PROFINET IO. The MRP ring guarantees that a single cable break does not isolate any device, while S2 guarantees that a single CPU failure does not stop cyclic I/O updates to the surviving CPU's slots. The two mechanisms are independent and both must be configured. Detailed redundancy figures are in the S7-1500R/H system manual.

S7-1500R Redundancy-Specific Network Considerations

The S7-1500R pair uses a dedicated redundancy connection cable (RJ45) and a PROFINET ring that includes the redundancy link. When you add a SCALANCE XC208 to the ring, the topology must satisfy three rules:

1. Both S7-1500R PROFINET ports (CPU 1 X1 P1 and CPU 2 X1 P1) are ring ports and both must connect to ports on managed PROFINET devices. A direct cross-over cable between the two CPUs is the original MRP topology and does not require a switch, but it leaves no place to attach ET 200SP or HMI nodes. Adding a SCALANCE XC208 in line with the ring preserves MRP and adds copper ports for downstream devices.
2. MRP allows a maximum reconfiguration time of 200 ms with the default manager test interval of 50 ms. If the topology includes more than 50 PROFINET devices, increase the test interval to 100 ms (max 500 ms reconfiguration). On the SCALANCE XC208 this is configured under WBM > Layer 2 > MRP > Advanced > Test interval.
3. The S7-1500R pair is shipped with PROFINET device names plc-1 and plc-2 by default, and the primary always uses plc-1 even after a swap. The TP1200 Comfort should be configured to connect to plc-1 as the primary HMI connection and to plc-2 as the standby. TIA V16 Update 2 introduced the HMI connection to S7-1500R wizard that handles this for you.

Verification and Commissioning Checks

After the PROFINET name has been assigned and downloaded, walk through the following checks before placing the system in production.

1. SCALANCE XC208 LEDs: Power green steady, F LED off, RM green steady (ring closed), all used port LEDs green.
2. ET 200SP IM 155-6 PN: RN (RUN) green steady, ER red off, MT (Maintenance) off, BF (Bus fault) off.
3. TP1200 Comfort: RUN green steady, no red fault icon on the right of the screen.
4. S7-1500R primary CPU: RUN green, SF off, BF off, MAINT off. Backup CPU: RUN green, MAINT may be steady if the pair is in "backup" state; this is normal.
5. TIA Portal online > Devices & networks: all device icons show a green status with a check mark. The Comparison view should show "Project and target are identical".
6. Force a ring break by unplugging one ring cable at the SCALANCE XC208. The XC208 F LED must start flashing red within 1 s. Plug the cable back in; the F LED must clear within 5 s. Repeat for the second ring cable. This is the MRP recovery test.
7. Force a CPU swap by pulling the primary CPU's PROFINET cable. The backup CPU must take over within 200 ms and the ET 200SP modules must continue updating I/O. The TP1200 Comfort connection switches to plc-2 within 3 s without operator intervention. This is the S2 redundancy test.

If any of the seven steps above fails, return to the diagnostic buffer of the affected device, capture the most recent event ID, and reference the S7-1500R system manual and SCALANCE XC208 operating instructions for the corresponding remedy. Capture screenshots of the TIA Portal Online > Topology view, the diagnostic buffer, and the LED status of every device for the commissioning report.

Related Fault Codes and Diagnostics Matrix

Preventive Practices for Future Projects

To prevent the same name mismatch on future S7-1500R projects with SCALANCE switches and Comfort panels, follow these engineering practices.

• Use the Topology editor in TIA Portal V16 for every PROFINET network. The offline topology is downloaded with the project and validated online during commissioning, surfacing patch errors before the first cold start of the line.
• Adopt a strict PROFINET naming convention such as <line>-<device>-<index> (for example l1-xc208, l1-im155-1, l1-tp1200) and store the names in a project-wide constants DB. This makes the Assign PROFINET device name step traceable.
• Always use the Assign PROFINET device name tool from TIA Portal rather than the Web-Based Management. The WBM path Information > PROFINET IO > Name can be set manually, but the TIA Portal tool also pushes the IP address in the same operation and records the assignment in the project log.
• Use PRONETA 3.x (Siemens free network analysis tool) as a pre-commissioning audit. PRONETA scans the network, lists every reachable device with its current and expected name, and exports a CSV that can be compared with the project.
• After every hardware change (replacement of a switch, CPU, ET 200SP head, or HMI), re-run the Assign PROFINET device name step for the replaced device. The replacement device will ship with the factory name "" (empty string) and will be unreachable until the name is written back.
• Disable unused SCALANCE XC208 ports in the WBM (Layer 2 > Port configuration) and enable the "Bumpless restart after link change" option to keep MRP convergence time at the published 200 ms even on a heavily loaded ring.

FAQ