Resolving SINAMICS S120 No Telegram in TIA Portal V15.1

Problem Statement

When commissioning a SINAMICS S120 drive line-up over PROFIBUS DP using TIA Portal V15.1 and Starter v5.3 (or SCOUT), the drive frequently returns a No telegram diagnostic on the Infeed and axis Drive Objects (DOs) even though the CU320-2 telegram reports valid process data. All hardware LEDs—PLC SF/BF, CU RDY/COM, and drive object READY—indicate healthy operation, which leads engineers to dismiss the message as a display artifact. In practice, the symptom reflects a slot/telegram mapping mismatch between the S7-300 hardware configuration and the drive project, and it is fully resolvable without firmware changes or hardware replacement.

This article codifies the root cause, the exact TIA Portal V15.1 corrective sequence, and the verification steps that confirm the resolution on a representative line-up: CU320-2 DP (6SL3040-1MA00-0AA0), Basic Line Module, Double Motor Module, S7-300 CPU 317 (6ES7317 family), Starter v5.3, and SCOUT.

Affected System Components

The fault is independent of the specific SINAMICS firmware version (V4.7, V4.8, V5.1, V5.2 are all affected when the slot count is misconfigured) and is reproduced with both Starter v5.3 and SCOUT V5.x.

Root Cause: Slot/Telegram Mapping Mismatch

The SINAMICS S120 system exposes every Drive Object (DO)—CU, Infeed, Motor Module—as an independent PROFIdrive slot on the PROFIBUS slave. Each slot is identified by its slot index (0…255) and contains its own I/O address range on the PLC. The CU slot typically carries the standard CU telegram (390 by default, also called the DO1 telegram), the Infeed slot carries telegram 370, and each axis slot carries a Siemens servo telegram (102, 105, 106, or legacy 1–6).

When the S7-300 hardware configuration in TIA Portal V15.1 defines only one PROFIBUS slot in the slave device—the CU320-2 itself—the PLC writes process data only into the I/O range that TIA Portal allocates for that single slot. The Infeed and axis DOs receive zero PZDs and consequently report No telegram inside Starter/SCOUT. Because the CU slot is populated, the link stays alive (BF off) and the LED pattern looks healthy even though the higher-level process-data exchange is incomplete.

The same symptom also appears in three other cases:

• Slot indices are renumbered in TIA Portal but not updated in the Starter project (or vice versa).
• The telegram type chosen in TIA Portal differs from the one selected in Starter (e.g. TIA has 105, Starter has 102).
• Axis Separator slots are missing between non-contiguous DO addresses, leaving SINAMICS unable to resolve the PZD ownership.

Prerequisites

• TIA Portal V15.1 with the SINAMICS Startdrive option installed (6SL3072-4CA02-0XG0 for V15.1) OR the GSD file for CU320-2 imported from Siemens Industry Online Support (search entry ID 92063291 for the CU320-2 DP GSD).
• Starter v5.3 SP3 or higher (DVD 6SL3072-0AA00-0AG0) or SCOUT V5.3+.
• The offline drive project backed up before making changes (RAM-to-ROM after every parameter commit; project ZIP export for safety).
• S7-300 hardware catalog installed with the specific CPU 317 MLFB in TIA Portal (right-click → "Hardware catalog" → update if missing).
• PROFIBUS DP cable terminated at both ends (terminating resistor ON at the two end nodes only).

Step-by-Step Resolution in TIA Portal V15.1

1. Open the device configuration. In the project tree, double-click Devices & Networks, select the CU320-2 DP slave, and switch to the Device view.
2. Inspect the existing slot list. The default view typically shows only slot 0 (CU). Right-click the slot rail and confirm whether slots 1, 2, 3 are present. If only one slot exists, the configuration is incomplete.
3. Add a slot for the Infeed. Right-click the slot rail → Add object → select the Infeed entry under DO Infeed (e.g. Basic Infeed Telegram 370). Place it in slot 1.
4. Add slots for each axis. Repeat the operation for every Drive Object listed in Starter (Axis_1, Axis_2 for the Double Motor Module). Place Axis_1 in slot 2 and Axis_2 in slot 3. Choose the Siemens standard telegram that matches the Starter project (typically Servo Telegram 102, 10 PZD IN / 6 PZD OUT).
5. Insert Axis Separator slots. When the SINAMICS DOs are non-contiguous in slot numbering, or when the topology differs from a strict sequential assignment, insert an Axis Separator slot between each drive object slot. In TIA Portal V15.1 this is done from the hardware catalog: PROFIdrive → PZD telegrams → Axis Separator. Drag it onto the slot rail.
6. Verify slot-to-telegram mapping. Each DO slot's properties dialog should show the I/O address range (e.g. IW 256…QW 270 for slot 2 with telegram 102). Cross-check these against the Starter Configuration → PROFIBUS telegram configuration panel.
7. Compile the S7 project. Press Ctrl+B (Compile → Hardware). Resolve any address-overlap warnings—each slot must own a unique, non-overlapping I/O range.
8. Download to the S7-300. With the CPU in STOP, select the PLC → Download to device → Hardware configuration. Wait for the transfer to complete and confirm the CPU returns to RUN.
9. Reload the drive project. In Starter, click Load to drive (RAM), perform a RAM-to-ROM, and observe the PROFIBUS state.
10. Go online in Starter. Open the expert list, navigate to the Infeed and axis DOs, and confirm the control/status words now display numerical values instead of No telegram.

PROFIdrive Standard Telegram Reference

Standard Slot Map for CU320-2 DP with BLM + Double Motor Module

If the SINAMICS project uses non-sequential DO numbering (e.g. Axis_5 inserted between Axis_1 and Axis_2), an Axis Separator must be placed between the affected slots in TIA Portal so that the PZD address map does not shift.

Verification Procedure

1. Starter expert list. Go online with the CU320-2, browse to the Infeed DO (e.g. r0019[0] for operating display, r2050[0]…r2050[5] for received PZDs). Each value should display a hex/decimal number rather than No telegram.
2. SCOUT trace. Configure a 2-second trace on the axis control word (STW1, signal r0050[0]) and confirm the trace records the bit transitions sent from the S7 program.
3. S7 monitor. In TIA Portal, open an online watch table on the assigned I/O range (e.g. IW 256 for Axis_1 receive word 1). The values should mirror the drive's r2050 indicators.
4. RAM-to-ROM. After every successful verification step, commit the drive project via Target system → Copy RAM to ROM; this prevents the configuration from being lost on power-down.
5. Power-cycle test. With the drive OFF, switch off the 24 V supply to the CU, restore power, and re-check the online values. The slot map must survive a cold start.

LED Interpretation Matrix

Common Configuration Pitfalls

• Single slot in TIA Portal. The most frequent cause; the slave is collapsed into one PROFIdrive entry instead of one per DO.
• Mismatched telegram number. TIA Portal slot 2 is configured with telegram 105 but Starter project has telegram 102—PZDs are written to the wrong length and the drive rejects the frame.
• Wrong PROFIBUS address. The CU320-2 hardware DIP switch (S1) or parameter p0918 must match the address configured in TIA Portal (default 3 on CU320-2 DP).
• Missing GSD update. Older TIA Portal installations ship with a GSD that does not contain the latest SINAMICS telegram options. Update via Options → Manage GSD files.
• Topology mismatch. If the actual DRIVE-CLiQ wiring differs from the topology defined in Starter (e.g. Motor Module wired to port 2 instead of port 1), the SINAMICS DO numbering changes and the slot map must be regenerated.
• Axis Separator misuse. Adding axis separators between every slot when they are not required can break the PZD address continuity and trigger F08501.

TIA Portal V15.1 and Starter v5.3 Compatibility Notes

TIA Portal V15.1 (released March 2019) supports the SIMATIC S7-300/400 family and integrates SINAMICS Startdrive V15.1 as an optional add-on. When Starter v5.3 is used for SINAMICS S120 commissioning in parallel with TIA Portal V15.1, both tools share the same offline project via DSF/DPF export-import. The recommended workflow is:

1. Commission the drive in Starter v5.3; export the project as a DSF file (Project → DSF export).
2. In TIA Portal V15.1, import the DSF (Options → Import SINAMICS project) into the corresponding CU320-2 device.
3. Synchronise the slot map and I/O addresses between the two views; ensure both refer to the same telegram list.

If installation issues occur with TIA Portal V15.1, a full system restart is a documented workaround per Microsoft Q&A: Problems installing TIA Portal V15.1. For deeper commissioning reference, consult the SINAMICS S120 Function Manual and S120 List Manual available via Siemens Industry Online Support (search for "SINAMICS S120" and filter by manual type).

Frequently Asked Questions