SINAMICS S120 Firmware V2.5 SP2: Drive CLiQ SMI Motor Module Update Guide

The SINAMICS S120 drive platform relies on Drive CLiQ as the backplane between the Control Unit (CU310, CU310-2, CU320, CU320-2), Motor Modules (Single/Double Motor Modules), Terminal Modules (TM31, TM120, etc.), SMC/SME encoder modules, and Sensor Modules Integrated (SMI) on the motor side. Each Drive CLiQ node carries its own firmware image. Starting with SINAMICS V2.5, Siemens introduced an automatic firmware update mechanism that reconciles the firmware on every connected Drive CLiQ component with the firmware image stored on the CompactFlash (CF) card of the Control Unit. This article consolidates the field-proven rules for SMI detection, mixed firmware versions, downgrade behavior, CF-card sourcing, and the practical limits of reusing firmware from SIMOTION D packages.

1. Drive CLiQ Topology and SMI Hardware Detection

Drive CLiQ is a proprietary Siemens real-time serial link operating at a fixed baud rate over shielded twisted-pair wiring. Each node reports a unique identifier (component type, article number, serial number, hardware release, firmware version) that is parsed by the Control Unit during topology scan. The SMI (Sensor Module Integrated) is embedded inside the motor connector housing and converts resolver or sin/cos encoder signals into DRIVE-CLiQ frames that the S120 reads as the motor encoder and, where supported, as the electronic nameplate source.

When a motor with an SMI is wired to a Motor Module, the SMI must appear in the online topology under Drive CLiQ topology > Actual topology regardless of firmware version. If it is missing, the problem is hardware or wiring, not firmware. Verify, in order:

1. Drive CLiQ cable continuity: pin-out must follow the Siemens 6SL3060 standard (24 V, GND, DATA+, DATA-). Use only Siemens pre-assembled cables (e.g., 6FX5002 series) or pre-fabricated motor-side cables supplied with the motor.
2. 24 V supply on the SMI. The motor-side Drive CLiQ connector carries a 24 V feed that powers the SMI electronics. Loss of 24 V prevents the SMI from responding to topology queries, even though the cable data pairs are intact.
3. Termination and DRIVE-CLiQ port selection. A star topology with the Control Unit at the hub is mandatory. Daisy chains beyond the documented max length or using passive splitters cause intermittent detection.
4. Connectors seated and locking clips engaged. The D-sub style IP20 connector on booksize Motor Modules and the M17/M23 round connectors on motors must be fully torqued/locked.
5. Motor module DI/DO status. The SMI requires the Motor Module to be powered up (24 V electronics supply on the Motor Module). A Motor Module with no DC link pre-charge will still report a port, but the SMI handshake may be incomplete.

2. Firmware Compatibility Rules: CU320/CU310 vs SMI

SINAMICS S120 firmware has evolved through a number of major and service pack releases. The Control Unit (CU) and every Drive CLiQ component must be evaluated for compatibility at three levels:

For the canonical question: a CU320 running V2.5 SP1 HF6 and an SMI shipping from the factory with V2.5 SP2 firmware is a valid configuration. The CU's CF card holds the V2.5 SP1 image; the SMI carries V2.5 SP2. Because both share the V2.5 major release and the CU's CF image is the project's source of truth, the automatic firmware update feature will reconcile the SMI to V2.5 SP1 (or the SP level on the CF) on the next power-up.

3. Automatic Firmware Update Mechanism (V2.5 and Later)

Beginning with SINAMICS S120 firmware V2.5, the Control Unit compares the firmware version of every Drive CLiQ node against the firmware image stored on the CF card. Mismatches are corrected automatically on the next control section power-up (24 V on the CU) provided the following pre-conditions are met:

1. The set topology and actual topology match. Siemens STARTER / Startdrive may refuse the auto-update if components are added or removed after the last project download, or if a configured component is physically absent.
2. The CF card contains a complete firmware set, including the firmware for downstream Drive CLiQ components. The CF image is the master.
3. The CU has booted without active fault. A persistent F01910 topology error halts the upgrade cycle until the topology is corrected.
4. The drive objects involved are not in a safety-locked state (e.g., Safety Integrated with active commissioning lock).

During the update, alarm A01016 is raised — Firmware update in progress — and the affected drive is held in a non-operational state. The update typically completes in 30 to 180 seconds per component depending on the size of the firmware delta. After the upgrade, a power-up is required for the new firmware to become active.

4. Firmware Downgrade Behavior at Power-Up

Field experience confirms the following rule: the CF card image is the master in both directions. If the SMI ships with a newer firmware (e.g., V2.5 SP2) than the CF card (e.g., V2.5 SP1), the SINAMICS auto-update will downgrade the SMI to match the CF image. Conversely, if the SMI is older, it is upgraded to match. The Control Unit itself cannot be downgraded this way — the CU firmware is what is on the CF card and that image is the one the CU boots from.

This is a useful confirmation mechanism: by monitoring r0002 (Drive operating display) and r0017 (component firmware version) after each power-up, the engineer can verify that the live firmware on the SMI matches the project plan.

5. Obtaining SINAMICS S120 Firmware Files

SINAMICS S120 firmware is distributed by Siemens Industry Online Support. The current and historical firmware deliveries for CU310 / CU310-2 and CU320 / CU320-2 are listed in the Siemens support database, for example:

• SINAMICS S120 Firmware Version 2.6 SP2 HF19 for CU320 and CU310 — Siemens Support entry 33124038
• SINAMICS S120 Firmware Version 5.2 SP3 HF24 for CU320-2 and CU310-2 — Siemens Support entry 109780844

Historical V2.5 SP2 builds and the associated drive object packages are accessible via the legacy entry SINAMICS MICROMASTER / Starter distribution (Siemens Support ID 26233208). The firmware download bundle is shipped as a self-extracting archive containing:

• SINAMICS_S120_CU3xx_2_5_SP2.bin — the CU flash image
• Drive object firmware files (*.upd) for Motor Modules, Active Line Modules, Terminal Modules, encoder modules, and SMI
• Release notes describing defect fixes and the SP-level compatibility baseline

Place the firmware files in the appropriate folders on the CF card before inserting it into the CU. The conventional layout is:

/CF Card root
 ├── FW_UPDATE/         (CU firmware *.bin, *.upd files)
 ├── OEM/               (vendor-specific files)
 ├── PROJECT/           (STARTER/Startdrive archive)
 └── USER/              (license keys, AOP30 settings, logbook)

Always cross-check the article number of your CF card against the supported list. SINAMICS S120 V2.5 SP2 supports both the legacy 6SL3057-0AA00-2BA0 (2 GB) and the 6SL3057-0AA00-6BA0 (2 GB, V2.5+ recommended) cards. Older V2.4 cards may not have sufficient free space for V2.5 SP2 components.

6. Upgrading CU310 from V2.4 to V2.5 SP2

The CU310 (single-axis Control Unit) follows the same update procedure as the CU320. The recommended sequence is:

1. Back up the existing project. From STARTER: Project > Save to memory card and additionally Project > Save & compile to a separate archive location.
2. Insert the CF card into a card reader on the engineering PC. The CU310 CF card slot is accessible at the front.
3. Copy the V2.5 SP2 firmware files into the FW_UPDATE folder, preserving the original file structure.
4. Re-insert the CF card into the CU310 and power up the control section (24 V only). The CU detects the new firmware, raises alarm A01016, and begins the update.
5. Wait for the update to complete (typically 60–300 s). The RDY (Ready) LED will flash during the update. A red RDY LED sustained for more than 5 minutes indicates a fault — refer to the SINAMICS S120 List Manual for the LED flash code.
6. Perform a second power-up to activate the new firmware and clear alarm A01016.
7. Reconnect with STARTER and verify r0017 reports the expected V2.5 SP2 build. The set firmware version in the project must be updated to match.

If the CU310 was running V2.4 firmware, the upgrade to V2.5 SP2 is a major-version step only at the SP level — V2.4 and V2.5 share the same major family. The upgrade is supported and reversible in the field. Be aware, however, that some parameters introduced or retired between V2.4 and V2.5 require a project re-commissioning. The STARTER / Startdrive compare tool will flag any p-parameter differences.

7. Why SIMOTION D Firmware Cannot Be Reused

SIMOTION D is a motion controller that integrates a SINAMICS drive section on the same hardware. While SIMOTION D contains a SINAMICS subsystem, its firmware package is not interchangeable with a stand-alone SINAMICS S120 CU for the following reasons:

• The SIMOTION D firmware image combines the SIMOTION runtime and the SINAMICS drive image in a single signed binary. Extracting only the SINAMICS portion breaks the signature and the resulting file is rejected by the SINAMICS CU bootloader.
• SIMOTION D may include SINAMICS firmware versions (e.g., V4.x or V5.x) that are not compatible with a stand-alone V2.5 SP2 CU. The major version mismatch would prevent the CU from booting.
• License keys, OEM extension files, and technology packages are organized differently in SIMOTION D image containers.

Always obtain the stand-alone SINAMICS S120 firmware from the Siemens Industry Online Support portal and use the official CF-card image. The SIMOTION D package is reserved for SIMOTION D controllers only.

8. SMI-Specific Considerations for Mixed-Firmware Commissioning

When commissioning a motor whose electronic rating plate is read through the SMI, the following additional checks apply:

1. Confirm the motor part number, frame size, encoder type, and winding data have been read from the electronic rating plate (parameters r0108 for drive object configuration and p0301, p0304, p0305, p0311 for motor data).
2. If the motor data appears as default values (e.g., p0304 = 0), the SMI was not read correctly. Check the Drive CLiQ wiring and the SMI's firmware version, and verify that the auto-update completed.
3. For motors with DRIVE-CLiQ integrated, the encoder type and resolution are reported by the SMI automatically. Manual entry of p0400 and p0408 is not required and may cause conflict if attempted.
4. Confirm Safety Integrated compatibility when upgrading across major SP boundaries. The safety firmware (if licensed) must also match the new major release.

9. Commissioning Checklist

10. Troubleshooting Matrix

11. Field-Commissioning Notes

For a greenfield V2.5 SP2 cabinet build, the most reliable sequence is to apply the CF card image to all components at the panel shop, run a 30-minute soak with no faults, and then perform motor data identification. If a single component repeatedly fails the auto-update, capture r0017 (component firmware version) and the diagnostic buffer entries (DCC logbook, parameter r0947) before contacting Siemens support. The diagnostic buffer reveals whether the failure is due to a power interruption, a corrupt firmware file, or a hardware fault on the Drive CLiQ node.

For brownfield retrofits where existing V2.4 systems are upgraded to V2.5 SP2, perform the upgrade in two steps: first upgrade the CU to a transitional V2.5 build, validate the project, then re-load with the V2.5 SP2 CF image. This minimizes commissioning risk and allows parameter parity checks at each step.