Siemens 6SL3351-6GH34-1AB3 S120 Motor Module Upgrade

Product Overview

Siemens 6SL3351-6GH34-1AB3 S120 Motor Module Upgrade: Seamless Transition from Legacy Drive Systems

The Siemens 6SL3351-6GH34-1AB3 is a high-performance Booksize Motor Module within the SINAMICS S120 drive platform, rated at 410 A output current. This module is engineered for demanding servo and vector control applications across machine tools, printing presses, packaging lines, and heavy industrial automation systems. For facilities operating aging SIMODRIVE 611 systems, legacy MASTERDRIVES MC/VC units, or first-generation SINAMICS S120 Booksize configurations, the 6SL3351-6GH34-1AB3 represents a validated, drop-in-compatible upgrade path that preserves existing wiring infrastructure, DC bus architecture, and DRIVE-CLiQ communication topology.

When migrating from a SIMODRIVE 611D or 611U motor module, engineers frequently encounter challenges around power connector pinout differences, encoder interface compatibility, and regenerative feedback handling. The 6SL3351-6GH34-1AB3 addresses these concerns directly: it integrates natively with the SINAMICS S120 Control Unit CU320-2 DP or CU320-2 PN via DRIVE-CLiQ, eliminating the need for external encoder evaluation boards that older platforms required. The module’s DC link voltage range and internal current regulation are fully compatible with the shared DC bus configurations common in multi-axis Booksize installations, meaning existing Line Modules — such as the 6SL3130-series Active Line Module or Smart Line Module — do not require replacement during the upgrade.

Physical installation follows the standard Booksize form factor: the module mounts directly onto the standard S120 Booksize mounting rail and connects to the DC bus bar without modification. Cabinet space requirements are identical to predecessor Booksize Motor Modules in the same current class, making this a practical retrofit for control cabinets where panel real estate is constrained. The 24 V DC auxiliary power supply connection is standard across the S120 Booksize family, so existing 24 V SITOP power supply units feeding the cabinet do not need to be resized or relocated.

From a programming and commissioning perspective, the 6SL3351-6GH34-1AB3 is fully supported by STARTER and SINAMICS Startdrive (TIA Portal V15 and above). Existing drive parameter sets exported from older S120 Motor Modules can be imported with minimal adaptation — primarily updating the motor data set and encoder configuration to match the connected motor. For sites running SIMATIC S7-300 or S7-400 PLCs communicating via PROFIBUS DP, the CU320-2 DP retains full telegram compatibility (Telegram 1, 2, 3, 5, 105, 116), ensuring that existing PLC programs require no structural modification. Sites already migrated to S7-1500 with PROFINET can use the CU320-2 PN variant with equivalent parameter transparency.

Motor compatibility is broad: the module supports synchronous servo motors from the 1FK7, 1FT7, and 1PH8 families, as well as induction motors used in spindle and feed axis applications. Encoder interfaces support HTL/TTL incremental encoders, sin/cos 1 Vpp encoders, and EnDat 2.1/2.2 absolute encoders via the SMC (Sensor Module Cabinet-Mounted) family — including the SMC20 and SMC30 — which can be retained from the existing installation. This encoder interface continuity is a critical factor in reducing retrofit commissioning time on multi-axis machine tool spindle systems.

For facilities managing a phased migration strategy, the 6SL3351-6GH34-1AB3 can coexist on the same DC bus with other S120 Booksize Motor Modules of different current ratings, allowing axis-by-axis replacement without full system shutdown. This approach significantly reduces planned downtime windows and allows production to continue on unaffected axes during the migration period. Complementary components commonly required during such migrations include the 6SL3040-series DRIVE-CLiQ Hub Module for topology expansion, Voltage Sensing Module (VSM10) for line voltage monitoring, and Braking Module for axes with regenerative loads that exceed the line module’s feedback capacity.

All units supplied by TOPNLMS undergo pre-shipment functional verification including insulation resistance testing, DC bus charge/discharge cycle validation, and DRIVE-CLiQ enumeration confirmation. Units are shipped in original or equivalent anti-static protective packaging with full documentation. Standard lead time from Xiamen warehouse is 3–7 business days for stocked units, with express DHL/FedEx options available for urgent replacement scenarios.

Compatibility Comparison Table

Seamless Upgrade Solutions

A complete migration to the 6SL3351-6GH34-1AB3 typically involves coordinating several interdependent components within the S120 Booksize system architecture. The Control Unit CU320-2 DP (6SL3040-1MA01-0AA0) or CU320-2 PN serves as the central intelligence, managing all DRIVE-CLiQ-connected Motor Modules and Line Modules within the drive group. Where the existing installation uses a SIMODRIVE 611 Line Module for DC bus supply, replacement with a compatible S120 Active Line Module from the 6SL3130 series ensures regenerative energy feedback capability and harmonic compliance with modern grid standards.

For multi-axis cabinets, the DRIVE-CLiQ Hub Module Cabinet-Mounted (DMC20, 6SL3055-0AA00-6AA0) provides topology flexibility when the number of DRIVE-CLiQ ports on the CU320-2 is insufficient for all connected Motor Modules and Sensor Modules. Encoder continuity is maintained through the SMC20 Sensor Module Cabinet-Mounted for sin/cos and EnDat encoders, or the SMC30 for HTL/TTL incremental encoders — both connecting to the Motor Module via DRIVE-CLiQ without additional wiring to the Control Unit. For axes with holding brakes, the 6SL3362-series Brake Relay Module integrates directly into the Booksize assembly.

In applications where the legacy system used analog ±10 V speed setpoints from a SIMATIC S7 analog output module, the transition to digital PROFIBUS or PROFINET telegram-based control eliminates analog signal noise and drift — a common source of speed regulation instability in older installations. Terminal Module TM31 (6SL3055-0AA00-3AA0) can be added to the DRIVE-CLiQ topology to provide additional digital and analog I/O for local interlocking, without modifying the PLC program structure. For sites requiring safe torque off (STO) or extended safety functions, the Safety Integrated features of the 6SL3351-6GH34-1AB3 are activated via parameter and TIA Portal Safety configuration, compatible with F-CPU variants of the S7-1500 series.

Retrofit Guidance FAQ

Q: Can I reuse my existing motor and encoder wiring?
In most cases, yes. The motor power connector on the S120 Booksize Motor Module uses the standard Siemens Booksize power output interface. Encoder signals are routed through the SMC20 or SMC30 Sensor Module, which accepts the same encoder cable connectors used with SIMODRIVE 611 external encoder modules. A wiring adapter may be required at the SMC input connector depending on the legacy encoder cable termination style.

Q: Do I need to rewrite my PLC program?
No structural rewrite is required for PROFIBUS DP installations. Standard PLC drive telegrams (Telegram 1 for speed control, Telegram 5 for extended setpoints) are supported identically on the CU320-2 DP. For PROFINET migrations, the GSD/GSDML device description file for the CU320-2 PN must be installed in the TIA Portal hardware catalog, and the network address reassigned — the telegram structure remains unchanged.

Q: How do I handle the DC bus transition from SIMODRIVE 611 to S120?
The SIMODRIVE 611 and SINAMICS S120 Booksize DC bus systems are electrically incompatible and cannot be directly paralleled. A clean cutover approach — replacing the Line Module and all Motor Modules simultaneously during a planned shutdown — is the recommended strategy for single-cabinet systems. For large multi-axis systems, a phased approach using a separate S120 DC bus section fed by a new Line Module, with gradual axis migration, minimizes production impact.

Q: What commissioning tools are required?
SINAMICS Startdrive (available as a TIA Portal add-on from V15 onwards) is the recommended tool for initial commissioning, parameter backup, and firmware updates. STARTER (standalone) is also fully supported for sites not yet on TIA Portal. A standard PC with USB-to-RS232 adapter or PROFIBUS PC adapter (e.g., CP5711) is sufficient for initial connection; DRIVE-CLiQ-based commissioning does not require a separate hardware interface beyond the Control Unit’s onboard Ethernet port.

Q: Is physical cabinet space a concern?
The 6SL3351-6GH34-1AB3 follows the standard S120 Booksize form factor. Width, height, and depth dimensions are consistent with other Booksize Motor Modules in the same current class. If replacing a SIMODRIVE 611 module of equivalent power rating, the cabinet cutout and mounting rail positions will require adaptation to the S120 Booksize rail standard, but overall panel space consumption is comparable.

Warranty Assurance

Every 6SL3351-6GH34-1AB3 unit shipped by TOPNLMS is covered by a 12-month warranty from the date of shipment. Pre-shipment inspection includes DC bus capacitor charge verification, DRIVE-CLiQ port enumeration test, insulation resistance check on power output terminals, and visual inspection of all connectors and bus bar contacts. Units failing any inspection criterion are quarantined and not shipped.

In the event of a warranty claim, TOPNLMS provides a replacement unit dispatch within 5 business days of fault confirmation, with return shipping label provided for the defective unit. Our technical support team ([email protected]) is available to assist with fault diagnosis, parameter file review, and commissioning guidance during the warranty period. Replacement units are shipped with the same pre-shipment inspection certification as original orders.

For procurement teams, TOPNLMS issues a formal invoice, packing list, and certificate of inspection with every shipment. Export documentation for international orders (commercial invoice, HS code declaration) is prepared in compliance with Chinese customs regulations. Payment terms and volume pricing are available upon request for MRO and OEM procurement programs.

Stock availability is updated in real time. For urgent replacement requirements, contact our sales team directly to confirm lead time and arrange priority dispatch.