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Siemens SINAMICS S120: the modular drive system, components and formats
SINAMICS S120 is the Siemens modular drive system for single-axis and multi-axis applications: machine tools, packaging lines, printing, handling and, in the larger sizes, process plants. Instead of a single inverter, the S120 is made up of separate modules that work together: a Control Unit that handles closed-loop control, a Line Module that supplies the DC link and one or more Motor Modules that drive the motors. The modules communicate with each other over DRIVE-CLiQ.
The same system comes in three formats: Booksize for low and medium power, Chassis for high power and Cabinet Modules, i.e. modules already mounted in a cabinet. This guide is the general map: for each group you will find the part number roots and the link to the detailed guide.
⚙️ Control Units and system components
| Root | Components |
| 6SL3040 | Control Units CU320, CU320-2, CU310 and CU310-2 (PROFIBUS or PROFINET), CUA31 and CUA32 adapters. The root is shared with the CU305 Control Units of SINAMICS S110 and with the G130 Control Unit kit |
| 6SL3054 | S120 CompactFlash memory cards, with or without performance expansion; the root also includes the S110 and G120 cards |
| 6SL3055 | Encoder Sensor Modules (SMC20, SMC30, SME20, SME25, SME120, SME125), TM31 Terminal Module and AOP30 operator panel |
| 6SL3100 | Control Supply Module, Active Interface Module, braking and capacitor modules, resistors, Voltage Clamping Module |
| Go to the catalogue
6SL3040-1MA00-0AA0 – Control Unit CU320-2 DP | |
📖 Detailed guides: S120 control modules · Sensor Module, Terminal Module, DRIVE-CLiQ and memory card
⚙️ Booksize format: Line Modules and Motor Modules
| Root | Components |
| 6SL3130, 6SL3131, 6SL3136, 6SL3430 | 380–480 V three-phase supply Line Modules: Smart Line Module, Active Line Module and Basic Line Module |
| 6SL3120 | Single Motor Modules and Double Motor Modules with 600 V DC input, also in the Value version |
| 6SL3121, 6SL3126, 6SL3420 | Other design variants of 600 V DC Single and Double Motor Modules |
| 6SL3111 | Combi Power Module, supply and several axes in a single unit |
| Go to the catalogue | |
📖 Detailed guides: S120 Line Modules · S120 Motor Modules
⚙️ Chassis format
| Root | Components |
| 6SL3320, 6SL3321 | Chassis Single Motor Modules with DC input, in the 510–720 V DC and 675–1035 V DC ranges; Chassis-2 Motor Modules |
| 6SL3330, 6SL3335 | Chassis Line Modules: Smart, Basic and Active Line Modules, for 380–480 V and 500–690 V networks |
| Go to the catalogue | |
⚙️ Cabinet Modules
| Root | Components |
| 6SL3720 | S120 Cabinet Modules: in the catalogue they have a generic description, the module type is identified by the full part number |
| 6SL3730 | Line Modules in cabinet: Basic and Active Line Modules |
| 6SL3700 | Auxiliary cabinet modules: Line Connection Module, Central Braking Module and auxiliary supply. The root also includes some switches and fuses for SINAMICS V50 |
| Go to the catalogue | |
📖 Detailed guide: S120 Cabinet Modules 6SL3720 6SL3730
⚠️ Typical faults
- worn cooling fans, with temperature alarms and protection tripping
- aged DC-link capacitors, especially on modules left out of service for a long time
- power stages damaged by short circuits on the motor or cables
- DRIVE-CLiQ communication errors caused by cables, connectors or interface boards
- damaged memory cards or a configuration that the Control Unit can no longer read
- control electronics damaged by overvoltage, humidity or dirt in the cabinet
🛠️ E-Repair services for SINAMICS S120
As an Approved Partner Siemens – Industry Services, E-Repair supports production continuity:
🔧 Component-level repair in the certified E-Repair in-house laboratory, with diagnosis and intervention where technically possible.
♻️ Refurbishment with replacement of components subject to wear and functional testing according to the agreed scope.
🚚 Advance supply of a refurbished or new product, if available in stock and after a compatibility check.
🛠️ On-site and remote technical support for diagnosis and recommissioning.
✅ Standard 12-month warranty on the services for which it applies, extendable up to 24 months under the applicable conditions.
❓ Frequently asked questions
✔️ Can a single S120 module be replaced without changing the whole drive?
Yes, the system is modular and every Control Unit, Line Module or Motor Module has its own part number. Before replacement, check the full part number including the version, because the drive configuration is based on the installed modules.
✔️ What should I do with the CompactFlash card when the Control Unit goes for repair?
The memory card contains the firmware and the drive configuration: keep a copy and state in your request whether the card is shipped together with the Control Unit or stays in the machine.
✔️ How can I tell from the part number whether a module is Booksize, Chassis or Cabinet?
In most cases the root tells you: 6SL31 roots correspond to Booksize modules, 6SL33 to Chassis and 6SL37 to Cabinet Modules. If in doubt, send us the full part number from the rating plate.
📚 Further reading
👉 SINAMICS E-Repair services · 👉 SINAMICS S150 · 👉 SINAMICS S110 · 👉 Spare parts for chassis units · 👉 Mixed SIMODRIVE and SINAMICS systems
ℹ️ The information is general and indicative. Before purchase, installation or commissioning, check the data in the official Siemens documentation or contact E-Repair.
🔗 Most requested part numbers
Some product pages from the E-Repair catalogue for the series in this guide:
- 6SL3040-0JA00-0AA0 – SINAMICS S110 CONTROL UNIT CU305 DP WITH PROFIBUS INTERFACE…
- 6SL3054-0CD01-1AA0 – SINAMICS S120 CompactFlash card with firmware option Performance…
- 6SL3055-0AA00-2TA0 – SINAMICS S120 TERMINAL BOARD TB30 FOR CONTROL UNIT CU320 AND…
- 6SL3100-0BE21-6AB0 – SINAMICS S120 ACTIVE INTERFACE MODULE FOR 16KW ACTIVE LINE MODULE…
- 6SL3111-4VE21-6EA1 – SINAMICS S120 Combi Power Module input: 3AC 400V, 16 kW…
- 6SL3120-1SE11-7UA0 – SINAMICS S120 CONVERTER POWER MODULE PM340 INPUT: 3AC 380-480V…
