Roles within a SINAMICS S120 system
From the mains supply to the motor, the simplified energy path runs through the infeed and the shared DC link to the Motor Module. The Control Unit, encoder connection and additional system components handle control, feedback and expansion functions.
Control
Control Unit
Provides central communication, control and regulation functions for the assigned drive objects.
Common search terms: CU320, CU320-2 and CU310.
Infeed
Line Module
Supplies the DC link from the mains. Siemens distinguishes between Active, Smart and Basic Line Modules, among other variants.
The correct design depends on the mains supply, power rating and regenerative requirements.
Motor supply
Motor Module
Supplies the connected motor from the DC link. Depending on the system design, Single or Double Motor Modules may be used.
Match the exact type number, output current, design and cooling method.
Encoder connection
Sensor Module
Integrates suitable external measuring and encoder systems into the drive system and provides their signals for control.
Examples from the family include SMC10, SMC20, SMC30 and SME variants.
Signal expansion
Terminal Module
Adds defined digital, analogue or application-specific input and output functions to the system.
The exact function depends on the TM version.
System communication
DRIVE-CLiQ and hub components
Connects compatible system components and enables the exchange of control, diagnostic and encoder information.
Always check the permitted topology and participants for the specific project.
Identify the system role, then match the exact variant
The system map answers the first question: what function does the component perform? Sourcing or replacement then requires an exact type-number match. Even visually similar S120 components can differ in design, power rating, cooling, interfaces, firmware or approved system combinations.
Looking for a spare part?
Identify the exact order number
Use the complete Siemens order number and compare the required version with the manufacturer documentation and system requirements before ordering.
Frequently asked questions about SINAMICS S120 components
Is every SINAMICS S120 Motor Module compatible with every Control Unit?
No. The product family alone is not sufficient. At a minimum, the complete order numbers, design, firmware and engineering status, and the existing system configuration must be checked.
How can I identify the role of an existing S120 component?
Use the complete Siemens order number and the product designation on the nameplate. Terms such as Control Unit, Line Module, Motor Module or Sensor Module identify the system role, but they do not replace verification of the exact variant.
What information does REHA-Components need for a spare-parts request?
Send the complete order number, clear photographs of the nameplate and, if known, the component's role in the machine. For urgent downtime requests, details of the controller, adjacent modules and the displayed fault message are also useful.
Technical sources
The component roles are based on Siemens documentation for the modular SINAMICS S120 system. Specific selection and compatibility decisions must also be checked against the current documentation for the exact order number.