Direct answer: The SINAMICS G120X offers PROFINET, PROFIBUS DP, and USS or Modbus interfaces, and the right choice follows the controller you already run. Use PROFINET for modern real-time networks, PROFIBUS DP for legacy fieldbus plants, and USS or Modbus for simple serial speed control.
The SINAMICS G120X is a general-purpose drive family spanning 11 kW to 132 kW and beyond, and the right communication interface is decided by your controller, not by the drive. PROFINET fits modern Siemens and many third-party PLCs; PROFIBUS DP suits legacy fieldbus plants; USS and Modbus cover simple serial control. Match the interface to the network you already run.
| Interface | Topology | Choose when |
|---|---|---|
| PROFINET | Ethernet, real-time | Modern PLC, fast I/O, diagnostics |
| PROFIBUS DP | Fieldbus, RS-485 | Legacy DP plants, existing bus |
| USS / Modbus | Serial RTU | Simple speed control, no PLC bus |
Choosing the G120X interface
PROFINET for the modern backbone
PROFINET is the default for new plants: fast cyclic data, a single cable for control and diagnostics, and the richest fault reporting through the controller. Choose it whenever the PLC already speaks PROFINET.
Selection decision tree
- Modern PLC, fast I/O, rich diagnostics? → PROFINET
- Existing DP fieldbus plant? → PROFINET DP
- Only start, stop, and a speed setpoint, no bus? → USS or Modbus RTU
If the drive sits on a current control network, PROFINET gives you real-time setpoint control, fast diagnostics, and seamless integration with Siemens controllers. The G120X 90 kW unit and the 11 kW model both ship with PROFINET-ready control boards.
G120X interface FAQ
PROFIBUS DP for the installed fieldbus
PROFIBUS DP fits existing installations that still run the fieldbus; it is slower and less diagnostic than PROFINET but ubiquitous in legacy drive networks. Specify DP when you are dropping the G120X into a plant that has not moved to PROFINET.
USS and Modbus for serial simplicity
USS and Modbus RTU are the serial fallbacks for a small controller or a retrofit with no fieldbus at all. They are simple and cheap but give limited diagnostics, so reserve them for basic start-stop and speed setpoint jobs.
Can I change the interface after purchase?
No, the interface is set by the control unit you order; it is not a field-selectable option. Match the interface to the controller before purchase, because swapping it later means replacing the CU, not flipping a setting.
Which interface gives the best diagnostics?
PROFINET gives the deepest diagnostics: parameter access, fault history, and predictive data straight into the PLC, followed by PROFIBUS DP. USS and Modbus are control-only and leave you troubleshooting with a handheld, so pick them only when diagnostics are not required.
Related reading: SINAMICS G120X 22 kW drive; SINAMICS G120X 132 kW drive; OPC UA and MQTT in industrial HMIs
