F07800 Fault in Siemens SINAMICS G120 Drive

F07800 Drive: No Power Unit Present in the Siemens SINAMICS G120 Drive indicates that the Control Unit cannot detect or communicate with the connected Power Unit. During startup, the Control Unit reads the Power Unit parameters through the DRIVE-CLiQ interface. If the parameters cannot be read, no parameters are stored in the Power Unit, or communication is interrupted, the drive generates Fault F07800 and prevents operation.

F07800 Fault in Siemens SINAMICS G120 Drive


This fault generally indicates a problem with the DRIVE-CLiQ communication, Power Unit, Control Unit, or drive topology configuration, rather than a motor or application fault.

Possible Causes

  • DRIVE-CLiQ cable interrupted.
  • Loose DRIVE-CLiQ connector.
  • Damaged DRIVE-CLiQ cable.
  • No communication between the Control Unit and Power Unit.
  • Power Unit parameters cannot be read.
  • No parameters stored in the Power Unit.
  • Faulty Power Unit.
  • Defective Control Unit.
  • Incorrect drive topology configured in the commissioning software.
  • Incorrect topology downloaded to the Control Unit.
  • Incomplete or interrupted commissioning.
  • Firmware incompatibility between the Control Unit and Power Unit.
  • Internal communication hardware failure.
  • Internal PCB fault.

Solutions

  • Perform a complete POWER ON by switching OFF and ON all drive components.
  • Check the DRIVE-CLiQ cable between the Control Unit and the Power Unit.
  • Verify that the DRIVE-CLiQ connectors are securely connected.
  • Replace the DRIVE-CLiQ cable if it is damaged.
  • Inspect the Power Unit for faults.
  • Replace the Power Unit if necessary.
  • Check the Control Unit for proper operation.
  • Replace the Control Unit if defective.
  • Verify the drive topology in the commissioning software.
  • Correct the topology configuration if necessary.
  • Download the correct parameter set again using the commissioning software.
  • Verify firmware compatibility between the Control Unit and Power Unit.
  • Contact Siemens technical support if the fault persists.

Additional Information

The Siemens SINAMICS G120 consists of a Control Unit (CU) and a Power Unit (PU) that communicate through the DRIVE-CLiQ interface.

During startup, the Control Unit automatically reads identification and parameter information from the connected Power Unit.

Fault F07800 is generated when:

  • The Power Unit cannot be detected.
  • Power Unit parameters cannot be read.
  • No parameters are stored in the Power Unit.
  • DRIVE-CLiQ communication is interrupted.

According to Siemens, this fault can also occur if an incorrect drive topology is selected during commissioning and downloaded to the Control Unit.

The recommended corrective actions are:

  • Perform a complete power cycle.
  • Inspect the DRIVE-CLiQ cable and connectors.
  • Check the Power Unit and Control Unit.
  • Correct the topology and download the parameters again using the commissioning software.

Unlike a Power Unit Hardware Fault, F07800 indicates that the Control Unit cannot identify or communicate with the Power Unit, preventing normal drive initialization.

Common Symptoms

  • Drive displays F07800 Drive: No Power Unit Present.
  • Drive will not complete startup.
  • Motor cannot be started.
  • Power Unit is not detected by the Control Unit.
  • DRIVE-CLiQ communication is unavailable.
  • Fault appears immediately after power-up.
  • Fault occurs after replacing the Control Unit or Power Unit.
  • Fault appears after downloading an incorrect topology.
  • Commissioning cannot be completed.
  • Drive remains in the fault state until communication is restored.

Recommended Troubleshooting Sequence

  1. Switch OFF power to all drive components.
  2. Perform a complete POWER ON cycle.
  3. Inspect the DRIVE-CLiQ cable.
  4. Verify all DRIVE-CLiQ connectors are securely connected.
  5. Replace the DRIVE-CLiQ cable if damaged.
  6. Check whether the Power Unit is detected.
  7. Inspect the Power Unit for hardware faults.
  8. Inspect the Control Unit for proper operation.
  9. Verify the configured drive topology in the commissioning software.
  10. Correct the topology if necessary.
  11. Download the correct parameters to the Control Unit.
  12. Verify firmware compatibility between the Control Unit and Power Unit.
  13. Restart the drive.
  14. Confirm that the Power Unit is recognized.
  15. Contact Siemens technical support if the fault persists.

Power Unit Communication Check Table

Check PointAction
Power cycleSwitch OFF and ON all drive components
DRIVE-CLiQ cableInspect for damage or disconnection
DRIVE-CLiQ connectorsVerify secure connections
Power UnitCheck for proper detection and operation
Control UnitInspect for faults
Drive topologyVerify commissioning configuration
Parameter downloadDownload the correct parameter set
Firmware compatibilityConfirm matching firmware versions
Drive startupVerify normal initialization
Siemens technical supportContact if the fault remains after inspection

Preventive Maintenance Tips

  • Inspect DRIVE-CLiQ cables and connectors during scheduled maintenance.
  • Avoid disconnecting DRIVE-CLiQ cables while the drive is powered.
  • Verify the correct drive topology before downloading parameters.
  • Use only Siemens-approved Control Units, Power Units, and DRIVE-CLiQ cables.
  • Maintain backups of commissioning data before hardware replacement.
  • Ensure firmware compatibility when replacing drive components.
  • Keep connectors clean and securely fastened.
  • Protect communication cables from vibration and mechanical damage.
  • Perform a complete power cycle after hardware replacement or topology changes.
  • Record recurring F07800 faults to assist long-term diagnostics.

Proper inspection of the DRIVE-CLiQ communication link, Control Unit, Power Unit, commissioning topology, and parameter configuration, along with ensuring compatible firmware and correct hardware connections, will help prevent recurring F07800 Drive: No Power Unit Present faults in Siemens SINAMICS G120 drives, ensuring reliable hardware recognition, successful drive initialization, and dependable long-term operation of the drive system.

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