Siemens Fault 0a7991 Best Extra Quality -
If the drive attempts the ID routine but fails or keeps re-triggering the alarm, your data might be wrong. Re-verify: Rated Voltage (p0304) Rated Current (p0305) Rated Power (p0307) Rated Speed (p0311) 4. Manual Deactivation
If the drive is used in a testing facility (Factory Acceptance Tests) without a physical motor attached, or if operational constraints prevent current injection, you can turn off the routine entirely. Dealing with Motor ID ( code 7991 ) - SiePortal - Siemens
Set P1900 to an appropriate value (e.g., 1 for identification at standstill, or 2 for identification with rotation). siemens fault 0a7991 best
Alarm A07991 often pairs with communication bus warnings like or BF (Bus Fault) lights. When the Profinet or Profibus connection to the main PLC is interrupted, the drive may drop its active configuration status and default back to commissioning parameters. Best Practices to Resolve Alarm A07991
This is the recommended "best" method, as it ensures your drive is performing at its peak efficiency. If the drive attempts the ID routine but
The application demands more torque than the motor can produce.
This public link is valid for 7 days and shares a thread, including any personal information you added. This link or copies made by others cannot be deleted. If you share with third parties, their policies apply. Can’t copy the link right now. Try again later. FAULT NO. F30001 - SiePortal - Siemens Dealing with Motor ID ( code 7991 )
Engineers testing control panels in a workshop before shipping them to a plant site often encounter this alarm because no physical motor is wired to the VFD terminals yet. The Common Companion: Alarm A08526
If you are staging equipment in an office, running tests without a motor attached, or working on a system before final installation, you will encounter A07991 alongside missing motor faults. You can bypass the calibration expectation using the official technical forum recommendations on the Siemens SiePortal Support Forum:
Restore physical network links and ensure the PLC project is actively running.
Wait for the identification to finish; once complete, the drive will return to a ready state and the alarm should disappear. Save the data by performing a RAM to ROM copy to ensure the settings are stored. Workaround for Testing (Without Motor/FAT):
