This notification can be triggered in several typical scenarios:
Clear all external safety interlocks and pass an active ON signal to the drive via your local operator panel (BOP/IOP) or your connected controller.
Technicians may purposely set P1900 ≠ 0 or P1910 ≠ 0 to manually trigger the motor data identification routine—at which point A7991 appears as confirmation.
The Siemens fault or alarm code (often searched as 0a7991 or A7991) explicitly means "Drive: Motor data identification activated" . This code is an automated notification built into the firmware of the Siemens SINAMICS drive family —including the G120, G120C, S120, and G150 series—stating that the variable frequency drive (VFD) is actively seeking to measure and map the electrical characteristics of the connected motor. siemens fault 0a7991
When a drive is first commissioned or its motor parameters are reset, it enters a "standby" mode for identification. Siemens SiePortal The Routine:
If the drive is fully wired to its intended industrial motor, the easiest way to make A07991 disappear is to let it finish its automated routine.
The fault code 0A7991 is a specific error code generated by Siemens systems to indicate a particular problem. While the exact meaning of this code can vary depending on the specific Siemens product or system it appears in, a general approach to understanding and troubleshooting such faults will be discussed. This notification can be triggered in several typical
The diagnostic buffer usually provides:
To resolve this alarm, users on Siemens SiePortal suggest the following:
Give the drive a "Run" command. The motor may whistle or make noise for several seconds while it measures the winding resistance and inductance at a standstill. This code is an automated notification built into
Ensure the motor is at a standstill and the configuration is complete.
Do not disable stall protection permanently unless advised by Siemens support.
Depending on the drive model and control unit firmware version, the alarm might be displayed with or without a leading zero:
To safely bypass the code for benchmark testing, change parameter . This modification temporarily drops the strict hardware validation metrics, allowing you to debug your communication interfaces, I/O setups, and control loops before shipping the hardware panels to the field. Handling Secondary Communication Failures ( A8526 )
: Different Siemens families (G120, S120, Simodrive) use slightly different numbering. Error