Siemens Fault 0a7991 Verified [ CERTIFIED ]

If the alarm cannot be cleared through standard parameter changes, performing a factory reset and reconfiguring basic settings may be necessary to clear the drive's internal state. Siemens SiePortal Operational Impact The most significant impact of A07991 is that it typically prevents the drive from starting

Sometimes the PLC constantly sends a command to initiate ID run. Ensure the control word from the PLC is not triggering p1900 upon every power-up. Associated Fault: A8526

Connect online to the drive and monitor these traces: siemens fault 0a7991

Set (Control mode: V/f standard) if advanced vector control isn't needed immediately. 3. Resolving Persistent Alarms (A07991 + A8526)

This is the preferred approach, especially during commissioning or after motor replacement. If the alarm cannot be cleared through standard

Common root causes:

: If a previous optimization routine was interrupted by a power failure, a sudden stop command, or an disconnected load, the drive retains the identification state. Associated Fault: A8526 Connect online to the drive

After the alarm vanishes, execute a RAM to ROM copy operation (e.g., set P0971=1 ) to ensure the newly identified motor data is stored permanently, surviving a power cycle.

It often appears during initial commissioning or after changing motor-related parameters . How to Resolve the Alarm