If you want, I can tailor this write-up to a specific Siemens product (SINAMICS, SIMATIC, etc.), include sample console commands or screen-capture examples, or produce a one-page printable checklist.
The drive is receiving an active "OFF" command while you are trying to start the identification process. siemens fault 0a7991 best
(such as the G120, G120C, or S120). This is a commissioning alarm, not necessarily a hard fault, meaning the drive is waiting to perform a measurement of the motor's electrical characteristics. Siemens SiePortal How to Resolve Alarm A07991 If you want, I can tailor this write-up
– Rare but possible: defective RAM, failed processor, or damaged backplane connector. If you want