The code 0A7991 (commonly referred to as A7991 or A07991 in Siemens documentation) is a specific alarm for Siemens SINAMICS drives, such as the G120, G130, or S120 series. It indicates that Motor Data Identification is Activated. Understanding Alarm A7991
. It typically appears during the initial setup or commissioning of Sinamics drives (such as the G120 or S120) and means the drive is waiting to perform a measurement of the motor's electrical characteristics. Siemens SiePortal How to Resolve Fault A07991
Conclusion
When motor parameters have been changed but not yet measured. Best Methods to Clear A07991 1. Perform the Motor Identification Run (Recommended)
If the CPU is overloaded, it may miss a communication cycle.
Fault 0A7991 means:
A critical data packet did not arrive within the expected time window (timeout). The drive's safety logic interprets this as a loss of deterministic control, so it triggers a fault (not just a warning) and typically shuts down the drive to prevent erratic behavior or damage.
Follow this exact procedure using the IOP/BOP-2 or STARTER software. We will assume a standard induction motor (IM) and V/f or vector control.