Siemens Fault 0a7991 [best]

: Apply a standard "ON" or "Start" command via your PLC, input terminals, or operator panel.

You have inputted standard motor nameplate data (voltage, current, power) and the drive automatically schedules a standstill or rotating optimization for the next power-on/run command.

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.

Depending on whether you are running a live motor or testing equipment on a test bench, use one of the standard engineering paths below to clear the notification. siemens fault 0a7991

By understanding the root cause—primarily the activation of P1900 or P1910 parameters—and taking appropriate action, you can minimize downtime and ensure your SINAMICS drive operates reliably for years to come. For persistent cases or those involving the simultaneous A08526 alarm, refer to the advanced troubleshooting sections or contact Siemens Technical Support with your system details ready.

Fault typically indicates "Motor blocked" or "Motor stalled" . The drive detects that although it is applying torque/speed reference, the motor rotor is not moving as expected.

: The feature was turned on via configuration parameters, but the drive never received a subsequent "ON" command to start the physical measurement. : Apply a standard "ON" or "Start" command

At its core, alarm A07991 is an , not a critical error, and the motor itself is not necessarily faulty. This message is displayed when the drive has been configured to perform an automatic measurement and optimization routine for the connected motor. In industry terms, the "Motor Data Identification" process is active.

Perform a RAM to ROM save (Parameter p0971 = 1 ) to permanently store the new data. 2. Manually Deactivate the Routine

The Siemens fault code 0A7991 has been reported by several users, indicating a specific issue with Siemens equipment or systems. As a reviewer, I aim to provide an in-depth analysis of this fault code, its possible causes, and potential solutions. The motor may whistle or make noise for

: If a drive restarts while waiting for a measurement command, the request can get stuck or reset, keeping the alarm flagged on subsequent boot-ups.

Some users have reported seeing both A7991 and A8526 alarms simultaneously. In these cases, the drive's BF (Bus Fault) LED is also often illuminated. While A7991 is a status notification about Motor Data Identification, A8526 is a more serious alarm indicating that no cyclic connection exists between the drive and the controlling PLC.

Understanding and Resolving Siemens Fault Code A07991 (Motor Data Identification Activated)