Siemens Fault 0a7991 May 2026

Siemens Alarm A07991 (or A7991) on SINAMICS G120/S120 drives indicates that Motor Data Identification (ID) is active, requiring a motor ID run or manual adjustment to clear. The condition is resolved by running a motor identification, setting parameter P1900 to 0, or bypassing calculations via P340 during commissioning. For detailed solutions and forum discussions, visit Siemens SiePortal Dealing with Motor ID ( code 7991 ) - SiePortal - Siemens

Case E: Tuning for High-Inertia Loads (Fans, Centrifuges)

High-inertia loads take time to accelerate. The default p2178 (typically 1–2 seconds) is too short. siemens fault 0a7991

If you cannot perform the identification (e.g., for factory testing without a motor), set parameter P1900 = 0 to inhibit the measurement. Siemens Alarm A07991 (or A7991) on SINAMICS G120/S120

In some cases, setting p1300 = 0 (V/f control mode) is also used to bypass complex motor modeling . Finalize the Setup The default p2178 (typically 1–2 seconds) is too short