Siemens Fault 0a7991 Jun 2026

Experts on the Siemens SiePortal Forum often suggest specific sequences for persistent alarms:

Specifically, this fault usually indicates a In many documented cases, this fault is triggered when the Control Unit (CU) cannot verify the parameters of the Power Module (PM) or when a fieldbus communication (such as PROFINET or PROFIBUS) times out.

Alarm A07991 is an informational notification that the . It's not a real fault or error in the traditional sense, but rather a notice that the drive is prepared to perform a calibration and tuning routine.

The causes of fault 0A7991 can be diverse and may include: siemens fault 0a7991

Follow these three approaches depending on whether you want to the motor identification or deactivate it temporarily.

If the PLC is not connected, set p2030 to 0 (Disable fieldbus).

"I/O access error when updating the process image input table. The module is either defective, incorrectly parameterized, or not physically present." Experts on the Siemens SiePortal Forum often suggest

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

In essence, the drive commands the motor to accelerate to a target speed. The internal speed encoder (or sensorless vector control) reports back the actual speed. If the actual speed remains significantly below the target speed for a defined period (set by parameter p2178 ), the drive assumes the motor is mechanically blocked and trips.

The Siemens code is not a permanent hardware fault, but rather a warning alarm indicating that the Motor Data Identification (motor tuning) is active. While this is a standard part of the commissioning process for SINAMICS drives like the G120 or G120C, it can be frustrating if it prevents the drive from starting in normal operation. Review of Fault A07991 The causes of fault 0A7991 can be diverse

Method 1: Perform the Motor Identification Run (Recommended)

Siemens fault code 0A7991 (A07991) is a standard notification that the motor data identification routine is active. It is neither a safety hazard nor an indication of motor failure. Whether you decide to complete the identification process for optimal drive performance or simply disable the function for immediate operation, following the steps in this guide will help you resolve the issue quickly and effectively.

Are you currently performing an , or did this alarm appear suddenly on a drive that was already running ? How can resolve the alarm Code 7991 and 8526 - SiePortal

An engineer or technician may have intentionally activated the routine by setting parameters like P1900 (Motor Data Identification) or P1910 (Static Motor Data Identification).