The code A7991 (often appearing in logs as part of a longer string like 0a7991) is a Siemens drive alarm indicating that the motor identification has not yet been performed or completed. This typically occurs during the initial commissioning phase of a SINAMICS drive. Recommended Fixes
If the drive is in V/f control mode, ensure P1300 = 0 and P1900 = 0. Common Issues siemens fault 0a7991
Crucial Step: Perform a "RAM to ROM" save to ensure the settings are not lost when power is cycled. The code A7991 (often appearing in logs as
: This is an alarm, not a fault. It indicates that the drive is currently performing a "Motor Data Identification" (motor ID run) to measure the motor's electrical characteristics. Solution : When the drive outputs torque >
Complete the Configuration: Ensure all motor parameters (rated voltage, current, power, speed, etc.) have been correctly entered in the commissioning software. Perform Motor Identification:
When the drive outputs torque > p2175 but speed remains < 5% of setpoint for longer than p2177 or p2178, the system triggers 0A7991.
Although the exact cause may vary depending on the device, here are some potential reasons for the fault:
p2175 : Torque threshold for blocked motor detection (in % of rated torque).p2177 : Dwell time for blocked motor detection (seconds).p2178 : Maximum time for speed deviation monitoring (seconds).