: Sometimes, industry-specific forums or communities can be a good resource. There, you might find discussions about common issues, including fault codes.
Understanding and Resolving Siemens Alarm A07991: The Complete Guide If you're working with Siemens SINAMICS drives (like the G120 or S120), encountering Alarm A07991
The most "correct" way to clear this alarm is to allow the drive to perform its identification. : Issue a "Start" or "Run" command to the drive.
Depending on whether you actually want the drive to learn the motor or just want it to get moving, you have two main paths:
In Siemens SINAMICS drive systems, the alarm (often referred to as fault 0a7991) indicates that Motor Data Identification is activated . This is not a critical hardware failure but rather a status message indicating the drive is prepared to perform a measurement of the motor’s electrical characteristics. Understanding Alarm A07991 siemens fault 0a7991 best
According to Siemens technical documentation , here are the most effective methods to clear this alarm:
Depending on the operational stage of your machinery, use one of the following methods to resolve the alarm.
The drive obtains these values by running a series of high-frequency test currents through the motor windings while it remains stationary (standstill measurement) or during low-speed rotation. Common Causes for A07991 Triggers
: Apply an standard ON command (Bit 0 of control word 1 via PLC or local control). : Sometimes, industry-specific forums or communities can be
The Siemens fault 0A7991 can be a challenging issue to resolve, but by understanding its causes, symptoms, and troubleshooting procedures, users can minimize downtime and ensure optimal device performance. Regular maintenance, proper configuration, and firmware updates can help prevent this fault from occurring. If you are experiencing this fault and are unsure about how to resolve it, it is recommended to contact Siemens support or a qualified technician for assistance.
💡 Always use Siemens-certified Green PROFINET cables in high-vibration or high-voltage environments.
To really master your Siemens drive, it's helpful to understand the two main parameters at play. The table below clarifies their roles.
The alarm is triggered when the drive's internal motor model needs to be calculated or updated. The motor is an electromechanical device whose electrical characteristics (like resistance and inductance) can change slightly over time with temperature and use. The drive requires this data to build an accurate mathematical model, ensuring better efficiency, higher torque accuracy, and better protection. : Issue a "Start" or "Run" command to the drive
in Siemens drive systems (such as SINAMICS S120 or G120) refers to a
: The operator or PLC requested a static or rotating motor identification routine to optimize performance parameters.
Motor stalled, common in asynchronous motors without proper static optimization. Siemens SiePortal Troubleshooting Tips for Siemens Drives
: If you don't need the identification (e.g., during testing or a Factory Acceptance Test), set p1900 = 0 to inhibit the process.