Siemens Fault 0a7991 |work|
A: No – the fault prevents damage. It trips before excessive current melts windings. However, repeated fault cycles can stress the insulation.
: A food processing plant using a SINAMICS G120 to drive a dough mixer reports recurring fault 0A7991 every morning at first start, but runs fine rest of the day.
Follow these three approaches depending on whether you want to the motor identification or deactivate it temporarily.
Caution: Only perform rotating ID with the load disconnected or safely decoupled. siemens fault 0a7991
"I/O access error when updating the process image input table. The module is either defective, incorrectly parameterized, or not physically present."
A: Not recommended. You can set p2118[0] = 7991 and p2119[0] = 0 to change it from F (fault) to I (info) – but this removes protection against real mechanical damage. Use only for debugging.
If you have persistent issues even after following this guide, contact Siemens Technical Support with your diagnostic buffer export and hardware configuration file for advanced analysis. A: No – the fault prevents damage
, for example, is a common overload fault often confused with others. Search the Manual
: If you encounter F7991 instead of A7991, this indicates a critical fault condition such as motor blockage, mechanical overload, or incorrect motor model parameters, requiring immediate inspection of the mechanical system.
Because it prevents standard operation until the drive successfully profiles the motor or the function is disabled, engineers and technicians must address it during commissioning or system restarts. Root Causes of Alarm A07991 : A food processing plant using a SINAMICS
If you are working with Siemens SINAMICS drives—particularly the —you might encounter the alarm code A07991 , often displayed as "A07991 (N) Drive: Motor data identification activated". While classified as an alarm (indicated by the 'A'), it directly inhibits normal drive operation, preventing the motor from running until the identification process is completed or bypassed.
There are three common scenarios that activate this alarm: