At its core, this fault indicates that the drive has lost its PROFINET communication connection. PROFINET (Process Field Net) is the standard Industrial Ethernet standard used for data exchange between the drive and the PLC (Programmable Logic Controller) or higher-level control systems.
This isolates the problem to the motor, encoder, or drive parameters. Perform a Quick Commissioning from scratch. Then test the motor uncoupled. If fault persists, replace the encoder or run sensorless (p1300=20). siemens drive fault 7902
For vector control with encoder:
When faced with Fault 7902, follow this logical sequence to isolate the problem. At its core, this fault indicates that the
Siemens drive fault 7902 is rarely a mystery—it is a cry for help from a drive that sees motion but achieves none. By understanding the relationship between p2175, p2177, motor parameters, and your mechanical system, you can transform this frustrating fault into a manageable diagnostic tool. Perform a Quick Commissioning from scratch