| Root Cause | Solution |
|------------|----------|
| PLC in STOP | Set PLC to RUN or reconfigure drive to ignore missing telegram (p2040 = 0 – not recommended for safety) |
| p2040 too short | Increase p2040 to at least 2–3× bus cycle time |
| Loose connector | Reseat or replace bus connector |
| Wrong telegram type | Match p0922 with PLC configuration (e.g., standard telegram 1 for speed control) |
| No termination | Activate termination on both ends of PROFIBUS segment |
| EMI | Check cable routing, add ferrites, verify shield grounded at both ends |
| Faulty option board | Replace communication board (e.g., CBE20 for PROFINET) |
Fault code 7902 is typically categorized under “Drive: Motor overtemperature” or, more specifically, a “Temperature sensor fault” depending on the firmware version and drive series. In most Siemens drive documentation (Sinamics S120/G120 parameter list), F07902 translates to:
“Motor temperature monitoring has responded. The motor temperature calculated by the thermal motor model or directly measured via a temperature sensor (KTY84, PT100, or PTC thermistor) has exceeded the permissible limit.” siemens drive fault code 7902
However, a critical nuance often missed: In some Siemens drive firmware versions, code 7902 can also indicate a wire break or short circuit in the temperature sensor feedback circuit, rather than actual overheating. This dual nature makes it a tricky fault to diagnose without systematic testing.
To avoid future occurrences of fault code 7902: | Root Cause | Solution | |------------|----------| |
In the complex world of industrial automation, Siemens drives (ranging from the venerable Masterdrives to the modern Sinamics S120, G120, and S150 families) are known for their robustness. However, like any precision electronic equipment, they occasionally halt production with an error code. Among the more cryptic and frustrating alarms for maintenance technicians is Siemens drive fault code 7902.
If you are staring at a panel displaying “F07902” or “Fault 7902,” you know production has stopped. This article provides a deep dive into what this fault means, why it occurs, and—most importantly—a step-by-step guide to getting your machinery back online. “Motor temperature monitoring has responded
Contact professional help if: