"It’s not the PLC," Elias murmured, scrolling through the parameters. "The PLC is talking to the drive just fine. The Profibus light is green. This fault... it means this drive isn't hearing its partner."
: The physical load on the motor is too high, preventing it from reaching the required speed. siemens drive fault code 7902
If you see , your drive has been "orphaned." It thinks the controller (PLC) has abandoned it. 95% of the time, this is a broken cable, a loose connector, or the PLC being stopped. "It’s not the PLC," Elias murmured, scrolling through
| Cause | Explanation | |-------|-------------| | | KTY84 or PT100 open circuit. Drive interprets infinite resistance as overtemperature. | | Short circuit | Short across sensor leads = zero resistance, also interpreted as fault. | | Wrong sensor type configured | Parameter p0600 (temperature sensor type) set to “no sensor” but sensor wired, or vice versa. | | Sensor connected to wrong terminals | Example: KTY connected to terminals for PTC thermistor. | | Faulty sensor | Internal damage to the thermistor or RTD. | | EMI interference | Noisy signal lines cause erratic resistance readings. | This fault
When fault 7902 appears:
Subject: G120XA solution to warning F7902 motor out of step - Siemens