Siemens Drive Fault Code 7902 [portable]

If using encoder feedback, verify the encoder signal is accurate.

Gather the following before calling:

Once the drive registers that the motor has stalled, it does not shut down immediately. It waits for the duration defined in (Motor Stalled Delay). If the condition persists for that entire period, the drive outputs Fault 7902 and trips.

Option 1: Quick Troubleshooting (Best for LinkedIn/Professional Forums) siemens drive fault code 7902

| 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) |

Before typing in numbers, ensure parameter p0300 (Motor Type) is precisely set (e.g., 1 for induction motor, 2 for synchronous motor). This changes the drive's underlying internal algorithms.

Here are three post options tailored for different audiences: If using encoder feedback, verify the encoder signal

: Incorrectly set motor data (voltage, current, or frequency) or missing motor identification (ID) runs.

Ensure match the motor nameplate precisely.

| 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. | If the condition persists for that entire period,

Update the corresponding drive parameter to accurately reflect this topology. 3. Inspect the Physical Motor and Cable Integrity

This distinction is crucial for targeted troubleshooting.

Troubleshooting Siemens Drive Fault Code F07902: Causes and Solutions

Incorrect nameplate data (kW, Amps, RPM) entered during commissioning.

The load inertia is higher than what the motor was designed for, causing it to stall during acceleration. 2. Parameterization and Commissioning Issues