Thermal Sensor Error (OC/SC)

What does InFb mean?

A thermal sensor detected error, indicating either an open circuit (OC) or short circuit (SC) in the internal thermal sensor circuit. This prevents the drive from accurately monitoring its internal temperature, risking overheating and damage if left unresolved.

• Internal thermal sensor element failure (e.g., thermistor degradation) within the drive's control circuit.
• Open circuit detected in the internal thermal sensor wiring path on the drive's control board.
• Short circuit across the thermal sensor terminals or its internal wiring, resulting in an invalid resistance reading.
• Component manufacturing defect in the drive's internal thermal sensing circuit causing erroneous readings.

Click steps to track your progress.

1. 1

   Power down the drive and verify the resistance across the internal thermal sensor terminals (e.g., X1-1 and X1-2) on the control board using a multimeter.

2. 2

   Compare the measured resistance value to the expected range specified in the drive's hardware manual (e.g., 5-15 kOhms at 25°C).

3. 3

   If the resistance is out of range (indicating OC or SC), visually inspect the sensor's solder joints and PCB traces for visible damage.

4. 4

   If no external damage is apparent and the resistance is incorrect, replace the control board or the entire drive assembly.