Cause : Control card over temperature comes when the control card has reached its trip temperature of 75 °C or the temperature of the control card has exceeded safe operating limits. 

Here's how you might address an "over temperature" error related to a control card:

1. Immediate Action: If the control card is reporting an over-temperature error, it's crucial to take immediate action to prevent damage to the card and associated components. Shut down the device and allow it to cool down.

2. Check Ventilation: Poor ventilation or restricted airflow can contribute to elevated temperatures within the device enclosure. Ensure that the device is installed in a well-ventilated area and that any ventilation openings are not obstructed.

3. Inspect Cooling Systems: Many electronic devices, especially those operating in industrial environments, are equipped with cooling systems such as fans or heatsinks to dissipate heat. Check that these cooling systems are functioning correctly and free from obstructions.

4. Reduce Load: High loads or excessive usage can generate additional heat within the device, contributing to temperature rise. Consider reducing the load on the device or limiting its operation to avoid prolonged periods of high temperature.

5. Check Ambient Conditions: Ambient temperature and environmental factors can affect the operating temperature of electronic devices. Ensure that the device is operating within its specified temperature range and that ambient conditions are within acceptable limits.

6. Inspect Control Card: Visually inspect the control card for any signs of damage or malfunction, such as burnt components or melted solder joints. These signs may indicate a more severe underlying issue that requires further investigation or repair.