System malfunction

What does F-21 mean?

An internal system malfunction has occurred within the inverter electronics, potentially influenced by electromagnetic compatibility (EMC) issues. This fault causes an immediate switch-off and inhibits operation, signifying a critical internal hardware or software problem that requires expert attention.

• Critical internal self-test failure at power-up, indicating a fundamental hardware or firmware issue.
• Inconsistent internal software state detected, possibly due to race conditions or incorrect task scheduling.
• Faulty clock crystal or oscillator on the main control board, affecting CPU timing and synchronization.
• High-frequency electrical noise coupled into internal circuits, causing transient logic states.
• Power supply sag or momentary interruption during inverter initialization, leading to an incomplete startup sequence.

Click steps to track your progress.

1. 1

   Perform multiple power cycles, waiting at least 1 minute between cycles, to allow all internal capacitors to discharge fully and reset internal states.

2. 2

   Measure the incoming control power supply voltage (e.g., 24VDC terminals) for stability during the inverter's power-up sequence.

3. 3

   Remove all external communication cables (e.g., fieldbus, Ethernet) and I/O connections and attempt to power up the inverter in isolation.

4. 4

   Inspect the control board visually for any signs of physical damage, overheating components, or loose ribbon cable connections.

5. 5

   Verify that the inverter's input power quality is stable, without frequent sags or swells, using a power logger connected to the mains input.