Modern, microprocessor controlled inverters are equipped with extensive mechanisms of self-diagnosis. These diagnostic systems:

• check the correct operation of a functional blocks inside the inverter
• supervise in a real time conditions the operating parameters (power supply, inverter & converter circuits, load, etc) to ensure the inverter is operating in a safe operation area

In case of a faulty operation of the inverter, very often an alarm is raised on an operator's panel with an error code. That provides an information leading to possible causes of a fault. The following table summarizes the error codes for Danfoss inverters: