External equipment failure is one of the common faults in inverter operation. For Oulu frequency converters, external equipment failure is displayed as ERR/FU15 on the operation panel. The causes and troubleshooting methods for external equipment failure are as follows:

An external fault signal is input through the multi-function terminal S. Troubleshoot peripheral faults, confirm that the machinery permits restart (parameter P8-18), and reset the system to resume operation.