Beckhoff · EL6900 Operating Instructions
This diagnostic code (found within FA00:03 Supply error) signifies that the supply voltage to the primary microcontroller (μC1) has exceeded its maximum permissible limit. Overvoltage can cause immediate damage to the microcontroller, leading to erratic behavior or complete failure of the terminal's safety functions.
Click steps to track your progress.
Measure the input supply voltage to the EL6900 terminal using a multimeter at the power terminals.
Verify that the external power supply unit providing power to the terminal is operating within its specified voltage range.
Check for any transient voltage spikes on the supply line using an oscilloscope.