We have an S120 CU310 with 1PH7 motor with drive click. There is an RFI-filter and braking resistor on the drive. The apllication is a weight the motor has to pull up or let down on controlled speed.
When the weight is going down (motor is regenerating) we often get the error 6310 which relates to an incorrect parametrised input voltage, but the input voltage is set as default to 400V, which is also measured. DC-link voltage is 540V when not regenerating, 760V when regenerating (so, the braking resistor works). We do not get dc-link overvoltage errors. The error happens more often when starting or stopping the downward movenment, but can also happen during the continius movement downward.The error 6310 however does not stop the drive movement, the control stays on.
What could be the reason for this illogic error?

Thanks