50
Analog input select
Vacon · 20 Compact AC Drive
What does 50 mean?
This fault indicates that the current at an analogue input (configured for a 4-20mA range) is below 4mA, or the voltage at an analogue input (configured for a 2-10V range) is below 2V. This typically points to a broken or loose control cable or a failure of the signal source device.
Source: Vacon 20 Compact AC Drive
Open Manual (Page 56)