BECKHOFF BK3xx0 - Manual (Page 21)

Notes on the Documentation
Fieldbus Components 19
Power Supply
Bus Coupler / Bus Terminal Controller and Bus Terminal
Supply (Us)
BKxx00, BKxx10, BKxx20 and LCxxxx
The Bus Coupler / Bus Terminal Controller require a 24 V
DC
supply for their operation.
The connection is made by means of the upper spring-loaded terminals labeled 24 V and 0 V. This supply voltage
feeds the Bus Coupler / Bus Terminal Controller electronics and, over the K-Bus, the electronics of the Bus
Terminals. It is electrically separated from the potential of the field level.