I/O Terminal /
MOUNTING AND WIRING
17
3.4 Power
Supply
The Bus Coupler / Bus Terminal Controller require a 24 VDC 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
Standard-Bus, the electronics of the Bus Terminals. It is electrically separated from the
potential of the field level.
DANGER!!
For the compliance of the UL requirements Us should only be supplied:
By a 24 VDC supply voltage, supplied by an isolating source and protected by means of
a fuse (in accordance with UL248), rated maximum 4 Amp.
By a 24 VDC power source, that has to satisfy NEC class 2.
A NEC class 2 power supply shall not be connected in series or parallel with another
(class 2) power source!