Instructions

Earthing and shielding | Potential ratios
246 1432790000/03/02.2014Manual u-remote
8.2 Potential ratios
Basic aspects
As regards the potential ratios of a u-remote system, the fol-
lowing aspects must be kept in mind:
– The power supply of the coupler and I/O modules as well
as field power is provided via the power supply at the
power-feed module (PF)
– A potential-free design is made possible through the use
of an isolated power supply at the system power supply
and the field power supply
The block diagram shows the typical design of a u-remote
system. The power supply concept here makes sure that,
starting with a certain capacity utilisation, power refresh is
implemented using power-feed modules.
Versorgungskomzept
+24 V DC
5
3
2
2
+24 V DC
+24 V DC
DI/AI
Systembus
U
SYS
UIN
UOUT
DI/AIDO/AO PF-O PF-IDO/AO
+24 V DC
u-remote power supply concept
Potential-free design
In a potential-free design, the reference potentials of control
and load circuits are galvanically isolated from each other.
A potential-free design is necessary for the following:
– Use of the power-feed module (in both the PF-I and PF-O
variants), i.e. in all AC load circuits
– DC load circuits that cannot be coupled
Potential-free installation depends on the type of earthing.
Non-isolated design
In a non-isolated design, the reference potentials of control
and load circuits are galvanically connected to each other.