Beckhoff ATH2000-0250, Руководство по эксплуатации

Страница: 74 / 100

Electrical installation
74 ─── Version: 1.0 eXtended Transport System
8.3
Earthing of the supply
No fuses exist
The figure below is for illustration purposes only. No necessary
fuses exist or are pictured in the simplified illustration.
P
o
w
e
r
S
u
p
p
ly
2
4
V
P
o
w
e
r
S
u
p
p
ly
4
8
V
C
o
n
tr
o
l
c
a
b
in
e
t
e
a
rt
h
EtherCAT cable
Control circuit
The EN60204-1 standard, clause 9.4.3.1. Earth faults stipulates that
24 V
DC
control circuits must be earthed. The earthing prevents the
automatic start-up of a machine in the case of a cross-circuit.
U
U
I 48V
I 24V
I compensation = 0 A
R 24 V
R 48 V
I 48 V
I 24 V
U 48 V
U 24 V
1,5 mm²
1,5 mm²
4 mm²
4 mm²
4 mm²
Modules Supply line 3G 4 mm² / 2 x 1,5 mm²
Power supplies
Load current circuit
Beckhoff recommends that you don't earth the 48 V power
supply unit
The 24 V
DC
return line (1.5 mm
2
) could be overloaded.
If the 48 V power supply unit is earthed, the currents will be distrib-
uted to the 48 V
DC
and 24 V
DC
back wires in accordance with the im-
pedances. Equalizing currents will then flow via the earth on the
power supply unit, as a result of which the 24 V
DC
return line
(1.5 mm
2
) could be overloaded.