Phoenix Contact 2861205, User Manual

Page: 37 / 88

Surge protection
5981_en_06 PHOENIX CONTACT
37
Version 1b
(recommended)
If it is not possible to implement grounding at both ends because of equalization currents
arising as a result of different grounding systems, choose one of the following options:
– Use a double shielded cable in which the outer shielding is grounded at both ends.
– Lay a supplementary wire for the remote bus cable.
– Ground the shield indirectly using a type TERMITRAB-SLKK5-F/110AC surge
protective device (see Phoenix Contact TRABTECH catalog) (Figure 5-2).
Figure 5-2 Basic circuit diagram: Remote bus protection, version 1b
The remote bus cable is wired between the two surge arresters and the TERMITRAB
modular terminal block as illustrated in Figure 5-2. The remote bus cable shield must be
connected at both ends using a shield clamp of type UFBK-SAS (see Section 9.2, “Ordering
data”) to the surge arrester of field multiplexer A and to the TERMITRAB terminal.
Version 2
(not recommended)
This version is suitable if only a 3-wire cable with no shield is available. In this case, only the
DATA and DATA signals and the reference potential GND
DATA
are connected. The shield
connection of both field multiplexers is left open.
Figure 5-3 Basic circuit diagram: Remote bus protection, version 2
F i e l d
M u l t i p l e x e r
A
D A T A
G N D
D A T A
S h i e l d
D A T A
F i e l d
M u l t i p l e x e r
B
D A T A
G N D
D A T A
S h i e l d
D A T A
S
u
rg
e
p
ro
te
c
ti
o
n
8
1 0
4
1 2
7
9
3
1 1
S
u
rg
e
p
ro
te
c
ti
o
n
7
9
3
1 1
8
1 0
4
1 2
R e m o t e b u s c a b l e
I N O U T I N O U T
U F B K - S A S
5 9 8 1 B 0 2 7
T E R M I T R A B
F i e l d
M u l t i p l e x e r
A
D A T A
G N D
D A T A
S h i e l d
D A T A
F i e l d
M u l t i p l e x e r
B
D A T A
G N D
D A T A
S h i e l d
D A T A
S
u
rg
e
p
ro
te
c
ti
o
n
8
1 0
4
1 2
7
9
3
1 1
S
u
rg
e
p
ro
te
c
ti
o
n
7
9
3
1 1
8
1 0
4
1 2
R e m o t e b u s c a b l e
I N O U T I N O U T
5 9 8 1 B 0 2 8