Phoenix Contact 2861205, User Manual

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IB IL 24 MUX MA-PAC
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PHOENIX CONTACT 5981_en_06
5.1 Surge protection for the remote bus cable
Electromagnetic fields affecting the remote bus can disturb data transmission, and in
extreme cases can damage the electronics of the field multiplexer. Phoenix Contact offers
two surge arresters from the TRABTECH range particularly designed for the field
multiplexer to protect the remote bus interface: DATA-PLUGTRAB.
Connection methods The surge arrester for the field multiplexer is connected in a different way, according to the
cable type. The following circuit diagrams (Figure 5-2 through Figure 5-5) illustrate various
methods of connection.
The use of versions 2 through 4 may nevertheless be necessary for the following reasons:
– A cable type other than the recommended type has already been laid
– The distance between the field multiplexer stations is too great for the shielding to be
connected (because of increased capacitive load)
– Cost savings are required
Version 1a
(recommended)
In this version the DATA and DATA signals, the reference potential GND
DATA
and the shield
are connected. The surge arrester should be installed as directly as possible next to the field
multiplexer head station. The wiring between the field multiplexer and the surge arrester can
then be carried out using simple stranded wires. The shield is to be grounded at both ends
(Figure 5-1). Connect it using shield clamps of type UFBK-SAS shield clamps at both surge
arresters.
Figure 5-1 Basic circuit diagram: Remote bus protection, version 1a
The appropriate ordering data can be found in Section 9.2, “Ordering data” or in the
TRABTECH catalog from Phoenix Contact.
ACHTUNG:
To operate the field multiplexer under unfavorable electromagnetic interference
conditions, Phoenix Contact recommends version 1a and 1b which use a 3-wire, shielded
cable. Versions 2 through 4 are not recommended from the point of view of surge
protection.
Ground both field multiplexer stations (see also "Grounding" and "Additional grounding"
on page 16).
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 3 5