configuration of the RS485 link
choosing the connecting
cable
Local links by direct cable
Choice of a cable depends both on the
relevant sector of application and on
the flowrates and the environment in
question. For information, the following
transmission cables can be chosen:
Industrial sector:
one, two or three conductor pairs per
cable;
8
Example of configuration in the 4 wire topology.
5V
Rp
SA3-3
polarity
SA3-1
Ra
SA3-2
polarity
Rp
receive
0V
data
5V
SA3-4
Rp
SA2-1
polarity
SA2-3
connection
if
end of line
Ra
SA2-2
polarity
Rp
0V
transmit
data
SineWave™
polarised but non terminated
line
1 2 3 4
1 2 3 4
SA2
SA3
NB: polarisation is possible both in reception and transmission.
shielding per conductor pair;
multi-strand conductors;
telephone shielded twisted pairs may
be used
Tertiary sector:
one, two or three conductor pairs per
cable;
cable shielding if required;
shielded or unshielded telephone
pairs may be used.
SineWave™ JBUS communication system installation: E-51027160XT/AC
(cont.)
5V
Rp
SA3-3
R-
R-
SA3-1
Ra
R+
R+
SA3-2
Rp
receive
0V
data
5V
SA2-4
SA3-4
Rp
SA2-1
T-
T-
SA2-3
Ra
T+
T+
SA2-2
Rp
0V
transmit
data
SineWave™
non polarised and non
terminated line
1 2 3 4
1 2 3 4
SA2
SA3
Domestic:
one or two conductor pairs per cable;
telephone pairs may be used.
Protection
All the shieldings are earthed on
either side.
5V
Rp
SA3-3
R-
R-
SA3-1
matching
Ra
R+
R+
SA3-2
Rp
receive
0V
data
5V
SA2-4
SA3-4
Rp
SA2-1
T-
T-
SA2-3
Ra
T+
T+
SA2-2
Rp
0V
transmit
data
SineWave™
non polarised but terminated
line if end of line
1 2 3 4
1 2 3 4
SA2
SA3
MGE UPS SYSTEMS
SA2-4