Schneider Electric LUFP7 Switch User Manual


 
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2. Hardware Implementation of the LUFP7 Gateway
2.5.3. Wiring Recommendations for the Modbus Network
Use a shielded cable with 2 pairs of twisted conductors,
connect the reference potentials to one another,
maximum length of line: 1,000 metres
maximum length of drop line / tap-off: 20 metres
do not connect more than 9 stations to a bus (slaves and one LUFP7 gateway),
cable routing: keep the bus away from power cables (at least 30 cm), make crossings at right angles if
necessary, and connect the cable shielding to the earth on each unit,
adapt the line at both ends using a line terminator (see diagram and VW3 A8 306 RC termination below).
D(B)
D(A)
120
1 nF
4
5
— Line termination recommended at both ends of the line — — VW3 A8 306 RC line termination —
To make it easier to connect the units using the topologies described in chapter 2.5.1 Examples of Modbus
Connection Topologies, page 15, various accessories are available in the Schneider Electric catalogue:
1) Hubs, drops, taps, and line terminations:
LU9GC03 hub .....................
(“star” topology)
This passive box has 8 female RJ45 connectors. Each of these connectors can
be connected to a Modbus slave, to a Modbus master, to another Modbus hub,
or to a line termination.
VW3 A8 306 TF3 drop box......................
(“bus” topology with VW3 A8 306 TF3 drop boxes)
This passive box includes a short lead with a male RJ45 connecto
r
allowing it to be connected directly to a Modbus slave, without
having to use a different cable. It is fitted with 2 female RJ45
connectors for the connection of two Modbus cables of the
VW3 A8 306 R•• type.
2-way TSXSCA62 subscriber connector.
(“bus” topology with tap boxes)
This passive box has a printed circuit fitted with screw terminals
and allows the connection of 2 subscribers to the bus (2 female
15 point SUB-D connectors). It includes the line termination when
the connector is located at the end. It is fitted with 2 screw terminals
for the connection of two double twisted pair Modbus cables.
TSXCA50 tap box....................................
(“bus” topology with tap boxes)
This passive box allows a Modbus unit to be connected to a screw
terminal. It includes the line termination when the connector is
located at the end. It is fitted with 2 screw terminals for the
connection of two double twisted pair Modbus cables.
VW3 A8 306 RC double termination .......
(all topologies)
Each of these two red passive boxes is a male RJ45 connecto
r
3 cm long containing an RC line termination (see diagram and
illustration above). Only the abbreviation “RC” is shown on these
boxes.