User`s manual

Hardware Configuration Examples
14
02/2005
Using Bus
topology with tap
boxes
This topology is similar to the previous one, except that it uses TSXSCA62
subscriber connectors and/or TSXCA50 subscriber connectors. We recommend
using a VW3 A8 306 connection cable and the TSXCSA•00 Modbus cables.
Connect the RJ45 connector on the VW3 A8 306 cable to the Modbus connector on
the LUFP7 gateway.
TSXSCA62 / TSXCA50 tap boxes
TSXSCA62 box:
This passive box has a printed circuit fitted with screw terminals and allows the
connection of two subscribers to the bus two female 15 point SUB-D connectors.
It includes the line termination when the connector is located at the end. It is fitted
with two screw terminals for the connection of two double twisted pair Modbus
cables.
TSXSCA50 box:
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 two screw terminals for the connection of two double twisted pair Modbus
cables.
Wiring
recommen-
dations
General wiring recommendations for the Modbus network:
Use a shielded cable with 2 pairs of twisted conductors.
Connect the reference potentials to one another.
The maximum length of line is 1000 meters.
The maximum length of drop line / tap-off is 20 meters.
Do not connect more than 9 stations to a bus (8 slaves and one LUFP7 gateway).
Keep the bus away from power cables (at least 30 cm).
If crossings are necessary make then at right angles.
Connect the cable shielding to the earth on each unit.
Adapt the line at both ends using a line terminator.
VW3 A8 306