CLIVET WSAT-YSC4, Manual

Page: 23 / 76

Modbus - RS485
Option
LED BSP
Modbus / LonWorks / Cable requirements
Couple of conductors twisted and shielded Section of conductor
0,22mm2…0,35mm2 Rated power between conductors < 50 pF/m
Nominal impedance 120
Ω
Recommended cable BELDEN 3106A

very RS485 serial line must be set up using the ‘In/Out’ bus
system.

Other types of networks are not allowed, such as Star or Ring
networks.

The difference in potential between the earth of the two RS485
devices that the cable shielding needs to be connected to must
be lower than 7 V

There must be suitable arresters to protect the serial lines from
the effects of atmospheric discharges

A 120 ohm resistance must be located on the end of the serial
line. Alternatively, when the last serial board is equipped with
an internal terminator, it must be enabled using the specific
jumper, dip switch or link.

The cable must have insulation features and non-flame
propagation in accordance with applicable regulations.

The RS485 serial line must be kept as far away as possible
from sources of electromagnetic interference.
A. Unit
B. Metal conduit
C. Metal septums
D. Metal-lined sheath (sleeve)
5 - ELECTRICAL CONNECTIONS