18 WSA-XEE 122-402
M02S40N16-00
5.10 Modbus - RS485
LED BSP communication with AP1 module LED BUS communication with Modbus
green communication ok green communication ok
yellow software ok but communication with AP1
down
yellow startup / channel not communicating
red ashing: software error red communication down
xed: hardware error
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Unit Parameters Modbus
Parameters Short description Description
P0445: T1 bus termination Termination resistor activation on T1 POL902 [0] port = Passive [1] = Active
P0446: T2 bus termination Termination resistor activation on T2 POL902 [0] port = Passive [1] = Active
A. Unit
B. Metal conduit
C. Metal septums
D. Metal-lined sheath (sleeve)
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
•
Every 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 dierence 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 eects 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 specic jumper, dip switch or link.
•
The cable must have insulation features and non-ame propagation in accordance with applicable regulations.
•
The RS485 serial line must be kept as far away as possible from sources of electromagnetic interference.
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