RS485 cable requirements
RS485 network topology must be arranged as
bus
(point to point), connection to
star
,
ring
or
triangle
is not possible !!!
Maximal length of RS485 line is
500 meters.
The first and the last device on the bus should have terminating resistor
120
Ω
be-
tween
A
and
B
lines. (some devices do already have this implemented inside, it can be
activated by DIP-switch or by software command - see manual to specific device)
Meeting these requirements is essential for seamless communication, partic-
ularly in environments with high surrounding electromagnetic interference (i.e.
substations, server rooms, utility rooms).
Installation manual
7
