16
cable. To minimise noise on the network when no transmission is occurring, a pull up and pull down
resistor are req
uired. Typical values for both resistors are in the range from 650 to 850 Ω.
Figure 4.6.1
Connecting sun[e] to a typical RS-485 network
not connected
[+]
8 to 30 VDC
[
-
]
8 to 30 VDC
c
o
m
m
o
n
[+]
d
a
t
a
[
-
]
d
a
t
a,
RS-485 A /
A
’
sun[e]
wire
white
black
blue
grey
brown
,
RS-485 B / B’
RS-485 network
shield
shield