Vaisala GMW95 - Connecting Several Transmitters on same; Figure 18 Wiring GMW95; Figure 19 Several Transmitters on same RS-485 Line; Line

Chapter 3 ________________________________________________________________ Installation
VAISALA ________________________________________________________________________ 29
Wiring GMW95
The RS-485 line of the transmitter is isolated from the power supply. A
separate ground reference terminal (GND) is provided for the RS-485
connection.
If you are using a shielded cable, you can use the Shld terminal to hold
the exposed part of the shield. Note that the Shld terminal is floating
(not electrically connected).
1209-014
Figure 18 Wiring GMW95
Connecting Several Transmitters on Same RS-485
Line
Set the RS-485 termination jumper to “ON” on the transmitter that is at
the end of the line. This terminates the line with a 120 Ω resistor. For
location of the jumper, see Figure 4 on page 17.
Connect the cable shield to ground on the building controller side.
1209-015
Figure 19 Several Transmitters on Same RS-485 Line
D-
-
Vs
D
+ +Vs
+
-
Power supply
1
8
..
. 3
5
VD
C
or 24 VAC ±20%
RS-
485
S
hl
d
GN
D
Transmi
tter
D-
-Vs
D+
+Vs
Shld
GND
B
uild
ing
con
trol
ler
Tra
nsm
itter Transm
itt
er
Power
s
upp
ly
D-
D+
+Vs
-Vs
GND
SHIEL
D
RS-48
5:
BAC
net or
MO
DBU
S
mas
ter
Connect shield on controller side
Set RS
-485
t
ermination jum
per
D
-
-
Vs
D+
+Vs
Sh
ld
GN
D
D-
-
Vs
D+
+Vs
Shld
GND