Wiring Gmw95; Connecting Several Transmitters On Same; Line; Figure 18 Wiring Gmw95 - Vaisala CARBOCAP GMW90 Series User Manual

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).
Shld GND D- D+
RS-485
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.
Building controller
Power
+Vs
supply
-Vs
D+
RS-485:
BACnet or
D-
MODBUS
master
GND
SHIELD
Connect shield on controller side
Figure 19 Several Transmitters on Same RS-485 Line
-Vs +Vs
Power supply
+
18 ... 35 VDC
-
or 24 VAC ±20%
Transmitter
+Vs
-Vs
D+
D-
GND
Shld
1209-014
Transmitter Transmitter
+Vs
-Vs
D+
D-
GND
Shld
Set RS-485
termination jumper
+Vs
-Vs
D+
D-
GND
Shld
1209-015