NI WSN-3230/3231 User Guide and Specifications
18
ni.com
NI WSN-3231 RS-485 Port
Wiring the RS-485 Port
The NI WSN-3231 has one 18 position combicon screw terminal for connectivity to RS-485, DIO, and
sensor power.
Figure 14.
NI WSN-3231 Pinout
Operating Modes
The NI WSN-3231 has two operating modes: four wire operating mode and two wire auto mode.
Four Wire Mode
In this mode, output buffers and receivers are always enabled. In this mode of operation, you have two
different pairs of transmission and reception lines and so the transmission lines (TX+ and TX–) are
always enabled for transmission and they always drive the lines. Likewise, the reception pair (RX+ and
RX–) are always ready to accept the bytes.
Two Wire Auto Mode
In this mode, the transmitter is enabled automatically when needed and disabled as soon as transmission
is finished. The receivers are disabled whenever the transmitter is enabled, to avoid the echo. This is the
recommended mode of operation for 2-wire data transmission, because you do not have to enable or
disable the transmitters manually.
Battery Considerations
The expected battery life of your NI WSN-3230 and NI WSN-3231 can vary greatly based on your
NI LabVIEW WSN program, sampling interval, length and baud rate of serial transmission, serial
cabling, temperature, and type of cells. The following graphs are provided as a reference to demonstrate
estimated battery life under common conditions. For more information, refer to
ni.com/info
and enter
WSNBatterylife
.
1
0
2
3
4
5
6
7
9
8
10
11
12
1
3
14
15
16
17
DIO PWR
DGND
DIO 1
DGND
DIO 0
S
EN PWR 12V
DGND
NC
NC
NC
NC
NC
DGND
RX-
RX+
DGND
TX-
TX
