NI WSN-3212 User Guide and Specifications
22
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Controlling Digital Inputs and Outputs
The NI WSN-3212 device has four bi-directional digital I/O channels, and each channel supports four
operational modes: Drive High Only, Drive Low Only, Drive High and Low, and Tristate. Use the
Node
Properties
dialog box in the LabVIEW Project Explorer window to change DIO settings.
Figure 22.
Simplified Circuit Diagram of One DIO Channel
Terminals 9–17 are the DIO section on the 18-position screw terminal connector. Each DIO channel has
a signal terminal (DIO.
x
) and a ground terminal (D GND). There is also a terminal for the positive
terminal of DIO Power (DIO PWR), which is only required when one of the DIO channels is configured
for sourcing output. There is an internal digital input terminal which reads the digital output current state
or the value of DIO.
x
when configured for Tristate mode. The NI-WSN software controls the different
modes of operation by turning on and off the high side and low side switches.
You can connect a variety of industrial devices such as solenoids, relays, and indicators to the
NI WSN-3212 device. Refer to the
section to ensure compatibility. The Drive High Only
and the Drive High and Low modes require an external power supply connected to the DIO PWR
terminal.
The following sections discuss how to configure the NI WSN-3212 device for different types of input
and output and how to connect external devices to the NI WSN-3212 DIO terminals.
Connecting Sourcing Digital Outputs
You must connect an external power supply to the NI WSN-3212 to source digital outputs. This power
supply provides the current for the devices you connect to the NI WSN-3212. Connect the power supply
positive lead to DIO PWR terminal and the power supply negative lead to one of the D GND pins. The
DIO PWR terminal on the NI WSN-3212 is internally connected to each digital channel. You can
connect only one external voltage supply to the device. Refer to the
section for
information about the power supply voltage range.
Note
You must use 2-wire ferrules to create a secure connection when connecting more than one
wire to a single terminal on the NI WSN-3212.
You can connect sourcing digital outputs to the NI WSN-3212 in either Drive High Only Mode or Drive
High and Low Mode. In either mode, connect the device to DIO.
x
and connect the device common to
the D GND terminal closest to that DIO.
x
terminal.
DIO PWR
High
S
ide
S
witch
DIO.
x
D GND
Low
S
ide
S
witch
DI
(Intern
a
l)
NI W
S
N-
3
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