NI WSN-3214 User Guide and Specifications
32
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•
The channel is high impedance when the channel is turned off (1).
•
When driving inductive loads, use an external flyback diode or snubber circuit, as shown in
Figure 31.
Figure 31.
Connecting a Device to the NI WSN-3214 in Drive Low (Sinking) Mode
3V TTL Logic (Open-Collector with Pull-Up)
The 3V TTL Logic (Open-Collector with Pull-Up) mode can be used to connect to 3 V and 5 V logic
inputs with TTL Logic compatible thresholds. When using this mode:
•
The DIO
x
terminal is pulled-up to 3 V through a pull-up resistor for a DIO output value of 1 and
driven low to ground for a DIO output value 0.
•
The DIO line is read with 3V TTL Logic input thresholds.
•
A supply voltage is not required on DIO PWR.
Figure 32.
Connecting a Device to the NI WSN-3214 in 3V TTL Logic Mode
Drive High and Low (Sinking and Sourcing)
When using
Drive High and Low (Sinking and Sourcing)
mode:
•
Connect the device to DIO
x
and connect the device common to the DGND terminal corresponding
to that DIO
x
terminal.
•
The DIO
x
terminal is driven to the voltage supplied to DIO PWR when you turn on the channel,
and is driven to DGND when you turn off the channel.
DIO
x
Fly
ba
ck Diode
DGND
Low
S
ide
S
witch
DI
(Intern
a
l)
Extern
a
l
Power
Su
pply
+
–
NI W
S
N-
3
214
Device
DGND
Extern
a
l
Power
Su
pply
+
–
DIO
x
Low
S
ide
S
witch
DI
(Intern
a
l)
NI W
S
N-
3
214
TTL Device
TTL
P
u
ll Up
3
V