NI sbRIO-961x/9612XT/963x/9632XT/964x/9642XT
34
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Protecting the NI sbRIO Device from Flyback Voltages
If a digital output channel is switching an inductive or energy-storing
device such as a motor, solenoid, or relay, and the device does not have
flyback protection, install a flyback diode as shown in Figure 26.
Figure 26.
Connecting a Flyback Diode to the NI sbRIO 964
x
/9642XT
I/O Protection
The NI sbRIO-964
x
/9642XT is protected against overcurrent, inrush, and
short-circuit conditions in accordance with IEC 1131-2.
Each digital output channel on the NI sbRIO-964
x
/9642XT has circuitry
that protects it from voltage and current surges resulting from short circuits.
Caution
The NI sbRIO-964
x
/9642XT can be damaged under overvoltage and reverse bias
voltage conditions. Check the voltage specifications for all devices that you connect to the
NI sbRIO-964
x
/9642XT.
Excessive current through a DO pin causes the channel to go into an
overcurrent state. In an overcurrent state, the channel cycles off and on until
the short circuit is removed or the current returns to an acceptably low level.
Refer the
section for typical trip currents.
Each channel has a status line that indicates in software whether the
channel is in an overcurrent state. Refer to the software help for information
about the status line.
6–35 VDC
External
Power
S
upply
+
–
D GND
V
sup
Inductive
Device
DO
Flyback
Diode
