National Instruments NI 9476 - Manual (Page 10)

NI 9476 Operating Instructions and Specifications 10 ni.com
Protecting the Module from Flyback Voltages
If the module is switching an inductive or energy-storing device
such as a solenoid, motor, or relay, and the device does not have
flyback protection, install an external flyback diode as shown in
Figure 4.
Figure 4. Connecting a Flyback Diode to the NI 9476
External
Power
Supply
NI 9476
+
_
COM
V
sup
Inductive
Device
DO
Flyback
Diode