Chapter 4
Connecting Lighting and External Devices
NI 177x Smart Camera User Manual
4-4
ni.com
Connecting to a PNP Device
Because a PNP input device requires a sourcing input, you must use an
external pull-up resistor. Note that the resistor will invert the output signal
so that the open collector output disables the PNP input device.
Connect the ground of the NI 177x Smart Camera and the PNP input device
to a common ground.
Note
Each open collector output can sink up to 100 mA.
Figure 4-3.
Connecting to an External PNP Input Device
Protecting Against Inductive Loads
When an inductive load, such as a relay or solenoid, is connected to an
output, energy stored in the inductor may cause a voltage spike when power
is removed. This flyback voltage can damage the outputs and the power
supply.
The Power & I/O Accessory for NI 177x Smart Cameras (781993-01)
includes integrated flyback diodes so that no additional wiring is required.
If you are not using the Power & I/O Accessory for NI 177x Smart
Cameras, you must install a flyback diode to limit flyback voltages at the
inductive load. Mount the flyback diode as close to the load as possible.
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