National Instruments NI 9401, Manual

Page: 9 / 11

Connecting a Serial Peripheral Interface Device
You can connect a Serial Peripheral Interface (SPI) device to the NI 9401.
Figure 3.
Connecting an SPI Device to the NI 9401
NI 9401
DIO3:0
Configured
for Output
DIO7:4
Configured
for Input
SPI Device
SCLK
MOSI
MISO
SS DIO0
DIO1
DIO2
DIO4
Connecting Digital Devices
You can connect several types of digital devices to the NI 9401.
Figure 4.
Connecting Digital Devices to the NI 9401
+5 V
+5 V
DIO1
COM
DIO7
NI 9401 LED
Switch
DIO0
TTL Signal
DIO3:0
Configured
for Input
DIO7:4
Configured
for Output
Overcurrent/Short-Circuit Protection
The overcurrent protection allows only a specified amount of current through the
output channels to protect the NI 9401 from short circuits. If the NI 9401 goes into an
overcurrent state, the module sets all the DIO channels to high impedance for
approximately 280 ms.
When the channels are in an overcurrent state, the NI 9401 can accept new line
direction configuration and output state data but cannot pass valid input data to the
software.
Where to Go Next
© National Instruments
9
NI-9401