©
National Instruments Corp.
7
NI 9403 Operating Instructions and Specifications
Each channel has a DIO pin to which yo
u
can connect a digital
inp
u
t or o
u
tp
u
t device. The 32 DIO channels are internally
referenced to COM, so yo
u
can
u
se any of the fo
u
r COM lines as a
reference for the external signal.
Yo
u
can independently config
u
re each DIO channel in software for
inp
u
t or o
u
tp
u
t. The DIO channels have Schmitt trigger inp
u
ts and
are compatible with 5 V TTL logic devices. Each inp
u
t channel has
hysteresis for improved performance with noisy and
non-monotonic inp
u
t signals. Each channel also has a p
u
ll-down
resistor and incl
u
des overvoltage, overc
u
rrent, and short-circ
u
it
protection. Refer to the
section for more information
abo
u
t inp
u
t thresholds and overvoltage protection. Refer to the
Overcurrent/Short-Circuit Protection
section for more
information abo
u
t overc
u
rrent and short-circ
u
it protection.
