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Chapter 4
Signal Connections
DAQCard-DIO-24 User Manual
4-8
©
National Instruments Corporation
Figure 4-3.
Digital I/O Signal Connections
Caution:
Do not exceed any of the maximum ratings of input or output signal
connections on the DAQCard-DIO-24. Doing so can damage the
DAQCard-DIO-24 and the computer. Exceeding the maximum
connections includes connecting any power signals to ground and vice
versa. National Instruments is not liable for any damages resulting from
any such signal connections.
Power Connections
Pin 25 of the I/O connector pr5 V from the PC Card I/O channel
power supply. This pin is referenced to GND and can be used to power
external digital circuitry that draws up to 1.0 A. The +5 V power supply
is fused by a thermal resettable fuse rated at 1.0 A. Note that the thermal
resettable fuse will begin to open after exceeding 1.0 A and will return
to normal operating conditions when cooled. The actual current
available from this signal may be less than 200 mA, depending on the
TTL Signal
82C55A
Port B
82C55A
Port A
9 PB7
27
GND
I/O Connector
DAQCard-DIO-24
LED
+5 V
+5 V
12 PB4
21 PA3
!