National Instruments USB-6008/6009 Manual De Usuario

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© National Instruments Corporation
15
USB-6008/6009 User Guide and Specifications
Figure 12.  Example of Connecting a Load
Caution
Exceeding the maximum input voltage ratings or maximum output ratings, which 
are listed in the 
, can damage the DAQ device and the computer. National 
Instruments is not liable for any damage resulting from such signal connections.
Source/Sink Information
The default configuration of the USB-6008/6009 DIO ports is open 
collector, allowing 5 V operation, with an onboard 4.7 k
Ω pull-up resistor. 
An external, user-provided, pull-up resistor can be added to increase the 
source current drive up to a 8.5 mA limit per line as shown in Figure 13. 
The USB-6009 ports can also be configured as active drive using the 
DAQmx API, allowing 3.3 V operation with a source/sink current limit of 
± 8.5 mA. Refer to the NI-DAQmx Help for more information about how to 
set the DIO configuration.
1
P0.0 configured as an open collector digital output driving a LED
2
P0.2 configured as a active drive digital output driving a LED
3
P0.4 configured as a digital input receiving a TTL signal from a gated invertor
4
P0.7 configured as a digital input receiving a 0 V or 5 V signal from a switch
+5 V
LED
Switch
I/O Connector
 GND
P0.0
P0.1
P0.2
P0.3
P0.4
P0.5
P0.6
P0.7
+5 V
LED
1
2
3
4
TTL Signal