Source/Sink Information - National Instruments USB-6008 User Manual

LED
2
3
4
1. P0.0 configured as an open collector digital output
driving an LED
2. P0.2 configured as an active drive digital output
driving an LED
Caution
can damage the device and the computer. National Instruments is not liable for any
damage resulting from such signal connections. Refer to the NI USB-6008 Device
Specifications or NI USB-6009 Device Specifications for more information.

Source/Sink Information

The default configuration of the NI USB-6008/6009 digital I/O ports is open collector,
allowing 5 V operation, with an onboard 4.7 kΩ 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 the following figure.
4
This document uses NI-DAQmx naming conventions. Open-drain is called open collector and
push-pull is called active drive.
Figure 14. Example of Connecting a Load
+5 V
1
LED
+5 V
Switch
Exceeding the maximum input voltage ratings or maximum output ratings
4
TTL Signal
I/O Connector
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
NI USB-6008/6009 User Guide | © National Instruments | 19
P0.0
P0.1
P0.2
P0.3
P0.4
P0.5
P0.6
P0.7
GND
NI USB-6008/6009