Appendix B
Common Questions
B-6
ni.com
Caution
If you enable a PFI line for output, do
not
connect any external signal source to it;
if you do, you can damage the device, the computer, and the connected equipment.
What are the power-on states of the PFI and DIO lines on the
I/O connector?
At system power-on and reset, both the PFI and DIO lines are set to
high-impedance by the hardware. Hence, the device circuitry is not actively
driving the output either high or low. However, these lines may have pull-up
or pull-down resistors connected to them as shown in Table 4-5,
. These resistors weakly pull the output to either a
logic-high or logic-low state. For example, DIO(0) is in the
high-impedance state after power on, and Table 4-5 shows that there is a
50 k
Ω
pull-up resistor. This pull-up resistor sets the DIO(0) pin to a logic
high when the output is in a high-impedance state.
AIGATE
—
ND_IN_EXTERNAL_GATE
WFTRIG
AO Start Trigger
ND_OUT_START_TRIGGER
UPDATE*
AO Update
ND_OUT_UPDATE
UISOURCE
—
ND_OUT_UPDATE_CLOCK_TIMEBASE
AOGATE
—
ND_OUT_EXTERNAL_GATE
Table B-1.
Signal Name Equivalencies (Continued)
Hardware
Signal Name
LabVIEW
Route Signal
NI-DAQ Select_Signal