Справочник Пользователя для National Instruments NI PCI-6111

If you enable a PFI line for output, do not connect any external signal source to 

it. Connecting external signals to enabled PFI lines can damage the device, the computer, 
and the connected equipment.

At system power-on and reset, both the PFI and DIO lines are set to 
high-impedance by the hardware. This means that 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 4-3, 

. 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 4-3 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. 

Table C-1.  Signal Name Equivalencies

AIGATE

—

ND_IN_EXTERNAL_GATE

AOGATE

—

ND_OUT_EXTERNAL_GATE

CONVERT*

AI Convert

ND_IN_CONVERT

SISOURCE

—

ND_IN_SCAN_CLOCK_TIMEBASE

STARTSCAN

AI Scan Start

ND_IN_SCAN_START

TRIG1

AI Start Trigger

ND_IN_START_TRIGGER

TRIG2

AI Stop Trigger

ND_IN_STOP_TRIGGER

UISOURCE

—

ND_OUT_UPDATE_CLOCK_TIMEBASE

UPDATE*

AO Update

ND_OUT_UPDATE

WFTRIG

AO Start Trigger

ND_OUT_START_TRIGGER