Table 4-3. Digital I/O Connector Pin Assignment - National Instruments DAQ PCI-4451 User Manual

Chapter 4 Signal Connections
Signal Name
DIO<0..7>
DGND
+5 V
RESERVED1
EXTSTROBE*
PFI0/TRIG1 (EXT_TRIG)
PFI1/TRIG2 (PRETRIG)
CONVERT*
PFI3/GPCTR1_SOURCE
PFI4/GPCTR1_GATE
UPDATE*
PCI-4451/4452 User Manual

Table 4-3. Digital I/O Connector Pin Assignment

Reference Direction
DGND Input or
Output
— —
DGND Output
DGND Output
DGND Output
DGND Input
Output
DGND Input
Output
DGND Output
DGND Input
Output
DGND Input
Output
DGND Output
Description
Digital I/O channels 0 through 7—Channels 6 and 7 can
control the up/down signal of general-purpose counters 0
and 1, respectively.
Digital Ground—This pin supplies the reference for the digital
signals at the I/O connector as well as the +5 VDC supply.
+5 VDC Source—These pins are fused for up to 1 A of +5 V
supply. The fuse is self-resetting.
RESERVED—This pin is reserved. This signal is always high.
External Strobe—This signal can be toggled under software
control to latch signals or trigger events on external devices.
TRIG1—As an input, this is a source for the data acquisition
trigger.
As an output, this signal can drive external applications to
indicate that a trigger on the device has occurred. TRIG1 is the
start acquisition signal.
In LabVIEW, referred to as AI Start Trigger for both input and
output.
PFI1/TRIG2 (PRETRIG)—As an input, this is one of the
PFIs.
As an output, this is the TRIG2 signal. In pretrigger
applications, a low-to-high transition indicates the initiation of
the posttrigger conversions. TRIG2 is not used in posttrigger
applications.
In LabVIEW, referred to as AI Stop Trigger for both input and
output.
A high-to-low edge on CONVERT* indicates that an A/D
conversion is occurring.
In LabVIEW, referred to as AI Convert.
PFI3/Counter 1 Source—As an input, this is one of the PFIs.
As an output, this is the GPCTR1_SOURCE signal. This signal
reflects the actual source connected to the general-purpose
counter 1.
PFI4/Counter 1 Gate—As an input, this is one of the PFIs.
As an output, this is the GPCTR1_GATE signal. This signal
reflects the actual gate signal connected to the general-purpose
counter 1.
A high-to-low edge on UPDATE* indicates that a D/A
conversion is occurring.
In LabVIEW, referred to as AO Update.
4-6 © National Instruments Corporation