Digital I/O; Timing Signal Routing; Figure 3-11. Low-Hysteresis Analog Triggering Mode - National Instruments DAQ PCI E Series User Manual

Digital I/O

Timing Signal Routing

© National Instruments Corporation
highValue
lowValue
Trigger

Figure 3-11. Low-Hysteresis Analog Triggering Mode

The analog trigger circuit generates an internal digital trigger based on
the analog input signal and the user-defined trigger levels. This digital
trigger can be used by any of the timing sections of the DAQ-STC,
including the analog input, analog output, and general-purpose
counter/timer sections. For example, the analog input section can be
configured to acquire n scans after the analog input signal crosses a
specific threshold. As another example, the analog output section can
be configured to update its outputs whenever the analog input signal
crosses a specific threshold.
The PCI E Series boards contain eight lines of digital I/O for
general-purpose use. You can individually software-configure each line
for either input or output. At system startup and reset, the digital I/O
ports are all high impedance.
The hardware up/down control for general-purpose counters 0 and 1 are
connected onboard to DIO6 and DIO7, respectively. Thus, you can use
DIO6 and DIO7 to control the general-purpose counters. The up/down
control signals are input only and do not affect the operation of the DIO
lines.
The DAQ-STC provides a very flexible interface for connecting timing
signals to other boards or external circuitry. Your PCI E Series board
uses the RTSI bus to interconnect timing signals between boards, and
the Programmable Function Input (PFI) pins on the I/O connector to
connect the board to external circuitry. These connections are designed
3-17
Chapter 3 Hardware Overview
PCI E Series User Manual