User Guide

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Correlated vs. Static DIO Modules

Digital I/O module capabilities are determined by the type of digital signals

that the module is capable of measuring or generating. Static digital I/O

modules are designed for signals that change slowly and are accessed by

software-timed reads and writes. Correlated digital I/O modules are for

signals that change rapidly and are updated by either software-timed or

hardware-timed reads and writes. For more information about Digital I/O

modules, refer to the Digital I/O section.

cDAQ Module Interface

The cDAQ Module Interface manages data transfers between the

USB-STC2 and the C Series I/O modules. The interface also handles

autodetection, signal routing, and synchronization.

USB-STC2

The USB-STC2 features independent high-speed data streams; flexible

AI and AO sample timing; triggering; PFI signals for multi-device

synchronization; flexible counter/timers with hardware gating; digital

waveform acquisition and generation; and static DIO.

AI and AO Sample Timing

The USB-STC2 contains advanced analog input and analog output timing

engines. A wide range of timing and synchronization signals are available

through the PFI lines. Refer to the Analog Input Timing Signals and

Analog Output Timing Signals sections for more information about the

configuration of these signals.

Triggering Modes

The NI cDAQ-9172 supports different trigger modes, such as start trigger,

reference trigger, and pause trigger with analog, digital, or software

sources. Refer to the Analog Input Triggering and Analog Output

Triggering sections for more information.

Independent Data Streams

The NI cDAQ-9172 supports four independent high-speed data streams;

allowing for up to four simultaneous hardware timed tasks, such as analog

input, analog output, buffered counter/timers, and correlated digital

input/output.