Software-Timed I/O

NI-DAQmx Key Concepts

Software-Timed I/O

Requirement

The I/O tasks do not support hardware-timed operations.

Solution

Apply software timing to your time-critical loop by using the Timed Loop in LabVIEW or asynchronous timers in LabWindows/CVI. Configure your NI-DAQmx tasks to use on-demand timing.

Advantages

  • You can perform I/O control loops with operations that are not hardware-timed.
  • Read, process, and write operations are confined to the software timing period that you define with the Timed Loop or asynchronous timers.

Restrictions

I/O samples suffer from software jitter.

Sample Application

An example of this kind of application is a digital I/O control loop. The application monitors the state of several discrete inputs and toggles the corresponding output based on the control algorithm. Hardware timing is not available for single-point digital I/O tasks in NI-DAQmx.

Timing Diagram

Related Topic

LabVIEW example for software-timed I/O