Application Case 3—Hardware-Timed Input, Software-Timed Output

Requirement

"My analog input task needs to be hardware-timed. My output task does not need hardware synchronization with the sample clock edge."

Solution

Use the DAQmx Real-Time»Report Missed Samples property, which returns an error if new samples are available before the read operation finishes converting samples from the previous iteration.

Advantages

Restrictions

Output updates suffer from software jitter because they are not hardware-timed.

Sample Application

An example of this kind of application is an analog control loop that reads samples from a specific number of multiplexed analog input channels, processes the data using a control algorithm (such as PID), and writes the new control values to the analog output channels using a software-timed task.

Sample Timing Diagram

Sample Implementation

Sample Block Diagram

Notes