CLAD Data Acquisition & Instrument Control 3

Question 1

In LabVIEW, which GPIB function sends a command string to an instrument and which receives the response?

Accepted Answer

VISA Write then VISA Read

Answer

The standard VISA query pattern is VISA Write (to send the SCPI command) followed by VISA Read (to receive the instrument's response string).

Question 2

What is the role of the 'samples per channel' input on DAQmx Read?

Accepted Answer

It specifies how many samples to read per call from the buffer

Answer

Samples per channel tells DAQmx Read how many data points to return for each channel in this single call from the hardware buffer.

Question 3

Which LabVIEW Express VI provides a guided interface for configuring DAQ measurements without manually wiring DAQmx VIs?

Accepted Answer

DAQ Assistant

Answer

The DAQ Assistant Express VI presents a configuration dialog that generates the underlying NI-DAQmx code and returns data directly.

Question 4

A counter task is configured to measure the frequency of a digital pulse train. Which DAQmx counter measurement type should be selected?

Accepted Answer

Frequency

Answer

The Frequency measurement type counts edges over a known gate time to compute frequency (Hz) of the input signal.

Question 5

What is the NI-DAQmx task state machine order when performing a hardware-timed acquisition?

Accepted Answer

Create → Configure → Start → Read → Stop → Clear

Answer

The standard NI-DAQmx flow is: create the task, configure channels and timing, start the task, read data, stop the task, and clear (free) resources.

CLAD Practice Test