LabVIEW Demos

In the LabVIEW repository for openDAQ, apart from the low level functions for controlling the device (sub-VI), you can find a couple of demo applications intended for testing them in the two main modes of operation of openDAQ: Command-Response mode and Stream mode. These examples have a similar functionality as the Python demos, although they have fewer features.

Both applications will try to connect automatically with openDAQ once the correct serial port has been selected. Remember that the device uses a VCP driver to communicate via USB with the computer, so a new serial port will appear in your PC after you plug it. Once the device gets connected, a square-LED indicator will turn on in both examples, in the bottom of the window. 

LabVIEW repository for openDAQ

 

DAQControl demo in LabVIEW

The demo is very similar to the same program in Python. In this case, we have four tabs instead of just three:

Analog Input Tab

In this tab we will find controls to manage and configure software controlled analog acquisition for openDAQ:

§  Ch+: Set up the positive channel for the analog acquisition. It can be any channel from A1 to A8.

§  Ch-: Set up the negative channel for the analog acquisition. For [M] model, it can be any channel from A5 to A8 (we will have a differential reading), AGND (we will get a single-ended reading) or VREF (internal voltage reference of 2.048V). For [S] version, negative channel must be the adjacent analog input couple (A7 for A8, A6 for A5, and so on), or GND for a SE reading.

§  Range: Input voltage range for the selected analog channels. 

§  Rate: The sampling rate to get a chart graph of the selected channels. Note that all the control is carried out by the software, so the period will not be maintained with high precision. You can select periods from 100ms to 65535ms.

Once the Start button is pressed, the analog acquisition will continue indefinitely, until the Stop button is pressed or the software is closed. The graph will be cleared out every time the acquisition begins.

 

Analog Output Tab

The tab has a simple control to select the output voltage in the DAC terminal of openDAQ, and an Update button to set the new value.

Digital I/O Tab

The digital tab has controls and indicators to handle the terminals D1 to D6 of the device. Any of these terminals can be configured as an input or as an output, using the adequate radio button. Each connection has an icon representing its last state, which may be a high output (D3 in the figure), a low output (D1 and D2), a high input (D4 and D6) or a low input (D5).

 

Timer-Counter Tab

This tab has controls to manage Timer 1 utilities of openDAQ.

The Counter control will start a hardware counter on terminal D5. Rising edges of an incoming digital signal though this pin will be counted by the hardware and the total amount will be displayed on the text indicator.

Capture will start capture mode of openDAQ, which is useful to detect the period and the duty cycle of an incoming signal. The signal that is to be analyzed must be connected to terminal D5. In the radio buttons, it can be selected which part of the signal is going to be measured (high or low times). Results will be displayed in the text indicator, with an update rate of 1 second. Units are µs.

PWM control configures port D5 as a modulated square wave output, 0 to +5V of total amplitude. User must configure the period of the output signal, in microseconds (µs), and its duty cycle (ON time), in percentage (%).

 

DAQControl demo in Python

 

EasyDAQx1 demo in LabVIEW

The demo is similar to the EasyDAQ program in Python, but it has a much more limited functionality. The application has controls to configure Experiment 1 in Stream Mode. Only one experiment can be configured, and only an analog input experiment.

The interface provides controls to setup the analog channel (positive and negative inputs, range and scan rate). It also provides Play&Stop buttons for controlling the execution.

Two numeric inputs (Gain & Offset) allow users to set up the line equation of a specific sensor, and the final value represented in the graph will be calculated using those values (Final Value= Gain x Voltage + Offset).

The interface also has a control to configure the DAC output of the device.

 

EasyDAQ demo in Python