Discover a new laboratory view or get to know LabView

Currently, the use of computers in scientific research is not limited to simulation based on mathematical models. We have long been accustomed to the fact that the computer is used to receive, process and analyze signals from real physical objects and manage them. In this case, there is a need for electrical sensors, signal converters and special software. All these elements occupy a large space and require secondary transformations and signal processing. In addition, additional calculations and calculations are required, for example, to determine the error of instruments during calibration, recalculation of physical parameters of media, etc.

To simplify routine operations when checking instruments and when taking data from various sensors, hardware-software complexes (AIC) can come into my hands. I got a miracle of the Hungarian genius based on the LabView environment, which I would like to share my experience with. It looks like this:


Here we see a small-diameter oil mass flowmeter with a current output (left), a laptop with a program (right) and the LabView hardware itself (blue blocks with a white frame behind the laptop).

The LabVIEW programming environment is a software and hardware complex for developing applications of a graphical “block-type” algorithm that allow interrogation of sensors installed at the research object, processing of the received information, signal generation for its control in the 60 V range (from –30 V to + 30 V for alternating signals; from 0 to 60 V for unipolar). LabView used the technology of virtual measuring instruments (VIs), that is, when operating a small base of VIs, you can reuse the same components of virtual instruments without acquiring additional hardware, software, and without repeating the routine that increases the code.

The hardware part represents a variety of interface devices that are built into the computer or connected to its ports, devices for generating and processing real electrical signals, sensors that record various physical processes, etc., which have a universal interface and can interact with various hardware and operating systems. I came across a desktop version with three modules - voltage, current and combined.

As far as I was able to determine, the agro-industrial complex has support for many devices, that is, it is not necessary, as usual, to write drivers and data transfer protocols (RS-232, GPIB 488, TCP / IP, etc.), and accordingly debug communication algorithms , enter entropy, etc. ... Regarding cross-platform, I managed to fully work with the agro-industrial complex on MacOS and Windows7, I couldn’t test on Linux and Solaris.

Virtual Instruments written in this environment simulate real physical instruments. For example, by measuring the temperature of an object, I turned on a cooler or heaters.

On the basis of the LabView environment, I developed a complex for working with measuring equipment with analog or digital outputs. For analog outputs, it is possible to work with both current and voltage outputs. Appearance of the front panel for monitoring output values:

Analog Input Front Panel

The panel simultaneously displays the signal level, flow rate, accumulated volume since the start of the test, the largest and smallest flow rate value, flow deviation from the average and a graph that allows you to monitor the ripple during the measurement process. I used ready-made blocks for statistical analysis, since there are a lot of them in the package.

The block diagram of the operation of this virtual device, which is also the program itself:

Analog Input Block Diagram

If it is necessary to correct or add new functions, it’s enough for the operator to add a small block, for example, to add real-time error control during the measurement, just add a block to the Diagram:

Error calculation

This virtual device does not have to be played every time for each channel, you can simply use it as a ready-made Sub - Instrument and receive already processed values, and only those that are necessary. For one data acquisition channel, the diagram of the same device will look like this:

Abbreviated instrument with sub-instrument

To increase the number of devices or channels from which the signal is received, it will be enough to copy the required number of times the three objects located on the left side of the diagram.
A virtual device for processing digital output data:

Pulse Processing

And its program looks like this: The

Pulse Processing Block Diagram

versatility of these virtual devices allows you to combine them into one complex for several minutes with a few clicks of the mouse. You can simultaneously use the voltage, current, pulse outputs using these two programs. Thus, we get a replacement for 27 real devices using only three modules and two programs. I add that programs can be compiled into executable files, in * .exe, in * .app, etc. There are even options with an independent system, that is, without using a computer, but with a self-soldering module, for example, some touchscreen and your favorite controllers, but until this test, my hands haven’t reached yet ...

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