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Data Acquisition Tech

Written by Michael Lynes

An Overview

Data acquisition technology (DAQ tech) is relevant and important—but that doesn’t mean we can’t have a little fun with it. In this article, I’ll give a brief overview, present some of the key players, and cover a real-world DAQ application. 

  • What is data acquisition technology?
  • Who are key companies in the DAQ industry?
  • How is DAQ used?
  • Data acquisition technology
THE CUTTING EDGE OF THE CUTTING EDGE

Data acquisition tech—not a phrase that just rolls off the tongue, is it? It brings to mind actuarial tables, insurance statistics, and forensic accountants. “Yup,” you think, as your eyelids become heavier, “Seems like a snoo-o-o-ooze fest of a topic. Boring doesn’t even come close. Good thing it’s February, and no one will notice if I nod off in my chair.”

Well, wake up! Because you could not be wrong-er-er. Data acquisition technology (DAQ tech) is where the high-speed digital rubber meets the potholed analog road. As every engineer knows, the “real world” is a messy, noisy, unstable place, full of transients, stray alpha particles, and cats. DAQ tech smooths that bumpy highway, turning it into nice clean numbers that we can process, filter, and analyze.

Speaking of messy, noisy, and the digital-to-analog interface, we now come to a division into camps. On one side we have the stylish, clean-cut, Digital Data Engineers, or DDEs. In their world, transitions take zero time, transistors are always saturated, and clock edges are sharp and square. These world-beating, young, super-techs spend their days crafting pristine analytical algorithms that don’t want to sully their high-speed switches with mucky analog gunk. No! Their beautiful ones and zeros want other beautiful ones and zeros to play with. The stink, ick, and mire of the real world makes them sigh.

In the other camp, we have the Old Guy Electrical Engineers, or OG-EEs. Open the tent flaps here and you will find a motley assortment of flux-spattered, grizzled veterans. Among their ranks are everything from torque-obsessed DC motor freaks, high-tension powerline transmission guys, twitchy Macro Assembler mavens, and crotchety old tube amp types. To them, DAQ tech is just a fancy name for some puffed-up collection of op-amps and shift registers.

“Why the [expletive deleted] would I need that stuff?” they grumble into their coffee-stained beards. “I can design my own interface from scratch, and it will be better! In fact,” they continue while digging through their bone pile of half-roasted prototypes from the late nineteen-nineties, “I’ll bet I have the perfect start right here! Give me a tick and I’ll be right with you.” Fortunately, they barely notice as you avoid eye contact and back away slowly.

Look, I get it. And, as a genuine, first-digital-generation, card-carrying OG-EE myself, I appreciate the sentiment. After all, tubes do sound better. Seriously though, the build-it-from-bare-metal-up, caveman-engineering approach may make you feel like the biggest, baddest silverback on the banana pile, but when your boss stops by and asks how your prototype is coming along, and you give her a wild-eyed, spittle-flecked lecture about data hold times, cumulative gate propagation delays, and wandering reference voltages, don’t expect her to be impressed. Work smarter not harder, my OG-EE caveman friend! The wheel has already been invented, and these days you don’t have to go out and start your own silicon wafer fab just so you can design an ultrasonic sensor array.

Anyway, let’s personalize this a bit. As I mentioned in a previous article, I am an olde tyme embedded systems guy. I’ve spent most of my career a literal spark gap away from the bare metal. I am also, (ahem)—pushes glasses to the absolute top of the nose—an expert in data communications, telecommunications, and control systems, with a smattering of experience in digital signal processors (DSPs), and software-defined radio (SDR). When I started out, there were no such things as ready-made digital DAQ devices. If you wanted to sample voltage levels to detect a contact closure so that your application would hopefully start or stop what it might be doing, you had to roll your own design to do it.

I found myself doing these types of operations repetitively, so in self-defense I started to collect successful designs and put them into my personal bag of tricks for future reference. Over time, I became comfortable with a family of devices that I knew worked well for my application, reusing the circuits and the firmware routines (written in long-dead assembler language, dark now to all save those few who are skilled in the arcane tongues) to save myself the time and the headache of re-designing.

My library of hand-carved jigsaw pieces was very handy. It allowed me and my fellow engineers to leverage prior art, shortcutting the design process and making the end product more reliable. The drawback of this approach was that, in the landscape of prehistoric Pangea-gineering in which I grew up, the ground would often shift. A new line of linear ICs might come out and render your old one obsolete. Even worse, your application might change platforms—say from a nice, sane, memory-mapped architecture to the Wild West of multiplexed data and address busses and page-mapped I/O. When any of these things happened, all your tricks would have to change as well. Bereft of your fancy tools, you would be crouching in the entrance of your metaphorical cave, stone axe in hand, chipping flints and trying to strike a spark to get your application running again.

These frequent ground shifts led to a lot of frustration—the real mother of invention. After all, no engineer likes re-solving a problem they’ve solved before. After having to toss out all our hard work a few times too many, I and many of my fellow OG-EEs began to develop robust, reusable DAQ devices. From these humble origins, the industry now known as DAQ tech arose.

DEFINITIONS

As you can see, DAQ tech is a broad subject. Through research for this article, I found many different views of what it is, and there are arguments to be made to include this or that specific technology or application. To some, DAQ tech is more like customer relationship management, where user information, identity, and experience metrics are gathered and processed using data acquisition technology across the entire corporate ecosystem. This type of DAQ tech might be a topic for a future article. But to stay in our lane for now and keep this discussion more engineering-focused, I will offer my own definition as a limiting case.

To wit, I will define a DAQ tech device as an integrated peripheral (as opposed to a raw electronic component such as an ADC or a shift-register), which has a certain utility to gather and present information to a higher-level processing agent. I am also going to stick to digital DAQ, leaving analog DAQ devices such as transducers, amplifiers, tuners, filters, and multiplexers for a separate discussion. Further, I’ll restrict the “smarts” or intelligence of these peripherals, so that we can focus on 85% of the market, rather than entertain the concept of data acquisition and processing sub-systems. This confines the class of items that fall into DAQ tech to devices that, in and of themselves, do not produce a user-facing result, but rather render or transpose information from an analog or noise-filled environment to one where the levels and values are manipulated by digital or non-analog means. This definition is still broad, but I like it.

There is also the Wikipedia definition [1] of DAQ, and though I’m not a big fan of Wiki-world in general, it goes like this:

“Data acquisition is the process of sampling signals that measure real-world physical conditions and converting the resulting samples into digital numeric values that can be manipulated by a computer. Data acquisition systems, abbreviated by the acronyms DAS, DAQ, or DAU, typically convert analog waveforms into digital values for processing.”

The Wiki-people sort of dance around the definition as well, throwing in the ‘T’ word (“typically”) to cover themselves. But the gist of their description agrees with mine, in that DAQ devices are meant to be used as components of a larger system rather than as stand-alone appliances. For example, a wireless IoT sensor that reports the temperature of a room might integrate a DAQ device into its design. The specific DAQ device might be configured to sense the ambient temperature and to provide outputs such as the average temperature value, an instantaneous real-time sample, and the temperature range over a given period. Then this information would be passed on to a higher-level process, and perhaps combined with metadata regarding location or time of day. That resulting conjoined data might be further packaged into IP packets in a specific protocol, or rendered on an HTML-5 webpage, and ultimately become the output of the IoT device. One could plausibly argue that the entire IoT device itself is also a form of DAQ—but that is just “turtles all the way down,” and as I mentioned we want to stay focused.

THE MARKET AND THE PLAYERS

The DAQ market is huge. It’s estimated to be $1.7 billion in 2021 and to grow to $2.3 billion over the next five years, with many players large and small [2]. As you can see in Figure 1, there was a dip in demand for DAQ tech during the pandemic, but the overall need is strong and growing. There are a lot of companies in this space, and they can be grouped into rough categories [3]. There are a few larger firms, such as National Instruments (NI) and Keysight, who offer DAQ devices as part of their product line and include customized packaging and integrated user software to interface to their DAQ tech systems. There are also smaller, niche players, like Dewesoft and Keyence, who focus on specific markets and strategic partnerships.

Figure 1
DAQ Tech market size
Figure 1
DAQ Tech market size

Here is an overview of the players in the market. This is by no means an exhaustive list. Indeed, I don’t mention many companies that serve broad swathes of this space. References to these and several others are available in the Article Materials and Resources Archive on the Circuit Cellar website. And, as always, your research will turn up still more candidates.

NI: The three-thousand-pound gorilla in the DAQ market is NI. This Texas-based company has operated in the instrumentation and sensing market for over 40 years, and they have become the de-facto benchmark by which all other instrumentation is measured (see what I did there?). NI has a comprehensive focus on DAQ tech, and few modern labs will be without some NI devices.

NI’s line of scalable, modular DAQ devices is known as CompactDAQ. As you can read on their website, CompactDAQ is portable and customizable technology, allowing engineers to develop solutions from a suite of over 70 integrated DAQ modules that can work together to synchronize measurements across an IP network. Their high-quality C Series I/O modules offer built-in sensor-specific or signal-specific input conditioning. Using this comprehensive line-up, you can mix and match modules to build an accurate and repeatable measurement system that meets your needs.

Because of their built-in IP capabilities, CompactDAQ devices allow the user to digitize data closer to the analog sensor environment, minimizing noise and delay and simplifying cabling. These modular systems can collect, validate, and deliver data at any distance, in any environment (Figure 2). This is because NI has designed these devices to be compact and rugged, able to perform in the most demanding field conditions—tested to withstand -40°C to +70°C, and up to 30g of impact shock. For wet conditions, NI’s IP67-rated FieldDAQ devices are also available, with the same I/O performance profile.

Figure 2
CompactDAQ Systems
Figure 2
CompactDAQ Systems

NI has a complete line of USB, plug-n-play DAQ devices for smaller applications that don’t need to scale. The DAQ-6003 (Figure 3) provides ease of use, a simple setup, and does not require programming skills as it interfaces directly with NI’s DAQExpress software suite. For more complex operations, this line of devices is also supported by LabVIEW.

Figure 3
USB entry-level DAQ
Figure 3
USB entry-level DAQ

For those of us OG-EEs who program in real languages (cough cough “C” cough), LabVIEW has often been overlooked. However, despite its cute WYSIWYG graphical interface and basic scripting language, LabVIEW is the preeminent choice for scientists and professional lab technicians (Figure 4).

Figure 4
LabVIEW example application
Figure 4
LabVIEW example application

At Rudolph Research we are using National Instruments and LabVIEW to perform some of our precision Standards Lab work, as well as for certain early instrumentation prototypes. I will go into one of our specific case scenarios later in this article.

KeySight: Keysight is a UK-based company with deep roots in the test and measurement space. They have a full lineup of DAQ products (Figure 5). These are split into benchtop integrated systems that are packaged like purpose-built oscilloscopes for multi-channel data gathering, to more modular, portable, and lighter-footprint USB-based devices.

Figure 5
Keysight DAQ USB lineup
Figure 5
Keysight DAQ USB lineup

All their devices integrate seamlessly with their BenchVue software suite, designed to be run on your PC (Figure 6). This software suite allows you to gather data, write scripts and control other peripherals based on the inputs that are received. It is a powerful set of tools for laboratory integration, much like LabVIEW.

Figure 6
Keysight BenchVue
Figure 6
Keysight BenchVue

Keyence: Founded in 1974, Keyence is a Japanese manufacturer of industrial automation and inspection equipment, with a worldwide presence. They offer a full lineup of sensors, metrology, control systems, and machine vision and inspection systems. Their Multi-Input Modular Data Acquisition System provides a wide range of integrated capabilities (Figure 7), measuring strain, acceleration, current flows, and voltages from a variety of in-house and third-party sensors. Keyence offers free software to interface to their DAQ instrumentation, and many white papers to assist end-users in picking the right DAQ tech for their needs [4].

Figure 7
Keyence Multi-Input Modular DAQ
Figure 7
Keyence Multi-Input Modular DAQ

Dewesoft: Dewesoft is a smaller company that has been in the DAQ space for over 20 years. They focus on specific industries and modalities, including automotive, vibrational analysis and combustion analysis (Figure 8). Their claim to fame is an innovative integrated software suite called DewesoftX. This is described as more of a plug-n-play system than LabVIEW. It allows engineers to configure and integrate various sensor data streams, including CAN Bus data, into one comprehensive format without a lot of intensive and time-consuming programming. The display example in Figure 9 demonstrates how an automotive test application can be integrated, with various sensor data streams synchronized on the same display.

Dewesoft has also made innovations at the hardware level. Their DualCoreADC provides an impressive 160dB dynamic range for signal acquisition, with sampling rates up to 200kS/s per channel (Figure 10). This type of performance is difficult to achieve, and requires a ton of engineering and low-level embedded expertise—which, of course, is a great argument for buy-versus-build. You can provide the front-end performance needed while allowing your core application team to focus on the overall deliverable.

Figure 8
Dewesoft applications
Figure 8
Dewesoft applications
Figure 9
DewesoftX example display
Figure 9
DewesoftX example display
Figure 10
DualcoreADC dynamic range
Figure 10
DualcoreADC dynamic range
REAL-WORLD EXAMPLES—STANDARDS LAB

“Okay,” you say, “I haven’t fallen asleep yet, and I feel slightly smarter about DAQ tech. That’s well and good. But this is all theory! What about a real-world example of DAQ tech in action?”

Well, I am soooo glad you asked. It just so happens that at Rudolph Research Analytical, my current employer, we are using NI’s LabVIEW—combined with some genuine OG-EE roll-your-own type equipment that was made in our shop, as well as some off-the-shelf DAQ from NI—to perform a critical, precise, and profitable set of operations in our Standards Lab.

One of the newer initiatives that Rudolph has engaged in is the production of liquid standards. Simply put, these are NIST-certified standards for pure distilled water, sugar and water solutions measured in Brix, alcohol and water solutions measured in percentage alcohol or proof, as well as iso-octane standards for the fuel and refining industries. I can see your yawn forming, so I’ll cut to the chase.

One of the requirements for producing reliable liquid standards is a highly controlled external environment. A consistent record—of the temperature, humidity, and other factors—must be maintained to meet the certification requirements imposed by NIST, and to allow them to verify compliance. To accomplish this, Rudolph has dedicated a laboratory space to producing these standards, and instrumented it with a high precision balance, along with a hands-free robot of our own design that flame-seals the ampules of liquid after they are tested and verified.

Developing the above process would take a prohibitive amount of time, especially if all the sensors, the logic to monitor them, the code to control the verification, and the standards sealing process had to be developed from scratch. Taking advantage of LabVIEW and components provided by NI’s DAQ tech, we were able to rapidly prototype integrate, test, and iterate this system. This allowed us to efficiently develop the initial process flow, and then refine it until it met all our objectives.

The ability to employ precisely engineered and well-tested subsystems from a vendor like NI, and then combine them under the robust control of LabVIEW, as well as leverage its flexible architecture to extend control to our own home-made production and ampule-sealing robot, made this project feasible and lowered the barriers to entry. Control of the core process flow is all done through LabVIEW, and we use NI DAQ tech to provide the inputs for temperature and other critical environmental factors. LabVIEW and NI are also used to continuously monitor and record the lab environment, as well as to measure the properties of the produced standards. We can produce certified traceable liquid standards with highly controlled and repeatable values for refractive index, density, and so on, and produce a report of all laboratory activities for the certifying body to review.

Bottom line—Profit: Using NI DAQ tech and their LabVIEW programming interface, we were able to set up a high-precision liquid standards production area and get it certified in under fourteen months. The liquid standards produced are sold to our customers, providing a revenue stream for the company. We also use them for our own internal testing. This adds to the bottom line as well as cost savings—rather than pay for fluids from another vendor, we use our own in-house-produced traceable fluids for quality control and post-manufacturing tests.

All this was made possible due to a lot of hard work by our internal science and laboratory team, but also because of the leverage we were able to exert with NI’s DAQ tech and LabVIEW products. A win-win all around.

CONCLUSION

And that brings us back to the beginning, or is it the end? Not to get too philosophical, but it’s both. The youthful, lithe, spring-in-their-step DDE’s can finally make peace with their older, gruffer, analog-war-weary OG-EE compadres. Together they can agree that DAQ tech, while not a panacea, is an important and relevant tool that every engineer of any age can use to make his or her products more reliable, efficient, and ultimately profitable.

As always, your mileage may vary, so do your own research. There are literally hundreds of types of DAQ tech available, and many companies that can serve your niche industry needs. And finally, cheer up! February is short, Spring is coming, and the Force (AKA the ubiquitous calibrated engineering hammer) will always be with you. 

Data acquisition technology (DAQ tech) is relevant and important—but that doesn’t mean we can’t have a little fun with it. In this article, I’ll give a brief overview, present some of the key players, and cover a real-world DAQ application.

REFERENCES
[1] Wikipedia article on data acquisition: https://en.wikipedia.org/wiki/Data_acquisition#:~:text=A
[2] Markets and Markets report on DAQ market: https://www.marketsandmarkets.com/Market-Reports/data-acquisition-system-market-160241507.html?gclid=CjwKCAiAheacBhB8EiwAItVO28AZwXIolYvyvYX-xKuW8DeSr6-9nBIGmoTzBxEGRPRx-PAOIZClUhoC_PwQAvD_BwE
[3] Polaris Market Research report on DAQ market: https://www.polarismarketresearch.com/industry-analysis/data-acquisition-system-market
[4] Keyence Whitepaper Library: https://www.keyence.com/ss/products/daq/lab/

RESOURCES
Dewesoft: www.dewesoft.com
KeySight: www.keysight.com
National Instruments: www.ni.com

PUBLISHED IN CIRCUIT CELLAR MAGAZINE • FEBRUARY 2023 #391 – Get a PDF of the issue

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Michael Lynes is an entrepreneur who has founded several startup ventures. He was awarded a BSEE degree in Electrical Engineering from Stevens Institute of Technology and currently works as an embedded software engineer. When not occupied with arcane engineering projects, he spends his time playing with his three grandchildren, baking bread, working on ancient cars, backyard birdwatching, and taking amateur photographs. He’s also a prolific author with over thirty works in print. His latest series is the Cozy Crystal Mysteries. Book one, Moonstones and Murder, is already in print, and book two is on its way. His latest works include several collections of ghost stories, short works of general fiction, a collection called Angel Stories, and another collection called November Tales, inspired by the fiction of Ray Bradbury. He currently lives with his wife Margaret in the beautiful, secluded hills of Sussex County, New Jersey. You can contact him via email at mikelynes@gmail.com.

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Data Acquisition Tech

by Michael Lynes time to read: 14 min