VTI Instruments
A Deep Dive into Data Acquisition
and Functional Tests
Functional testing is a critical part of the product development process, and it is essential for high-stakes industries such as automotive, military, aviation, and medical. By testing products at each stage of development, engineers can identify and fix problems early on, saving time and money in the long run.
In addition to functional testing equipment, engineers also need access to data acquisition systems. Data acquisition systems collect data from sensors and other devices and monitor the performance of products in real-time. Data acquisition systems identify problems early on and can also be used to collect data for analysis and troubleshooting.
Functional testing and data acquisition are critical for product development and testing. By using the right test and measurement equipment, engineers can improve their data's accuracy and reliability, leading to faster product development, higher test accuracy, enhanced cost savings, and easy regulatory compliance.
This web page will cover why test and measurement technology are so important to the success of your designs. It’s based on our eBook, The Complete Guide to Better Test and Measurements. We’ll start with Data Acquisition:
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About the Author
Chris Gibson
Senior Product Line Manager
The entire data acquisition process revolves around sensors. Sensors monitor a physical property associated with your device, converting that property into a corresponding electrical signal. Different parameters that engineers often measure include:
|
■ Temperature |
■ Load or Force |
For instance, putting a sensor on an engine can help you measure the engine's response given specific stimuli. Is the engine getting too hot at certain speeds? How does the engine handle certain environmental conditions, such as rain or hail? Does the engine start breaking down when facing operational vibration levels or other forces? All of these questions can be answered with sensors.
Signal integrity is crucial for accurate data acquisition, ensuring the quality and reliability of test and measurement results. Since the real world is imperfect, signal degradation is bound to occur with every test. Especially when dealing with lengthy cables and external noise sources, the measurements can be contaminated by noise and interference which compromise the desired data. This is particularly true at connection points.
While you cannot expect perfect signal integrity, if enough degradation happens, you will end up with false test results, completely ruining the validity of your data acquisition system. With how expensive and time-intensive functional tests are, you need to secure the signal integrity of your data acquisition systems as much as possible.
To secure signal integrity, it is essential to minimize leakage and errors in the system and employ signal conditioning techniques such as amplification, excitation, linearization, filtering, and isolation. While signal integrity can degrade as the signal moves from one instrument to another, you essentially have the same effect if you have improper signal conditioning. Either will give you false results and/or cause your test to fail.
The best way to maintain the accuracy of test and measurement results is to have built-in signal conditioning. Not only does this lead to more efficient data acquisition systems, but it can also help to mitigate signal degradation from the conditioner.
There needs to be more than one suitable sensor. To maintain accurate and reliable data acquisition, you often need multiple high-quality sensors placed all over the product you are testing.
For instance, when testing a new fighter jet, you will probably need to place hundreds or thousands of little sensors all over the aircraft. Remember, you are not just testing for one thing when you perform a functional test. A single fighter jet – potentially destroyed in the test – can cost millions of dollars. You need to test out as many capabilities and properties as possible, using as many sensors as possible, not to waste the test.
The right data acquisition system will provide box-to-box synchronization to help precisely correlate all acquired data.
How you distribute those sensors and allow them to work together as part of a complete data acquisition system is essential. This is where synchronization and scalability come into play.
The right data acquisition system will provide box-to-box synchronization to help precisely correlate all acquired data. Synchronization ensures your sensors, controllers, and every other testing instrument integrates correctly. The more unified and integrated your system is, the faster and more efficient your data acquisition will be.
When you can easily integrate and synchronize multiple devices, your data acquisition system is scalable. This is important when you require large data sets or when your testing and data acquisition needs change. Properly synchronized and scalable systems will have the architecture to handle anywhere from tens to thousands of channels.
The global white goods market, including refrigerators, is experiencing significant growth, with consumers increasingly adopting connected home appliances and emphasizing energy efficiency. Manufacturers need help in testing refrigerators, such as maintaining accurate and uniform temperatures, ensuring recovery times, and complying with energy-efficiency standards. The U.S. Department of Energy has proposed new energy-efficiency standards for refrigerators to lower energy costs and reduce pollution.
A worldwide appliance manufacturer performs extensive tests and measurements on refrigerators in large walk-in environmental chambers. They monitor temperatures, AC input voltages, and frequencies to assess performance under different conditions. The manufacturer wanted to expand and upgrade its testing facilities while ensuring global compatibility and compatibility with its proprietary software.
AMETEK Programmable Power provided solutions for both the test system's power supply and data acquisition aspects. The manufacturer chose the Asterion AC AST 1501 single-phase sources to test the refrigerators' response to power fluctuations. Two solutions were proposed for data acquisition: replacing legacy data loggers with the EX1048A precision thermocouple measurement instruments or using the EX1401 isolated thermocouple and voltage measurement instruments for decentralized testing. The manufacturer ultimately chose a hybrid approach using the EX1401 instruments in a centralized rack-based architecture.
AMETEK Programmable Power offers comprehensive drivers and turnkey software solutions to support different programming environments, including the Virtual Panels graphical user interface and EXLab software for remote control, monitoring, and data analysis. They also provide products for measuring parameters beyond temperatures, such as vibration, audible noise, durability, and electrical safety.
By offering accurate and reliable power and data acquisition systems, AMETEK Programmable Power and its VTI Instruments brand help streamline the test and measurements of white goods, including refrigerators, and meets manufacturers' evolving needs regarding efficiency, compliance, and global compatibility.
Functional tests are what help you to validate your designs. They allow you to monitor and record data on the physical integrity and performance of your machines and equipment and streamline the testing of complex electronic systems.
A lot of functional testing revolves around black box testing. Black box testing is where you test out software by examining its functionality without knowing or considering the internal structure of the software. The main goal is to verify that all operational requirements are met, looking at everything from the end user's view.
Black box testing is the gold standard for qualifying equipment in many high-level industries, and ensuring your black box testing is up to code should be a top priority. Testing is a critical step to ensuring that whatever design capabilities you had in mind have transferred to the actual product.
Automated test equipment (ATE) can help to ensure that your black box testing is efficient as possible. The more automated you can make your functional tests—without compromising their ability to output reliable data—the better. Switching systems play a vital role in automated test systems by allowing ATE engineers to distribute Input/Output (I/O) instrumentation to multiple test points. ATE engineers rely on automatic switching systems to ensure high-speed testing where strict sequences and combinations must be observed.
The more automated you can make your functional tests—without compromising their ability to output reliable data—the better.
Specifically, relays, which are electronically operated switches, help enable automated tests with strict sequences and combinations of switching. The most common types of relays used in automated test system switching are:
■ Electromechanical relays
■ Reed relays
■ Solid-state relays
Using automated switching systems can mitigate the chance of testing errors and inaccuracies, especially regarding human error. The configuration of your switching system is determined by your test specification, which comes from the functional test that you are performing. This leads to more standardized and repeatable test sequences.
When performing a functional test, accuracy, and reliability are of the utmost importance. You must be able to count on the results of your test and measurements to qualify any equipment properly.
Since your switching system can affect the accuracy of your functional tests, you will want to prioritize better switches and relays. The ideal switch or relay will have the ability to:
| ■ | Meet the current, resistance, and voltage needs of your application’s testing parameters |
| ■ | Minimize voltage drop and resistance across the switch during tests |
| ■ | Reduce rise time and fall time during state changes |
Since your switching system can affect the accuracy of your functional tests, you will want to prioritize better switches and relays.
However, since no system is ever perfect in real life, you must factor in the effects of the switch itself and your switching hardware when calculating overall system accuracy. As signals encounter various forms of interference and sources of error when traveling to a destination, signals are often degraded when passing through a connecting cable or switch point. This is especially true with unshielded cables, which often cause current leakage that impacts measurement accuracy.
While no switch is perfect, designing better switching systems will help to minimize any impact on test results and thus improve the accuracy of your functional tests. The importance of high-quality switching systems is even more apparent when discussing one-shot destructive tests.
When designing switching software, it is best to take a modular systematic approach. Rather than treating your switching system as an afterthought and trying to assemble a collection of individual switch modules, a proactive modular approach allows you to consolidate everything into a single mainframe. This results in an optimized switching system with a high-channel count capacity and a reduced footprint.
Modular switching systems also give ATE engineers the design flexibility to use domain-specific modules (i.e., power, RF, and low-frequency) that can be combined to cover whatever range of the signal spectrum you need. Switching systems depend on individual switch modules to operate like a single subsystem, interfacing through external cabling, mass interconnect panels and test adapters to construct higher channel count multiplexers or matrices.
Ignoring how everything comes together as a unified system can lead to:
| ■ | Delayed Development Timelines |
| ■ | Increased Switching System Complexity |
| ■ | Integration Difficulties |
| ■ | Reduced Signal Integrity |
A Western European university is constructing a new wind tunnel facility to enhance its aerospace engineering department. The wind tunnel is vital for testing physical prototypes of aircraft and validating computational fluid dynamics (CFD) simulations. The university decided to outfit the wind tunnel with a data-acquisition system provided by AMETEK Programmable Power's VTI Instruments brand to acquire data on parameters like lift, drag, and performance of various components.
The chosen data-acquisition solution offers LXI-based instruments known for their accuracy, reliability, and ease of use. The system supports synchronization through the IEEE 1588 Precision Time Protocol (PTP), allowing automatic synchronization of all instruments. Scalability and cost-effectiveness were additional factors influencing the university's decision, along with the flexibility of the software environment. VTI Instruments' solution supports open-source programming languages, aligning with the department's preference.
The university selected VTI Instruments' products for strain and temperature measurements, including the EX1403A precision bridge and strain-gauge instrument for flight load tests, and the EX1401 isolated thermocouple and voltage measurement instrument for temperature measurements.
Vibration measurements were conducted using integrated electronics piezoelectric (IEPE) accelerometers with the EMX-4350 smart PXIe digitizers and the EMX2500 embedded LXI/PXIe controller for connectivity.
Other products employed in the wind tunnel facility include:
• The EX1200-3608 signal generator for waveform generation.
• The EX1202 LXI two-slot half-rack mainframe for switching and data acquisition.
• The EX1200-7500 for digital I/O.
The university's experience with VTI Instruments' data-acquisition solutions showcased the flexibility, scalability, accuracy, and reliability of AMETEK Programmable Power's products. The instruments support industry standards such as LXI and IEEE 1588 and offer compatibility with various programming environments, including Linux, Windows, LabVIEW, and REST.
VTI Instruments' capabilities extend beyond aerospace engineering and cater to diverse disciplines requiring data acquisition and analysis. Additionally, AMETEK Programmable Power provides programmable DC power supplies, AC sources, and electronic loads, complementing the data-acquisition system and addressing a range of academic requirements.
While reliable and accurate tests and measurements are great for any operation, certain industries and applications depend more on functional tests. These include:
Aerospace and Defense: Test and measurement solutions are critical for the most demanding aerospace and defense applications, including commercial and military aircraft and spacecraft ranging from submarines to satellites. This industry finds it crucial to have functional testing hardware and data acquisition systems designed to acquire large amounts of data at high data rates and with high accuracy. With its decades of experience serving the aerospace and defense industry, VTI Instruments offers a wide range of standard high-performance products, and it can work with customers to develop custom systems based on COTS technology.
Automotive and Transportation: There are a wide range of automotive and transportation applications. An engine-control unit (ECU), for example, ensures optimal performance of internal-combustion engines. In response to sensor readings, an ECU adjusts engine actuators to control air/fuel ratio, ignition timing, and other factors. ECUs present extensive test challenges. In addition to ECU test, VTI Instruments serves wind-tunnel tests, train infrastructure monitoring and vehicle road testing and has provided solutions for engine test cells.
Communications: In addition to supporting tests and measurements for wireless devices, VTI Instruments provides broadband interface solutions for a variety of broadband application areas, ranging from ground base stations to airborne radar. And, is the only high-performance test and measurement switching provider that offers microwave switching solutions in three different platforms: LXI for high-density, low-cost switching (including custom switching solutions); PXIe for operation in existing PXI test and measurement solutions; and VXI for existing large-scale switching solutions.
Commercial: Manufacturers of commercial products require flexibility to keep pace with evolving technologies, standards and customer demand in various product categories. In the white goods category, for example, companies are investing heavily in R&D to meet customer demand for smart appliances, and tests and measurements have full solutions to improve accuracy.
Semiconductor: As new smartphones, tablets, laptops, and internet of things devices proliferate, they will need chipsets to manage data flow for their cellular, Wi-Fi, or other wireless communications capabilities. VTI Instruments has extensive experience supporting chipset test, including working with a manufacturer of Wi-Fi and Bluetooth chipsets that needed to verify its products could work with both Wi-Fi and Bluetooth.
A military depot required a comprehensive test system for slip rings, which transfer power and signals between stationary and rotating parts of equipment. The slip rings needed to meet various performance requirements, including high current transfer, data communication capabilities, environmental resilience, shock and vibration resistance, and compliance with EMI specifications. The testing regime involved measurements such as resistance, capacitance, insulation resistance, dielectric strength, torque, current draw, and encoder output.
AMETEK Programmable Power and its VTI Instruments brand provided a solution for the depot's test system. They offered a range of programmable AC and DC power products, switching devices, and data acquisition instruments that could fulfill the requirements. The depot benefited from technical advantages, durability, extensive military experience, and competitive pricing by purchasing all the necessary equipment from a single vendor.
VTI Instruments presented the EX1200 family of modular and scalable multifunction instruments suitable for various mechanical data acquisition and electronic test applications. They also offered the Asterion programmable AC + DC power-source family, which provided high power density in a compact form factor. The selected products included data acquisition mainframes, high-voltage switches, digital multimeters, multifunction I/O cards, and power sources capable of sustaining high currents.
The flexibility of the variety of products allowed for custom modifications. These modifications could perform unique measurements required for the slip-ring test system. The deployed test system received positive feedback, opening up opportunities to provide equipment for testing motors and generators used in military equipment.
This project highlighted the benefits of procuring power supplies, switching devices, and data acquisition equipment from a single vendor. AMETEK Programmable Power's reputation for reliability, experience in the military and aerospace markets, and competitive pricing contributed to the successful partnership, as they offer a comprehensive range of catalog and custom-engineered products to meet various test-system needs in military and aerospace applications.
As part of the AMETEK Programmable Power team, VTI Instruments specializes in precision modular instrumentation and systems for electronic signal distribution, acquisition and monitoring. Known for putting signal integrity at the forefront, VTI Instruments creates data acquisition systems and functional test equipment that produce reliable data the first time, every time.
AMETEK Programmable Power and VTI Instruments offer data acquisition systems to help you achieve better data acquisition in the world’s most demanding applications. Products include both hardware and software solutions, such as:
The EX1403A Precision Bridge and Strain Gauge Instrument sets a new industry standard for strain and bridge measurements. Based on a flexible data acquisition platform, the EX1403A offers superior signal integrity for the highest performance measurements possible while controlling overall test hardware costs.
In addition to instrumentation, VTI specializes in data acquisition software designed for sensor-based measurements such as temperature, pressure, strain, voltage, and digital states. Turnkey, full-featured software solutions include EXLab and X-Modal III.
AMETEK Programmable Power and VTI Instruments offer several functional test devices for better testing in the world's most demanding application. Products span different modular instruments and modular switching devices, including:
As an extension of VTI’s EX1200 Series switch family, the SMX Series offers the market's largest collection of PXIe (not PXI) switches. All SMX products offer space-saving, high-density designs without compromising on performance.
VTI’s EX7000 product family offers modular microwave switch assemblies with an LXI-complaint LAN interface, enabling superior micro wave and RF testing. All products are rack-mountable and range in size from 1U to larger systems as required.
VTI’s SMIP™ signal switching Series has helped revolutionize the automated signal-switching market by providing an unprecedented level of modularity, density, and performance for the VXIbus platform.
EX1200 Instrument Family (LXI)
The award-winning EX1200 product family delivers a modular, scalable Series of multifunction, configurable switching units. As the highest density switch and measure/control subsystem available today, the EX1200 Series offers uncompromised performance and signal transparency.
Experience the ultimate power solutions tailored precisely to your needs. As a global leader in electronic instruments and power systems, AMETEK Programmable Power specializes in pioneering highly differentiated power and testing equipment for the most groundbreaking products around the globe. In fact, customers from multiple disciplines and hundreds of companies worldwide trust our expertise for projects ranging from a single power supply to meticulously engineered systems.
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