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How High-Quality Switching Enables Better Automated Testing Systems

March 25, 2021

In order to create better products, you need better means of testing. From designing a new airplane engine to making updates to the defense grid, functional tests and black box testing ensure that any new products or updates meet your requirements.

Accurate and reliable testing gives you the peace of mind and validity to put the name of your business on the line when selling a design. But achieving the levels of testing that you require isn’t as simple as flipping a switch. It’s making sure that you get the right switch.

That’s because the only way to ensure accurate and reliable testing is to put a focus on switching and automated testing. Through high-quality automatic switching systems, you can ensure uncompromised measurement integrity, enabling:

  • Increased test system performance and accuracy to meet tight measurement specs
  • Lower testing costs by reusing expensive assets while reducing false pass/fail errors and intermittent faults
  • Application-level detail through software-configurable switch personalization


Switching: The Core of Every Test Station

Testing systems are only as good as the sum of their parts. In order for your functional tests to work – which in turn is what ensures that your products work – you need to consider the individual components of your system.

One of the most important elements of testing is switching since it is in the path of virtually every measurement. Switching systems can affect the accuracy of your testing results, making them vital to the success of any functional test. An ideal signal switching subsystem will:

  • Preserve signal integrity
  • Operate within application-specific current, resistance and voltage parameters
  • Minimize voltage drop across the switch during tests
  • Reduce rise time and fall time during state changes

It’s important that your switching systems are automated so that you mitigate the chance of any errors or inaccuracies during testing. By getting rid of human error, you can produce more standardized and repeatable test sequences. Automated switching technologies and software allow you to distribute Input/Output (I/O) instrumentation to multiple test points, making your functional tests more efficient and capable of performing more complicated testing faster.

The Importance of Modularity

With testing systems so dependent on the separate test instruments that they are comprised of, it’s important to make sure that those instruments work together well. Even a high-performing switch will produce substandard results if not integrated well.

That’s because signals are often degraded as they pass from one instrument to another through connecting cables or switch points. This is due to various forms of interference and sources of error. Signal integrity is highly dependent on switching and all of the interconnection interfaces that are part of the signal transmission path. The more the signal is degraded, the less accurate the results of the test will be.

By taking a modular approach and looking at the testing system as a whole, you can improve the performance and accuracy of your system. Since you are looking at how each instrument connects, you can mitigate any signal degradation. Advanced switching modules work to maximize the integrity of test signals by minimizing the effects of unwanted transmission stubs, shielding against radiated signals in adjacent card slots, and extending the usable bandwidth of the system.

Benefits of taking a modular systematic approach to testing and switching include:

  • Increased testing scalability/flexibility by adapting to different test station personalities
  • Improved testing accuracy and reliability by enhancing signal integrity
  • Better system integration through less cabling requirements
  • Test asset footprint reduction
  • Enhanced software modularity

Designing switching systems in a modular form factor also allows you to develop test stations in a reduced footprint without compromising the integrity of your test data.

SMX Switching Products: Integral Parts of Your Testing Solution

As an integral part of the AMETEK Programmable Power team, VTI Instruments is known for designing precision modular instrumentation and switching systems for highly competitive markets such as commercial aerospace, government and defense, automotive, and civil engineering. With a focus on signal integrity, VTI specializes in creating accurate and reliable test equipment.

Knowing how important switching is to functional test systems, the experts at VTI have created the SMX series: the largest collection of PXIe switch products on the market. Designed for high-density modular implementation, the SMX family uses the same switch driver that’s used by EX1200, creating a seamless integration process between product families. This level of modularity makes it easy to transition from a low-medium switch system in PXI Express to a larger switch system in the EX1200. You can also combine the two platforms if needed, offering unrivalled flexibility. The switch driver will seamlessly give you path level access across platforms. That way, you don’t need to worry about which switch is in which platform.

By implementing extensive signal path shielding, isolation and built-in health monitoring, VTI Instruments' SMX series doesn’t compromise on performance or reliability. Its software-configurable switch subsystems also increase flexibility while helping to control costs since a single unit can easily be used for different testing applications.

As a part of the SMX series, VTI Instruments' new PXIe switch cards utilize advanced layout techniques and advanced shielding methods to ensure optimal signal transparency. These switch cards offer over 30X the isolation of comparable cards, greatly improving system performance and credibility. By reducing marginal signal levels, you also reduce false pass/fail conditions and test-altering glitches.

VTI’s software-configurable card design enables customized switching solutions for any application. Our technology offers a Soft Front Panel (SFP) programming interface for comprehensive path level programming, along with advanced debugging functions to verify signal paths without having to install drivers or develop application software.

No matter what your testing needs are, VTI Instruments' new SMX product family can help ensure that your tests are accurate and reliable. SMX series products include:

  • General Purpose Switch products (SMX-2000/5000 series)
  • Multiplexers (SMX-3000 series)
  • Matrix Switching (SMX-4000 series)
  • RF Switching (SMX-6000 series)
  • Microwave switch products (SMX-7000 series)