Supporting Industry Innovation with PXI Switching and Simulation Systems Designed to Sustain Your Test System
When designing mission-critical equipment for aerospace and defense applications, failure is not an option; therefore, extensive testing and simulation using highly reliable automated test equipment (ATE) are required. Beyond ensuring ATE is designed for high performance and to execute tests reliably, ATE used in the aerospace and defense industry must also support long lifecycles and offer the flexibility and agility needed to meet evolving test requirements over time. When a component needs to be changed in ATE designed for aerospace and defense system testing, the revalidation process can be cumbersome – both in cost and time commitment – therefore, integrators and end users really need to work with suppliers who plan for long-term production and support.
This case study explores two examples of how Pickering switching and simulation products support the unique needs of both integrators and aerospace and defense companies who need high-performance, high-reliability ATE.
Pickering Helps Integrators Differentiate Test Solutions
As an integrator, when bidding on the development of a test solution for one of the key players in the aerospace and defense industry in the US, you will likely face stiff competition from several solutions providers. Often, price will not be the deciding factor for these companies like it would for many mass-produced consumer goods. Instead, aerospace and defense contractors are highly focused on developing flexible solutions designed to meet their test needs now as well as a decade or two into the future.
For integrators, this means you need to be sure your solution is agile enough to meet evolving requirements while also offering some other unique value propositions for the end user. However, this can be difficult to do when you are creating a complex test solution using many vendors’ components.
Recently, Pickering worked with DMC, a long-term integrator partner, to differentiate their test solution and win a contract to build a PXI-based test system for sophisticated ground support equipment. For this test system, DMC needed to be sure all selected suppliers could help them meet the following key requirements under the following conditions:
- Since longevity and long-term support were critical, the system would use a combination of PXI modules and Ethernet-based communication to an LXI mainframe. Components needed to be compatible with these open-standard platforms to be supported for 15 to 20+ years.
- All components had to be designed for reliability since a failure could lead to a signal misfiring or a short, which could cause a dangerous situation or damage to the expensive test equipment.
- The system also needed components that support easy and early detection of faults during run-time operations.
To meet these requirements, DMC needed a switching solution that consisted of a variety of switches that all provide high signal integrity, ensure test system safety, offer the ability to detect faults quickly, and come with a long-term support commitment. Since DMC has worked with Pickering for nearly 15 years, they knew we could easily work together to architect a switching solution that would meet all their end user’s unique requirements. They knew this was possible because, in addition to the broad range of commercial off-the-shelf (COTS) switches we offer, they were familiar with our experience making modifications to our standard products to produce switching solutions that offer the exact functionality required.
After reviewing the switching requirements of this system with DMC, it was clear that standard switches would not meet all the switching needs of this test solution. Since there are many risks of a switch not performing exactly as expected, DMC was not willing to take a chance on using a switch that could cause signal integrity issues between the DUT and measurement equipment.
With minimal non-recurring engineering (NRE) costs, we collaborated with DMC to extend our PXI-based switching portfolio. We developed switching modules (40-619 series) that met the exact specifications this end user required, providing the ability to directly monitor contact state and detect relay faults in-situ. We also helped DMC enhance the safety and reliability of their test solution through the following products:
- 60-103B-002 LXI Modular Switching Chassis – We added a feature to our standard 60-103B chassis to develop a new modular switching chassis that has an added safety feature to asynchronously force relays open upon a system fault condition.
- 40-792 Series PXI 2MBit/s 75Ω Tributary Daisy-Chain Switch – We modified an existing COTS switch to provide DMC’s preferred topology for switching 75 Ω impedance-matched communication signals.
- We conformally coated all modules to reduce the risk of potentially hazardous situations caused by the environment in which the test system is residing.
Pickering's PXI monitored multiplexer, PXI tributary daisy-chain switch and LXI modular switching chassis used in this application
As a result of our ability to quickly and cost-effectively provide semi-custom components that also have the guarantee of long-term support like any of our COTS products, we were able to elevate DMC’s solution compared to competitor offerings.
Beyond our product flexibility, we provided DMC with several other advantages that helped further delineate their solution from competitor options. First, this switching solution enables high channel density, which means this test solution offers a smaller footprint than competitor options. Additionally, for switching and routing of communication signals, our solution provides superior impedance matching to avoid the possibility of reflections occurring and disrupting signal integrity, resulting in poor test results. We also provided a unique “failsafe mode” for this solution so that, when an external signal is received by our chassis, it will force all relays to their open state. With this “failsafe mode” feature, relays can protect the test system by disconnecting the DUT from the test equipment in the event of an external fault condition.
Switching and Simulation Tools Support High-Density, Multi-Purpose Avionics Field Test Systems
For military aircraft in the field, engineers or technicians perform maintenance and make upgrades at regular intervals to ensure safety as well as on an as-needed basis when there is an issue with an in-service plane. With frequent maintenance needed and the large number of military planes in use around the world, it is not practical to send planes back to a manufacturer or to send service technicians out into the field every time maintenance is required. Instead, plane manufacturers or third parties develop field test systems so that this maintenance, known as depot maintenance, can be performed in the field at depots worldwide. When troubleshooting electrical issues with a plane, these test systems are designed to identify the lowest level line-replaceable unit (LRU) that can be swapped to address the issue instead of performing component-level diagnostics. This approach helps save time and money on repairs and puts planes back in service much faster.
For one large military plane manufacturer, the depot test system they built and sold to end users of its planes was large and expensive; therefore, many end users did not want to purchase this system and preferred to contract maintenance and support to another provider. To resolve this issue, the company needed to develop a more flexible, adaptable, cost-effective, and smaller system, but the development of this test system was not straightforward since this type of diagnostic field testing requires supporting a wide variety of LRUs with various signal types. For example, the module could be required to switch between a MIL-STD-1553 avionics bus and a 1kW power supply; therefore, a modular switching subsystem that offers versatility to be custom configured is critical.
To meet these requirements, this company approached Pickering because they recognized us as a leader in providing PXI-based modular switching and simulation solutions that remain supported for many years. During our initial discussions, we determined they needed purpose-built switch modules that could perform high-density switching, as portability is crucial for field test systems. This was an easy requirement for us to meet since our modular switching approach inherently allows supporting many different test instruments in a small footprint.
In addition to providing the switching for this test system, the customer also decided it was best to use our PXI-based linear variable differential transformers (LVDTs) to measure linear displacement since we could simplify the integration of our PXI-based simulators into the test system versus their prior option. The LVDT modules can be used to test the avionics equipment to be sure it is reading the electrical signals from the sensors for potential errors. The LVDT sensor can also be hooked up to an LRU (processor unit, engine unit, etc.) to generate signals to simulate displacement and measure linear displacement to ensure the control system reacts appropriately.
Pickering's PXI-based linear variable differential transformer (LVDT) module (41-670)
As a result of this new PXI-based test system using Pickering products at its core, this customer can now offer its customers a more competitive, comprehensive, and compact long-term support solution for depot testing.
Key Differentiators for Selecting Pickering Products for Aerospace and Defense ATEs Agile Development from Design to Manufacturing
Over the years, ATE system developers have realized that when the vast Pickering portfolio of switching and simulation products does not have exactly what they need to meet their test system requirements, they do not need to settle on a sub-optimal solution. Instead, our engineers have the expertise, and the desire, to collaborate with customers to modify our COTS products to design and develop the exact switching and simulation solution required. Our general PXI and switching expertise, combined with our ability and willingness to engage with customers to develop specific solutions to meet all their ATE system needs, truly sets us apart: as most of our competitors do not provide options beyond their standard COTS parts.
A Proven Track Record of Long-Term Product Support
When parts in an ATE used for aerospace and defense applications become obsolete, it is a huge undertaking to revalidate the system design for new parts. These companies need a commitment from their suppliers that they will continue to support components even if something reaches its end of life (EOL). At Pickering, we recognize the immense amount of time and money customers invest in developing their products, test systems, and the corresponding test sequences; therefore, we help customers preserve their test investment by offering a commitment to support components 15-20 years from the date of delivery. We also strive to provide functional replacements for obsolete components and can often manufacture older versions of products as special orders for compatibility purposes.
Long-Lasting Solutions that Fit Your ATE Requirements
Some companies learn the hard way that they should have put more thought into their switching/relays when test systems quickly fail or become unsupported. In the aerospace and defense industry, however, the lesson is too costly to learn. As shown throughout these two case studies, between our expertise and knowledge of working on PXI-based ATE systems for aerospace and defense applications and the fact that our core competency is switching and simulation – 100 percent of our company is dedicated to these solutions – Pickering is well prepared to ensure your ATE is built to last for at least the length of your planned production.
