Aerospace Data Acquisition Application Case Study

Aerospace Data Acquisition Applications

VXI DAQ System for Aeropropulsion Laboratory Testing

Customer Case

A boat manufacturer who was planning to buy surplus gas turbine helicopter engines from the United States government to power speedboat racers, wanted to verify the engines performance and evaluate the seller's warranty before purchasing. The manufacturer's solution was to engage the Aeropropulsion Laboratory in Canada that is equipped with KineticSystems high performance VXI based data acquisition test systems.

The Aeropropulsion Laboratory is part of the National Research Council of Canada's (NRC) Institute of Aerospace Research (IAR), Canada's national aerospace laboratory. IAR facilities include eight wind tunnels, air compressor/exhauster facilities, engine test cells, a full-scale structural fatigue rig, aeroacoustics chambers, a Flight Data Recorder Playback Center, and a fleet of eight research aircraft. The Aeropropulsion Laboratory provides consulting services, engages in collaborative research, and licenses its technology to a wide range of clients who need solutions in the areas of design, strength, durability, structural integrity and performance of aircraft, gas turbine engines and space structures.

The engine test cells of the Aeropropulsion Laboratory need the flexibility to test a tank engine one day, an after-burning turbojet the next and a helicopter engine after that. All high performance testing that is conducted for both corporate and government organizations. For example, one of the engine test cells in the Aeropropulsion Laboratory consisting of two test beds equipped with VXI systems has been used to measure temperatures and pressures for a helicopter engine manufactured by General Electric. A second test cell with another VXI system has been used to test a new General Aviation turbo-fan engine manufactured by Pratt & Whitney.

Two of the Aeropropulsion Laboratory's test cells are equipped with VXI systems that were purchased exclusively from KineticSystems. High channel count, flexibility, reliability, tight specifications and a wide range of product selections are just a few reasons why the Aeropropulsion Laboratory selected KineticSystems VXI solutions.

Although testing helicopter engines for speedboats may not be an everyday occurrence, it highlights the versatility, flexibility and high performance testing the Aeropropulsion Laboratory is able to provide using KineticSystems VXI solutions.

KineticSystems Case Solution

The engines destined for speedboats were Lycoming T53-L-13 1400 shp engines used in Huey helicopters designed for military and medical service during the Vietnam war. The engine is capable of producing 1400 shp (shaft horsepower) at 64 psi of torque on a standard day (59 degrees F) at sea level (29.92 HG). Applied to a helicopter, this provides enough power to carry up to 12 troops, with a crew of two. The UH-1D Hueys have a range of 293 miles (467km) and a speed of 127 mph (110 knots).

Brought into the NRC Aeropropulsion Laboratory engine test cells, the T53 engines were hooked up to a dynamometer and VXI instrumentation, run up to power, and monitored with a full set of checkouts to verify engine performance.

According to Brian Barry, Technical Officer and Data Acquisition Specialist at the Aeropropulsion Laboratory, two of their facility's test cells are equipped with VXI systems to provide the precision measurements and the level of confidence among clients who need high performance testing.

"When the clients see our VXI system, they know we're in the big leagues," says Barry. "When I bid on a project, we can say we have VXI equipment and that benchmarks our ability."

When Barry first began working at the Lab in the 1990's, test equipment consisted of DEC PDP-11 computers with a NEFF front end. Soon afterward, the Lab replaced the PDP-11's with VAX 3100's, retaining the NEFF front end. VAXs, of course, had PDP-11 compatibility mode built in. However, frequent changes in client testing requirements meant frequent reconfiguration of the VAXs. Says Barry, "It takes a lot of manpower to manage a bunch of VAXs. It takes considerable time to write the software, let alone do all the system management. So, I pushed for PC-based data acquisition."

Although the Lab first purchased PC-based SCXI (Signal Conditioning EXtension for Instrumentation) equipment, the performance level was not as high as VXI and SCXI was proprietary hardware built by a single vendor. "We have a van with SCXI testing equipment which we use for outside testing," says Barry. "VXI is our high-end; really high-end."

Why did the Lab consider VXI (VME eXtension for Instrumentation)?

"A lot of our clients were using VXI," says Barry. "You get more performance out of the VXI. If you look at the specs of VXI equipment, you'll see temperature accuracy is better, channel rates are higher and reliability is presumably better. And at the end of the day, it's a multivendor standard, so we're not limited to vendors."

Nevertheless, the NRC Aeropropulsion Lab purchased KineticSystems VXI hardware exclusively. "The hardware is beautiful," says Barry. "There's no knocking it. When KineticSystems says a module will scan at 100 kHz; it scans at 100 kHz. Signals are nice and clean. There are several features you don't find with VXI equipment from other manufacturers. KineticSystems provides per channel amplifiers and permits more flexibility when you set up scan rates. For example, if you look at a 32-channel temperature module from another well-known VXI vendor, you can only read in groups of 10, 20 or 32 channels. You can't read the first five, skip 15 and then read the next 10. You can't have any one module's address appear twice in the scan. KineticSystems lets you read in groups of 4."

"There are also pre- and post-filtering gains on KineticSystems signal conditioning modules. You can set prefiltering gain in groups of eight and post-filtering gain individually. And the filters tend to be better. Another VXI vendor limits setting the filter for the whole cart. So, there's some tweak-ability you don't get with other vendors. One's a Chevy; the KineticSystems is the Rolls Royce."

According to Barry, few vendors have as wide a VXI product selection as KineticSystems. In fact, a provider of some of the Lab's previous PC-based test equipment not only didn't have much of a selection, Barry says, "It looked like they had taken their PXI equipment and soldered it onto bigger boards. So I figured I'd end up with all the limitations I already had." Barry says KineticSystems VXI cards also provided several advantages unavailable from other VXI vendors, including:

  • High channel count flexibility
  • Fiber optic interface providing a fast, accurate and convenient alternative to thick cables

The Aeropropulsion Laboraty has two installed VXI systems. The first system consisted of the following components:

PC System:

  • LabVIEW Application Software
  • V122 – KineticSystems PCI Host Adapter Providing an Interface Between the PCI Bus and the Fiber Optic Network
  • GPIB Interface for a Pressure Scanner

Test System Front End (all KineticSystems Modules):

  • V195 – 13-Slot, C-Size VXI Mainframe with 1,000 W Power Supply
  • V120 – Slot-0 Controller with Fiber Optic Interface to one or more VXI Mainframes. It is a slave device on the fiber optic network and receives its commands from the V122 host adapter. The fiber-optic network supports distances between nodes up to 2 km (6,560 feet) with an I/O throughput up to 10 Mbytes/second.
  • V208 – 16-bit Analog-to-Digital Converter that processes up to 100,000 samples/second with a 4 Mb buffer.

Modules Cabled to Test Bed (all KineticSystems Modules):

  • V243 – 48-channel (high level) voltage measuring, signal conditioning MUX. Includes programmable gain per channel and 2-pole, active, low-pass Butterworth filters on each channel. Filter cutoff frequencies and pre-filter gains are software selectable.
  • V243 – 96-channel (low-level) temperature measuring, signal conditioning MUX. Same features as module above.
  • V635 – 8-channel 100 kHz Frequency Counter.

Other Equipment:

  • Pressure Scanner
  • Barometer
  • Frequency to Voltage Converter, 14 Channels
  • DC Power Supplies
  • 28 Dedicated Wet Pressure Transducers
  • 4 RF Conditioners for Flowmeters

Typically, the test cell reads voltages off engines, pressure transducers and thermocouple temperatures.

Reflecting on the VXI system, Barry singled out the V243, commenting, "The V243 is great because you can set gain per channel, you can set filtering in groups of 8 channels and you can vary the scan list. You can look at different groups of channels as you choose."

According to Barry, since one of the engine test cells was large enough to accommodate two engines, they divided the cell into two; creating both an East and a West test bed. By installing a separate counter card (V635) and two additional V243 MUXs, two test beds are fully instrumented within the cell using one mainframe. Although they cannot conduct testing in both test beds simultaneously, the Lab has significantly shortened configuration time between tests.

Typically, the engine test cells read less than 100 channels for any one test, often only 30 – 40 analog channels. However, Barry reports they will be using 300 channels requiring 100 kHz Analog-to-Digital conversion.

A second test cell at the same facility is also outfitted with a VXI test system. Chief differences between this cell and the East/West test bed previously described are:

  1. Upgraded PC System
  2. Pressure Scanner that does not need a GPIB Interface
  3. Frequency to Voltage Converter – 7 Channels
  4. 14 Dedicated Wet Pressure Transducers
  5. The same KineticSystems Mainframe and Modules are used in this cell as the previous dual test bed cell.

Says Barry, "With KineticSystems product, you can be sure it's high-quality hardware with nice, tight specs. Of course, given the price of VXI, you expect the best. I think VXI is high-end and KineticSystems does a good job with the hardware. I have not been disappointed with their hardware at all."

So, should you ever witness the winning of a speedboat race by a boat featuring a powerful T53 gas turbine engine, you may recall the Canadian Laboratory and the KineticSystems VXI test system used to verify the engine performance.

KineticSystems Case Recommended Products

The primary KineticSystems products used in this application are:

  • V120 - FOXI VXI Slot-0 Controller
  • V122 - FOXI PCI Host Adapter
  • V195 - 13-Slot, C-Size, VXI Bus Mainframe Chassis
  • V208 - 16-Bit, 100,000 Sample/sec ADC Subsystem
  • V243 - 96-Channel, Low-Level Signal Conditioner
  • V635 - 8-Channel, 100 KHz Frequency Counter

Aerospace Application Request

We encourage you to contact us and discuss your aerospace application in more detail with our engineering team. KineticSystems can provide tailored custom data acquisition hardware and software solutions to meet specific aerospace application requirements.