For business aircraft companies, fast and efficient maintenance is critical in meeting safety requirements and flight schedules. To expedite troubleshooting, aircraft engineers are relying on portable PC-based data acquisition systems.

Application Summary
An electrical engineering department at a major manufacturer and operator of business aircraft gets weekly requests to assist field-service engineers with a wide variety of technical problems. Just about any electrical system can be involved with these technical crises, which require the simultaneous collection of numerous variables for troubleshooting purposes. Because of the wide variety of complex aircraft systems and signal levels, off-the-shelf instruments do not provide the performance required to conduct thorough testing.

Potential Solution
Until recently, the only data acquisition instruments available for aircraft troubleshooting were either large strip-chart recorders that made data transfer inconvenient or even larger test-and-measurement instruments that took up too much room in the aircraft being tested. In addition to large size and lack of portability, there were no convenient sources of 110 AC power aboard many planes to operate the systems.

IOtech’s Solution
The aircraft engineers worked with IOtech to develop a self-contained, battery-operated, portable PC-based data acquisition solution based on IOtech’s DaqBook. The system accommodated eight differential (16 single-ended) analog inputs (expandable to 256), two analog outputs, four digital inputs, 24 general purpose digital I/O channels (expandable to 192), and five frequency/pulse I/O channels.

Housed in a DBK10 expansion enclosure for signal conditioning cards, IOtech’s DBK11 screw-terminal and DBK82 thermocouple cards were used to connect various transducers and thermocouples to the DaqBook. A DBK80 multiplexer (MUX) card was used when more than 16 inputs were required.

The system was powered by a DBK30A, NiCad battery module, which was ideal for in-flight testing applications. The DaqBook, DBK10, and DBK30A all matched the typical form factor of a notebook PC (8-1/2” x 11” x 1-3/8”) and were fastened together with Velcro-style tabs. The compact system was packaged in a soft-sided suitcase that was easily wheeled to various test sites. The total system weighed less than 20 pounds, much less than previous test systems.

In a typical troubleshooting scenario, the system is rolled to an aircraft in a maintenance hanger or on a tarmac. The appropriate transducers are attached to various aircraft components and/or aircraft operating systems to gather data from desired sources. As the signals are collected, the DaqBook converts the data and transfers it to the PC. DaqView, a Windows-based data-logging software program supplied with all of IOtech’s DaqBook systems, allows users to set up the application and save acquired data directly to disk or hard drive.

Conclusion
The DaqBook’s A/D performance and programmable channel/gain sequencer make the system particularly useful for applications, like aircraft system testing, that require flexibility, high channel-count and speed requirements. The system’s extensive I/O and signal conditioning capabilities, combined with its high mobility and low cost per channel, make it an effective alternative to larger, less-capable strip-chart recorders and other test-and-measurement instruments.

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