Anubhav Garg - Hindustan Aeronautics Limited
Trilok Kumar -
Hindustan Aeronautics Limited (HAL), a Navratna central public sector undertaking, is a premiere aeronautical company in southeast Asia with 20 production, overhaul, and service divisions, 10 of which are co-located R&D centers across the country. Our spectrum of expertise encompasses design, development, manufacture, repair, overhaul, and upgrade of aircraft, helicopters, aero engines, industrial and marine gas turbines, accessories, avionics, and system and structural components for satellites and launch vehicles.
We needed to create test equipment for a solid-state flight data recorder (SSFDR) to simulate and generate the following parameters:
• 22 analog output parameters (range 0 V to 10 V)
• 20 discrete output parameters (range 0 V to 28 V)
• Two frequency output parameters (range 7 kHz to 5.5 kHz)
• One audio output parameter (1 kHz pulse)
• Five transistor–transistor logic TTL output parameters
• 16 ARINC 429 output parameters
In the previous system, we used 6U/3U PXI/CompactPCI extensions outsourced from different vendors with their own customized hardware and software. The hardware was bulky, unreliable, incomplete in technical detail, and quickly became obsolete. It also came with very poor vendor support. These cards were customized for the particular test bench, so we could not use them for other platforms. The software code was written in VC++, which was difficult to understand and change. In addition, the software GUI was not user-friendly.
NI CompactDAQ Chassis-Based System
We replaced the previous system with set of NI C Series modules combined with a USB-based NI CompactDAQ chassis to generate and simulate the analog I/O, discrete I/O, and frequency I/O. We used an NI USB-to-RS422 converter as the telemetry interface for data analysis and an NI USB-to-RS232 converter to fuse the code in the flash memory of the solid-state flight data recorders SSFDR. The analog and frequency signals generated by the NI modules were very accurate and reduced rig calibration.
We easily programmed these compact modules with the user-friendly GUI in LabVIEW, which we used as the common software to test the different platforms of flight data recorders. Some of the tests were difficult and time-consuming to implement in VC++. For example, the elapse time test required perfect synchronization during data reception at the RS422 converter because it had to capture the time parameter of 256 words every 15 seconds. We easily implemented this test using the event structure feature of LabVIEW. In addition, it was difficult to generate noneditable reports such as PDF in VC++, but LabVIEW offered PDF format file generation. The test equipment required one-tenth tolerance to the flight data recorder tolerance, which was easily provided in the analog and frequency module.
Saving Money and Space
The test rig we developed using NI hardware and LabVIEW software reduced our costs by approximately 2X and freed us from dependency on an external vendor. Tests of in-flight data recorders are difficult to implement in VC++ compared to LabVIEW. For example, threading is far easier to implement in LabVIEW than in VC++. NI trainers came to our location to give us basic LabVIEW programming training. The technical support in Bangalore is excellent and exceeded our expectations at every critical time of our project.
Figures 4 and 5 show the size reduction of the new system compared to the previous system by using C Series modules such as the NI 9264 and NI 9221. Because of the new system’s portability, we can easily test units at different locations. We also have excellent technical support and backward compatibility with NI products.
Hindustan Aeronautics Limited
Hindustan Aeronautics Limited, Avionics Division HAL, Korwa