Client:

NASA - Ames Research Center
National Full-Scale Aerodynamic Complex
Moffett Field, California

Product:

Series 6100 Transducer Signal Conditioning System

Requirement

After three years of inactivity the National Full-Scale Aerodynamics Complex (NFAC) at NASA, Ames Research Center, Moffett Field California is set to reopen for testing in February 2007. Initial tests will be on the UH-60 independent blade control system. The complex will be operated by NASA for the U.S. Air Force's Arnold Engineering Development Center (AEDC). In order to resume operation, the facility required new, 240-channel and 276-channel data acquisition systems.

NFAC is the largest wind tunnel in the world. This subsonic tunnel, which can test planes with wing spans of up to 100 feet, is over 1,400 feet long and 180 feet high. It has two test sections: one 80 feet high and 120 feet wide, the other 40 feet high and 80 feet wide. Air is driven through these test sections by six 15-bladed fans. Each fan has a diameter equal to the height of a four-story building. The fans are powered by six 22,500-horsepower motors.

Solution

Jacobs Sverdrup, the Air Force contractor supplying the data acquisition systems, and NASA selected Pacific Instruments to supply the signal conditioning. The NFAC facility experiences high common mode potentials due to its physical size and high-power equipment, making Pacific’s Model 6160 with 300 Volt common mode capability the ideal choice. An integral six-pole (36 dB/octave), low-pass filter with programmable bandwidth enables digitizing the amplifier output at multiple sample rates without incurring alias errors.

Due to the very large scale of this facility, it is not always possible to localize and control transducer grounding. The Model 6160's isolated excitation and input means that transducers may be floating or grounded at various locations around the facility without creating "ground-loops" that would degrade measurement accuracy. For calibration, NASA employs four-step shunt, which is an optional feature of the 6160. High accuracy, 0.01%, shunt calibration resistors are mounted on plug-in modules that install on the signal conditioning amplifier. The module is easily removed and sent to the calibration laboratory for periodic verification. This avoids having the signal conditioning amplifiers out of service while resistor accuracy is verified.

Each of the two systems consist of multiple 32-channel enclosures that have USB 2.0 interfaces. A Control Processor interfaces multiple enclosures to a single Ethernet port that is used to program and control the signal conditioning. A high-level instruction set simplifies channel programming. Of particular value to NASA is the 6160’s signal monitor. A portable test fixture, used for transducer installation troubleshooting, it plugs into a connector on the front of the signal conditioning module and provides test points for excitation, sense, calibration, transducer input and amplifier input and output.

Features Important to this Application:

1. 300 Volt common mode
2. Fully floating input and excitation power
3. 4-Step shunt calibration with removable resistor module
4. High accuracy with gains 1 to 5,000 and 100 kHz bandwidth
5. Six-pole anti-aliasing filter
6. “Front panel” signal monitor

Learn More

Get more information about Series 6100 Transducer Signal Conditioning Systems.

Contact

For additional information about testing low and high speed wind tunnels with Pacific Instruments Series 6100 signal conditioning, please contact us with your application.

Phone: 925-827-9010

Email: salesrequest@pacificinstruments.com