On Wing Aircraft
Engine Diagnostic System
by James Beleau, Project Engineer
Abstract:
VI Engineering Inc. has developed an On-Wing Performance
Module Diagnostic Tool Kit for large scale aircraft engines.
The test is performed in-situ on aircraft engines mounted
in flight position on the plane. Each test is automatically
controlled to perform on an engine during power-up of
the Diagnostic tool kit device. The application has no
user interface, or communication options with outside
computers. The only input and output of this device will
be a compact flash card, LEDs, and DIP switches. The tests
procedures involve a schedule of RPM, Temperature, or
Pressure set points. The steady value at each set point
will be logged, as well as historical data for the duration
of the test.
Products Used:
LabVIEW 7.0
NI-DAQ 7.0
Measurement & Automation Explorer 3.0
cFP-2020 Compact FieldPoint Controller
cFP-TC-120 8-Channel Thermocouple
cFP-AI-100 8-Channel Analog Input
cFP-BP-4 4 Slot Backplane
cFP-VIE-513
The Challenge:
VI Engineering Inc. has developed an On-Wing Performance
Module Diagnostic Tool Kit for a large aerospace engine
manufactured. The test is performed on aircraft engines
that are mounted in flight position. Each test will be
automatically controlled to perform on an engine during
power-up. The tests procedures follow a pre-programmed
schedule of RPM, Temperature, or Pressure set points.
The steady value at each set point is logged, along with
historical data collected for the duration of the test.
The Solution:
Using NI hardware and software for I/O and a Tri-way custom
housing, VI Engineering has produced a low cost, high
temperature, and rugged data logging solution. The programming
from, V I Engineering, uses LabVIEW Real-time to produce
an easy, plug and play data collection scheduler.
Overview:
This application will have no user interface, or communication
options with outside computers. The only input and output
of this device will be a compact flash card, LEDs, and
DIP switches. The system has provisions for supplying
outputs for 2 LED’s. LED indicators will show the
states after power up to indicate status of Device. Test
status and error states are communicated to the user this
way. The system has provisions for 3 user configurable
DIP Switches. These are used to set the device to input
configuration data and run tests.
Simple operation
The device will boot up in one of two modes depending
on dip switch setting. The Normal mode will check for
updated setup and calibration files on the compact flash
card, begin data acquisition, begin the FIFO data buffer
for pre-trigger scans, then wait for the first trigger
condition to be met. Upon meeting the first trigger, the
pre-trigger scans will be saved and the historical data
log will begin streaming data to the compact flash card.
An LED turns green signaling when data is being logging.
This same LED will shut off when the test is complete.
If an error condition is met, this LED will turn red and
the application will abort. The Extract mode will retrieve
the current setup and calibration files from the device
onto the compact flash.
Custom module
The cFP-VIE-513 is an I/O module configured to enable
two specific types of measurements on a pair of incoming
pulse trains. The first measurement is the phase shift
between the two pulse trains and the second measurement
is the frequency of the first pulse train. There are two
digital inputs on the 513, one for each pulse train. Each
of these signals is passed through a digital filter prior
to use by the rest of the module in order to reduce the
effects of electrical noise. With this custom NI hardware
the On-Wing diagnostic is able to figure phase difference
and RPM of the plane engine.
Data
All data files will be recorded to the CF. If there is
no CF found, then this will be an error condition and
will be displayed as such on the LED indicators. Data
file structure and format are spreadsheets compatible
with excel, but it is expected that there will be 2 recorded
files.
Data log file – a complete historical log of the
entire test schedule, this will show all data in a logged
format with time as the x-axis.
Data Point log – will record point data based on
the test schedule defined by the Setup file. It is expected
that this data will be used for the analysis package
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