Sensors
REVOLUTIONARY
DIGITAL SENSOR
PLATFORM FOR
HUMS & VHM
Smart sensors can process advanced machinery diagnostic
outcomes and communicate the results over a CAN bus
// BRIAN JOHNSON
Health and usage monitoring systems
and fixed wing aircraft machinery
diagnostics are entering a new era as
the aerospace industry moves toward
better asset management and eventually to
unmanned operations. Owners and
operators are expecting the advanced
aircraft and machines of the future to have
the ability to self-diagnose vibration
conditions that could lead to catastrophic
failure or to unanticipated downtime. This
expectation requires a quantum leap in
digital sensing technology – not just an
improved version of the technology we
have today.
To reach these goals, Dytran has
developed CAN-MD (Controller Area
Network – Machinery Diagnostic), a
sensor-based digital machinery diagnostics
platform. CAN-MD sensors feature
onboard digital signal processing (DSP)
capability that computes Condition
Indicators (CIs) directly on each sensor.
CAN-MD sensors incorporate powerful
microprocessors that enable data reduction
and algorithm processing to be performed
in near real-time at each sensor location,
not in a post-processing box elsewhere on
the aircraft. Diagnostic outcomes from
each sensor are broadcast continually on
the bus in CAN frames where they can be
compiled in a logger or trended for
immediate distribution to the Cloud.
Sensors communicate in normal CAN
frames at normal bus rates leaving no
downtime between measurements; every
sensor is processing data, all the time, with
no multiplexing needed.
PROCESSED AT THE SOURCE
The revolutionary CAN-MD platform
offers an efficient, cost-effective
monitoring solution for Health and usage
monitoring systems / Vehicle Health
Monitoring (HUMS / VHM) applications.
CAN-MD is ideal for vibration health
monitoring of mechanical aircraft systems
including engines, transmissions, bearings,
and gears, as well as propeller balancing
and engine test cell monitoring.
Conventional analog-sensor HUMS
systems require large wire bundles to be
run throughout the aircraft in a classic
“hub-and-spoke” arrangement back to a
central box, requiring one cable for each
accelerometer. Since vibration sensors
produce incredible volumes of raw
dynamic data, it must be sent to a
centralized processing box for DSP,
algorithm overlay, and CI generation. Postflight,
a maintenance engineer then takes
on the time-consuming task of analyzing
the data to determine if there are any
faults developing or trends that are of
150 SHOWCASE 2020 \\ AEROSPACETESTINGINTERNATIONAL.COM
2 // The 3409A CAN–MD
accelerometer provides a
standalone vibration
sensor that can measure,
condition, digitize, process
and communicate
data directly from the
sensor itself
concern. This approach adds unnecessary
weight to the aircraft, increases
installation costs, limits the number of
sensors that can acquire data at any given
time and requires tedious data analysis.
CAN-MD has now solved the toughest
machinery sensing challenge: going alldigital
1
with high-level, broadband vibration
data processed at the source.
FLEXIBLE CONFIGURATION
User-configurable firmware in the
CAN-MD platform optimizes each
individual monitoring location for the best
possible results. Each sensor is a node that
can be configured to look for specific fault
characteristics depending upon the
monitoring task at hand. In addition to
collecting vibration data and processing
spectral data, CAN-MD accelerometers can
also post condition indicators on the bus
automatically and / or when instructed. A
CI is the result of the onboard DSP and
algorithm processing functions performed
by CAN-MD sensors.
CIs are provided as outputs on the CAN
bus and are the primary bits of
information sent to dashboards, either
locally or in the Cloud. This is the most
significant part of the CAN-MD system.
CIs are then used to trend developing
faults, predict failures, or trigger alarms for
2
1 // CAN-MD developer kits
are customized to include
all the necessary CAN-MD
components to meet a
customers’ specific
application needs
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