LVDT displacement sensors

LVDT displacementDéplacement
Source of innovation
Systèmes inertiels
Enregistreurs de chocs
& Microélectronique
Competitive Advantages
Sensorex, European leader in LVDT sensors, offers a wide range of technical solutions for linear
displacement measurements.
Contactless measurement with unlimited service life
An LVDT (Linear Variable Differential Transformer) is a transformer which
supplies a voltage proportional to the displacement of a ferromagnetic core
(moving element).
This type of sensor comprises primary winding fed by an alternating
sinusoidal signal and two secondary windings.
The core slides insides these windings, channels the flow and generates
voltages V1 and V2 inside each secondary winding, with the amplitudes
dependent on its position.
The output signal is then demodulated to obtain a DC voltage representative
of the core position.
The demodulation in ratiometric mode (difference/sum) optimises the
sensor performances and reduces thermal deviation and sensitivity to
supply variations.
The differential mode is nevertheless still used for less demanding
applications (mode detection).
Extreme performance
Measuring range:
0 to 400 mm
(± 200 mm)
Sensitivity deviation: ± 0.5%
Linearity deviation: ± 0.2% PE
(± 0.1% PE possible)
Thermal zero drift: < 10 ppm PE/°C
Thermal sensitivity drift: < 70 ppm/°C
Operating temperature: - 55°C to + 200°C
(+ 235°C possible)
Over one million hours
Proven, mastered technology
Contactless measurement: There is no physical contact
between the core and the windings.
Unlimited service life: the lack of contact gives the
sensor a virtually unlimited service life and outstanding
reliability. These criteria allow its use in fatigue or severe
and demanding fields.
Infinite resolution: the LVDT is an inductive sensor and its
resolution is limited only by that of the processing
Excellent repeatability (< 10-5 PE) and insensitivity to
transverse movements, suitable for hard environnement:
thanks to its design, windings built into a hermeticallysealed stainless steel body and moving element totally
independent of this system.
Insulation between input and output.
Products & A
Reliability and Safety
To ensure system safety, our sensors can be built into multiple
and redundant measuring channels.
Simplex, duplex, triplex and quadruplex sensors are all available.
This integration requires total
control of magnetic interference
(tracking and crosstalk) between
the various measuring channels
positioned in parallel or in series
in the sensor's housing.
Adapted, innovative solutions
The fly-by-wire concept is systematically adopted by new programmes to take advantage of the numerous advantages of
electric flight controls.
Our various types of sensors are particularly suitable for servo-control applications to major actuator position (SV, EHA,
EBHA et EMA), mode detection and deltaP. They are also built into servo-valves and engine servo-mechanisms (VBV - lowspeed electric vehicle).
They can easily be integrated in the very heart of cylinders and valves thanks to their design and resistance to pressure; this
is especially advantageous for protection and therefore for reliability and service life.
We have acquired full knowledge of "smart LVDT" concepts over the years and have fully developed them fully (qualification
under Do160D) by incorporating digital intelligence.
We are pushing the limits of technology with error compensation and digitisation of the output signal, thereby improving the
performances considerably. We are thus able to meet the requirements of future generation actuators and new potential
applications are opened up to us.
In terms of system safety, this approach ensures maximum monitoring cover.
To maintain its independence and anticipate risks of obsolescence, Sensorex has developed its own ASIC circuit (CISIC) for
LVDT sensor conditioning together with a universal digital compensation module (HCN) in hybrid technology.
S m a r t
S e n s o r
By integrating a digital signal processing stage to its devices, Sensorex is bringing a
new generation of sensors: the Rugged Enhanced Digital Sensors – REDS.
The new SX20MD is the perfect illustration of this concept.
The core of the signal conditioning circuit is our DCH module (Digital Compensation
Hybrid) which enables linearization and temperature compensation, therefore
considerably improving the performance of all sensor types. Thanks to this design,
REDS sensors are the most accurate on the market place.
r t
S m a
s o r
S e n
Our programmes of excellence are our references
Over 100,000 LVDT displacement sensors are in operation in the entire Airbus fleet of aircraft as well as in the majority of
military and civilian helicopter, business jet, regional jet and launcher programmes.
Industrial Excellence
R&D expertise
•Design and manufacture of passive and active
LVDT to specification.
•Small to high value production runs,
short deadlines
•SAMCEF (calculation by finite elements in vibratory and thermal conditions)
•Expertise and software tool for assessing
reliability under MIL-HDBK 217
•Modelling, 3D flows
•Obsolescence watch
•Thermal and vibration tests
•HALT/HASS machine
•2400 m workshops
•340 m2 clean rooms
- 1 laser trimming machine
- 1 EB welding machine
- 4 programmable winders
- 5 climatic chambers
- 5 test benches
•Organisation by product lines:
- Helicopter line
- Business jet line
- AI-LR line
- Special LVDT line
(small quantities/high complexity)
- Industrial LVDT line (catalogue)
•Work organisation
(reduction in manufacturing cycle):
- round-the-clock (1 night shift and 2 day shifts)
- seven days a week (1 weekend shift)
•Industrial optimisation of various lines:
- LEAN approach
- 5S approach
- PIC (medium-term forecasting)
•Versatile, qualified operators with on-going
training (training budget: 10% of turnover)
ready to serve customers.
Certifications and standards
ISO 14001 (mid-2007)
ISO 9001 version 2000
EN 9100
- DO 160 (environment)
- DO 178 (software)
- DO 254 (hardware)
- ABD 100
- MIL STD 883
- MIL HDBK 217
- EG 13
Partnership & Innovation
Fuelled by a desire to consolidate the positions acquired and increase its market shares, Sensorex can now rely on
the complete R&D, marketing and industrial expertise of Vibro-Meter and the Meggit Group to meet increasingly
exacting applications, as shown by our on-board measuring systems in the most recent aeronautical (flight
controls and engines) programmes and new-generation spatial launchers.
Vibro-Meter and Sensorex have also been selected for several European research projects in partnership with the
biggest actors in the sector, to identify and develop new, key detection and miniaturisation technologies.
At the same time, re-engineering projects are in progress for existing products, with a particularly selective
design-to-cost approach.
Thanks to the ONE MEGGITT organization and the Xiamen manufacturing site in China, Sensorex benefits from
outstanding industrial capabilities in Asia.
The transfer of technologies and the different trainings undertaken on the Xiamen site offers Sensorex an
additional production site and the possibility of impoving its general competitiveness.
For this ambitious on-going improvement initiative, Sensorex has received several awards in recognition of the
best industrial performances in our sector.
Very recently our R&D teams were awarded the Product Innovation prize for the development of our HCN universal
digital module. This is recognition for our active and innovative initiative of over twenty years in mechatronics and
positions us favourably for the new technological challenges.
Our strategy is simply to become the essential partner for your future projects.
A center of excellence for design and production
05/2009 -
International Business Park • BP 63108
74166 Archamps • France
Tel.: +33 (0) 450 95 43 70 • Fax: +33 (0) 450 95 43 75 • E-mail: [email protected]