BINP CAPACITIVE AND ULTRASONIC HYDROSTATIC LEVEL SENSORS A.G. Chupyra, G.A. Gusev, M.N. Kondaurov, A.S. Medvedko, Sh.R. Singatulin BINP, 630090, Novosibirsk, Russia - PowerPoint PPT Presentation

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BINP CAPACITIVE AND ULTRASONIC HYDROSTATIC LEVEL SENSORS A.G. Chupyra, G.A. Gusev, M.N. Kondaurov, A.S. Medvedko, Sh.R. Singatulin BINP, 630090, Novosibirsk, Russia

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DESY BINP BINP CAPACITIVE AND ULTRASONIC HYDROSTATIC LEVEL SENSORS A.G. Chupyra, G.A. Gusev, M.N. Kondaurov, A.S. Medvedko, Sh.R. Singatulin BINP, 630090, Novosibirsk ... – PowerPoint PPT presentation

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Title: BINP CAPACITIVE AND ULTRASONIC HYDROSTATIC LEVEL SENSORS A.G. Chupyra, G.A. Gusev, M.N. Kondaurov, A.S. Medvedko, Sh.R. Singatulin BINP, 630090, Novosibirsk, Russia


1
BINP CAPACITIVE AND ULTRASONIC HYDROSTATIC LEVEL
SENSORS A.G. Chupyra, G.A. Gusev, M.N.
Kondaurov, A.S. Medvedko, Sh.R.
SingatulinBINP, 630090, Novosibirsk, Russia
2
  • INTRODUCTION.
  • MODIFICATIONS OF CAPACITIVE LEVEL SENSOR SAS,
    SASE.
  • MODIFICATIONS OF ULTRASONIC LEVEL SENSORS ULS,
    ULSE.
  • COMPARISION OF TWO KINDS OF THE SENSORS.
  • CONCLUSION.
  • REFERENCES.


3
  • Introduction
  • Slow ground motion study for future accelerator
    projects and alignment of large accelerator
    machine components with high accuracy are
    important tasks now. One of the prevalent tools
    for solution of these tasks are Hydrostatic Level
    Sensors designed to work into the Hydrostatic
    Levelling System, which is based on principle of
    communicating vessels.
  • Since 2000 year BINP took part in development
    and fabrication of Hydrostatic Level Sensors in
    the network of team-work with FNAL and SLAC. For
    this time some modifications of capacitive and
    ultrasonic HLS sensors were developed.
  • During last 9 years more then 300 sensors of
    both type were fabricated and delivered to FNAL,
    SLAC, KEK and Montana Tech.

4
  • The biggest delivery of BINP HLS sensors (138
    capacitive and 49 ultrasonic) was made at 2008 to
    SLAC for LCLS project. The sensors were
    installed by SLAC team on the LCLS Undulator
    magnet line at the end of 2008.
  • Spring 2010
  • 12 SASE and 12 ULSE were delivered to FNAL for
    Montana Tech Laboratory,
  • 10 SASE were delivered to KEK.

5
  • MODIFICATIONS OF CAPACITIVE LEVEL SENSOR SAS,
    SASE.

BINP data acquisition module.
Fogale HLS sensor at Aurora mine, March 2000,
Illinois.
6
The task was to develop hydrostatic level sensor
for slow ground motion study at different sites
for NLC project. It was decided to develop
capacitive HLS sensor. Capacitive HLS sensor
works on principal of capacitance-based
sensing. The principal is to create a capacitor,
the liquid surface being one electrode, the
sensor electrode placed in air medium upper of
water surface being the second electrode of
capacitor, the capacitance of which is measured
in order to derive the distance between these two
electrodes. One of disadvantage of existing at
that time Fogale HLS sensor was analog
representation of output signal. It took to use
long multiwire cables for data acquisition and
power supply. It was decided that electronics of
the developed sensor had to have a built-in
microcontroller to provide measurements, initial
calculation of signals and interface for digital
representation of the measuring data. The RS-485
interface was choose for the data acquisition
system.
7
  • A method used for the measurement is to convert
    variable capacitance into frequency, after that
    to convert the frequency to digital form.
  • The developed circuit uses the idea presented at
    the work of N.Toth and Gerard C.M. Meijer 1.
  • General idea of the converter is an RC-generator
    with oscillating frequency determined by its
    internal parameters. To connect by turns Cr and
    Cz one can measure 3 periods T0,T1, T2 and
    calculate Cz removing parasitic capacitance C.

8
  • T0? 11 ?sec
  • T2 gt 1118 ?sec (depending on water level in
    vessel).
  • The time value of 214 periods is measured to
    determine the all periods.
  • Measurement time for 3 periods is about 1 sec.
  • Frequency of data acquisition is no more 2 Hz.
  • Because measured Cz is normalized with help of
    reference Cr the all drifts of last one directly
    influences on measured level value. Temperature
    coefficient for used Cr is 030x10E-6 ?.
  • Another feature of the capacitive sensor is
    level noise dependence from measuring level.
    Greater distance between free water surface and
    the electrode gt less capacitance and worse ratio
    signal/noise.

9
  • There is also nonlinear dependence of measuring
    level from capacitance. So
  • each sensor needs in calibration. Linearization
    with 3-d order polynom is used.

10
Test system from 4 prototype SAS sensors and 2
Fogale HLS sensors at BINP.
11
SAS sensor at Sector 10, SLAC.
SAS electrode
12
  • The capacitive Hydrostatic Level Sensor is a
    device with two independent parts
  • Upper part is with electronics
  • lower part, usually named as vessel, filled with
    the water.
  • Lower volume was designed in four modifications
  • a)     Vessel-1 with separate outlets for
    connecting with air tubes and 12 mm water tubes
    for the systems with fully-filled lower tubes.
  • b)     Vessel-2 with 2 outlets of 22 mm diameter
    for half-filled tubes.
  • c)     Vessel-3 with 2 outlets of 50 mm diameter
    for half-filled tubes.
  • d) Vessel-4 with one outlet of 33,4 mm
    diameter for half-filled tubes.

13

a)
b)
c)
d)
14
  • The development of last modification of
    capacitive level sensor was initiated
  • by SLAC for control system of LCLS Undulator
    magnet line.

The electronics of SASE is mounted on two printed
circuit boards. The board 1 includes Lantronix
XPort 3, Power supply controller, DC-DC
converter and transformer. The board 2 includes
CgtF converter and flash microcontroller. The
board 1 is at the right side, the board 2 is at
the left one.
15
  • 3. MODIFICATIONS OF ULTRASONIC LEVEL SENSORS
    ULS, ULSE.
  • The development of ultrasonic level sensor also
    was initiated by SLAC in 2004
  • for control of LCLS Undulator magnet line.
  • A pulse-echo method is used in ultrasonic HLS for
    water level measurements.
  • The ultrasonic hydro-location is well known and
    widely distributed method
  • of distance measurements for many applications.
  • One of precise methods was described by Markus
    Schlösser and Andreas Herty
  • at their report presented at the 7th IWAA4.
    Their idea is to locate not only the
  • water surface in a vessel, but also two addition
    surfaces with calibrated distance
  • between them and at the calibrated distance to
    alignment reference target.

16
  • Principle of organizing the
  • reference surfaces at the ULSE
  • (from the M. Schlösser A. Herty report)
  • H - distance from the water surface Hw
  • to external reference surface (point) Hp

17
  • Some basic principles of ultrasonic sensor
  • Pulse-echo method for water level measurements
  • Determine the location of free water surface in a
    vessel
  • Determine the location of reference reflective
    surfaces
  • Accurately measuring the time required for a
    short ultrasonic pulse, generated by a transducer
    to travel through a thickness of water, to
    reflect from the free water surface or from the
    reflective surface, and to be returned to the
    transducer.
  • The result is expressed by the relation
  • d is the distance,
  • v is the velocity of sound waves in water,
  • t is the measured round-trip transit time.

18
  • Special transducers gt immersion transducers
  • These transducers are designed to operate in a
    liquid environment.
  • They usually have an impedance matching layer
    that helps to radiate more sound energy into the
    water and to receive reflected one.
  • Immersion transducers can be equipped within a
    planner or focused lens.
  • A focused transducer can improve sensitivity and
    axial resolution by concentrating the sound
    energy to a smaller area.
  • The sound that irradiated from a piezoelectric
    transducer does not originate from a point, but
    from all the surface of the piezoelectric
    element.
  • Round transducers are often referred to as piston
    source transducers because the sound field
    resembles a mass in front of the transducer.

19
  • For a piston transducer with
  • Diameter D,
  • Central frequency f,
  • Sound velocity V.
  • Estimation of the near/far zone transition point
    N.

Sound field pictures of the typical piezoelectric
transducer
20
  • Near zone gt Far zone
  • The ultrasonic beam is more uniform in the far
    field zone
  • The transition between these zones occurs at a
    distance
  • N ? "natural focus" of a flat (or unfocused)
    transducer.
  • This near/far distance N is very significant
    This area just beyond the near field where the
    sound wave have maximum strength.
  • Optimal measurement results will be obtained when
    reflective surfaces are close to N area
  • N lt d lt 2N
  • This requirement determines the minimal distance
    from transducer to target surfaces.

21
Unfocused immersion transducer parameters Table
1
Parameter \ Transducer Type Units V310-RU Panametric H10 KB 3 Krautkraemer H10 KB 3T General Electric (Krautkraemer )
Central frequency f MHz 5.0 10.0 7.0
Transducer diameter D mm 6.35 5.0 5.0
Beam spread angle a/2 Degree (rad) 1.365 (0.0243 ) 0.884 (0.0154) 1.263 (0.022)
near/far distance N mm 33.6 41.7 29.2
22
Time 0.2microsec/div Amplitude 0.2 V/div
Typical time response of V310-RU transducer
23
The goal of the sensor electronics is to measure
time intervals with the accuracy as fine as
possible and to calculate the resulting values.
Time diagram of one measuring cycle
24
  • Drawings of Krautkraemer and GE (former
    Krautkraemer) transducers.

25
Typical characteristics of GE H10KB3T transducer.

26
  • Real oscillograms of reflected signals.

27
  • Ultrasonic HLS prototype with Panametric
    transducer

28
Ultrasonic HLS prototype with Krautkraemer
transducer
29
Last mechanical design of ULSE.

30
  • ULSE for Montana Teach.

31
  • 5. COMPARISION OF TWO KINDS OF THE SENSORS
  • Ultrasonic sensor has a lot of benefits in
    comparison with
  • capacitive one
  • more high absolute accuracy
  • more sensitivity at more high sample rate
  • measuring data dont depend on electronics drifts
    (temperature and time) because of calibration
    capability during each measuring cycle
  • no dependence of relation signal/noise from
    measuring level
  • high linearity of transfer coefficient (output
    signal gt level)
  • no need in precise calibration only accurate
    measurement of two linear sizes for reference
    part

32
  • Test of the ULSE and SASE sensors
  • green line ULSE level, blue line SASE level,
    purple line level difference.

33
  • Noise test of the sensors
  • green line ULSE level, blue line SASE level,
    purple line level difference.

34
  • Capacitive level sensors have now only two
    benefits.
  • Capacitive sensors are more inexpensive. For
    ultrasonic sensor price of transducer forms
    considerable part of costs.
  • Capacitive sensors are working during many years.
    There is a big experience of work with them.
    Ultrasonic level sensors have not such
    experience.
  • So very important question! What is
    reliability of the ultrasonic
  • transducers? How long they can work without
    essential
  • worsening of their characteristics?! gt about
    half of used
  • transdusers of H10KB3 type have failed since end
    of 2008!
  • New modifications of the transducers with more
    protected place
  • of cover soldering will be tested.

35
  • CONCLUSION
  • The future behind Ultrasonic hydrostatic level
    sensors
  • Operating experience will grow gt about 140
    sensors were installed at Desy, more 30 at SLAC,
    3 at FNAL and 12 will be installed at South
    Dacota.
  • The technology of the transducers fabrication
    will be improved
  • The cost in process of growth of manufacture
    probably will be decreased
  • Next plans
  • Fabrication of the ultrasonic sensors with last
    modification of the Krautkraemer transducers for
    long test measurement gt order for the
    transducers is under progress
  • Upgrade of the sensor electronics for increasing
    sensitivity at least twice and for improvement
    of convenience of work gt more diagnostics and
    possibility of interfaces choice by user (Power
    over Ethernet, RS-485, Canbus).

36
  • 6. REFERENCES
  • 1 Ferry N. Toth and Gerard C.M. Meijer A
    Low-Cost, Smart Capacitive Position Sensor, /
    http//ieeexplore.ieee.org/iel1/19/5183/00199446.p
    df ./
  • 2 A. Chupyra, M. Kondaurov, A. Medvedko, S.
    Singatulin, E. Shubin SAS family of hydrostatic
    level and tilt sensors for slow ground motion
    stadies and precise alignment Proceeding of 8th
    IWAA04, Geneve, 2004.
  • 3 http//www.lantronix.com/device-networking/emb
    edded-device-servers/xport.html
  • 4 M. Shlösser, A. Herty, High precision
    accelerator alignment of large linear colliders
    vertical alignment. Proceedings of the 7th IWAA,
    Spring-8, 2002.
  • 5 A. Chupyra, G. Gusev, M. Kondaurov, A.
    Medvedko, Sh. Singatulin The ultrasonic level
    sensors for precise alignment of particle
    accelerators and storage rings Proceeding of 9th
    IWAA06, SLAC, 2006.
  • 6 A. Chupyra, G. Gusev, M. Kondaurov, A.
    Medvedko, Sh. Singatulin The ultrasonic level
    sensors for precise alignment of particle
    accelerators and storage rings Proceeding of
    10th IWAA08, KEK, 2008.

37
  • Thank you for attention!
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