FR2714562A1 - Remote interrogation of a plurality of probes. - Google Patents

Abstract

Undifferentiated probes (S1 to S4) are for example embedded in concrete. An interrogator device (DI) gradually increases the energy level of a common activation wave (HFDI) that it emits to these probes. Depending on a level test received, a probe (possibly a few) will completely return the activation wave, with a sequence of time shifts of the same predetermined quantity and of random direction. The interrogator device compares the level of the energy of the activation wave transmitted with that returned by the probe (s). If there is no variation in the average level of energy received for a predetermined time corresponding to the return of a single probe, it transmits an individual address to the probe thus activated. Ambiguities can be dealt with by moving the interrogator device.

Description

Remote interrogation of a plurality of probes.

  The invention relates to the remote interrogation between a

  interrogator device and a plurality of probes,

  when you want to operate wirelessly.

  It finds a general application in the remote interrogation of probes capable of capturing data from

  parameters of predetermined quantities: physical, chemical

  to transmit them to an interrogation device.

  remote from said probes. It finds particular application in the remote monitoring of probes embedded in a lossy environment such as concrete to know, for example, the moisture content of concrete at a point and a

given moment.

  Remote interrogation facilities are already known

  between an interrogator device and a plurality of probes.

  Generally, a chosen probe is likely to transmit

  predetermined parameter data to the

  interrogator only at the end of a recognition of an individual address previously stored in the

  probe after individualization of it.

  In practice, the individualization of the probes is performed during a programming operation in which each probe is presented in front of a programming device which

  introduces an individual address.

  Such programming presents a heavy maintenance since it requires the passage of all the probes in front of

the programming device.

  The invention provides a solution to this problem.

  A first object of the invention is to provide an individual

  probes in which the programming of the address

  individual is easy and light implementation.

  Another object of the invention is to provide probes

  likely to respond only when asked.

  Yet another object of the invention is to provide probes

  able to be active without internal power.

  In the first place, the subject of the present invention is a method of remote interrogation between a device

  interrogator and a plurality of probes of the type described above.

before.

  According to an important characteristic of the invention, the indi-

  A probe's refresh includes the following steps:

  - 1) on the interrogation device, gradually increase

  the energy level of a common activation wave and transmit said common activation wave simultaneously to the probes; - 2) on one or more probes, at the end of a test involving the level of the activation wave thus received, totally returning the activation wave with a sequence of time offsets of the same predetermined quantity and random sense; - 3) at the interrogator device, comparing the energy level of the transmitted activation wave with that returned by the probe or probes; - 4) in case of non-variation of the average energy level received during a predetermined time corresponding to the return of a single probe, transmit the individual address to the probe thus activated and store said address in the probe in order to

  to individualize it, whereas in case of corresponding variation

  the simultaneous return of several probes, move the

  interrogator device and return to step 1).

  At low levels of radiated energy, the probes are approached and / or favorably oriented; at high levels, one reaches the most distant probes, or the

less well oriented.

  According to another aspect of the invention, the recognition of an individualized probe comprises the following steps: i) at the interrogator device, transmitting the common activation wave modulated by the individual address of the probe to be recognized; ii) at each probe, demodulating the common activation wave thus received to extract the modulating individual address; iii) compare the individual address thus extracted with the individual address previously stored in the probe after individualization thereof, and in case of identity proceed to the transmission of parameter data from

  from the probe thus recognized to the interrogator device.

  Advantageously, the transmission of the parameter data of an individualized and recognized probe to the interrogator device comprises the modulation of the activation wave

  common by the parameter data to be transmitted.

  Secondly, the present invention relates to a remote interrogation facility between an interrogation device and a plurality of probes for the implementation of

  of the process mentioned above.

  Thirdly, the subject of the present invention is a probe disposed at a location remote from an interrogation device capable of remotely activating said probe by transmission of a common activation wave, the probe thus activated being capable of transmitting predetermined parameter data to the interrogator device upon recognition of an individual address

  previously stored in said probe after individualizing

  of it. According to another important characteristic of the invention, the probe comprises:

  receiver-probe means for receiving the activation wave

  common opinion emanating from the interrogating

  level of energy is likely to be increased gradually

  tively; test probe means for testing the level of the activation wave thus received; means of return-probe capable according to the result of this test, to totally return the common activation wave with a sequence of time offsets of the same

  predetermined quantity and random direction, in order to indi-

  quer the interrogator device that only said probe returns the activation wave; storage-probe means for storing the address

  of the probe transmitted by the device

  when a single probe returns the common activity wave. Preferably, the return-probe means comprise:

  an oscillator capable of generating a low frequency signal

  this; and a comparator whose input receives a low level noise signal and whose output delivers an output signal sampled at the frequency of the low frequency signal to form the sequence of time offsets of the same quantity and

of random meaning.

  Advantageously, the probe further comprises: demodulating means for demodulating the activation wave modulated by the individual address of the probe to extract said individual modulating address; - Probe processing means adapted to compare the individual address thus extracted with the individual address previously stored in the probe after individualization

  of the latter, and in case of identity, the said means of

  ment-probe being able to control the transmission of

  parameter data from the probe.

  According to one embodiment of the invention, the means

  receiver-probes comprise at least one antenna.

  According to another embodiment of the invention, the probe has a parallelepipedal general shape and the means

  receiver-probes comprise first and second antennas

  nes-loops arranged respectively on first and

  second adjacent faces of the parallelepiped.

  Alternatively, the probe is of planar shape having a face

  upper and lower face, and the receiving means

  Probe-sensors comprise first and second wire antennas arranged perpendicular to each other on the same or a respective face of the probe. In another variant, the spherical-shaped probe, and the receiver-probe means comprise first and second wire antennas arranged perpendicularly with respect to each other, each antenna comprising one end

  lodged in the sphere and a free end.

  Advantageously, the probe-processing means comprise means for transforming the common activation wave thus received into a supply voltage capable of supplying power.

said probe.

  According to another aspect of the invention, the common activation wave is a microwave signal of the order of 500 MHz to

2 GHz.

  According to a particular application of the invention, the plurality of probes is embedded in a medium at a loss such that

concrete.

  Fourthly, the subject of the present invention is a remote interrogator device of a plurality of probes, said device being capable of remotely activating a selected probe by transmission of a wave.

  common to the probes, said probe being susceptible to

  to transmit predetermined parameter data

  to the interrogator device at the end of a recognition

  of an individual address previously stored in

  said probe after individualization thereof.

  According to another important characteristic of the invention, the interrogator device comprises: transmission-interrogator means for transmitting a common activation wave simultaneously to said probes, the energy level of the common activation wave being able to to be gradually increased; interrogation-processing means capable of comparing the energy level of the activation wave thus transmitted

  with that returned by the probe (s), and in case of

  tite corresponding to the return of a single probe, the transmission-interrogator means being capable of transmitting the individual address to the probe thus activated for the purpose of individualizing it.

  According to another aspect of the invention, the device

  The controller further comprises modulator-interrogator means

  able to modulate the activation wave by the individual address

  dual probe to individualize and / or recognize.

  Preferably, the interrogator device comprises demodulator-interrogator means adapted to demodulate the activation wave modulated by the parameter data in order to

treat them.

  Other features and advantages of the invention

  will appear in the light of the detailed description below.

  after and appended drawings in which: - Figure 1 is a block diagram of the remote interrogation system according to the invention;

  FIG. 2 schematically represents the essential means

  and constituting a probe according to the invention;

  FIG. 3 is a flowchart illustrating the individualization

  a probe according to the invention; and

  FIG. 4 is a flowchart illustrating the recognition of

  sance of an individualized probe according to the invention.

  In FIG. 1, an interrogator device DI is capable of

  to remotely interrogate a plurality of individual probes

  dualised in S1 to S4. The device DI remotely activates a probe selected by transmitting a common HFDI activation wave to the probes. The probe is activated after a test involving the energy level of the activation wave received. After activation, it transmits predetermined parameter data to the interrogator device. In known manner, the transmission of the parameter data is carried out after a recognition of an individual address previously stored in said probe after

individualization of it.

  For reasons of safety and cost, it is planned, according to

  the invention, to individualize the probes in a single step.

  programming step of the individual address of each probe. This operation takes place for example when the probes are embedded in the concrete, as part of a monitoring application of the moisture content and the constraints of said concrete. Those skilled in the art know that remote interrogation through a medium with a relatively high attenuation (for example a lossy medium such as concrete) can cause activation and response of several probes simultaneously, although these activation simultaneous response and response are more unlikely than in

nothing.

  To not program the same individual address to two different probes, an early solution consists in moving the interrogator device (more precisely its ADI antenna). Indeed, the energy level of the activation wave varies as a function of the distance separating the device

interrogator and the probes.

  However, it remains to detect that there are two probes in train

to answer simultaneously.

  A solution for detecting the simultaneous response of two probes consists in introducing into the responses of the probes a message making it possible to inform the interrogating device

  a simultaneous response of probes.

  In practice, it is intended according to the invention to totally return the received activation wave with a sequence of

  time offsets of the same quantity and random direction.

  That is, once activated, the probe responds by

  fully seeing the incident energy transported by the common activation wave to transmit a binary "0" or "1" with further a sequence of time offsets

  of the same quantity and random sense.

  For example, if the common activation wave, of a level sufficient to activate the interrogated probe, first represents a binary "1", said probe returns in full this

  "1" by temporally shifting it by a predetermined amount

  born for example r / 3 and in the positive direction. Then, if the common activation wave, of a level sufficient to activate the interrogated probe, represents another binary "1", said probe returns this "1" integrally by always shifting it from

  n / 3 either in the positive direction or in the negative direction.

  As will be discussed in more detail below, it is this

  sequence of time offsets of the same predetermined quantity

  born and of random meaning which is the solution according to the invention.

  to the problem posed by the simultaneous response of two probes. Reference is now made to FIG. 3, which illustrates in detail the individualization of a probe according to the invention. During step 10, at the interrogator device DI, a common HFDI activation wave is transmitted simultaneously to the probes S1 to S4, the energy level of the wave being variable. During the steps 12 for the probe S1 or 14 for the probe S4, after a test 13 or 17 involving the level of the activation wave thus received 11 or 15, the wave of activation 19 or 21 with a sequence of time offsets all of the same predetermined amount and meaning

  which will be described in more detail below.

  In step 20, at the interrogator device, the energy level of the activation wave is compared.

  transmitted with that returned by the probe or Si or S4.

  In case of non-variation of the average energy level received during a predetermined time (step 22) corresponding to the return of a single probe, for example here the probe Si, it is intended to transmit the individual address to the probe S1 activated and to store, at the level of this one, the address

  thus transmitted with a view to individualizing it (step 26).

  For example, the predetermined duration during which the analysis of the average energy level received is equal to a plurality of elementary cycles of the low signal.

  frequency F which will be described in more detail below.

  Advantageously, it is provided, at the level of the probe S1, to acknowledge reception of the address thus transmitted and to inhibit

  the means generating the sequence of time offsets.

  In case of variation (step 30), corresponding to the simultaneous return of several probes, it is planned to move the

  interrogator device and return to step 10.

  In a particular, but not limiting, application of the invention, in which the probes are sensors embedded in the concrete to capture data of parameters such as the humidity and the stress of the concrete, the individualization

  as described above has the advantage of allowing the use

  all identical probes, and to drown them in the concrete during the stages of construction of a building by

example.

  With such an individualization, it is no longer necessary to

  present all the probes before a program device

  this allows for very light maintenance

said probes.

  It is recalled that, in known manner, a chosen probe, for example the probe S4, is capable of transmitting predetermined parameter data to the interrogator device DI only after recognition of an individual address previously stored in said

  probe If after individualization of it.

  Reference is now made to Figure 4 which illustrates the

  recognition of the probes after individualization of those--

  this. In step 100, the HFDI common activation wave modulated by the individual address of the probe to be recognized is transmitted. The probes S1 to S4 receive this activation wave as well

  modulated and demodulates it to extract the individual address

  dual modulating (step 102 for probe S1 and step 104

for the S4 probe).

  At each probe (S1 to S4), it is planned to compare

  the individual address thus extracted and the individual address

  duel previously stored after individualization of

each probe (steps 106 and 108).

  In case of identity (steps 110 or 112), the parameter data picked up by the probe (steps 114 or 116) are transmitted. Advantageously, the transmission of the parameter data of an individualized and recognized probe consists in modulating

  the HFDI activation wave which serves both for the individual

  and this time it is modulated by the data of parameters to transmit the wave

thus individualized and recognized.

  With reference to FIG. 2, a probe according to the invention comprises receiver-probe means for receiving the HFDI activation wave emanating from the interrogator device DI. These receiver-probe means are advantageously means

  forming an antenna 200. For example in the context of an application

  In the case of concrete, in which the probes are generally parallelepipedal in shape, the probe receiving means 200 consist of first and second loop antennas respectively arranged on first and second adjacent faces.

  said parallelepiped (not shown).

  For example, the parallelepiped forming a sensor has a size

about 2 cm on the side.

  The diameter of each antenna loop is of the order of 1 cm. It should be noted that with an arrangement of loop antennas on adjacent faces, the probe is capable of

  receive the HFDI activation wave along two polar axes

  perpendicular, which allows for better reception

  tion and processing of the activation wave whatever

the orientation of the probe.

  Means for transforming the activation wave are provided for transforming the common activation wave as well as

  received HFDI at a supply voltage capable of supplying

  Maintain the different constituent elements of the probe

  when it is questioned by the interrogation

  tor. In a first variant, the probe is of flat shape and has an upper face and a lower face. Under these conditions, the receiver-probe means comprise

  first and second wire antennas disposed perpendicularly

  stretching relative to each other on the same face or on

a respective face.

  In a second variant, the probe is of spherical shape, the receiver-probe means comprise first and second wire antennas arranged perpendicularly to one another.

  relative to each other, each antenna comprising one end

  housed in the sphere and a free end.

  In known manner, the transformation means are constituted

  killed by a transformer 202, filtering means 204 and

  a capacity 206 capable of storing said supply voltage

  mentation thus obtained by the transformation means 202.

  The capacity 206 has a value of, for example, 33 nF.

  The antenna or antennas of the probe and the transformer are for example made according to a homogeneous technology for example copper / ceramic. The probe is completed by test-probe means capable of testing the level of the activation wave thus received. These test means 210 perform a thresholding of the level of the activation wave received. Means of regulating

  power 220 regulate the supply voltage of the probe.

  They include for example a converter of the "STEP DOWN" type sold by the American company LINEAR TECHNOLOGY under the reference LT 1073. This converter is for example

made of silicon.

  The test means 210 comprise, for example, a voltage comparator with a chosen threshold level, for example 10 mV

  when the common activation wave is a hyperfrequency signal

  frequency of the order of 500 MHz to 2 GHz and that the supply current thus obtained by the reception

  and the transformation of the HFDI signal is of the order of 500 pA.

  For example, the test means 210 are made of silicon by the American company LINEAR TECHNOLOGY under the reference

LT 1073.

  In particular to implement steps 19 and 21 described above with reference to FIG. 3, the probe comprises return means 230, able to totally return the received activation wave with a sequence of time offsets.

  of the same predetermined quantity and random direction.

  It is recalled that this sequence of time offsets of the same predetermined quantity and random direction is the solution according to the invention to the problem posed by the answer.

simultaneous two probes.

  For example, the generating means of the sequence of temporal shifts of random direction comprise: an oscillator generating a low frequency signal F; and a comparator whose input receives a low-level noise signal and whose output delivers an output signal sampled at the frequency F to form a sequence of time offsets of the same quantity, for example between n / 6 and r / 3 and of random meaning. It should be noted that the sampling frequency F is not necessarily precise insofar as it is not necessary to synchronize it, for example with that of the others.

probes.

  Associated with the return-probe means 230, there is provided processing means 240 for storing the individual address of the probe transmitted by the interrogator device.

  presence of a single return of the activation wave.

  These storage means consist, for example, of shift registers associated with programmable memory means of the EEPROM type or non-programmable type of type.

fuse.

  Modulator / demodulator-probe means complete the return means 230 to demodulate the activation wave modulated by the individual address of the probe in order to

  extracting said individual address and storing it.

  Moreover, the processing-probe means 240 are able to compare the individual address thus extracted with the individual address previously stored in the probe after individualization thereof. In case of identity between the individual address thus extracted and the address

  previously memorized, the means of

  are able to activate the transducer part 250.

  This transducer portion 250 is for example constituted by a piezoresistive transducer such as that sold by SIEMENS under the reference KPY 57A and capable of capturing at least one physical parameter PP. The transducer delivers an analog signal representing the

physical parameter thus captured.

  In the concrete application mentioned above, seven sensors may be provided, with: - 3 stress sensors having orthogonal main axes two by two; - 2 inclination sensors, which can be reduced

  to the antenna orientation axes because the geographical latitude

phic is known;

  - 2 sensors respectively for temperature and humidity

you.

  Analog-to-digital converting means 260 converts

  weave the analog signal into a digital signal, itself

  converted into digital coding for example in coding Manches-

b.

  The modulation-demodulation means 230 of the probe then modulate the activation wave by the digital signal

thus obtained.

  Advantageously, the time shift sequence generating means can use the comparator of

  test means 210 for generating said sequence.

  In practice, the modulator / demodulator means associated with the

  sensor return means 230 are made of silicon exclusively

  or in AsGa exclusively or in both these materials.

less in part.

  For its part, the interrogator device DI comprises TDI modulator / demodulator means (FIG. 1) capable of modulating the activation wave by the individual address to be transmitted and to demodulate the activation wave modulated by

  the parameter data for processing.

Claims (19)

claims   1. Method of remote interrogation between a device   terrocator (DI) and a plurality of probes (S1 to S4), wherein a selected probe is capable of transmitting predetermined parameter data to the interrogator device upon recognition of an individual address previously stored in said probe after   individualization thereof, characterized in that the indica-   Previewing the probe includes the following steps:   1) on the interrogator device (DI), increase   gressively the energy level of a common activation wave (HFDI) and transmit said common activation wave simultaneously to the probes,   2) on one or more probes, after an implicit test   as for the level of the activation wave thus received, totally return the activation wave with a sequence of time offsets of the same predetermined quantity and of random direction, 3) at the interrogator device, compare the level of the energy of the activation wave transmitted with that returned by the probe or probes, 4) in case of nonvariation of the average energy level received for a predetermined duration corresponding to the return of a single probe, transmit the address to the probe thus activated and store said address in the probe in order to   to individualize it, whereas in case of corresponding variation   the simultaneous return of several probes, move the   interrogator device and return to step 1).   2. Method according to claim 1, characterized in that the recognition of an individualized probe comprises the following steps: i) at the interrogator device, transmit the activation wave modulated by the individual address of the probe to be recognized ii) at each probe, demodulate the common activation wave thus received to extract the individual modulating address, iii) compare the individual address thus extracted with the individual address stored in the individualized probe, and case of identity, proceed to the transmission of the data of   parameters from the probe thus recognized towards the interrogator.   3. Method according to claim 1 or claim 2,   characterized in that the transmission of the para-   meter of an individualized and recognized probe towards the   interrogator includes the modulation of the activation wave   tion by the parameter data to be transmitted.   4. Remote interrogation facility between a device   interrogation station and a plurality of probes for   method according to one of claims 1 to 3.   5. Probe disposed at a location remote from an interrogation device capable of remotely activating said probe by transmission of a common activation wave, the probe being capable of transmitting parameter data   to the interrogating device at the end of a recon-   birth of an individual address previously stored in said probe after individualization thereof, characterized in that it comprises: receiver-probe means (200) for receiving the common activation wave emanating from the interrogator device of which   the energy level is likely to be increased progressively   - test-probe means (210) for testing the level of the activation wave thus received, - probe-return means (230) capable of   result of this test, to totally return the wave of   with a sequence of time offsets of the same predetermined amount and random direction to indicate to the interrogator that only said probe returns the activation wave, - storage-probe means (240) for storing the 'address   of the probe transmitted by the inter-   roger when a single probe returns the common activation wave. 6. Probe according to claim 5, characterized in that the return-probe means comprise: an oscillator capable of generating a low frequency signal (F);   a comparator whose input receives a low-level noise signal and whose output delivers an output signal sampled at the frequency of the low-frequency signal (F) to form the sequence of time offsets of the same   predetermined quantity and random direction.   7. Probe according to claim 5 or claim 6, characterized in that it further comprises: demodulator-probe means (230) for demodulating the activation wave modulated by the individual address of the probe to extracting said modulating single address, and - probe-processing means (240) suitable for comparing   the individual address thus extracted with the address   previously stored in the probe after indi-   vidualisation of the latter, and in case of identity to control   parameter data from the probe.   Probe according to one of Claims 5 to 7, characterized   in that the receiver-probe means (200) comprise at least less an antenna.   Probe according to one of Claims 5 to 8, characterized   in that it is of parallelepipedal general shape, and in that the receiver-probe means comprise first and second loop antennas disposed respectively on first and second adjacent faces of the parallelepiped.   10. Probe according to one of Claims 5 to 8, characterized   in that it is flat in shape with a superior surface   upper and lower face, and in that the receiver-probe means comprise first and second wire antennas arranged perpendicularly with respect to   the other on the same face or on a respective face.   11. Probe according to one of Claims 5 to 8, characterized   in that it is spherical in shape, and in that the receiver-wave means comprise first and second wire antennas arranged perpendicularly with respect to each other, each antenna comprising an end housed in   the sphere and a free end.   Probe according to one of Claims 5 to 11, characterized   in that the probe-processing means comprise means (202, 204) for transforming the activation wave into a supply voltage and storage means (206).   adapted to charge said supply voltage.   Probe according to one of Claims 5 to 12, characterized   in that the activation wave (HFDI) is a hyperfrequency signal   accordingly. 14. Probe according to claim 5 to 13, characterized in that the frequency of the activation wave is of the order of 500 MHz at 2 GHz.   15. Probe according to one of claims 5 to 14, characterized   in that it is drowned in a medium of losses.   Probe according to claim 15, characterized in that the middle is concrete.   17. Device remote interrogator of a plurality of probes, said device being capable of remotely activating a selected probe by transmission of a wave   common to the probes, said probe being susceptible to   to transmit predetermined parameter data   to the interrogator device at the end of a recognition   sance of an individual address previously stored in said probe after individualization thereof, characterized in that it comprises: transmission-interrogator means for transmitting the common activation wave simultaneously to said probes, the energy level the common activation wave being capable of being gradually increased; interrogator-processing means adapted to process the parameter data thus received, characterized in that it furthermore comprises:   the interrogator-processing means are suitable for   countering the energy level of the common activation wave thus transmitted with that returned by the probe or probes, and in case of nonvariation of the average energy level received for a predetermined duration corresponding to the return of a   probe, the probe-processing means being capable of   transmit the individual address to the probe   thus activated in order to individualize it.   Interrogator device according to claim 17,   characterized in that it further comprises modulatable means   interrogators capable of modulating the activation wave   by the individual address of the probe to individual to recognize it.   19. Device according to one of claims 17 and 18,   characterized in that it further comprises means for demodulating   latters-interrogator able to demodulate the activation wave   modulated by the parameter data for processing.