(19)
(11) EP 1 272 990 B1

(12) EUROPEAN PATENT SPECIFICATION

(45) Mention of the grant of the patent:
09.06.2004 Bulletin 2004/24

(21) Application number: 01919697.1

(22) Date of filing: 10.04.2001
(51) International Patent Classification (IPC)7G08B 5/38
(86) International application number:
PCT/IB2001/000592
(87) International publication number:
WO 2001/078026 (18.10.2001 Gazette 2001/42)

(54)

SECURITY DEVICE WITH BIDIRECTIONAL COMMUNICATION

SICHERHEITSVORRICHTUNG MIT ZWEIRICHTUNGSÜBERWACHUNG

DISPOSITIF DE SECURITE A COMMUNICATION BIDIRECTIONNELLE


(84) Designated Contracting States:
AT BE CH CY DE DK ES FI FR GB GR IE IT LI LU MC NL PT SE TR

(30) Priority: 11.04.2000 IT PD000084

(43) Date of publication of application:
08.01.2003 Bulletin 2003/02

(73) Proprietor: System Sensor Division Of Pittway Corporation
St. Charles, IL 60174 (US)

(72) Inventor:
  • ZAMBON, Cristiano
    I-34100 Trieste (IT)

(74) Representative: Modiano, Guido, Dr.-Ing. et al
Modiano & Associati SpA Via Meravigli, 16
20123 Milano
20123 Milano (IT)


(56) References cited: : 
EP-A- 0 974 947
DE-A- 19 754 222
FR-A- 2 672 145
DE-A- 19 744 210
FR-A- 2 643 210
   
       
    Note: Within nine months from the publication of the mention of the grant of the European patent, any person may give notice to the European Patent Office of opposition to the European patent granted. Notice of opposition shall be filed in a written reasoned statement. It shall not be deemed to have been filed until the opposition fee has been paid. (Art. 99(1) European Patent Convention).


    Description

    TECHNICAL FIELD



    [0001] The present invention relates to a security device with bidirectional communication.

    [0002] More particularly, the invention relates to a security device capable of communicating both with a control unit and directly with a user.

    BACKGROUND ART



    [0003] It is known that most currently commercially available security systems generally have the following operating criterion.

    [0004] A control unit manages peripheral units (usually sensors or actuators) by means of a two-wire line or by means of radio systems.

    [0005] More recent security systems in fact allow to address (via hardware or software) the peripheral units. In this case, the control unit determines whether, according to the control program, the environmental parameters detected by the sensors correspond or not to an alarm condition and the control unit therefore activates, if appropriate, the corresponding alarm procedures, such as visual or acoustic signals or the like.

    [0006] Usually, communication between the control units and the peripheral units is entrusted to proprietary protocols which are compatible with the power supply requirements, if any, of the sensors and most of all with the requirements of sturdiness and immunity to noise which are typical of a security system.

    [0007] Clearly, the possibility of communication between the control unit and the peripheral units allows higher flexibility and maintenance capability of the security system and ultimately gives an added value to the system as a whole.

    [0008] However, communication between the control unit and the peripheral units is entrusted exclusively to a two-wire line, as mentioned, such as for example a bus, or to radio systems.

    [0009] In practice, the only option is to act from the control unit toward the peripheral units and it is not possible to act directly on said peripheral units, thus bypassing the control unit.

    DISCLOSURE OF THE INVENTION



    [0010] The aim of the present invention is to provide a security device with bidirectional communication capability which allows users to act directly on the peripheral units in addition to acting on them from the control unit.

    [0011] Within this aim, an object of the present invention is to provide a security device with bidirectional communication capability which allows to use the normal visual indication device of a peripheral unit for interacting with said peripheral unit.

    [0012] Another object of the present invention is to provide a security device with bidirectional communication capability which allows to interact with a peripheral unit directly at the site where said peripheral unit is installed.

    [0013] Another object of the present invention is to provide a security device with bidirectional communication capability which is highly reliable, relatively simple to manufacture and at competitive costs.

    [0014] This aim and these and other objects which will become better apparent hereinafter are achieved by a security device with bidirectional communication capability, comprising logic control means which are adapted to control at least one LED for indicating the operating status of a peripheral unit in which said security device is accommodated, characterized in that it comprises at least one resistor which is connected in parallel to said at least one LED, for converting into voltage light energy received from said at least one LED, said LED being connected to means for evaluating said voltage generated thereby, said means being in turn connected to said logic control means.

    BRIEF DESCRIPTION OF THE DRAWINGS



    [0015] Further characteristics and advantages of the invention will become better apparent from the description of preferred but not exclusive embodiments of the device according to the present invention, illustrated only by way of non-limitative example in the accompanying drawings, wherein:

    Figure 1 is a circuit diagram of the security device according to the present invention;

    Figure 2 is a block diagram of the interaction between a peripheral unit which accommodates the security device according to the present invention and an external unit;

    Figure 3 is a block diagram of a second embodiment of the interaction between a peripheral unit in which the device according to the invention is incorporated and an external unit.


    WAYS OF CARRYING OUT THE INVENTION



    [0016] With reference to the figures, and initially with reference to Figure 1, the security device according to the present invention, generally designated by the reference numeral 10, comprises logic control means 12 which are connected to memory means 13 and to management means 14 which are adapted to manage the operation of at least one LED.

    [0017] The logic control means 12 are connected to a power buffer 15, which is adapted to drive at least one LED 16 which provides an indication of the operating status of the peripheral unit in which the security device is accommodated.

    [0018] The peripheral unit can be for example a sensor or an actuator.

    [0019] A resistor 17 is interposed between the output of the power buffer 15 and the LED 16 and allows to reduce the current in output from the power buffer 15 for supplying power to the LED 16.

    [0020] The particularity of the invention is that the LED 16 is used not only as a device for signaling the operating status of the peripheral unit but also in reverse, as explained in detail hereinafter.

    [0021] The LED is in fact usually a device designed to convert electric energy into light energy, with a photoelectric effect, in order to provide in this case an indication of the operating status of the peripheral unit.

    [0022] In the device according to the invention, the LED also acts as a photodiode, i.e., it performs the opposite conversion, from light energy to electric energy.

    [0023] It is in fact known that a p-n junction, if crossed by a current, can emit photons whose energy is linked to the type of doping of the junction. Likewise, if a p-n junction is illuminated by photons of the appropriate energy, hole-electron pairs are produced which, by flowing through the junction, generate a current which is proportional to the intensity of the incident light.

    [0024] Obviously, the efficiency of quantum conversion, i.e., the amount of current that can be generated in relation to a given incident light energy, is very low for an LED, since the LED is an optoelectronic device designed and optimized for the opposite conversion, i.e., from electric energy to light energy.

    [0025] However, the photocurrent that is obtained from the LED if it is illuminated appropriately with a light source tuned to the same wavelength as the LED is capable of providing a signal whose amplitude is sufficient to allow processing by an amplifier-comparator block.

    [0026] Therefore, by modulating the signal of the illuminating source with a train of pulses, it is possible to reconstruct said signal at the output of the signal processing system.

    [0027] In this manner, an additional semiduplex communication channel is available which, in addition to the conventional two-wire line that connects the peripheral unit to a control unit, allows communication with said control unit.

    [0028] In practice, the security device 10 according to the invention therefore comprises an additional resistor 18 which is connected in parallel to the LED 16 so as to convert into voltage the current generated when the LED 16 acts as a receiver.

    [0029] The number of resistors 18 is of course equal to the number of LEDs 16 provided in output to the peripheral unit that accommodates the security device 10.

    [0030] Switching means 19 are further provided in order to connect the voltage signal produced by the LED 16 when it is lit to comparator means 20 which are adapted to compare said voltage signal with a comparison voltage 21, so as to generate a signal 22 which represents the difference between the voltage detected by the LED 16 and the reference voltage 21 sent by the logic control means 12.

    [0031] The amplifier-comparator 20 further allows to amplify said voltage difference signal.

    [0032] The switching means 19 are therefore normally operatively open when the LED 16 acts as an optoelectronic device for indicating the operating status of the peripheral unit, i.e., when it provides an external indication of the operation of said peripheral unit.

    [0033] Vice versa, when the LED 16 acts as a receiving element the switching means 19 are closed, activating the path that connects the LED 16 to the amplifier-comparator means 20, shifting the power buffer 15 to a high-impedance state.

    [0034] Substantially, a second communication channel, this time of the optical type, is created alongside the normal two-wire or radio communication channel that connects the peripheral unit to the control unit (which is not shown in the figures).

    [0035] Figure 2 is a schematic view of a peripheral unit 30 which internally accommodates the security device 10 according to the present invention.

    [0036] The reference numeral 16 designates, in this case, again the LED for external indication of the operating status of said peripheral unit.

    [0037] In order to illuminate the LED 16 from outside and thus make it act as a receiving element, a first embodiment provides for an external unit 31 which is appropriately provided with an optical input and output device.

    [0038] In the first embodiment shown in Figure 2, the optical input and output device comprises at least one ultrabright LED 32 which is arranged to the side of a photodiode or phototransistor 33 so that the LED 32 is capable of illuminating the LED 16 of the peripheral unit 30 and thus make it act as a receiving element.

    [0039] At the same time, the photodiode 33 of the external unit 31 allows to receive light information from the LED 16 of the peripheral unit 30.

    [0040] The external unit 31 is appropriately interfaced mechanically with the peripheral unit 30 so as to keep the optical input and output device 32, 33 at a short distance from the LED 16.

    [0041] In a second embodiment, shown in Figure 3, the peripheral unit 30 is again interfaced with the external unit 31, but in this case the optical input-output device is constituted by at least one optical fiber 34.

    [0042] This last solution allows the operator to program, test and obtain data from peripheral units even if they are located in difficult and awkward positions, without having to remove the peripheral unit from its support.

    [0043] In practice it has been observed that the security device according to the invention allows to obtain an additional bidirectional communication channel which is added alongside the normal communication channel provided between a peripheral unit and a control unit meant to control the operation of said peripheral unit.

    [0044] Moreover, the "optical" channel thus created allows the operator to act directly on the peripheral units in the operating environment, i.e., at the installation site, with consequent advantages in terms of operation and maintenance.

    [0045] Moreover, the security device according to the invention can be easily integrated in a control unit of a commercially known type with a minimal increase in its dimensions.

    [0046] The device thus conceived is susceptible of numerous modifications and variations, all of which are within the scope of the inventive concept; all the details may further be replaced with other technically equivalent elements.

    [0047] In practice, the materials employed, so long as they are compatible with the specific use, as well as the dimensions, may be any according to requirements and to the state of the art.


    Claims

    1. A security device with bidirectional communication capability, comprising logic control means which are adapted to control at least one LED for indicating the operating status of a peripheral unit in which said security device is accommodated, characterized in that it comprises at least one resistor which is connected in parallel to said at least one LED, for converting into voltage light energy received from said at least one LED, said LED being connected to means for evaluating said voltage generated thereby, said means being in turn connected to said logic control means, said voltage being indicative of the response of said security device to a signal sent from an external unit.
     
    2. The device according to claim 1, characterized in that said means for evaluating said voltage generated by said at least one LED comprise amplifier and comparator means adapted to compare said voltage generated by said LED with the reference voltage generated by said logic control means, in order to obtain a voltage difference signal which is adapted to be sent to said logic control means.
     
    3. The device according to claims 1 and 2, characterized in that said amplifier and comparator means are connected to said at least one LED by virtue of switching means.
     
    4. The device according to one or more of the preceding claims, characterized in that said logic control means drive said at least one LED by means of a power buffer.
     
    5. The device according to one or more of the preceding claims, characterized in that at least one resistor is interposed between said power buffer and said at least one LED and is connected in series to said at least one LED.
     
    6. The device according to one or more of the preceding claims, characterized in that it comprises an external unit which is adapted to interface with said peripheral unit that accommodates said security device, said external unit being provided with an optical input and output device adapted to communicate with said at least one LED.
     
    7. The device according to claim 6, characterized in that said optical input and output device of said external unit comprises at least one ultrabright LED and at least one photodiode or phototransistor.
     
    8. The device according to claim 6, characterized in that said optical input and output device of said external unit comprises at least one optical fiber.
     
    9. The device according to one or more of the preceding claims, characterized in that said logic control means are connected to memory means and to means for managing said at least one LED.
     
    10. An external unit for transmitting an optical signal to an LED of a peripheral unit provided with a security device according to one or more of the preceding claims, characterized in that it comprises an optical input and output device which is adapted to communicate bidirectionally with said at least one LED of said peripheral unit.
     
    11. The external unit according to claim 10, characterized in that said optical input and output device comprises at least one ultrabright LED and at least one photodiode or phototransistor.
     
    12. The external unit according to claim 10, characterized in that said optical input and output device comprises at least one optical fiber.
     
    13. The external unit according to one or more of claims 10 to 12, characterized in that it is interfaced mechanically with said peripheral unit, so as to keep said optical input and output device in a position in which it faces said at least one LED of said peripheral unit.
     
    14. A method for providing an optical communication channel between a security device of a peripheral unit and an external control unit, characterized in that it comprises the steps of

    using at least one LED of said security device of said peripheral unit to receive an optical signal sent by said external unit, said LED indicating the operating status of said peripheral unit;

    converting said optical signal received by said at least one LED into a voltage signal, using a resistor connected in parallel to said at least one LED;

    evaluating said voltage signal by way of evaluating means which are connected to logic control means adapted to control said at least one LED, said method being performed in the environment where said peripheral unit is installed.


     
    15. The method according to claim 14, characterized in that the step of evaluating said voltage signal comprises the amplification and comparison of said voltage signal with a reference voltage sent by said logic control means.
     
    16. The method according to claim 14, characterized in that it comprises the step of connecting said at least one LED with means for evaluating said voltage signal by way of switching means.
     


    Ansprüche

    1. Sicherheitsvorrichtung mit bidirektionaler Kommunikationsmöglichkeit, welche Logiksteuerungen umfasst, die so ausgelegt sind, um mindestens eine LED-Funktion für das Anzeigen des Betriebsstatus einer peripheren Einheit zu steuern, in welcher die Sicherheitsvorrichtung untergebracht ist;
       dadurch gekennzeichnet, dass sie mindestens einen elektrischen Widerstand aufweist, der mit der mindestens einen LED-Funktion für das Umwandeln in eine Lichtspannungsenergie in Reihe geschaltet ist, die von der mindestens einen LED-Funktion erhalten wird, wobei die LED-Funktion mit Vorrichtungen für das Auswerten der dadurch generierten Spannung verbunden ist, und wobei diese Vorrichtungen wiederum mit Logiksteuerungen verbunden sind, wobei die generierte Spannung die Antwort der Sicherungsvorrichtung auf ein Signal hin anzeigt, das von einer Außeneinheit gesendet worden ist.
     
    2. Sicherheitsvorrichtung nach Anspruch 1, dadurch gekennzeichnet, dass eine Vorrichtung für das Auswerten der Spannung, die von mindestens einer LED-Funktion generiert worden ist, Verstärker- und Komparatoreinrichtungen aufweist, die so ausgelegt sind, um die von der LED-Funktion generierte Spannung mit der von den Logiksteuerungsvorrichtungen generierten Referenzspannung zu vergleichen, um dabei ein Spannungsdifferenzsignal zu erhalten, das zum Senden an die Logiksteuerungsvorrichtungen ausgelegt wird.
     
    3. Sicherheitsvorrichtung nach Anspruch 1 und 2, dadurch gekennzeichnet, dass die Verstärker- und Komparatoreinrichtungen mit mindestens einer LED-Funktion aufgrund von Schaltmittel verbunden sind.
     
    4. Sicherheitsvorrichtung nach einem oder mehreren der voranstehenden Ansprüche, dadurch gekennzeichnet, dass durch die Logiksteuerungsvorrichtungen mindestens eine LED-Funktion mittels eines Energiebuffers angetrieben wird.
     
    5. Sicherheitsvorrichtung nach einem oder mehreren der voranstehenden Ansprüche, dadurch gekennzeichnet, dass mindestens ein elektrischer Widerstand zwischen dem Energiebuffer und der mindestens einen LED-Funktion angeordnet ist, und der mit der zumindest einen LED-Funktion in Reihe geschaltet ist.
     
    6. Sicherheitsvorrichtung nach einem oder mehreren der voranstehenden Ansprüche, dadurch gekennzeichnet, dass sie eine Außeneinheit umfasst, welche so ausgelegt ist, dass diese mit der peripheren Einheit mit einer elektronischen Anpassschaltung gekoppelt ist, in welcher die Sicherheitsvorrichtung untergebracht ist, wobei die Außeneinheit mit einer optischen Eingangs- und Ausgangsvorrichtung ausgestattet ist, die so ausgelegt ist, um mit mindestens einer LED-Funktion kommunizieren zu können.
     
    7. Sicherheitsvorrichtung nach Anspruch 6, dadurch gekennzeichnet, dass die optische Eingangs- und Ausgangsvorrichtung der Außeneinheit mindestens eine ultrahelle Leuchtdiode und mindestens eine Photodiode oder einen Phototransistor aufweist.
     
    8. Sicherheitsvorrichtung nach Anspruch 6, dadurch gekennzeichnet, dass die optische Eingangs- und Ausgangsvorrichtung der Außeneinheit mindestens einen optischen Lichtwellenleiter aufweist.
     
    9. Sicherheitsvorrichtung nach einem oder mehreren der voranstehenden Ansprüche, dadurch gekennzeichnet, dass die Logiksteuerungsvorrichtungen mit einer Speichereinrichtung und mit Mittel für das Handhaben von mindestens einer LED-Funktion verbunden sind.
     
    10. Außeneinheit für das Übertragen eines optischen Signals an eine LED-Funktion von einer peripheren Einheit, in der die Sicherheitsvorrichtung gemäß einem oder mehreren der voranstehenden Ansprüche bereitgestellt wird, dadurch gekennzeichnet, dass die Außeneinheit eine optische Eingangs- und Ausgangsvorrichtung umfasst, die so ausgelegt ist, um mit mindestens einer LED-Funktion der peripheren Einheit bidirektional kommunizieren zu können.
     
    11. Außeneinheit nach Anspruch 10, dadurch gekennzeichnet, dass die optische Eingangs- und Ausgangsvorrichtung mindestens eine ultrahelle Leuchtdiode und mindestens eine Photodiode oder einen Phototransistor aufweist.
     
    12. Außeneinheit nach Anspruch 10, dadurch gekennzeichnet, dass die optische Eingangs- und Ausgangsvorrichtung mindestens einen optischen Lichtwellenleiter aufweist.
     
    13. Außeneinheit nach einem oder mehreren der Ansprüche 10 bis 12, dadurch gekennzeichnet, dass diese mit der peripheren Einheit über eine elektronische Anpassschaltung mechanisch gekoppelt ist, um so die optische Eingangs- und Ausgangsvorrichtung in einer Position halten zu können, in der sie der mindestens einen LED-Funktion der peripheren Einheit gegenüberliegt.
     
    14. Verfahren für das Bereitstellen eines optischen Kommunikationskanals zwischen einer Sicherheitsvorrichtung aus einer peripheren Einheit und einer äußeren Steuereinheit, dadurch gekennzeichnet, dass es die folgenden Schritte umfasst:

    Benutzen von mindestens einer LED-Funktion der Sicherheitsvorrichtung aus der peripheren Einheit zum Empfang eines optischen Signals, das von der Außeneinheit gesendet worden ist, wobei die LED-Funktion den Betriebsstatus der peripheren Einheit anzeigt;

    Umwandeln des optischen Signals in ein Spannungssignal, das von mindestens einer LED-Funktion empfangen worden ist, wobei ein elektrischer Widerstand verwendet wird, der mit mindestens einer LED-Funktion in Reihe geschaltet ist;

    Auswerten des Spannungssignals mittels Auswertevorrichtungen, die mit den Logiksteuerungsvorrichtungen verbunden sind, die so ausgelegt sind, um mindestens eine LED-Funktion steuern zu können, wobei das Verfahren in der Umgebung ausgeführt wird, in der die periphere Einheit installiert ist.


     
    15. Verfahren nach Anspruch 14, dadurch gekennzeichnet, dass der Schritt des Auswertens des Spannungssignals das Verstärken und den Vergleich des Spannungssignals mit einer Referenzspannung aufweist, die von den Logiksteuerungsvorrichtungen gesendet worden ist.
     
    16. Verfahren nach Anspruch 14, dadurch gekennzeichnet, dass es den Schritt des Verbindens von mindestens einer LED-Funktion mit Vorrichtungen für das Auswerten des Spannungssignals über Schaltmittel umfasst.
     


    Revendications

    1. Dispositif de sécurité permettant une communication bidirectionnelle, comprenant des moyens de commande logiques aptes à commander au moins une DEL pour indiquer l'état de fonctionnement d'un périphérique dans lequel est logé ledit dispositif de sécurité, caractérisé en ce qu'il comprend au moins une résistance montée en parallèle avec ladite au moins une DEL, pour convertir en tension l'énergie lumineuse reçue de ladite au moins une DEL, ladite DEL étant connectée à un moyen pour évaluer ladite tension générée par celle-ci, ledit moyen étant lui-même connecté auxdits moyens de commande logiques, ladite tension indiquant la réponse dudit dispositif de sécurité à un signal envoyé depuis un système extérieur.
     
    2. Dispositif selon la revendication 1, caractérisé en ce que ledit moyen pour évaluer ladite tension générée par ladite au moins une DEL comporte un amplificateur et un comparateur aptes à comparer ladite tension générée par ladite DEL avec la tension de référence générée par lesdits moyens de commande logiques, afin d'obtenir un signal de différence de tension apte à être envoyé auxdits moyens de commande logiques.
     
    3. Dispositif selon les revendications 1 et 2, caractérisé en ce que ledit amplificateur et ledit comparateur sont connectés à ladite au moins une DEL par l'intermédiaire de moyens de commutation.
     
    4. Dispositif selon une ou plusieurs des revendications précédentes, caractérisé en ce que lesdits moyens de commande logiques excitent ladite au moins une DEL par l'intermédiaire d'un organe de puissance.
     
    5. Dispositif selon une ou plusieurs des revendications précédentes, caractérisé en ce qu'au moins une résistance est intercalée entre ledit tampon de puissance et ladite au moins une DEL et est montée en série avec ladite au moins une DEL.
     
    6. Dispositif selon une ou plusieurs des revendications précédentes, caractérisé en ce qu'il comprend un système extérieur apte à assurer la liaison avec ledit périphérique qui contient ledit dispositif de sécurité, ledit système extérieur étant pourvu d'un dispositif optique d'entrée et de sortie apte à communiquer avec ladite au moins une DEL.
     
    7. Dispositif selon la revendication 6, caractérisé en ce que ledit dispositif optique d'entrée et de sortie dudit système extérieur comporte au moins une DEL ultralumineuse et au moins une photodiode ou un phototransistor.
     
    8. Dispositif selon la revendication 6, caractérisé en ce que ledit dispositif optique d'entrée et de sortie dudit système extérieur comporte au moins une fibre optique.
     
    9. Dispositif selon une ou plusieurs des revendications précédentes, caractérisé en ce que lesdits moyens de commande logiques sont connectés à une mémoire et à un moyen pour gérer ladite au moins une DEL.
     
    10. Système extérieur pour transmettre un signal optique à une DEL d'un périphérique pourvu d'un dispositif de sécurité selon une ou plusieurs des revendications précédentes, caractérisé en ce qu'il comporte un dispositif optique d'entrée et de sortie apte à communiquer de manière bidirectionnelle avec ladite au moins une DEL dudit périphérique.
     
    11. Système extérieur selon la revendication 10, caractérisé en ce que ledit dispositif optique d'entrée et de sortie comporte au moins une DEL ultralumineuse et au moins une photodiode ou un phototransistor.
     
    12. Système extérieur selon la revendication 10, caractérisé en ce que ledit dispositif optique d'entrée et de sortie comporte au moins une fibre optique.
     
    13. Système extérieur selon une ou plusieurs des revendications 10 à 12, caractérisé en ce qu'il est mis mécaniquement en liaison avec ledit périphérique de manière à maintenir ledit dispositif optique d'entrée et de sortie dans une position dans laquelle il est en regard de ladite au moins une DEL dudit périphérique.
     
    14. Procédé pour réaliser un canal de communication optique entre un dispositif de sécurité d'un périphérique et un système de commande extérieur, caractérisé en ce qu'il comprend les étapes consistant à
       utiliser au moins une DEL dudit dispositif de sécurité dudit périphérique pour recevoir un signal optique envoyé par ledit système extérieur, ladite DEL indiquant l'état de fonctionnement dudit périphérique ;
       convertir ledit signal optique reçu par ladite au moins une DEL en signal de tension, à l'aide d'une résistance montée en parallèle avec ladite au moins une DEL ;
       évaluer ledit signal de tension à l'aide d'un moyen d'évaluation qui est connecté à des moyens de commande logiques aptes à commander ladite au moins une DEL, ledit procédé étant mis en oeuvre dans l'environnement où est installé ledit périphérique.
     
    15. Procédé selon la revendication 14, caractérisé en ce que l'étape d'évaluation dudit signal de tension comporte l'amplification et la comparaison dudit signal de tension avec une tension de référence envoyée par lesdits moyens de commande logiques ;
     
    16. Procédé selon la revendication 14, caractérisé en ce qu'il comporte l'étape consistant à connecter ladite au moins une DEL avec un moyen pour évaluer ledit signal de tension par l'intermédiaire d'un moyen de commutation.
     




    Drawing