EP1315404B1 - Illuminated display device for displaying the operating state of a system, in particular for avionics - Google Patents

Abstract

The device has a set of lights (29) and a detection unit that checks for failure of the lights. Each light has m branches (31) with n serially connected light emitting diodes (32) in each branch. The inputs of the diodes are parallel connected and the outputs are connected to a selector (33). The selector connects the selected branch to the output terminal upon receiving signal from a controller (41). An Independent claim is also included for a process for management of a light signaling device related to the operating state of a system.

Description

TECHNICAL AREA

The present invention relates to a light information device relating to the operating state of a system and a method of managing such a device, particularly in the avionics field.

STATE OF THE PRIOR ART

To simplify the description, we will consider in the following, by way of example, an implementation of the invention in the avionics field.

Currently many signaling indicators type lights, such as light emitting diodes, are used in aircraft cockpits to inform pilots, possibly maintenance operators, operating states of the various systems present in these aircraft.

The loss of information provided by such an indicator, mainly in operational operation, can be tricky or even dangerous.

The pilots are therefore led to regularly check the good operating status of such indicators by means of a test command which has the effect of lighting a pre-determined set of these, for example those of the ceiling panel. The drivers must then change the faulty LEDs online.

Thus, as illustrated in FIG. 1, in a signaling assembly consisting of several LEDs 10 controlled by signals SV1, SV2, SV3, through diodes 11, a control button 12 causes all these LEDs to be lit simultaneously. allows the pilot to easily spot a light that remains off.

• une consommation importante pendant le test, surtout lorsque ces voyants sont des lampes à incandescence,
• une impossibilité de détecter un voyant tombé en panne postérieurement au test,
• une efficacité du test reposant sur la vigilance de l'opérateur.

Such a set has many disadvantages, and in particular:

• a significant consumption during the test, especially when these lights are incandescent lamps,
• an impossibility of detecting a light that has failed after the test,
• an effectiveness of the test based on the vigilance of the operator.

The replacement of incandescent lamps with light-emitting diodes has made it possible to increase the life of such indicators.

It is also known to use LEDs consisting each of several light emitting elements 20 in series / parallel assembly, as illustrated in FIG. 2. The failure of an element 20 does not then cause the indicator to fail, but a simple drop. of brightness. Such a device is not really fault-tolerant but has a degraded operating mode in case of failure.

US Pat. No. 3,781,853 discloses a maritime signaling system in which several light sources are connected together to project a simultaneous burst. The purpose of this system is to continue operate if one of the light sources fails. Each light source includes a flash beacon, a daylight controlled circuit, an off lamp detection circuit, and a lamp change circuit. The output power of each flash beacon synchronizes all light sources. In case one of the sources breaks down, the others continue to work.

The subject of the invention is a luminous information device for the operating state of a system making it possible to overcome the disadvantages of the devices of the prior art by detecting the failures of the signaling indicators and by guaranteeing a smooth operation even in presence of certain failures. The invention also relates to a method for managing such a device.

STATEMENT OF THE INVENTION

The present invention relates to a light information device relating to the operating state of a system comprising at least one indicator light and means for detecting failure of this or these indicators, characterized in that each indicator comprises m branches in parallel. each consisting of n light emitting diodes in series, and means for selecting a branch, m and n being integers such that: m ≥ 2 and n ≥ 1.

Advantageously, the first m ends of each branch are connected together, their second ends being connected to the different inputs of the selection means, which, as a function of a control command, connect a selected branch to the output of the device.

• un générateur de courant qui alimente ce voyant,
• un module de commande qui pilote le sélecteur ainsi qu'un interrupteur,
• cet interrupteur qui est relié entre la sortie du sélecteur et l'entrée du générateur de courant.

This device advantageously comprises the following circuits associated with each indicator:

• a generator of current which feeds this indicator,
• a control module which controls the selector and a switch,
• this switch is connected between the output of the selector and the input of the current generator.

Advantageously, each indicator, its control module and its switch are integrated in a single housing.

• dans le cas où le voyant est allumé, on vérifie son bon fonctionnement en contrôlant l'intensité consommée et la tension présente à ses bornes,
• dans le cas où ce voyant est éteint on le sollicite pendant une durée de l'ordre de quelques microsecondes non perceptible à l'oeil humain et on mesure à cet instant ses paramètres courant/tension.

The present invention also relates to a method for managing a light information device relating to the operating state of a system, comprising at least one indicator light and means for detecting failure of this or these indicators, in which each indicator comprises m parallel branches each consisting of n light emitting diodes in series, and means for selecting a branch, m and n being integers such that m≥2 and n≥1 this method comprising an automatic test step of all the LEDs of the system, characterized in that, during this test step, the following steps for each LED are:

• in the case where the indicator is lit, its functioning is verified by controlling the intensity consumed and the voltage present at its terminals,
• in the case where this indicator is off it is solicited for a duration of the order of a few microseconds not perceptible to the human eye and we measure at this moment its current / voltage parameters.

During the dynamic management step, the different branches of each indicator light are alternately illuminated with a scanning frequency of the order of a few kilohertz high enough not to be perceived by the human eye, the current / voltage parameters being checked at each scan. We no longer solicit a branch ai a defect is found in it. However, if all the branches are in default, but if at least one branch remains that is not in open circuit, we can requalify this (these) branch (es) as being functional (S)

In the case where a fault is found in at least one branch, the duty cycle of the other branches without fault is modified to keep the same overall brightness at the indicator whose at least one branch is in default.

The invention can advantageously be used in the avionics field.

Thus, in the method of the invention, a permanent automatic test of all the lights of the cockpit of an airplane is carried out and the pilot is thus relieved of this task. Such a continuous test makes it possible to avoid the non-detection. a hidden failure, by the pilot. In addition, the redundant structure of LEDs, allows an immediate dynamic management in case of failure of this first redundancy without visible repercussions at the level of the pilot, and thus without overload for this one.

BRIEF DESCRIPTION OF THE DRAWINGS

Figures 1 and 2 illustrate two devices of the prior art.

Figures 3 and 4 illustrate the device of the invention.

FIG. 5 illustrates an advantageous embodiment of the device of the invention.

DETAILED PRESENTATION OF PARTICULAR EMBODIMENTS

• un ensemble 30 émetteur de lumière composé de m branches 31 de n diodes électroluminescentes (DEL) 32 (avec m ≥ 2 et n ≥ 1) les n diodes de chaque branche étant connectées en série et dans le même sens, les m premières extrémités de ces branches 31 étant connectées ensemble à l'entrée E, leurs secondes extrémités étant connectées aux différentes entrées d'un sélecteur 33,
• ce sélecteur 33, qui en fonction d'un ordre de commande C, relie une des branches 31 sélectionnée à la sortie S.

The light information device of the invention comprises at least one indicator 29 such as that shown in FIG. 3, which comprises:

• a light emitter assembly composed of m branches 31 of n light-emitting diodes (LEDs) 32 (with m ≥ 2 and n ≥ 1), the n diodes of each branch being connected in series and in the same direction, the first m ends of these branches 31 being connected together to the input E, their second ends being connected to the different inputs of a selector 33,
• this selector 33, which as a function of a control command C, connects one of the branches 31 selected at the output S.

A voltage measuring device 34 connected between the input E and the output S of the indicator makes it possible to know the voltage at the terminals of this indicator. An intensity measuring device 35 connected at the output of the indicator 29 makes it possible to know the intensity of the current flowing through it.

As illustrated in FIG. 4, the indicator light 29 is powered by a current generator 40. A control module 41 controls, on the one hand, the selector 33 via a line 43 and, on the other hand, a switch 42 via a line 44. control module 41 contains a memory for storing the functional or non-functional state of each branch 31. The control signal of this module 41, conveyed on an external control line 45, is a conventional order given to a light (on /off). A line of record 46 allows report the state of this indicator 29 to external devices for alarm or maintenance purposes for example.

• dans le cas où un voyant est allumé, il est facile de vérifier son bon état de fonctionnement en contrôlant régulièrement l'intensité consommée et la tension présente à ces bornes.
• dans le cas où un voyant est éteint, on utilise le même principe de mesure en sollicitant brièvement ce voyant. On alimente alors ce voyant durant une durée de l'ordre de quelques microsecondes, non perceptible par l'oeil humain, en respectant les valeurs de commande nominales. On mesure, à cet instant, les paramètres courant/tension de ce voyant.

The method of the invention realizes a dynamic test of all the indicators 29, for example those of an aircraft cockpit, such as:

• in the case where a light is on, it is easy to check that it is in good working order by regularly checking the current consumed and the voltage present at these terminals.
• in the case where a light is off, the same measurement principle is used by briefly soliciting this light. This indicator is then powered for a duration of the order of a few microseconds, not perceptible by the human eye, respecting the nominal control values. At this moment, the current / voltage parameters of this indicator are measured.

The method of the invention also realizes a dynamic management of the redundancy of each indicator, which consists, with the aid of the selector 33, in alternately selecting the various branches 31 of this indicator with a sufficiently high scanning frequency order of a few kHz) not to be perceived by the human eye.

At each scan, the current / voltage parameters of the LED are checked. If a fault is found, the limb involved is no longer solicited and the other branches have their ignition timing changed to keep the same overall brightness at the indicator.

The method of the invention thus avoids the total loss of the indicator. Also, even when the indicator is not lit, the method of the invention continues its dynamic test by performing a brief command of the different branches. Upon the loss of a first branch, it is possible to develop a preventive maintenance message without the pilot being informed.

• voyant éteint

Thus, if we consider the two possible states of a seer; When the light is off or the light is on, the following operation is performed:

• light off

No order arrives on the external control line 45. The control module 41 opens and closes the switch 42 so as to supply the light 29 with sufficiently short pulses, for example of a duration of the order of a few seconds. microseconds, and spaced so that the light 29 appears extinguished to an observer.

Each pulse is switched successively by the selector 33 on one of the branches 31. It measures the voltage across this branch and the current flowing through it.

• un courant nul : le circuit est ouvert et la branche ne peut plus fonctionner. Elle est considérée comme non fonctionnelle.
• une tension plus faible que la tension nominale : une diode au moins est en court-circuit. Le fait de considérer ou non la branche comme fonctionnelle dépend du rapport entre le nombre de diodes en bon état et le nombre de diodes de la branche, qui se trouve égal au rapport entre la tension mesurée et la tension nominale. Le fabricant ou l'utilisateur décide à partir de quelle baisse d'efficacité une branche doit être déclarée non fonctionnelle.

Two cases of failure can be detected (a light-emitting diode knows only two modes of failure, the short-circuit or the open circuit):

• a zero current: the circuit is open and the branch can no longer function. It is considered non-functional.
• a voltage lower than the nominal voltage: at least one diode is short-circuited. Considering whether or not the branch is functional depends on the ratio between the number of diodes in good condition and the number of diodes in the branch, which is equal to the ratio between the measured voltage and the nominal voltage. The manufacturer or user decides from which efficiency drop a branch must be declared non-functional.

• voyant allumé

un ordre d'allumage est arrivé sur la ligne de commande extérieure 45. Le module de commande 41 ferme l'interrupteur 42 de façon à alimenter le voyant 29 en permanence. De manière cyclique, le sélecteur 33 commandé par le signal C alimente les branches 31 fonctionnelles les unes après les autres.Such an operating mode "light off" allows the control module 41 to know before any ignition command, functional branches that can be used in "light on" mode.

• light on

an ignition command has arrived on the external control line 45. The control module 41 closes the switch 42 so as to supply the indicator 29 permanently. Cyclically, the selector 33 controlled by the signal C supplies the functional branches 31 one after the other.

• un courant nul : le circuit est ouvert et la branche ne peut plus fonctionner. Elle est considérée comme non fonctionnelle.
• une tension plus faible que la tension nominale : une diode au moins est en court-circuit. Le fait de considérer ou non la branche comme fonctionnelle dépend du rapport entre le nombre de diodes en bon état et le nombre de diodes de la branche qui se trouve égal au rapport entre la tension mesurée et la tension nominale.

For each branch 31 powered, two failure cases can be detected:

• a zero current: the circuit is open and the branch can no longer function. It is considered non-functional.
• a voltage lower than the nominal voltage: at least one diode is short-circuited. Whether the branch is considered as functional depends on the ratio between the number of good diodes and the number of diodes of the branch which is equal to the ratio between the measured voltage and the nominal voltage.

One can have a degraded mode of operation in which all the branches are declared non-functional but in which however there remains at least one branch which is not in open circuit. In this case, the (or) branch (s) in question can (wind) be requalified as functional, the indicator emitting less light than during its nominal operation.

Any fault detection can lead to the issuance of a signal on the report line, intended for an operator and / or any maintenance system.

In an advantageous embodiment, as shown in FIG. 5, the indicator light 29, its control module 41 and the switch 42 are integrated in a single housing 50, with two supply lines 51, so as to present the appearance of an almost classic light.

Claims (10)

1. Light signalling device related to the operating state of a system, said device comprising at least one light and fault detection means with respect to said light or lights, characterized in that each light comprises m parallel branches (31), each formed by n light-emitting diodes (32) in series, and means (33) for selecting a branch, m and n being integers such that m ≥ 2 and n ≥ 1.
2. Device according to claim 1, wherein the m first ends of said branches are connected together, their second ends being connected to different inputs of the selection means (33) which, as a function of a control order (C), making it possible to connect a selected branch (31) to an output of the device (S).
3. Device according to claim 2, also comprising for each light:

   - a current generator (40) supplying said light (29),

   - a switch (42) connected between the output of the selection means (33) and the input of the current generator (40),

   - a control module (41) controlling the selection means and the switch (42) and containing a memory making it possible to store the state of each branch (31).
4. Device according to claim 3, wherein each light (29), its control module (41) and its switch (42) are integrated into a single box (50).
5. Use of the device according to any one of the claims 1 to 4 in avionics.
6. Process for the management of a light signalling device relating to the operating state of a system, said device comprising at least one light and means for detecting faults with respect to said light or lights, in which each light comprises m parallel branches (31), each formed by n light emitting diodes (32) in series, and means (33) for selecting a branch, m and n being integers such that m≥ 2 and n≥ 1, said process comprising an automatic testing stage for all the lights of the system, said stage comprising the following stages for each light:

   - in the case where the light is illuminated, its operating state is checked by monitoring the consumed intensity and the voltage present at its terminals,

   - in the case where the light is extinguished, it is activated for a few microseconds in such a way that the activation is not visible to the human eye and during said activation its current/voltage parameters are measured.
7. Process according to claim 6, wherein, during the dynamic management stage, alternating activation takes place of the different branches of each light with a scanning frequency of a few kilohertz and which is sufficiently high to ensure that the activation is not visible to the human eye, the current/voltage parameters being checked during each scan.
8. Process according to claim 7, wherein a branch is no longer activated if a fault is found therein.
9. Process according to claim 7, wherein if all the branches are faulty, but there is at least one branch which is not in open circuit, said branch or branches is requalified as being operational.
10. Process according to claim 7, wherein in the case where a fault is detected in at least one branch, the cyclic illumination ratio of the fault-free branches is modified in order to maintain the same overall brightness with respect to the light, whereof at least one branch is faulty.

Images