EP2395315A1 - Test method and system for an electro-pyrotechnical initiator - Google Patents

Abstract

The method involves optically measuring heat caused by electric current in an electro-pyrotechnic initiator (1), where the measurement is repeated for different current values. A calibration curve is determined from the measurements by supplying pulsating electric current to the initiator. The initiator is subjected to electromagnetic field. Heat caused by the field is optically measured, where the latter measurement is repeated for different field values. Electric current variation induced in the initiator based on the field is determined from the latter measurements and the curve. An independent claim is also included for a system for testing an electro-pyrotechnic initiator subjected to electromagnetic field.

Description

The present invention relates to a method and a test system for an electro-pyrotechnic initiator.

Usually, an electro-pyrotechnic initiator comprises a pyrotechnic charge, in particular a pyrotechnic powder, which is initiated by a resistive element placed in contact with this charge. This resistive element may be formed of a filament, in particular a cylindrical filament, which is preferably made of an alloy of high resistivity. The generation of an electric current in the resistive filament causes the heating of the latter by Joule effect, and this heating can trigger the pyrotechnic charge.

More particularly, although not exclusively, such an electro-pyrotechnic initiator is applied to a weapon system, including a missile.

It is known that an electric current can be induced in the resistive filament of the electro-pyrotechnic initiator when the latter is subjected to an electromagnetic field. In certain surrounding circumstances, it may even happen that the electric current induced in the electro-pyrotechnic initiator is such that it triggers the latter. Therefore, when a system, in particular a weapon system, which is equipped with such an electro-pyrotechnic initiator enters an area subjected to significant electromagnetic aggression, generated in particular by radars or by radio sources, these In some cases, electromagnetic aggression may cause an inadvertent tripping of the electro-pyrotechnic initiator and thus of the system in which it is mounted.

Also, to avoid such inadvertent tripping, it is necessary to test the electro-pyrotechnic initiator mounted on the corresponding system to verify if this assembly is able to withstand the electromagnetic attacks likely to be encountered in the operating conditions provided for said system or whether to protect it further.

1. a) dans une première étape de calibrage :
   • on alimente l'initiateur électro-pyrotechnique avec un courant électrique continu, qui est réglable en intensité ;
   • on réalise optiquement des premières mesures de l'échauffement provoqué par ce courant électrique dans ledit initiateur électro-pyrotechnique ; et
   • on détermine, à l'aide de ces premières mesures, une courbe de calibrage qui illustre la variation de l'échauffement de l'initiateur électro-pyrotechnique en fonction du courant électrique qui l'alimente ; et
2. b) dans une seconde étape de test :
   • on soumet l'initiateur électro-pyrotechnique à un champ électromagnétique ;
   • on réalise optiquement des secondes mesures de l'échauffement provoqué par ce champ électromagnétique dans ledit initiateur électro-pyrotechnique ; et
   • on détermine, à l'aide de ces secondes mesures et de ladite courbe de calibrage, la variation du courant électrique induit dans l'initiateur électro-pyrotechnique en fonction du champ électromagnétique, auquel il est soumis.

To carry out such a test, the following operations are generally carried out:

1. a) in a first calibration step:
   • the electro-pyrotechnic initiator is supplied with a continuous electric current, which is adjustable in intensity;
   • optically taking first measurements of the heating caused by this electric current in said electro-pyrotechnic initiator; and
   • using these first measurements, a calibration curve is determined which illustrates the variation of the heating of the electro-pyrotechnic initiator as a function of the electric current which supplies it; and
2. b) in a second test step:
   • the electro-pyrotechnic initiator is subjected to an electromagnetic field;
   • second measurements of the heating caused by this electromagnetic field in said electro-pyrotechnic initiator are optically performed; and
   • the variation of the electric current induced in the electro-pyrotechnic initiator as a function of the electromagnetic field to which it is subjected is determined by means of these second measurements and of said calibration curve.

This conventional method is very efficient for electromagnetic fields having sustained wave forms, because the Electrical currents induced in the electro-pyrotechnic initiator by this type of waveforms are continuous, as is the case for the electric currents taken into account in the calibration step of the test method.

However, the electromagnetic aggressions encountered in the theaters of operations or during specific tests are not always of maintained form, but may especially be of impulse form, so as to generate non-continuous currents in the electropyrotechnic initiators.

Therefore, the above-mentioned conventional testing method is not optimal for such types of electromagnetically unmaintained forms of aggression. This usual test method, although very efficient in its usual field of use, does not appear able to perform tests for all electromagnetic attacks that an electro-pyrotechnic initiator is likely to encounter.

The present invention aims to overcome these disadvantages. It relates to a method for testing an electro-pyrotechnic initiator, which makes it possible to carry out tests relating to any type of electromagnetic field to which it may be subjected, and in particular electromagnetic aggressions of non-maintained form.

1. a) dans une première étape (de calibrage) :
   • on alimente l'initiateur électro-pyrotechnique avec un courant électrique, et on réalise optiquement une première mesure de l'échauffement provoqué par ce courant électrique dans ledit initiateur électro-pyrotechnique, cette mesure étant répétée pour des valeurs différentes du courant électrique ; et
   • on détermine, à l'aide des premières mesures ainsi obtenues, une courbe de calibrage qui illustre la variation de l'échauffement de l'initiateur électro-pyrotechnique en fonction du courant électrique qui l'alimente ; et b) dans une seconde étape :
   • on soumet l'initiateur électro-pyrotechnique à un champ électromagnétique, et on réalise optiquement une seconde mesure de l'échauffement provoqué par ce champ électromagnétique dans ledit initiateur électro-pyrotechnique, cette mesure étant répétée pour des valeurs différentes du champ électromagnétique ; et
   • on détermine, à l'aide des secondes mesures ainsi obtenues et de ladite courbe de calibrage, la variation du courant électrique induit dans l'initiateur électro-pyrotechnique en fonction du champ électromagnétique, auquel il est soumis,
     est remarquable en ce qu'à l'étape a), pour déterminer ladite courbe de calibrage, on alimente ledit initiateur électro-pyrotechnique avec un courant électrique pulsé.

For this purpose, according to the invention, said method according to which the following operations are carried out:

1. a) in a first step (calibration):
   • the electro-pyrotechnic initiator is supplied with an electric current, and a first measurement of the heating caused by this electric current in said electro-pyrotechnic initiator is performed optically, this measurement being repeated for different values of the electric current; and
   • a calibration curve is determined with the aid of the first measurements thus obtained, which illustrates the variation of the heating of the electro-pyrotechnic initiator as a function of the electric current which supplies it; and b) in a second step:
   • the electro-pyrotechnic initiator is subjected to an electromagnetic field, and a second measurement of the heating caused by this electromagnetic field in said electro-pyrotechnic initiator is performed optically, this measurement being repeated for different values of the electromagnetic field; and
   • the variation of the electric current induced in the electropyrotechnic initiator as a function of the electromagnetic field to which it is subjected is determined using the second measurements thus obtained and of the calibration curve;
     is remarkable in that in step a), to determine said calibration curve, said electro-pyrotechnic initiator is supplied with a pulsed electric current.

The term "pulsed" means a uniform and uniform variation in the form of pulses, the duration of which can be determined (or of generation), as well as the duration of recurrence (or appearance), that is, say the frequency.

Advantageously, in step a), the different values of the pulsed electric current have pulses of holding times and variable recurrence times, and in step b), the electro-pyrotechnic initiator is subjected to an electromagnetic field. having pulsed-shaped electromagnetic waves for determining said variation of the induced electric current.

The present invention therefore proposes a new calibration step making it possible to determine the correspondence between the measured heating of an electro-pyrotechnic initiator and a current pulsed electric through the latter, which is at the origin of this heating, the resulting calibration curve can be used to determine in step b) the electric current actually flowing in the electro-pyrotechnic initiator as a function of a measured heating that is generated by electromagnetic aggression of unserviceable form, which can be at the origin of electric currents of this type.

Thus, thanks to the invention, there is obtained a complete test method for testing the electro-pyrotechnic initiator with respect to all types of electromagnetic aggression, of maintained form (using the usual calibration method) or of non-maintained form (using the new calibration method according to the invention).

In the context of the present invention, said pulsed electric current for supplying the electro-pyrotechnic initiator may be generated by any type of conventional pulsed current generator. However, in a preferred embodiment, in order to generate said pulsed electric current, a breaking device is arranged at the electrical connection between electrical supply means of the electro-pyrotechnic initiator and said electro-pyrotechnic initiator. power supply, which is likely to cut durations and variable recurrences.

Thus, the new calibration step can be implemented in a simple and low-cost manner by simply integrating a device for disconnecting the power supply into a conventional test system, as specified below.

Furthermore, advantageously, in a further step c), using said variation of the electric current induced in the electro-pyrotechnic initiator as a function of the electromagnetic field, an electromagnetic field value which generates an induced electric current is determined. having a predetermined value, in particular the value causing the triggering of the electro-pyrotechnic initiator or a value lower than the latter by a predetermined margin.

Thus, one can know the value of the electromagnetic field, from which the induced electric current may cause a triggering of the electro-pyrotechnic initiator. This information can be used, in particular, to ensure that this electro-pyrotechnic initiator can be used in the theaters of operations or during specific tests, envisaged.

The present invention also relates to a system for testing an electro-pyrotechnic initiator which is capable of being subjected to electromagnetic fields including in particular electromagnetic waves of non-maintained form.

• des premiers moyens pour alimenter l'initiateur électro-pyrotechnique avec un courant électrique ;
• des deuxièmes moyens pour réaliser optiquement des premières mesures de l'échauffement provoqué par ce courant électrique dans ledit initiateur électro-pyrotechnique, ces mesures étant répétées pour des valeurs différentes du courant électrique ;
• des troisièmes moyens pour déterminer, à l'aide de ces premières mesures, une courbe de calibrage qui illustre la variation de l'échauffement de l'initiateur électro-pyrotechnique en fonction du courant électrique qui l'alimente ;
• des quatrièmes moyens pour soumettre l'initiateur électro-pyrotechnique à un champ électromagnétique ;
• des cinquièmes moyens pour réaliser optiquement des secondes mesures de l'échauffement provoqué par ce champ électromagnétique dans ledit initiateur électro-pyrotechnique, ces mesures étant répétées pour des valeurs différentes du champ électromagnétique ; et
• des sixièmes moyens pour déterminer, à l'aide de ces secondes mesures et de ladite courbe de calibrage, la variation du courant électrique induit dans l'initiateur électro-pyrotechnique en fonction du champ électromagnétique, auquel il est soumis, est remarquable en ce que lesdits premiers moyens sont formés de manière à alimenter l'initiateur électro-pyrotechnique avec un courant électrique pulsé.

According to the invention, said test system, of the type comprising:

• first means for supplying the electro-pyrotechnic initiator with an electric current;
• second means for optically making first measurements of the heating caused by this electric current in said electro-pyrotechnic initiator, these measurements being repeated for different values of the electric current;
• third means for determining, using these first measurements, a calibration curve which illustrates the variation of the heating of the electro-pyrotechnic initiator as a function of the electric current which supplies it;
• fourth means for subjecting the electro-pyrotechnic initiator to an electromagnetic field;
• fifth means for optically performing second measurements of the heating caused by this electromagnetic field in said electro-pyrotechnic initiator, these measurements being repeated for different values of the electromagnetic field; and
• sixth means for determining, with the aid of these second measurements and of said calibration curve, the variation of the electric current induced in the electro-pyrotechnic initiator as a function of the electromagnetic field to which it is subjected, is remarkable in that said first means are formed to supply the electro-pyrotechnic initiator with a pulsed electric current.

• des moyens d'alimentation électrique dudit initiateur électro-pyrotechnique ; et
• un dispositif de coupure de l'alimentation électrique susceptible de réaliser des coupures de durées et de récurrences variables, qui est agencé au niveau de la liaison électrique entre lesdits moyens d'alimentation électrique et ledit initiateur électro-pyrotechnique.

In a preferred embodiment, which is simplified, said first means comprise:

• power supply means of said electro-pyrotechnic initiator; and
• a device for disconnecting the electrical power supply capable of making interruptions of variable durations and recurrences, which is arranged at the level of the electrical connection between said power supply means and said electro-pyrotechnic initiator.

In addition, advantageously, said second, third, fifth, and sixth means are part of an optical temperature measurement unit, which simplifies the implementation of tests according to the present invention.

The present invention thus makes it possible to know unambiguously, in the field of use considered, the value of the electric current flowing through the resistive filament of the electro-pyrotechnic initiator when the electromagnetic field to which it is subjected is of the pulsed type.

• de connaître le domaine d'emploi du système de test ; et
• d'améliorer les techniques de collage d'une fibre optique de l'unité de mesure optique sur le filament résistif de l'initiateur électro-pyrotechnique.

It also allows, as specified below:

• to know the field of use of the test system; and
• to improve the techniques for bonding an optical fiber of the optical measurement unit to the resistive filament of the electro-pyrotechnic initiator.

The figures of the appended drawing will make it clear how the invention can be realized. In these figures, identical references designate similar elements.

The figure 1 is the block diagram of an optical measurement unit that is applied to an electro-pyrotechnic initiator to perform a test according to the invention.

The figure 2 is a graph for explaining the characteristics of a test according to the invention.

The present invention is applied to an electro-pyrotechnic initiator 1 which is intended to be mounted in a system, and in particular in a weapon system such as a missile for example.

An electro-pyrotechnic initiator 1 comprises, in the usual way, a pyrotechnic charge, in particular a pyrotechnic powder, which is initiated by a resistive element placed in contact with this charge. This resistive element is preferably formed of a filament 2, in particular cylindrical, which generally consists of an alloy of high resistivity. The generation of an electric current in the resistive filament 2 causes the latter to heat up by the Joule effect and, from a certain value, this heating triggers the pyrotechnic charge of the initiator 1.

The present invention relates to a method and a system 3 for testing such an electro-pyrotechnic initiator 1.

This method comprises, in the usual way, a first calibration step, and a second test step.

• des moyens 4 pour alimenter l'initiateur électro-pyrotechnique 1 avec un courant électrique ;
• des moyens 5 pour réaliser optiquement des premières mesures de l'échauffement provoqué par ce courant électrique dans ledit initiateur électro-pyrotechnique 1, ces mesures étant répétées pour des valeurs différentes du courant électrique ; et
• des moyens pour 6 déterminer, à l'aide de ces premières mesures, une courbe de calibrage qui illustre la variation de l'échauffement de l'initiateur électro-pyrotechnique 1 en fonction du courant électrique qui l'alimente.

To implement the calibration step, said system 3 comprises, as shown in FIG. figure 1 :

• means 4 for supplying the electro-pyrotechnic initiator 1 with an electric current;
• means 5 for optically making first measurements of the heating caused by this electric current in said electro-pyrotechnic initiator 1, these measurements being repeated for different values of the electric current; and
• means for determining, with the aid of these first measurements, a calibration curve which illustrates the variation in the heating of the electro-pyrotechnic initiator 1 as a function of the electric current which supplies it.

To carry out this calibration step, the electro-pyrotechnic 1 is preferably made inert by removing its pyrotechnic charge, in particular a pyrotechnic powder. This makes it possible to avoid triggering the load during calibration and to gain easier access to the filament 2 for performing the optical measurements of the heating.

• une fibre optique 8 équipée d'un interféromètre, dont une extrémité 8A est collée sur le filament 2, dont on désire mesurer la température ;
• une unité d'analyse 9 qui réalise notamment le traitement des mesures réalisées ; et
• une interface homme/machine 10, par exemple un ordinateur portable, qui est reliée par une liaison 11 à ladite unité d'analyse 9 et qui comporte un écran 12 pour afficher les résultats des mesures.

In a preferred embodiment, said means 5 and 6 are part of a unit 7 for optical measurement of the temperature. Such an optical measurement unit 7 has, in particular, the advantage of being insensitive to electromagnetic aggression and not to make the system generally sensitive to electric fields. Said unit 7 comprises:

• an optical fiber 8 equipped with an interferometer, one end 8A is bonded to the filament 2, the temperature of which it is desired to measure;
• an analysis unit 9 which performs in particular the processing of the measurements made; and
• a man / machine interface 10, for example a laptop computer, which is connected by a link 11 to said analysis unit 9 and which comprises a screen 12 for displaying the results of the measurements.

• des moyens usuels (non représentés) pour soumettre l'initiateur électro-pyrotechnique 1 à un champ électromagnétique ; et
• des moyens, de préférence ladite unité 7 de mesure optique de la température ou une unité similaire, pour :
• réaliser optiquement des secondes mesures de l'échauffement provoqué par ce champ électromagnétique dans ledit initiateur électro-pyrotechnique 1, ces mesures étant répétées pour des valeurs différentes du champ électromagnétique ; et
• déterminer, à l'aide de ces secondes mesures et de ladite courbe de calibrage, la variation du courant électrique induit dans l'initiateur électro-pyrotechnique 1 en fonction du champ électromagnétique, auquel il est soumis.

Moreover, to implement the next test step which is preferably performed in an anechoic or reverberant chamber, said system 3 comprises:

• conventional means (not shown) for subjecting the electro-pyrotechnic initiator 1 to an electromagnetic field; and
• means, preferably said optical temperature measuring unit 7 or a similar unit, for:
• optically perform second measurements of the heating caused by this electromagnetic field in said electro-pyrotechnic initiator 1, these measurements being repeated for different values of the electromagnetic field; and
• with the aid of these second measurements and of said calibration curve, determining the variation of the electric current induced in the electro-pyrotechnic initiator 1 as a function of the electromagnetic field to which it is subjected.

To implement this second (test) step, the electro-pyrotechnic initiator 1 is preferably mounted in the system for which it is intended, in particular in a weapon system such as a missile, for example to obtain test conditions as close as possible to the operating conditions. In addition, in this second step, said electro-pyrotechnic initiator 1 is not rendered inert.

According to the invention, said means 4 of the test system 3 are formed so as to feed the electro-pyrotechnic initiator 1 with a pulsed electric current.

In the context of the present invention, the term "electric current (or electromagnetic field) pulsed" a variation of the electric current (or the electromagnetic field) which is in the form of regular pulses IM uniform over time t, whose retention (or generation) T1 times can be determined, as well as the duration of recurrence T2 (or appearance), as represented on the figure 2 for an electric current i. It can also be irregular pulses, but that we know and that we know how to reproduce. On the example of the figure 2 , the pulses IM have an intensity of value i0.

Therefore, in the calibration step, in order to carry out said first measurements, the means 4 generate different values of pulsed electric current which have IM pulses of holding times T1 and of variable recurrence periods T2, and at the step of test, to carry out said second measurements, the electro-pyrotechnic initiator 1 is subjected to an electromagnetic field having variable electromagnetic waves also of pulsed shape.

The present invention therefore proposes a new calibration step making it possible to determine the correspondence between the measured heating of an electro-pyrotechnic initiator 1 and a pulsating electric current passing through the latter, which is at the origin of this heating. The resulting calibration curve is then used to determine, in the test step, the electrical current actually flowing in the electro-pyrotechnic initiator 1 as a function of a measured temperature rise that is generated by non-electromagnetic electromagnetic aggression. maintained (which can be at the origin of electric currents of this type).

Thus, the test system 3 in accordance with the invention is complete and makes it possible to test an electro-pyrotechnic initiator 1 with respect to all types of electromagnetic aggression, whether they are of maintained shape (using a curve conventional calibration obtained from a continuous electric current) or non-maintained form (using a calibration curve according to the invention, obtained from a pulsed electric current), in the field of identified employment.

In the context of the present invention, said pulsed electric current for supplying the electro-pyrotechnic initiator 1 may be generated by any type of conventional pulsed current generator.

• des moyens 13 usuels d'alimentation électrique de l'initiateur électro-pyrotechnique 1 ; et
• un dispositif 14 de coupure de l'alimentation électrique qui est susceptible de réaliser des coupures de durées et de récurrences variables. Ce dispositif 14 est agencé sur une liaison électrique 15 entre lesdits moyens 13 d'alimentation électrique et ledit initiateur électro-pyrotechnique 1.

However, in a preferred embodiment, said means 4 comprise:

• common means 13 for supplying electricity to the electro-pyrotechnic initiator 1; and
• a device 14 for disconnecting the power supply which is capable of making breaks of durations and variable recurrences. This device 14 is arranged on an electrical connection 15 between said power supply means 13 and said electro-pyrotechnic initiator 1.

This preferred embodiment makes it possible to implement the new calibration step in a simple and low-cost way, integrating only a device 14 for cutting off the power supply in a usual test system.

Moreover, said system 3 (and in particular the unit 7) can determine, by means of said variation of the electric current induced in the electro-pyrotechnic initiator 1 as a function of the electromagnetic field, an electromagnetic field value which generates a induced electric current having a predetermined value, in particular the value causing the triggering of the electropyrotechnic initiator 1 or a value lower than the latter by a predetermined margin.

Thus, it is possible to know the value of the electromagnetic field, from which the induced electric current may cause an inadvertent tripping of the electro-pyrotechnic initiator 1. This information may be used, in particular, to reinforce the system provided with said initiator electro-pyrotechnic 1 when it is likely to be subjected to electromagnetic aggression capable of presenting at least one such value.

The system 3 can also perform tests on different types of initiators 1 or on different variants of the same initiator 1 in order to search for an electro-pyrotechnic initiator 1 which is not triggered by the electromagnetic attacks likely to be encountered in the theaters of operations envisaged or in specific tests envisaged.

The method and system 3 in accordance with the invention thus make it possible to know without ambiguity the value of the electric current flowing through the resistive filament 2 of an electro-pyrotechnic initiator 1 when the electromagnetic field to which it is subjected is of the pulsed type.

• de connaître le domaine d'emploi du système de test 3, en définissant à partir de tests les types d'agressions électromagnétiques que ledit système de test 3 est en mesure de détecter. On peut en particulier définir les fréquences limites des agressions électromagnétiques susceptibles d'être mesurées par ledit système de test 3; et
• d'améliorer les techniques de collage de la fibre optique 8 de l'unité de mesure optique 7 sur le filament résistif 2 de l'initiateur électro-pyrotechnique 1. En particulier, les coefficients thermiques des matériaux utilisés vont influer sur les mesures réalisées. On peut ainsi rechercher des types de collage permettant d'augmenter la résolution des mesures.

They also allow:

• to know the field of use of the test system 3, by defining from the tests the types of electromagnetic attacks that said test system 3 is able to detect. In particular, it is possible to define the limiting frequencies of the electromagnetic aggressions that can be measured by said test system 3; and
• to improve the bonding techniques of the optical fiber 8 of the optical measurement unit 7 on the resistive filament 2 of the electro-pyrotechnic initiator 1. In particular, the thermal coefficients of the materials used will influence the measurements made. It is thus possible to look for types of gluing that make it possible to increase the resolution of the measurements.

Claims (8)

A test method for an electro-pyrotechnic initiator subjected to an electromagnetic field, wherein the following steps are carried out: a) in a first step: the electro-pyrotechnic initiator (1) is supplied with an electric current, and a first measurement of the heating caused by this electric current in said electro-pyrotechnic initiator (1) is performed optically, this measurement being repeated for values different from the electric current; and - Using the first measurements thus obtained, determining a calibration curve which illustrates the variation of the heating of the electro-pyrotechnic initiator (1) as a function of the electric current which supplies it; and b) in a second step: the electro-pyrotechnic initiator (1) is subjected to an electromagnetic field, and a second measurement of the heating caused by this electromagnetic field in said electro-pyrotechnic initiator (1) is performed optically, this measurement being repeated for values different from the electromagnetic field; and the variation of the electric current induced in the electropyrotechnic initiator (1) as a function of the electromagnetic field to which it is subjected is determined using the second measurements thus obtained and of the calibration curve;
characterized in that in step a), for determining said calibration curve, said electro-pyrotechnic initiator (1) is supplied with a pulsed electric current. Process according to claim 1,
characterized in that in step a), the different values of the pulsed electric current have pulses of holding times (T1) and variable recurrence times (T2). Method according to one of claims 1 and 2,
characterized in that in step b), the electro-pyrotechnic initiator (1) is subjected to an electromagnetic field having pulsed-shaped electromagnetic waves for determining said variation of the induced electric current. Method according to one of claims 1 to 3,
characterized in that , to generate said pulsed electric current, at the electrical connection (15) is arranged between means (13) for supplying electric power to the electro-pyrotechnic initiator (1) and said electro-pyrotechnic initiator (1), a device (14) for cutting off the power supply, which is capable of making cuts of durations and variable recurrences. Method according to one of claims 1 to 4,
characterized in that in a further step c), with the aid of said variation of the electric current induced in the electro-pyrotechnic initiator (1) as a function of the electromagnetic field, an electromagnetic field value is determined which generates a induced electric current having a predetermined value. A system for testing an electro-pyrotechnic initiator subjected to an electromagnetic field, said system (3) comprising: first means (4) for supplying the electropyrotechnic initiator (1) with an electric current; second means (5) for optically making first measurements of the heating caused by this electric current in said electro-pyrotechnic initiator (1), these measurements being repeated for different values of the electric current; third means (6) for determining, with the aid of these first measurements, a calibration curve which illustrates the variation in the heating of the electro-pyrotechnic initiator (1) as a function of the electric current supplying it. ; fourth means for subjecting the electro-pyrotechnic initiator (1) to an electromagnetic field; fifth means (5) for optically performing second measurements of the heating caused by this electromagnetic field in said electro-pyrotechnic initiator (1), these measurements being repeated for different values of the electromagnetic field; and sixth means (6) for determining, with the aid of these second measurements and of said calibration curve, the variation of the electric current induced in the electro-pyrotechnic initiator (1) as a function of the electromagnetic field, to which it is submitted, characterized in that said first means (4) are formed to supply the electro-pyrotechnic initiator (1) with a pulsed electric current. System according to claim 6,
characterized in that said first means (4) comprises: means (13) for powering the electropyrotechnic initiator (1); and - A device (14) for disconnecting the power supply capable of making breaks of variable duration and recurrences, which is arranged at an electrical connection (15) between said power supply means (13) and said electro-pyrotechnic initiator (1). System according to one of claims 6 and 7,
characterized in that said second, third, fifth, and sixth means are part of an optical temperature measuring unit (7).

Images