RO133213B1 - Method and electronic module for evaluating electric contacts state and quality - Google Patents

Description

The present invention relates to a method and an electronic module for assessing the state and quality of electrical contacts, which involves both determining and storing the time stamp of signals of the type of rapid variation of the amplitude of an electrical signal of the type of direct electrical voltage, hereinafter referred to microvariation, which is based on the detection and counting of microvariations of a direct voltage type electrical signal (electrical microcuts or micropower cuts) between the poles of an electrical contact either at rest or in motion (vibrations). During the evaluation of their quality, the electrical contacts are traversed by a continuous current with the role of load or test. The invention applies to all electrical contacts and connectors that are used to make electrical circuits and wiring of components, modules and assemblies in the component or structure of portable, mobile equipment or machines or those that during their use or operation are subject to difficult environmental conditions represented by variations in temperature, humidity and vibrations.

In "Micro-variations detection system of electrical signal"; 2015; www.inter-net.ro presents a system for detecting microvariations of electrical signals, intended exclusively for the detection of a microvariation type signal that exceeds a threshold value and for a predetermined time interval, which it then counts. The disadvantage of this solution is that it does not allow defining the electrical profile of the detected signal, programming or changing the threshold values A and duration T, it does not have a memory dedicated to the experimental results, it does not allow a time stamp and it does not provide access to the buffer of experimental data during the testing process through a polling process initiated by a PC to which the microvariation detection and counting system is connected.

There are known methods and solutions for evaluating the quality of electrical contacts both mechanically and electrically. Thus, in order to evaluate the quality of an electrical contact, especially one that during its use is subjected to difficult environmental conditions represented by variations in temperature, humidity and vibrations, it is necessary to continuously measure the evolution of the electrical resistance value of the electrical contact under test as an action to assess their condition/quality.

This continuous measurement requires the use of products that can be part of two categories of measurement systems: (a) data acquisition systems, represented by specialized hardware modules that connect to a PC for the transfer and processing of measured data, or (b) instruments of testing and measurement, represented by digital multimeters that can display locally the value of the measured quantity and that can be connected to a PC for the transfer and processing of the measured data.

The two methods, (a) and (b), are characterized by different, diametrically opposed values in terms of sampling rate and measurement accuracy of the electrical signal, such as voltage or current, but both methods make an evaluation of the measured parameter only after going through a process of sampling and analog-digital conversion of the measured electrical signal, voltage or current, and another of the digital processing of the measured quantity. This method of digital processing of the analog information represented by the time variation of an electrical parameter of the electrical contact, such as direct voltage or the potential difference between the ends of the contact or direct electric current that runs through the parts that make up the contact, includes different periods of time necessary for the acquisition or analog sampling, analog-to-digital conversion, and digital interpretation or processing.

The main disadvantages of these types of methods are the following:

- the process of evaluating the state/quality of the electrical contacts is carried out intermittently, based on the sampling and analog-digital conversion sub-process and the numerical processing of the magnitude of the purchased analog electrical signals. Therefore, the performance and quality of the electrical contact quality evaluation process are dependent on the duration 1 of the entire process of acquisition and digital processing of the input signal, the duration of which depends on the sampling rate of the input electrical quantity; 3

- the process, specific to the method of digital processing of analog information, makes the performance in terms of sampling rate or real-time response relatively low and limited for both categories of measurement systems (a) and (b) , the analysis being limited to signals from a low frequency band below 500 Hz; 7 - although the evaluation, at the same time, during a test, of slowly varying parameters for one or more electrical contacts can generally be achieved by methods (a) 9 and (b) mentioned, however, it will be possible obtain within these tests only instantaneous or integrated values over a certain period of time that will only represent the value of the measured parameter 11 but not the result of the evaluation or processing in relation to a desired information;

- the mentioned tests require a post-processing that provides a much delayed 13 post-event evaluation of the input signal, which represents a major disadvantage of the method;

- the analysis of electrical signals in a low frequency band, for example up to 15 to 500 Hz, regarding their variation over time does not provide all the information necessary for a quality assessment regarding the entire spectrum of events in terms of duration and 17 their frequency of occurrence.

Also known is the solution described in patent US 4975800 Contact abnormality detection system, according to which contact abnormality is detected by generating vibrations, frequency spectrum analysis in the 200-500 Hz band and highlighting predetermined criteria. If the vibrations contain such frequency components, a decision block allows the abnormality of the contacts to be highlighted, before their definitive fall. The disadvantage of this solution lies in its complexity, stemming from the establishment of predetermined criteria for each type of contact subject to the test, as well as 25 due to the fact that the detection of anomalies is not done for contacts in their normal mode of use or operation, the contacts not being traversed by a electric load current 27 specific to their mode of use.

Also known is the technical solution from patent document 29 CN 101201378 (A) which relates to a system for testing instantaneous interruptions of electrical contacts comprising a computer and an adapter connecting a processor 31 and computer. The method of determining the time duration of the detected signal is a classic method of counting the duration of a digital signal between the rising and falling edges 33 or how long an analog signal exceeds a certain threshold value, regardless of how long the rise lasts or how large the amplitude of the detected signal is is above the imposed threshold value.35

Its disadvantage is that the system does not allow the selection of only microvariations with a given profile of amplitude and duration, it does not store the experimental results and not only a number of detected events, and it does not offer the functionality of the time stamp.39

Also known are methods of memorizing the time stamp of detected and counted events which is achieved by executing sequences of 41 instructions (software) with the help of a micro-programmed structure of the microprocessor type. Such methods based on the execution of some program algorithms are time-consuming 43 decreasing the real-time performance of the whole system because this last amount of time is added to the cycle of detecting, counting and remembering the moment of time at which it 45 occurred the detected event. In addition, the microcomputer's real-time clock, or its time base, has a fixed time resolution, defined by the computing equipment manufacturer, which is generally about 20 ms, making it unprogrammable and unadaptable to the specific requirements of many timing applications. real. 49

The technical problem solved by this invention consists in continuously obtaining additional information and of great utility to the evaluation of the quality of an electrical contact, through the continuous processing and analysis, in real time, of some rapidly changing signals, in a wide frequency band that exceeds the 100 kHz limit without the possibility of detecting repetitive microvariation signals at very small time intervals, e.g. < 100 ps, due to the high response time of all detection or test systems that include microcontroller or microprocessor microprogrammed structures.

The method and related electronic module for evaluating the state/quality of electrical contacts, according to the invention, assumes that, in addition to continuously measuring the value of an electrical signal, in general, slowly variable, of the direct voltage or direct current type, in order to subsequently calculate the value of the electrical resistance of an electrical contact by methods (a) and (b), it is possible to detect, from time to time, the presence of micro-variations, that is, of rapid amplitude variations of an electrical signal of the type of direct electrical voltage. These micro-variations are largely undetectable by methods (a) and (b) due to the large real-time constant of such microprogrammed systems, so that once these micro-variations begin to appear during the testing process, they notify those who perform the assessment of the quality of the electrical contacts that the process of deterioration or wear of the electrical contact under test has begun and that it will increase during the following periods of its testing or operation.

According to the method, the contact subject to evaluation is electrically tested, allowing to obtain technical information related to the parameter called the electrical resistance of the electrical contact during the use of the contact in real conditions of use or as close as possible to the real ones as well as in conditions arbitrarily defined or imposed by the experimenter.

Thus, the continuous amplitude exceeding of a certain threshold or limit value of the electrical contact resistance highlights the fact that (1) the pressing force at the level of the contact surface between the two parts or components of the electrical contact has decreased, that ( 2) the distance between the contact surfaces has increased and that, consequently, (3) the value of the electrical resistance measured between the 2 terminals of the electrical contact has increased beyond a certain technical limit and that this increase or variation of the electrical resistance is directly proportional to the value of the voltage electrical between the contact points during the variation duration of the detected signal.

Increased values of this variation in amplitude of the voltage at the terminals of the electrical contact, for example over 10...50, demonstrate that during this microvariation of the signal, as long as the measured value exceeds the detection limit, the electrical contact, practically, from the point from a mechanical point of view, it is no longer firmly established, and the current flow through that contact has an electric arc type component. This electric arc phenomenon leads over time to the mechanical damage of the contact surfaces and implicitly to the decrease in the electrical quality of the contact.

In addition, the continuous exceeding, for a certain period of time, of the limit value of the electrical contact resistance also highlights the existence of mechanical problems in the construction of the electrical contact components, for example the weakening of the elasticity of the materials from which the electrical contact components are made.

The method for assessing the state and quality of electrical contacts with the determination and storage of the time stamp of the counted events involves the following sequence:

- the parameters of the test cycle are defined based on which the state and quality of the electrical contacts can be evaluated, namely the time duration T, the moment of occurrence, the frequency with which the time stamp is to be defined, and the number of events during which they continuously have a voltage value measured between contact points 1 of the electrical or mechanical contact greater than a fixed or programmed threshold value A; 3

- the contact subject to evaluation is tested from an electrical point of view, allowing to obtain technical information regarding the parameter called the electrical resistance of the electrical contact during use of the contact in real conditions of use or as close as possible to the real ones as well as in defined conditions arbitrary or imposed by the experimenter; 7

- the variations in the value of the electrical voltage between the 2 poles of the electrical or mechanical contact are detected continuously and without interruption; 9

- counts according to the programming, optionally either until reaching a maximum value or a defined period of time, only those variations in the value of the electrical voltage between the 11 2 poles of the contact subject to testing that have a time duration greater than the value of scheduled minimum threshold A and if and only if each threshold value exceedance is continuous 13 for at least the entire imposed, fixed or scheduled time duration T;

- it is confirmed/certified in real time regarding the simultaneous fulfillment of the two conditions; 15

- at the time of memorization, information is added to each event regarding the time at which the detected, validated and counted event took place; 17

- the time stamp is determined for each counted event;

- based on the stored information, given by the presence or not of events that 19 demonstrate a certain degree of defect or wear of the electrical contacts subject to testing, the number of events, whose profile is defined and known using the A and T limits, 21 counted on the duration of the test cycle and respectively the time stamp of each event, an analysis is carried out, regardless of the value of the time base, regarding the number of events 23 detected, the time distribution of these events, as well as the analysis regarding the evolution over time of the degree of aging or failure of the device under test or regarding the time distribution of the defects and the evolution over time of their number or frequency.

In order to allow a quantitative analysis of the frequency of occurrence of microvariation type 27 signals defined by the experimenter by the parameters duration T and amplitude A, the method and the electronic module for evaluating the state/quality of the electrical contacts additionally include the 29 block for counting these occurrences.

In connection with this block for real-time counting of detected microvariations, the detection and counting method 31 is supplemented with a complex block for determining and storing the time stamp of each detected and counted microvariation. This feature, realized at the moment of detection of each microvariation that meets the conditions of amplitude A and duration T, provides high-accuracy analysis and post-processing facilities with regard to the evolution over time of the degree of aging or failure of the device under test or with regarding the time distribution of defects and the time evolution of their number or 37 frequency.

The electronic module that implements the measurement and evaluation method allows 39 the detection of microvariations of a continuous electric voltage type electrical signal, also called electrical microcuts (micro power cuts), which are defined by 2 parameters: amplitude, for example 41 from 500 mV to 5 V, and the duration, for example from 500 ns to 100 ps. These microvariations are counted up to a given maximum value or over a certain duration 43 of time and with a specialized submodule the determination and storage of their time stamp or the time at which they occurred is achieved. 45

The electronic module for assessing the state and quality of electrical contacts with the determination and storage of the time stamp of the counted events comprises a block of 47 counting microvariations of an electrical signal over an amplitude limit, the block being part of an electronic module for detection and counting MDN intended for detection and selecting only those signals that meet the conditions required by the evaluation and testing procedure with amplitude greater than a threshold limit value A for a time duration T, and comprising an amplitude level detection circuit that receives at its input a microvariation type signal with the duration < 100 ps and respectively a reference value or amplitude threshold limit, fixed or variable programmable and provides at the entrance of a block the time limit duration, the signal having the duration as long as the detected signal exceeds the amplitude limit, and the output of this block, under the shape of a calibrated pulse or benchmark for the time limit T, generated for each detection of exceeding the limit amplitude A, is applied to one of the inputs of a condition circuit of duration at least as long as the limit T, to which the signal is also applied, and a confirmation pulse for simultaneous fulfillment of both conditions, A and T being applied to the input of the valid microvariation counting block, and each detected and counted microvariation type signal, with the maximum resolution given by the MDN module, is applied to the input of a MAT module intended to generate the time stamp of the counted events.

The MAT time stamp generation and storage module includes a RAM type local memory block that stores the time stamp of each microvariation type signal detected and counted, the contents of the local memory being read by the microcomputer through a buffer, a management block of control signals for the functional blocks of this option, an oscillator-type block that generates a signal with a frequency depending on the resolution with which it is desired to define the time stamp, a block made as a counter that defines the time stamp, a block that is a buffer with an equal number of bits to those of the counter block, used to manage the transfer of the current timestamp stored in the oscillator type block to the memory block, which is completed with the data bus of the microcomputer or any other type of system calculation to which the detection and counting block is connected, and a block realized as a specialized circuit, of the address decoder type, which, together with the complex logic circuit block for managing control signals, performs the process of reading the data and transferring it to the data bus data of the microcomputer, BUS DATA (ECU), and thus generates, independently of a number of pulses of a time base or an oscillator, and not relativized to another previously detected and counted event, the time stamp of each detected microvariation type signal and counted as an individual, absolute time value of the occurrence of the event, expressed as days, hours, minutes, seconds, milliseconds, with an adjustable resolution and suitable for assessing the state and quality of contacts.

The electronic method and module for evaluating the state and quality of electrical contacts, according to the invention have the following advantages:

- continuous measurement of the input electric signal and real-time analysis of its evolution because the information processing is done at the level of the signal in analog form and not in its digital form, after an analog-digital conversion process, which represents a time-consuming stage time;

- the detection, selection and counting of microvariations of the selected type is done continuously without any interruption and without any possibility of not detecting any microvariation of the input electric signal of the continuous electric voltage type. Furthermore, in the case of a multichannel parallel type input structure, the minimum durations of microvariations detected on each channel will not increase by a multiplication factor equal to the number of input channels plus the switching time from one input channel to another because each measurement channel is independent, operating at maximum parameters, in parallel with the other channels, regardless of their number;

- allows the creation of applications whose duration is desired to be limited until 1 appearance of the first malfunction;

- systems based on this solution are not dependent on the number of 3 input channels, being able to process in parallel any number of input signals regarding any type of microvariation, this type of variation being able to vary from channel to channel or from a 5 input signal to another;

- the analysis procedures based on methods (a) and (b) contain interruption times of the 7 detection process. These times of non-detection or non-interpretation of the input signal value are represented by the times required for analog-digital conversion processes and 9 software algorithms for numerical processing of the measured quantity executed with the help of micro-programmed structures of the microcontroller or microprocessor type; 11

- the analysis methods based on the numerical processing of the measured signals can only detect microvariations with higher duration values, for example, greater than 13 100-150 με. In addition, in the case of a multi-channel input structure, the minimum durations of microvariations detected on each channel will increase by a multiplication factor equal to 15 the number of input channels to which will be added, for each channel, the switching time from one input channel to another because in classical structures, methods (a) and (b) use 17 a single analog-to-digital converter and not a parallel input signal processing structure; 19

- systems based on type (a) and (b) solutions are dependent on the number of input channels, being able to process only a limited number of input signals in parallel; 21 - the method of obtaining and storing in real time the time stamp of each detected and counted event is superior to all (classical) methods that use as a 23 time base to obtain the time at which a certain event happened, the time base of of the microcomputer or the calculation system associated with the data acquisition and processing system 25, the time base with a maximum resolution of 20 ms. Time base 13 from fig. 3 provides a resolution value independent of the computing system associated with the data acquisition and 27 processing system and with a higher resolution, for example 1 ms or better, depending on the application.29

Next, an example is given of the realization of a method and an electronic module for evaluating the state and quality of electrical contacts that allow the detection, counting31 of microvariations and the determination and storage of the time stamp of these microvariations of an electrical signal of the type of measured DC voltage between 2 poles of an electrical or mechanical contact 33, also in connection with fig. 1...3 represent:

- fig. 1, MDN electronic detection and counting module;35

- fig. 2, the MAT module for determining and storing the timestamp of detected and counted events;37

- fig. 3, timestamp structure, 32 bits;

- fig. 4, the shape of the detected signals; 39

- fig. 5, shape of undetected signals.

According to the method, during the measurement and testing process, the variation41 in amplitude of an electric signal of the type of direct electric voltage between 2 measurement points is detected, it is memorized if this signal exceeds a certain threshold value or 43 reference, it is determined if this exceeding the threshold value is continuous for a certain imposed time duration and, at the same time, the simultaneous fulfillment 45 of the two conditions is confirmed/certified or not: continuous amplitude exceeding of a certain threshold for at least a certain period of time. 47

Signals that simultaneously meet the 2 minimum amplitude and duration conditions are counted until a maximum value or a defined time period is reached.

The method allows in real time, in the final phase of processing the analyzed signal, to obtain and store the time stamp for each microvariation detected and counted. This constructive feature allows the user to further perform a much more complex analysis, regarding not only the number of detected events, but also regarding the time distribution of these events. Thus, it is possible to carry out an analysis regarding the evolution over time of the degree of aging or failure of the device under test as well as regarding the distribution over time of the defects and the evolution over time of their number or frequency.

Characteristic of this method is the fact that the time base proposed as part of the implementation module of the detection and counting method, is hardware and software independent from the operating system of the microcomputer, being able to provide a resolution for the time stamp value far superior to any other methods that they use microprogrammed hardware structures of the microcontroller or microprocessor type and in accordance with the precision requirements regarding the determination of the moment of time. This resolution for the time stamp can reach up to the time duration of the detected micro-variations, practically up to the maximum resolution for the phenomenon under study, i.e. the resolution with which the measurement and detection activities of the detection and counting module are performed.

In the logical sequence that follows, the operation algorithm of the activity of detection, certification and counting of microvariation type signals is detailed.

Assign START = ON;

While START = ON executes

Assign Slampl = OFF

While Slampl = OFF execute *read Input Signal (U or I), SI

If SI > Limit amplitude then

Assign Slampl = ON

Time = 1

Repeat *read Input Signal (U or I), SI

If SI < Amplitude Limit then

Slampl = OFF

End Clamp OFF

Time = Time + 1

Until Time = DURATION or Slampl = OFF

End If SI > ampl

End How long Slampl = OFF

Assign Count = Count + 1

If Count = CMax then

Assign START = OFF

End If Count

End START = ON

The logical sequence of these activities is implemented at the hardware level in an electronic detection and counting module, called MDN.

This electronic module, which is described in fig. 2, is formed by an amplitude level detection circuit, 2, which receives at the input a microvariation type seminal with duration < 100 :s and respectively a reference value or amplitude threshold limit, fixed or variable by programming, 3.

Block 2 is a comparator type circuit whose output has the logical zero value as long as the input signal has an amplitude lower than the amplitude of the threshold signal, represented by Vref, which can be fixed, defined by hardware or variable, defined by software. 3

As long as the amplitude of the input signal is greater than the amplitude of the threshold signal, the comparator circuit has the value of logic one at the output. 5 Thus, the comparator circuit will generate at the output a digital pulse with a duration equal to the duration of time that the microvariation type input signal has exceeded the maximum limit value 7, the threshold, for the contact resistance.

Block 2 provides at the input of a block 5 the duration time limit, a signal 4 with duration 9 in the logic one state as long as the detected signal exceeds the amplitude threshold limit.

Block 5 is a time circuit, of the monostable type, which, upon the appearance of the rising edge 11 of the signal 4, will generate a digital pulse with a fixed duration, defined by hardware, with the help of an RC type circuit. Optionally, the limit value of the digital pulse duration can be software selected 13 from several individually defined hardware values, so that the module can detect microvariation signals with different software selectable time durations. The output from this 15 block, in the form of a calibrated pulse or standard 6 for the limit time duration T, which is generated for each detection of exceeding the limit amplitude A, is applied to one of the inputs of a duration condition circuit 7 at least as long as the limit T, to which signal 4 also applies.

Block 7 is a circuit that performs the logical AND function between the output signal of the comparator circuit 2 19, with a duration equal to the duration of the microvariation type input signal exceeding an imposed threshold value, and the output signal of the time circuit 21 monostable type with a fixed duration and which represents the minimum duration that a microvariation must exceed a threshold value related to the amplitude. 2. 3

Thus, the duration of the microvariation selected in terms of amplitude is compared with the duration threshold value defined in hardware by the monostable type timing circuit 5, 25 Block 7 will generate a pulse, namely pulse 8, if and only if the duration of the signal of microvariation type input detected by block 2 exceeds a threshold value, regarding 27 duration, imposed.

In addition, block 7 stores and signals with the help of a specialized bistable circuit 29, the generation of a first signal of type 8. Thus, the user is informed that the electronic detection and counting block has detected a first error or a first defect in the function 31 ignition or any other device under test. This information is very important in order to realize applications whose duration is to be limited until the appearance of the first malfunction.

A block 9 for counting valid microvariations, according to conditions A and T receives at 35 input a pulse 8 to confirm simultaneous fulfillment of both conditions, A and T.

Signal 8 is a signal generated by block 7 as a result of the simultaneous fulfillment of 37 2 hardware checks made by blocks 2, 5 and 7 on the amplitude and duration of the microvariation type signal. 39

It certifies the microvariation of the input signal as a microvariation that simultaneously fulfills all the imposed selection conditions.41

Block 9 is an n-bit counter, say 8, that counts 8-type signals.

The number of microvariations detected by block 2 and counted by block 9 can be read by43 at block 9 during the process of detecting microvariations and after the end of this process.45

The scheme detects and counts only the signals whose time variation conforms to the announced method, namely: the detection and counting of microvariations of electrical signals that for a defined period of time have an amplitude greater than a value or imposed limit. In this case, the considered or detected signals are of the form shown in fig. 4 . Electrical signals of the form in fig. will not be detected or considered. 5. These signals, with durations t1, t2, t3 or t4, do not simultaneously satisfy the amplitude and duration conditions, i.e. amplitude > A and duration tx > T.

The implementation module of the method of determining and storing the time stamp, called MAT, includes:

- a first block 11 of local memory type RAM organized n x 32 bits, where n is the number of bits of the block 9. The output signal 10 of the block 9 is received at the input by a memory block 11 which stores the time stamp of each microvariation type signal detected and counted by the block 9. The contents of this local memory are read by the microcomputer by means of a buffer 16 .

- a block 13, in the form of an oscillator type circuit, generates a signal, called clock, CLK, with a frequency of 1 ms or any other, depending on the resolution with which it is desired to define the time stamp.

If the block 11 is a 32-bit data organized memory, the timestamp resolution is 1 ms according to the timestamp structure described in FIG. 4.

- a block 12 of the MAT structure, constitutes a complex logic circuit for managing the control signals for the functional blocks of this first functionality.

- a block 15, represented by a counter that defines the time stamp for each microvariation detected and counted. This timestamp is either the time since the start of the detection process, in which case the timestamp of the first detected microvariation is defined, or the elapsed time since the detection of the previous or previous microvariation.

For efficiency, according to those shown in fig. 3, the timestamp is defined as a sequence of day, hour, minute, second, millisecond information.

Each of these time entities is a counting circuit defined by a different number of bits and maximum value counted, namely: day, 3 bits, maximum value 7, hour, 5 bits, maximum value 24, minute, 6 bits, value maximum 60, seconds, 6 bits, maximum value 60, milliseconds, 10 bits, maximum value 1000.

- a block 14, which is a buffer with an equal number of bits to those of block 15, is used for managing the transfer of the current timestamp stored in block 15 to block 11.

- a block 17 which is a complex logic circuit for managing the control signals for the functional blocks involved in the process of reading the time stamp from the block 11 and transferring the data to the data bus of the microcomputer or any other type of computing system to which the detection and counting block is connected via buffer 16.

- a block 18 is a specialized circuit, of the address decoder type, which, together with the block 17, carries out the process of reading the data from the block 10 and transferring them to the DATA BUS (ECU).

Claims (3)

Claims 1 1. The method for assessing the state and quality of electrical contacts with the determination 3 and memorization of the time stamp of the counted events, characterized in that, during the assessment, the electrical contacts are traversed by an electric load current or 5 direct current type test, for obtaining technical information regarding the electrical resistance of the electrical contact during the use of the contact under real conditions such as 7 and under conditions defined arbitrarily or imposed by the experimenter and involves the following sequence: 9 - the parameters of the test cycle are defined on the basis of which the condition and quality of the electrical contacts can be evaluated, namely the time duration T, the moment of occurrence, the frequency with 11 that is desired to define the time stamp, and the number of events during which they continuously a value of the electrical voltage measured between the contact points 13 of the electrical or mechanical contact greater than a fixed or programmed threshold value A; 15 - the contact subject to evaluation is tested from an electrical point of view in order to obtain technical information regarding the parameter called the electrical resistance of the electrical contact 17 during use of the contact - the variations in the value of the electrical voltage 19 between the 2 poles of the contact are detected continuously and without interruption; - counts according to the programming, either until reaching a maximum value or a defined period of time, only those variations in the value of the electrical voltage between the 2 poles of the contact under test that have a time duration greater than the threshold value 23 scheduled minimum A and if and only if each exceedance of the threshold value is continuous for at least the entire imposed, fixed or scheduled time duration T; 25 - it is confirmed in real time regarding the simultaneous fulfillment of the two conditions; - at the time of memorization, information is added to each event regarding the time27 when the detected, validated and counted event took place; - the time stamp is determined for each counted event; 29 - based on the stored information, given by the presence or not of events that demonstrate a certain degree of defect or wear of the electrical contacts under test,31 the number of events, whose profile is defined and known with the help of the A and T limits, counted during the of the test cycle and respectively the time stamp of each event, a complex analysis is performed, regardless of the value of the time base, regarding the number of detected events, the time distribution of these events, as well as the analysis regarding the evolution over time of the degree of aging or failure of the device under test or regarding the time distribution of the defects and the evolution over time of their number or frequency. 37 2. The electronic module for evaluating the state and quality of electrical contacts with the determination and memorization of the time stamp of the counted events, characterized by the fact that it comprises a block (9) for counting microvariations of an electrical signal over an amplitude limit, the block (9) entering into the component of an electronic module (MDN) of 41 detection and counting intended for the detection and selection of only the signals that meet the conditions required by the evaluation and test procedure with the amplitude greater than a 43 threshold limit value A for a time duration T, and which comprises an amplitude level detection circuit (2) which receives at the input a microvariation type signal (3) with a duration of < 100 ps 45 and respectively a reference value or threshold limit amplitude, fixed or variable programmable and provides at the input a time limit block (5), the signal (4) having the duration for which the detected signal exceeds the amplitude limit, and the output from this block, in the form of a calibrated pulse or standard (6) for the time limit T, generated for each detection of exceeding the limit amplitude A, is applied to one of the inputs of a circuit (7) of a condition lasting at least as long as the limit T, to which the signal (4) is also applied, and a pulse (8) confirming the simultaneous fulfillment of both conditions, A and T being applied to the input of the block (9) for counting valid microvariations, and each microvariation type signal detected and counted, with the maximum resolution given by the module (MDN), is applied to the input of a module (MAT) intended for generating the time stamp of the counted events. 3. The electronic module according to claim 2, characterized in that the timestamp generation and storage module (MAT) comprises a block (11) of local RAM type memory which stores the timestamp of each detected and counted microvariation type signal, the contents of the local memory being read by the microcomputer by means of a buffer (16), a control signal management block (12) for the functional blocks of this option, an oscillator type block (13) that generates a signal with a function frequency of the resolution with which it is desired to define the time stamp, a block (15), realized as a counter that defines the time stamp, a block (14), which is a buffer with an equal number of bits to those of the block (15) , used for managing the transfer of the current timestamp stored in block (13) to block (11), which is completed with the data bus of the microcomputer or any other type of computing system to which the detection and counting block is connected, and respectively a block (17) complex logic circuit for management of control signals, a block (18) realized as a specialized circuit, of the address decoder type which together with the block (17) carries out the process of reading the data and transferring them to the data bus data of the microcomputer, BUS DATA (ECU), and thus generates, independently of a number of pulses of a time base or an oscillator, and not relativized to another previously detected and counted event, the time stamp of each detected microvariation type signal and counted, as an individual, absolute time value of the occurrence of the event, expressed as day, hour, minute, second, millisecond, with an adjustable resolution and suitable for assessing the state and quality of the contacts.