CH634144A5 - DEVICE FOR RECORDING ELECTRIC SIGNALS, VIEWED ON MOBILE MEDIA. - Google Patents

Description

The present invention relates to the field of devices for recording random disturbances that may appear in industrial systems, and more particularly, in electrical energy distribution networks.

In the latter case, in particular, the concept of service is fundamental, and any incident, such as a variation in the voltage of electrical energy, for example an overvoltage or an undervoltage which can go as far as a total interruption of distribution, requires that a complete analysis of the phenomenon can be carried out later to determine the causes and prevent its return. These causes are diverse, and can be linked to accidental damage to distribution lines or their associated components (circuit breakers, disconnectors); they can come from undesirable contacts or short circuits of which certain elements of these lines are temporarily the seat; when they are aerial, usually supported by pylons, a frequent cause of disturbances can be attributed to atmospheric electric discharges such as those due to lightning.

In all cases, the control of these disturbances, of an unforeseeable nature, requires, on the one hand, continuous monitoring and, on the other hand, the possibility of a subsequent analysis of each phenomenon; this results in the obligation to implement recording means.

Such means generally use an information medium, in the form of a moving band, where the quantities to be monitored are entered in the form of visible signals either directly or after appropriate processing.

In the great generality of the cases, the material adopted for the support is paper, which lends itself to a convenient direct visual examination, to subsequent additional inscriptions, to archiving on file.

Registration is most often done by inking or, less frequently, by photographic means with, in this case, possible need for treatment.

However, the continuous recording of the quantities to be monitored leads to an unacceptable consumption of paper, the incidents occurring only rarely, and, as has been said, randomly; and, with a view to reducing the quantity of the recording medium used, it has, in this sense, already been proposed to carry out the recording only when a disturbance appears.

This operation in triggered mode is then caused by the appearance of the disturbance itself, the recorder remaining inactive between two disturbances.

However, the exact determination of the causes of the incidents makes it desirable to know not only the disturbed regime as a whole, but also the stable state which immediately preceded the incident.

The recorder, when an incident occurs, must therefore start recording before the disturbed signal arrives, an obligation which can only be satisfied by the insertion of an organ introducing a delay between the moment where the signal corresponding to the disturbance triggers the recorder and the one where the recording itself started.

This body performs a function which, in the following, will be referred to as the pre-trip memory.

In some known paper tape recorders, the pre-trigger memory is of the mechanical type: it is produced by an intermediate support rotating in the form of a cylinder, on which are graphically recorded and then permanently erased for the last few seconds of the value to be checked; the transfer by contact on the strip of paper, usually stationary, takes place only in the event of an incident; the pre-trip memory is thus represented by the value of the angular offset between the writing and contact points between the rotating cylinder and the paper.

In other paper tape recorders, the pre-trip memory is electrically realized by a digital circuit of the shift register type; the analog quantity to be checked is previously transformed into digital quantity and, after being delayed, it is transformed again at the output into analog quantity for the final recording on paper tape.

Subject to accepting the reduced separating power and the low precision inherent in real-time recording on paper, satisfactory operation has been obtained from such disturbance recorders, at the cost of careful monitoring for the supply of tapes. paper and to maintain an optimal environment suitable for the recording process adopted.

However, in many other practical cases, these conditions cannot be satisfied. Indeed, by their particular characteristics, the disturbed electrical signals, which often appear in points of very distant networks and of difficult access, prohibit, by the wide frequency band which they contain, their routing by traditional electric lines, to a central measurement location where the recording devices could be conveniently grouped, monitored and maintained. One of the operating constraints of these devices is therefore their dispersal in natural sites that are often far apart, where only periodic visits are possible, widely spaced, to remove recorded media and, if necessary, replace it with blank media.

As a result, with a view to reducing paper consumption, the choice of a limited scrolling speed for the latter, with as a consequence a weak separating power, and a difficult analysis of the results, requiring examination with a magnifying glass; in general, the total capacity of the system is limited by the size of the paper roll.

It also follows that, in the event of an operating incident

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With the paper-based recorder, there is no longer any trace of the disturbance to be studied, seriously compromising the reliability of surveillance on remote sites.

It has been proposed, for better reliability, to substitute for the recording process on paper, recording on magnetic medium, practically exploited in the form of tape cassettes, either in analog form or in digital form.

However, given the orders of magnitude of the data to be recorded, the digital speed of input and output of a cassette remains low, limiting the performance of information rate per second, in particular when several input channels are at monitor; moreover, the cassettes are fragile, their frequent change is difficult at a remote site, and there is no material graphic trace directly visible at a remote site for analysis and additional annotations. The latter drawback, although associated with a significantly higher input rate, can be opposed in the case where the magnetic support is presented in the form of a flexible disc (floppy disc).

The present patent relates to a recording device which does not have any of these drawbacks, and which on the other hand presents the combined advantages of the two types of information medium, namely the magnetic medium in the form of a flexible disc and the paper in the form of a strip.

According to the invention, the known recording device on paper tape is kept in its entirety, and the fundamental characteristic of this consists in the insertion, between two links of this system, of an additional recording means with support. magnetic disk type.

The association of a flexible disc and a strip of paper thus achieves a combination cooperating towards a common goal, providing, on the one hand, a storage at large capacity and high resolution of a large number of information not directly accessible and, on the other hand, a means of direct visual examination for study and exploitation, the common goal achieved being reliability and precision in the knowledge of the disturbances in question.

According to a first mode of operation of the device, the paper tape recorder can remain inactive permanently, and its operation is triggered only during periodic visits under the supervision of the visiting agent, who can thus easily view any desired part of recording of the floppy disk, instantly.

The choice and monitoring of the agent ensures all guarantees of a good recording on paper, with an increase in the speed of the paper for better resolution.

According to a second operating mode of the device, which is particularly advantageous, the paper recorder may not be permanently installed on the site, but on the contrary may be provided by the visiting agent, a single recorder being able to then be used on several remote sites. . This operating mode is enabled by the invention, the means necessary for extracting, processing and recording on paper the information contained on the flexible disk, being already present to a large extent in the fixed part of the system, and the paper recorder is therefore lighter and more transportable.

According to a third mode of operation of the device, the paper recorder is placed in a central location, provided with technical means providing all guarantees of quality of registration, and the visiting agent ensures the delivery of the flexible disc recorded on the site, up to a drive for such discs located in the same central location.

The agent then no longer has, on the site, a means of permanent visualization of the information contained in the flexible disk; but the weight to be transported, that of the flexible disc, is then very reduced compared to the paper recorder of the second operating mode. It should then be noted that this mode of implementation of the invention, providing the advantage of performing secondary recording on paper from a primary recording on flexible disc, overcomes the limitations specific to direct recording on paper, of the known art, namely reduced resolution and / or high paper consumption and / or poor reliability. Each incident, or disturbance, can indeed be viewed on large-scale, high-resolution paper without difficulty, and known recorders, with inked pens for example, may be suitable for this role.

However, the invention, according to a preferred variant of embodiment, can be advantageously enhanced by a particular choice of the visualization recorder on paper, calling for an inscription by ultraviolet radiation on a paper sensitive to this radiation, created by the spot. mobile of a cathode oscilloscope; the lightness and simplicity of the resulting paper recorder are particularly advantageous in the case of the second operating mode indicated above.

This device makes it possible to write, in addition to the analog diagram recorded itself, all the alphanumeric identification information deemed necessary, and present on the magnetic medium (place of recording, date, time, etc.).

It should also be noted that the insertion of a flexible disk stage, where recording is usually carried out in digital form, is advantageously suitable for its association with a digital type pre-trigger memory, inserted either at the output. from this floor, either at its entrance.

Such a memory allows, in the latter case, a particularly advantageous mode of implementation of the flexible disc, by also subjecting it to the triggered regime, and leaving it inactive, like the paper recorder, between two disturbances.

It should also be noted that the intermediate recording on flexible disc brings a notable improvement to the reliability of the system, the flexible disc device being of essentially electronic design, of reduced electrical consumption, and comprising only a reduced number mechanical elements, moreover inactive in its monitoring function between two disturbances.

After recording on a strip of paper, there are thus two documents, providing an additional guarantee in the event of damage or loss.

Finally, it should be noted that the use, as an intermediate link, of a flexible disk device brings to the study of random disturbances all the advantages of recording data in digital form, in particular the search for disturbances. defined by their characteristics, the comparison between records of the same disturbance from different monitoring stations, the possibility of implementing any data compression law adapted to the type of disturbance, etc.

The invention will be better understood with the aid of the description below, based on the appended figures, where;

- fig. 1 represents a recording device on paper according to the known art,

- fig. 2 shows a recording device according to the invention.

Fig. 1 shows a recording device on paper according to the known art.

It comprises, along a first channel, an input adaptation stage 11 of the quantities or electrical signals to be recorded, stage consisting of a plurality of cells such as 12, a second multiplexing stage 7, connected to the first, a third signal delay stage 21, a fourth demultiplexing stage 17, synchronized with the multiplexing stage 7 by the link 20, and a fifth and last stage, a paper tape recorder 25, with a recording input, such than 18, connected to the previous floor.

The device of the known art further comprises a second channel 30, connected in parallel to the first channel after the multiplexing stage, channel connected to the paper tape recorder via a control circuit. recording 32. Finally, a time stamp circuit 41 is connected to a recording input 70 of the recorder.

The operation of such a device is as follows: the quantities or electrical signals corresponding to the data to be recorded are

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applied to input terminals such as 1, 2, 3 of level, bandwidth matching circuits, etc., such as 4, 5, 6 ... 12.

At the output of this first stage, the signals are applied to the input terminals such as 8,9,10 of a multiplexer circuit 7. The function of this second stage is to successively explore all the signals according to a regime of cyclic scanning, in order to supply the quantities thereof to a single output terminal 13.

The two channels 29 and 30 of the device are connected to this terminal. Via the direct channel 30, the appearance of a signal to be recorded triggers, through the control circuit of the recorder 32, the movement of the recording medium; by the delayed channel 29, the signal undergoes, in the signal delay stage 21, a transmission delay which, after the demultiplexing stage 17, will ensure the desired result of applying it to the input terminal of recording 18 of the recorder, only after the recording medium is in motion.

The design of the delay stage was guided by the fact that it is easier to delay the propagation of an electrical signal in digital form than in analog form. This is why, according to the prior art, the delay stage comprises an analog-digital converter circuit 42, a delay circuit, of the type known as the shift register 43, and a digital-analog converter circuit 44.

The disadvantages of such a recording device have already been indicated above, and result from the limitation of resolution of paper recordings made in real time. An alternative embodiment, which would consist of temporarily placing the signal in a semiconductor memory and then viewing it on paper with a higher resolution, would lead either to a very large dimension of this memory and / or to a limitation the duration of the recordable disturbances.

Fig. 2 shows a recording device according to the invention.

According to a drawing where the same elements as those of fig. 1 bear the same reference numbers, it is characterized by the insertion, in the delay stage 21, of a magnetic recorder with flexible disc.

The operation of such a device is as follows. The signals to be recorded, being applied in analog form to the inputs such as 1,2,3, and multiplexed in 7, are put in digital form in. the conversion stage 42. Us are then delayed, for the reasons already explained in detail above, in a semiconductor memory circuit 43, and introduced into the flexible disk recording stage 50. This stage 50 comprises a recording unit on flexible disk proper 51, associated circuits 52 for processing the signals to be recorded and a control unit 58 for recording operations. These include, on the one hand, recording on disc at 51 when a disturbance is detected, which results in an order transmitted by the link 59, on the other hand, recording on paper, when if desired, data stored at 51 by reading the disc and transfer to the paper recorder 12. The link 61 symbolizes the command of the recorder 25 for viewing on the paper 46.

At the output of the flexible disk recording stage, the signal is applied, as in the device of the known art of FIG. 1, a digital analog conversion stage 44, a demultiplexing stage 17 and a recorder 25 on paper tape.

The associated circuits 52 provide a time stamp function at 53, comprising a real-time counter, controlled by a synchronization line on an external time clock 54. The real-time counter also provides the signals for triggering input scans , via line 55. The associated circuits provide, on the other hand, at 56, a function for processing digital signals and, at 57, a function for formatting words and for inserting identification codes and dating. This processing comprises, according to an advantageous characteristic, a program for compressing the signals to be recorded according to their significant variations, thus aiming not to introduce stationary data into the flexible disk, thereby only memorizing the necessary information in a minimum volume. . The data compression program is as follows:

At the end of each scan cycle carried out by the multiplexing stage, the processing circuit compares the word which has just been stored on each of the channels with that stored on the corresponding channels during a previous scan cycle and , depending on the deviations observed, the circuit decides or not to proceed with the recording of the new scan.

- The decision is made for all the input channels according to the variations of all the channels: the recording is only omitted if all the channels have remained very close to the values taken as reference.

- For security reasons, the processing circuit limits the number of scans eliminated to a predetermined value.

- Each poll recorded is preceded by a code which indicates the number of those that have been eliminated since the last registration.

- The scan taken as reference for the comparison at time t can be that carried out at time t - 1, if the rest state of the monitored lines is completely unknown, or that carried out at time t - T, if a periodic signal of known period T is normally present on the lines.

The tolerances on the comparison and the limit value of the number of scans eliminated are defined according to the use of the recording device itself.

The visualization of the data can be easily carried out, as explained above, by the use of a digital-analog converter 44, followed by a demultiplexer 17, synchronized on the multiplexer 42 by the line 45, and connected to a recorder on paper 25.

Terminal 70 and link 60 in fig. 2 correspond to an arrival of signals already in digital form and for which it is not necessary to pass through the converter 42. With several digital inputs, multiplexing is also to be expected, it being understood that the synchronization of such an assembly can be '' easily perform from the control or management unit 58.

The insertion of a flexible disk recorder, with digital recording, brings moreover, if the paper recorder is suitable for recording data in digital form, the additional advantage of adding to the paper strip, in addition to the analog data corresponding to the signals, the date data, technical conditions, etc., directly in alphanumeric form according to any desired character encoding. This possibility is notably permitted by cathode ray tube recorders on paper sensitive to ultraviolet radiation.

According to a set of orders of magnitude provided by way of example, the following results have been obtained, depending on whether the disturbance recording device is produced according to known art or according to the invention:

For a typical paper scrolling speed of 20 cm / s, a standard paper roll 30 m long allows, according to known art, to record disturbances with a maximum total duration of 150 s, with finesse of given resolution; with the insertion of a flexible disk stage according to the invention, the maximum total duration becomes 400 s without data compression, and 700 s with compression.

Finally, by slowing down the flexible disc during recording on paper, the expansion of the time scale on paper allows an increase in the resolution smoothness of between five and ten times, while maintaining the paper consumption at a value reduced, by selecting only the disturbances considered interesting.

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Claims (5)

634144 1. Device for recording electrical signals corresponding to random disturbances with a view to viewing them on a paper tape recorder (25) comprising: input adaptation means (11) for receiving by inputs respective (1,2,3) the electrical signals and apply them to adaptation circuits (4,5,6,12); multiplexing means (7) for cyclic scanning of the adapted signals; analog-to-digital conversion means (42) for digital conversion of the multiplexed signals; a delay device (43) for delaying the digital signals; means for demultiplexing the delayed signals corresponding to disturbances, and a recorder (25) on paper tape fed by the output of the demultiplexer for viewing said disturbance signals, the device for recording electrical signals being characterized in that that it further comprises a flexible disk recording assembly (50) coupled to the delay device for receiving the delayed signals, comprising a removable flexible disk unit (51) and control means (58) for the rotation of the disc in order to record the delayed signals there each time a disturbance is detected, the disc remaining stationary in the absence of disturbances. 2. Device according to claim 1, characterized in that the recording assembly on flexible disc comprises said control means (58) for recording and reading on the disc and recording on paper, a time stamp circuit (53 , 54), a formatting circuit (57), and processing circuits (56) by compressing the data from the delay device. 2 3. Device according to one of claims 1 or 2, characterized in that the paper recording device (25) is of the cathode-ray tube and paper type sensitive to ultraviolet radiation. 4. Device according to one of claims 1 to 3, characterized in that the paper recorder (25) is produced in portable removable form. 5. Device according to one of claims 1 or 2, and in which a digital-analog conversion circuit precedes the demultiplexing circuit (17), characterized in that the paper recorder (25) is produced in removable portable form .