FR2523296A1 - LIGHT SCALE DISCHARGE IN GAS FOR MEASURING APPARATUS - Google Patents

Abstract

THE INVENTION CONCERNS METROLOGY. THE LUMINOUS LADDER CONTAINS, ASSEMBLED BETWEEN THEM IN A WATERTIGHT MANNER, A FRONT PLATE 1 WITH A TRANSPARENT ANODE 2, AND A BASE PLATE 3 PROVIDED WITH AT LEAST ONE ROW OF CATHODES 4 SERVING AS GRADUATION MARKS BETWEEN WHICH THE DISCHARGE IS TRANSMITTED FROM THE FIRST CATHODE SUCCESSIVELY TO THE OTHER CATHODES ON DISPLAY; THE CATHODES 4 ARE ARRANGED SO THAT THEIR ENDS ARE LOCATED ON AT LEAST FOUR SEGMENTS 5 OF A SOFT-CURVED CURVE WHOSE CURVATURE RADIUS ARE LOWER AT LEAST ONE ORDER OF QUANTITY THAN THE CURVATORY RADIUS OF LINE 6 JOINED BY THE EXTREME POINTS OF THE SAID SEGMENTS, AND IN THAT, BETWEEN THE EXTREME CATHODES OF THE SEGMENTS 5 MUTUALLY NEIGHBORING THE SAID CURVE IS PROVIDED FOR A MEANS 7 OF DISCHARGE TRANSFER ENSURING THE PRIMING OF THE CATHOD 4 COMING FIRST ON THE FOLLOWING SEGMENT OF THE ' LADDER, FROM THE PREVIOUS CATHODE 4. THE INVENTION APPLIES IN PARTICULAR TO ELECTRIC MEASURING EQUIPMENT INTENDED TO MEASURE CURRENT, VOLTAGE AND OTHER ELECTRICAL PARAMETERS IN CONTROL AND COMMAND SYSTEMS.

Description

The present invention relates to metrology and particularly relates to

a gas-discharge ladder

  in a gas for a measuring device.

  Gas discharge light scales are generally used in electrical measuring devices intended for measuring current, voltage and other electrical parameters in control and control systems. Existing analogue scales do not allow the operator to read the instrument readings without error, which significantly reduces the informative value of the devices in accuracy classes from 0.5 to 1.5. Optoelectronic scales improve the ergonomic qualities of the devices, but the rectilinear or circular graduation does not prevent the operator the errors when the reading takes place at the rate of about 1 sign per second. The linear scales which present the information in the form of a uniform rectilinear strip have, moreover, the disadvantage of misinforming the operator, and

  the reading error is 0.5%. In case of graduation

  the reading error is limited to a few hundredths percent only on a small part of the scale, while on the rest it is 0.3% because of reading errors occurring during reading of the indications, the operator can not fully use the

  measuring and control apparatus.

  There is a gas discharge light scale for an indicator (see "Discrete Scale Indicators" by V G Samorodov, Central Research Institute "Electronika", Moscow, 1977, p. 31) with two rows

  rectilinear cathodes used as graduation lines.

  One trait in five is highlighted, that is, offset

  following the vertical relative to the neighboring features.

  The cathodes, which are in the form of nickel layers deposited on an electric coating of a base plate, are grouped into three circuits each of which is connected to a power source. The scale contains an auxiliary cathode intended to prepare the discharge between

the cathodes of the ladder.

  During display, the anode placed on the front plate and the first cathode circuit are energized The first cathode, the closest to the auxiliary cathode, becomes the seat of a discharge Then the voltage is applied to the second The cathode circuit and the discharges starts on the second cathode disposed next to the first, the discharge goes off. Then, the voltage is applied to the third cathode circuit, and the third cathode becomes the seat of a discharge, while on the second cathode the discharge disappears As the fourth cathode is connected to the first circuit, the powering up of the first circuit causes the fourth cathode to start. The propagation of the discharge along the graduation continues until the order number of a cathode becomes equal to the quantity to be measured Then, the anode supply is cut off and the discharge on the scale stops The cycle of discharges is repeated to you several times and luminescence cathodes is

  provided by the operator as a continuous band of light.

  Said scale is difficult to read without error,

  and this, because of the equidistance of its graduation features.

  There is also a gas discharge light ladder for a measuring device, comprising a sealed assembly of a front plate with a transparent anode and a base plate carrying at least one row of cathodes serving as graduation lines and whose intervals, from the first to the last cathode, are covered by the discharge when the measured parameters are displayed (see "Discrete Scale Indicators" by VG Samorodov, Central Research Institute

"Elektronika", Moscow, 1977, P 34).

  Said light gas discharge ladder is circular, that is to say that its features are located along the rays, and the ends of the lines, on the arc of the circle One line out of five is highlighted by an excess of length The cathodes are in the form of conductive layers deposited on the dielectric coating of the base plate. The cathodes are grouped in three circuits, the raised lines forming a single circuit whose discharge current exceeds that of the other circuits because the largest area of the features in relief The scale has an auxiliary cathode

role of preparing the discharge.

  In view of the display, the anode is energized

  placed on the front plate and the first cathode circuit.

  On the first cathode, the closer to the auxiliary cathode, begins the discharge Then the voltage is

  applied to the second cathode circuit, and so on.

  The discharge on the second line is initiated by the discharge region of the first line The third line lights up at the next step of power switching At any moment there is discharge on a single cathode The spread of the discharge along the graduation continues until the order number of a cathode becomes equal to the quantity to be measured The successive luminescence of the discharges on the cathodes appears to the operator as a band

of continuous light.

  The graduation being circular, the reading error is important, especially on the parts of the scale where the inclination of the lines with respect to the vertical exceeds these parts occupy nearly half of the scale, also, for the circular scales, the reading error

  is it a few tenths percent.

  The present invention therefore aims at a gas discharge light scale for a measuring device, the graduation lines of which would be arranged so as to avoid the error of reading over the entire

length of the ladder.

  This object is achieved by means of a gas discharge light scale for a measuring device, comprising a sealed assembly of a front plate with a transparent cathode, and a base plate provided with at least one a row of cathodes serving as graduation lines and between which the discharge is transferred from the first successively to the following during the display of the parameters to be measured, said scale being, according to the invention, characterized in that the arrangement of the cathodes is such that their ends are on at least four segments of a gently sloping curve, the radii of curvature of said segments being at least an order of magnitude smaller than that of the line joining the end points of the segments, and that, between the extreme cathodes, arranged on the adjacent segments of the gently sloping curve, is disposed a means of

  transfer of the landfill in order to ensure the priming of

  first cathode placed on the next scale segment at

from the previous cathode.

  It is reasonable for the discharge transfer means to be in the form of a triangle-shaped cathode whose lateral sides are disposed in close proximity to the adjacent features of adjacent segments of the

gentle slope curve.

  It is useful that the ends of the cathodes lie on the segments of a curve whose convexity

  curvatures are oriented in the same direction.

  The gas discharge light ladder according to the invention has high ergonomic qualities and completely eliminates reading errors. Each line is distinguished from the neighbor by its arrangement on the segment of the gently sloping curve from one segment to another. the other, the groups of features are easy to distinguish from one another and are easily counted as a result of the large curvature of the segments. The operator perceives the tape as a band of repeated arcs. located on one of the diverging rays, the inclination of any ray by

  vertical ratio not exceeding a certain angle.

  The length of the arc of each segment is 800 and these arcs are arranged along the horizontal A

  The minimum reading error is obtained because the inclination

  maximum distance from the vertical of the rays along which the lines are arranged does not exceed 40. The invention will be better understood and other purposes, details and advantages thereof will become more apparent in the

  light of the explanatory description which will follow from

  various embodiments given solely by way of nonlimiting examples, with references to the accompanying non-limiting single drawing in which: FIG. 1 represents the gas discharge light scale for a measuring device (front view) according to FIG. 'invention; Figure 2 shows the section II-II of Figure 1 according to the invention; and

  FIG. 3 illustrates a particular embodiment

  of the discharge transfer means (on an enlarged scale),

according to the invention.

  The gas discharge light ladder for a measuring apparatus comprises a glass front plate 1 (FIGS. 1 and 2) on the surface of which is deposited a transparent anode 2, and a base plate 3 The base plate 3 carries at least one row of cathodes 4 in the form of metal plates or metallization layers deposited on an insulating layer (not shown) fixed on the base plate 3 + The cathodes 4 constitute the lines or marks of graduation, the ends said curves being arranged in a curve The curve is composed of at least four gently sloping segments 5, the number of which is determined by that of the graduation lines The number of traits 4 ts of graduation corresponds in turn to the class of prec 1 S n

of the measuring device.

  The radii of curvature of the segments 5 of the gently sloping curve are at least an order of magnitude smaller than that of the line 6 joining the end points of the segments. The lines are arranged in groups on the different segments. of each segment 5 is

  close to that of an arc and measure from 300 to 800.

  Such an arc length makes it possible to clearly distinguish between each other the neighboring segments 5 and, consequently, the neighboring groups of features, which ensures a better

reading accuracy.

  Between the lines of the neighboring segments 5 there is a discharge transfer means 7 serving to prime the first cathode 4 of the next segment of the scale, to

  from the previous cathode 4.

  The means 7 is presented in the example in the form of a cathode in the form of a triangle whose lateral sides are in the immediate vicinity of the lines

adjacent.

  According to an alternative embodiment, the extreme cathodes of the neighboring groups are provided with horns 8 (FIG. 3) placed close to one another to form

  the discharge transfer means 7.

  The convexity of the segments 5 of the curve along which the ends of the lines are arranged is

  oriented in the same direction (Figure 1).

  The scale comprises an auxiliary cathode 9 intended to initiate the discharge on the first cathode 4 of the scale, the closest to this cathode 9, at the moment

initial reading.

  The cathodes 4 of the ladder are electrically connected

  between them so as to form three separate circuits, connected to a power source (not shown), so that the first, fourth, seventh, etc., cathodes constitute the first circuit, the second, fifth, eighth, etc. , cathodes constitute the second circuit, which the third, sixth, ninth, etc., cathodes constitute

the third circuit.

  The scale has raised lines whose function is, in this case, filled by cathodes of the discharge transfer means 7 Scale encryption is optional; sometimes, for ease of reading, the numbers are shown on the front plate 1 next to the lines

highlighted.

  The order number of each line depends on its geometrical group and its position in the group. The angle between the one hand, the radius on which any of the lines are arranged, and on the other hand the vertical, does not exceeds 400, which ensures a high accuracy of the

reading.

  The operation of the luminous ladder for discharge

  in a gas according to the invention is carried out as follows.

  The reading of the indications provided by the measuring apparatus takes place in the working mode of the scale and begins with the energizing of the anode 2 (FIG. 1) and the priming of the auxiliary cathode 9. in circuit the first cathode 4, o discharge occurs through the connection with the discharge region of the auxiliary cathode 9 Discharge lit on the first cathode 4 is maintained for a time sufficient to ensure the

  required speed of operation of the ladder and the

  of the normal discharge regime, then the circuit of the first cathode 4 is cut off and simultaneously the circuit of the second cathode 4 is energized Discharge occurs only on the second cathode 4, which is due to its near the discharge area of the

first cathode 4.

  After the extinction of the second cathode, the ignition of the third cathode 4 is carried out analogously and the process is repeated until the initiation of the discharge on the cathode 4 whose order number is defined by the value of the magnitude to be measured; The number of lit lines corresponds to the value to be displayed, these lines being perceived by the operator as a corrugated band of light

keep on going.

  The presentation of the graduation lines highlighted in the form of figures whose contour is close to a triangle makes it possible to better delimit the groups and to draw a ciphered line, the orientation of the sides of said lines along the lines of the contiguous groups ensuring the better the transfer of the discharge between groups of features. Thus designed, the scale according to the invention ensures optimal reading conditions not only in the case where the lines are located on portions of curves whose centers of curvature are located on the same side of the curve, but also when part of the features are located on the parts of a periodic curve whose centers of

  curvature are arranged on both sides of it.

  Comparative tests for reading the scale according to the invention and that of the known indicator have shown that, on reading 700 indications regularly distributed along the scale, the relative reading error constitutes, for the scale of the known indicator, 0.54%,

  and for the scale according to the invention, 0.06%.

R E V END I C AT IO N S

  Gas discharge light scale for a measuring apparatus, of the type comprising, in a sealed manner, a front plate (1) with a transparent anode (2), and a base plate (3) provided with at least one row of cathodes (4) serving as graduation marks between which the discharge is trani: c of the first cathode successively to the other cathodes during the display of the parameters to be measured, characterized in that the cathodes (4 ) are arranged so that their ends are situated on at least four segments (5) of a curvature curve whose radii of curvature are at least one order of magnitude smaller than the radius of curvature of the line (6) which joins the extreme points deadits segments, and in that, between the extreme cathodes of the segments (5) mutually adjacent to said curve, is

  a discharge transfer means (7) ensuring the amor-

  cathode (4) coming first on the segment

  next scale, from the cathode (4) above.

  Gas-discharge light scale according to Claim 1, characterized in that the discharge transfer means (7) is a triangular-shaped cathode whose lateral sides are in close proximity to the adjacent cathodes arranged on them. adjacent segments (5) of said gently curved curve, 3 gas discharge light scale according to

  one of claims 1 and 2, characterized in that

  the ends of the cathodes (4) are located on the segments (5) of a curve whose convexity successive curvatures

is oriented in the same direction.