CH711009A2 - Mass graduation with signal-compensating markings. - Google Patents

Abstract

The invention relates to a material measure (20) for an inductive position measuring system which is formed by a material strip (23) which consists of a ferromagnetic material, wherein the material strip (23) is elongated along a measuring direction (11). Along the measuring direction (11) are arranged a plurality of markings (21) on the strip of material in a row, wherein the markings (21) are respectively formed by openings or recesses of constant depth, wherein the markers (21) each have a marking outline (50), and wherein the markers (21) encode a binary random number sequence. Each marker outline (50) is disposed entirely within an associated imaginary rectangle (60) having first, second, third and fourth rectangle sides (61; 62; 63; 64), the spacing of the third rectangle sides (63) of two Immediately adjacent imaginary rectangles (60) is an integer multiple of a first pitch. According to the invention, the clear distance between two immediately adjacent imaginary rectangles (60) is different from an integer multiple of the first pitch.

Description

The invention relates to a material measure according to the preamble of claim 1.

From EP 2 502 030 B1, a material measure is known, which is intended for use in a position measuring system. The position measuring system is an absolute position measuring system, wherein the markings of the physical scale code a binary random number sequence. The material measure is read inductively by a scanning device. For this purpose, two types of dimensional embodiments come into consideration, namely those which consist of a material with high electrical conductivity, such as copper (eddy current principle) and those which consist of a ferromagnetic material. The present invention is concerned with the latter type.

In inductive scanning typically differentially interconnected coil pairs are used to minimize the signal offset. In EP 2 502 030 B1, these are arranged side by side transversely to the measuring direction, two complementary rows of markings being used. The individual coils of a coil pair are firmly wired together. The applicant has proposed in the not yet disclosed German patent application with the file number 10 2014 216 036.7 a position measuring system that includes only individual coils, which are arranged in the measuring direction in a row. These are dynamically interconnected during operation in different ways, so that the individual coils of a differential coil pair are arranged side by side in the measuring direction. The present invention addresses a problem that occurs primarily in the latter type.

When the receiver coils are moved over a side boundary of a marker, the amplitude of the alternating voltage induced in the receiver coils does not change abruptly, but rather there is a steady increase or decrease in the signal amplitude.

In the known position measuring systems, the markings of apertures or recesses are formed in a strip of material. The corresponding marking outline is rectangular. The width and the clear distance of the rectangles are each an integer multiple of a first pitch. Experiments by the applicant have shown that the induced AC voltage of a single receiver coil, which is exactly centered on an aligned transversely to the measuring direction edge portion of a Markungsumrisses, has an amplitude which is greater than 50% of the maximum amplitude of the induced AC voltage. This considerably complicates the signal evaluation.

An advantage of the invention is that the evaluation of the induced in the receiver coils AC voltages for position determination is particularly simple. In particular, the amplitude of the alternating voltages induced in the receiver coils at a defined position in relation to the division grid corresponding to the first pitch is substantially equal to 50% of the maximum signal amplitude.

According to the independent claim it is proposed that the clear distance between two immediately adjacent, imaginary rectangles is different from an integer multiple of the first pitch. This results in a shift of the signal transition with respect to the mentioned division grid. Said clear distance is preferably selected such that the amplitude of the alternating voltages induced in the receiver coils at a defined position with respect to the division grid corresponding to the first pitch is substantially 50% of the maximum signal amplitude. Said clear distance is the distance of the third and the fourth side of the rectangle of the immediately adjacent imaginary rectangles.

The material band preferably has a constant thickness, which is preferably smaller than the first pitch. The thickness is, for example, 0.3 mm, the first pitch being, for example, 1 mm. The width of the material band is preferably greater than the first pitch, wherein it is for example 5 mm. The material band is preferably made of stainless steel. The markings may be filled with a non-ferromagnetic material, preferably being empty or filled with air. The transmitter winding arrangement and / or the receiver coils are preferably designed as planar winding arrangements. The material measure is preferably part of a guide rail of a linear roller bearing, which is designed, for example, according to EP 1 052 480 B1. If the first or the second side of the rectangle are associated with a plurality of straight sections of the marking outline, which are parallel to the measuring direction and are arranged offset transversely thereto, then said rectangular sides preferably coincide with those straight sections which in total have the greatest length.

In the dependent claims advantageous refinements and improvements of the invention are given.

It can be provided that the marking outlines in each case completely coincide with the associated imaginary rectangle. This is the embodiment which has the least difference compared to the known dimensional scale, while still giving the above-mentioned advantage. This dimensional standard is just as easy to produce as the known dimensional scale. In this case, preferably a photochemical etching process is used.

It can be provided that the third side of the rectangle is associated with a single straight third edge portion of the respective marking outline, wherein the fourth side of the rectangle is associated with a single straight fourth edge portion of the respective marking contour, wherein the third and the fourth edge portion are arranged parallel to each other, whereby they enclose with the measuring direction an angle different from 90 °. In the simplest case, the marking outline is designed in the form of a parallelogram. However, the marking outline may have a shape deviating from a parallelogram in the region of the first and the second side of the rectangle. By this marking outline of the movement path of the scanning device is compared to the scale lengthened by the continuous signal transition takes place at a marking boundary. This ensures that, in each position of the scanning device, each marking boundary of at least one receiver coil is detected in such a way that an alternating voltage is induced whose amplitude lies between the minimum and the maximum amplitude of the induced alternating voltages. This simplifies the determination of the random number sequence read by the material measure. In addition, a positional error of the scanning device with respect to the dimensional scale transversely to the measuring direction has a lower effect than in the above-proposed rectangular shape of the marking contour.

It can be provided that the third side of the rectangle is associated with an outwardly or inwardly bent extending third edge portion of the Markierungsumrisses, wherein the fourth side of the rectangle is associated with an outwardly or inwardly bent extending fourth edge portion of the Markierungsumrisses. Preferably, the third and the fourth edge portion are mirror-symmetrical to each other. It is conceivable that the third and the fourth edge section run in the form of a kink-free arch. The term "bent" is intended to include but also courses of the third and fourth edge portion, which have a kink.

It can be provided that the third and the fourth edge portion each have two straight subsections which enclose an angle which is greater than 90 °. This ensures that the signal curve in the region of a marking boundary is substantially linear. The third and / or the fourth edge portion are preferably formed mirror-symmetrically with respect to a center line of the dimensional scale. Preferably, the third and / or the fourth edge portion have exactly two straight subsections.

It can be provided that the two associated straight subsections adjoin one another in a corner or in a circle radius. The circle radius is preferably made small.

It can be provided that the first and the second side of the rectangle associated edge portions of the marking outline are formed mirror-symmetrically to each other. As a result, signal errors can be avoided, especially those that are not compensated.

It can be provided that the first rectangular side is associated with at least a fifth edge portion of the Markierungsumrisses, which extends bent relative to the measuring direction, wherein the second side of the rectangle at least a sixth edge portion of the Markierungsumrisses is associated, which is bent with respect to the measuring direction. It has been found that the amplitude of the alternating voltages induced in the receiver coils in some positions of said receiver coils in the region of a marking boundary can reach a value which is above the maximum value which theoretically should only occur if the receiver coil is completely over ferromagnetic material , It may also happen that said amplitude falls below a minimum value which theoretically should only occur when the receiver coil is completely over air or a non-ferromagnetic material. This effect can be compensated by the proposed design of the marking outline. The term "bent" is intended to include but also courses of the fifth and sixth edge portion, which have a kink. The fifth and the sixth edge portion may optionally be bent inwards or outwards.

It can be provided that the fifth and / or the sixth edge portion has at least one straight subsection.

It can be provided that the fifth and / or the sixth edge portion has at least one bend-bent subsection.

It can be provided that the first edge portions of all marking outlines are arranged in alignment in the measuring direction, wherein the second edge portions of all marking outlines in the measuring direction are arranged in alignment. During operation of the position measuring system, the material measure is preferably set under tension in such a way that the predetermined first pitch is maintained very precisely. The proposed embodiment of the marking contour cracks avoids that the dimensional scale assumes a deviating from the exact straight shape course. This would result in errors when reading the marks.

It can be provided that the distance of the third and the fourth side of the rectangle between 20% and 50% of the first pitch is greater than the nearest integer multiple of the first pitch. With this design of a marking contour, the signal profile explained above as being preferred results in the region of a marking boundary.

The inventive graduation is preferably used in a position measuring system, wherein a scanning device is provided which has at least five receiver coils which are arranged in the measuring direction in a row, wherein the scanning device has a transmitter winding arrangement which is immovable relative to the receiver coils, wherein the scanning device is movable in the measuring direction along the scale, wherein the receiver coils, the transmitter coil assembly and the scale are arranged so that the position of the scale relative to the scanning affects the inductive coupling between the transmitter coil assembly and the receiver coils. The distance of all pairs of adjacent receiver coils in the measuring direction is preferably equal to a constant second pitch. The second pitch is preferably equal to or less than the first pitch, for example, 0.8 mm.

It can be provided that the transmitter winding arrangement defines a plurality of separate transmitter surfaces, which are arranged in the measuring direction in a row, wherein in a transmitter surface at most one associated receiver coil is arranged. In such a position measuring system, the problem underlying the invention occurs particularly strongly, so that the inventive compensation is particularly advantageous. The receiver coils are preferably arranged completely within the respective associated transmitter surface.

It is understood that the features mentioned above and those yet to be explained not only in the combination specified, but also in other combinations or alone, without departing from the scope of the present invention.

The invention will be explained in more detail below with reference to the accompanying drawings. Show it: <Tb> FIG. 1 <SEP> is a rough schematic representation of a position measuring system according to a first embodiment of the invention; <Tb> FIG. 2 <SEP> is a rough schematic representation of a part of a dimensional scale according to the first embodiment of the invention according to FIG. 1; <Tb> FIG. 3 <SEP> is a rough schematic representation of a part of a dimensional scale according to a second embodiment of the invention; <Tb> FIG. 4 is a rough schematic representation of a part of a dimensional scale according to a third embodiment of the invention; <Tb> FIG. 5 is a rough schematic representation of a part of a dimensional scale according to a fourth embodiment of the invention; <Tb> FIG. FIG. 6 shows a roughly schematic cross section of the position measuring system according to FIG. 1, wherein the markings are formed as openings; FIG. and <Tb> FIG. 7 is a representation corresponding to FIG. 6, wherein the markings are formed as recesses.

Fig. 1 shows a rough schematic representation of a position measuring system 10 according to a first embodiment of the invention. The position measuring system 10 comprises a scale 20 and a scanning device 30. The scale 20 is designed as a material strip 23, which consists of a ferromagnetic material, for example made of stainless steel, for example, it has a constant thickness of 0.3 mm. The measuring scale 20 extends with a constant width 27 in a measuring direction 11. Along the measuring direction 11, a multiplicity of markings 21 are arranged in a row on the dimensional scale 20, which are based on a constant first pitch λ. The markings 21 may be formed either as apertures (# 22 in Fig. 6) or as recesses (# 22a in Fig. 7) of constant depth. The markers 21 may have two states, they may or may not be present. The markers 21 encode a binary random number sequence, wherein a first pitch λ corresponds to a binary digit of this code. The shape of the marks will be explained below with reference to Figs. The markings 21 are designed so that no transverse webs are required in the material band, which are arranged at a distance of the first pitch λ regularly spaced on the material strip 23. Transverse to the measuring direction 11 on both sides of the markings 21, the metal strip 23 has a respective side web 24, so that a contiguous dimensional scale 20 results. The markings 21 are preferably formed as a space filled with air. But they can also be filled with a material which is not ferromagnetic, for example with brass.

The scanning device 30 is movable in the measuring direction 11 relative to the material measure 20. Preferably, the material measure 20 is attached to the guide rail of a linear roller bearing, wherein the scanning device 30 is attached to the associated guide carriage. A corresponding linear roller bearing is known from DE 10 2007 042 796 A1. The scanning device 30 comprises an evaluation module 34, which is preferably designed in the form of a separate electronic board. The remainder of the scanning device 30, namely the transmitter winding arrangement 41, the receiver coils 40, the switching device 70 and the operational amplifier 80, are arranged in close spatial proximity to the graduation 20, whereas the evaluation module 34 can have a larger spatial distance from the graduated mass 20.

The transmitter winding assembly 41 and the receiver coils 40 are each formed as a planar winding arrangements. In Fig. 1, only one winding circulation is shown in each case, wherein both the transmitter winding arrangement 41 and the receiver coils 40 actually each have a plurality of substantially parallel turns of turns. In Fig. 1, a center line 25 is located both in the sender coil assembly 41 and in the dimensional scale 20. 1, congruent to one another, wherein the transmitter winding arrangement 41 and the receiver coils 40 are arranged at a short distance from the material measure 20 (compare FIGS. 6 and 7). Thus, the scale 20 influences the inductive coupling between the transmitter coil assembly 41 and the receiver coils 40. an alternating current fed into the transmitter winding arrangement 41 induces in the receiver coils 40 an alternating voltage whose amplitude depends on the position of the scanning device 30 relative to the graduated mass 20.

The sender winding arrangement 41 is in the present case designed as a meandering structure, wherein it delimits a plurality of separate transmitter surfaces 42, which are arranged in the measuring direction 11 in a row. The transmitter coil assembly 41 includes first and second groups 44; 45 of serpentine formed conductor tracks 43, which intersect several times along the measuring direction 11. At the point marked with the number 46, the said tracks 43 are connected to each other in such a way that the transmitter winding arrangement 41 is formed by a single continuous track. Alternatively, the transmitter coil assembly 41 may be composed of a plurality of individual coils each circumscribing a single associated transmitter surface 42, optionally connected in series or in parallel. When the transmitter winding arrangement 41 is supplied with an alternating current by the alternating current source 31, an alternating electromagnetic field of substantially equal magnitude results in all transmitter surfaces 42, the field direction being opposite in directly adjacent transmitter surfaces 42. The AC power source 31 is preferably part of the evaluation module 34.

In the transmitter surfaces 42, a single receiver coil 40 is completely arranged in each case. In spatial proximity to the receiver coils 40, the operational amplifier 80 is arranged, which is preferably formed fully different. Two adjacent receiver coils 40 each have a constant second pitch 5 in the measuring direction 11, which is for example 0.8 mm. The circuitry of operational amplifier 80 is shown greatly simplified in FIG. 1, with only the two feedback resistors 85, 85 indicative of full differential operational amplifier 80 being used. 86 are shown. The first feedback resistor 85 connects the first input terminal 81 of the operational amplifier 80 to the first output terminal 83 of the operational amplifier 80. The second feedback resistor 86 connects the second input terminal 82 of the operational amplifier 80 to the second output terminal 84 of the operational amplifier 80.

The first and second output ports 83; 84 are connected on the input side to an analog-to-digital converter 32, so that the analog-to-digital converter 32 can measure the corresponding electrical measuring voltage M. The corresponding digital value is passed on to a programmable digital computer 33. The programmable digital computer 33 and the analog-to-digital converter 32 are preferably part of the evaluation module 34, wherein they are most preferably designed in the form of a microcontroller.

The first and second input ports 81; 82 are connected via a switching device 70 to the various receiver coils 40. The switching device 70 comprises a first signal line 75, which is connected to the first input terminal 81 of the operational amplifier 80. Further, a second signal line 76 is connected to the second input terminal 82 of the operational amplifier 80. In each case one terminal of each receiver coil 40 is connected to a third signal line 77. The respective other terminal of a receiver coil 40 is connected via an associated switching means 71; 72 with either the first or the second signal line 75; 76 connected. Preferably, each switching means 71; 72; 73; 74 has a first state in which it has a first electrical resistance, wherein it has a second state in which it has a second electrical resistance, wherein the second electrical resistance is at least 1000 times greater than the first electrical resistance, wherein the at least one switching means between the first and the second state is switchable. In the context of the present application, it is assumed that a receiver coil 40 in the second state of the associated switching means 71; 72 is not connected to the operational amplifier 80. Preferably, the switching means 71; 72; 73; 74 used on the basis of semiconductors. Thus, for example, a first electrical resistance of 0.9 Ω can be achieved, wherein a second electrical resistance can be achieved, which results in a signal attenuation of at least 60 dB. A corresponding switching means is the subject of the data sheet, which was available on 19.03.2015 under the Internet address http://www.ti.com/lit/ds/symlink/ts5a623157.pdf.

In Fig. 1, seven receiver coils 40 are shown by way of example, which are each marked with an index n, which counts up along the measuring direction 11. It is understood that the position measuring system 10 may have significantly more, for example thirty, receiver coils 40. The receiver coils 40 with the indices n = 1, 3, 5, 7 are each connected via a first switching means 71 to the first signal line 75. The respectively arranged therebetween receiver coils 40 with the indices n = 2, 4, 6 are each connected via a second switching means 72 to the second signal line 76. The interconnection described above results in that the two selected receiver coils are connected together differentially, wherein they are connected on the input side to the operational amplifier 80. Accordingly, external interference fields which act on both receiver coils 40 in the same way do not affect the measurement voltage M. For the proper differential interconnection of two receiver coils, it depends on the winding direction of the respective receiver coils and on which terminal is connected to the third signal line 77 at.

With the fourth switching means 74, the third signal line 77 is connected to the first input terminal 81 of the operational amplifier 80. Thus, only a single receiver coil 40 is connected on the input side to the operational amplifier 80, which is connected via a second switching means 72 to the second signal line 76. Incidentally, when a single receiver coil 40 is to be used which is connected to the first signal line 75 via a first switching means 71, only the third switching means 73 alone is closed. With the third switching means 73, the third signal line 77 is connected to the second input terminal 82 of the operational amplifier 80.

The first to fourth switching means 71; 72; 73; 74 are preferably driven by the programmable digital computer 33, wherein the corresponding control lines are not shown in Fig. 1.

FIG. 2 shows a rough schematic representation of a part of a material measure 20 according to the first embodiment of the invention according to FIG. 1. Below the scale 20, a diagram is shown in which a stress ratio k is plotted over a position x. The position x is the position of a single receiver coil (No. 40 in FIG. 1) relative to the physical scale 20. The voltage ratio k indicates the amplitude of the alternating voltage induced in the receiver coil under consideration. The value 100% occurs when the receiver coil is completely over ferromagnetic material. When the receiver coil is completely over a mark 21, the voltage ratio is approximately 0% since the inductive coupling between the transmitter winding assembly and the receiver coil is very weak due to the lack of ferromagnetic material.

In the first embodiment, the marking contour 50 is rectangular, so that the imaginary rectangle 60 completely coincides with the marking contour 50 according to the independent claim. The imaginary rectangle 60 has first, second, third and fourth rectangle sides 61; 62; 63; 64. The first and second rectangle sides 61; 62 are parallel to the measuring direction 11, wherein the third and the fourth side of the rectangle 63; 64 perpendicular to the measuring direction 11. The distance 65 of the first and the second side of the rectangle 61; 62 corresponds to the width of the marking 21. This is slightly smaller than the width 27 of the material strip 23, so that the two opposite side bars 24 remain standing, which hold the material strip 23 in one piece. The distance 66 of the third and fourth side of the rectangle 63; 64 is the length of the mark 21. In the present case, this is somewhat larger than an integral multiple of the first pitch. As can be seen from FIG. 1, the first pitch λ can be determined by measuring, for example, the distances of the third rectangle sides 63 of all markings 21 , wherein the shortest of these distances is equal to twice the first pitch λ.

The distance 66 or the clear distance (No. 67 in FIG. 1) of two immediately adjacent imaginary rectangles 60 is selected such that the path distance 13 of the 50% values 12 of the stress ratio k is as exactly as possible an integer multiple of the first Pitch is λ. For example, if the first pitch λ is 1.0 mm, the pitch 66 may be 1.4 mm, with the pitch (No. 67 in FIG. 1) being 0.6 mm, for example.

Fig. 3 shows a rough schematic representation of a portion of a material measure 20 according to a second embodiment of the invention. The marking outline 50 is in the form of a parallelogram, so that it no longer coincides completely with the imaginary rectangle 60. The imaginary rectangle 60 is shown in FIG. 3 with dashed lines. The single straight first edge portion 51 of the marking contour 50 is located completely on the first rectangle side 61, wherein the first rectangle side 61 is longer than the first edge portion 51. The single straight second edge portion 52 of the marker contour 50 is located entirely on the second rectangular side 62, wherein the second rectangular side 62 is longer than the second edge portion 52.

The third side of the rectangle 63 is associated with a single straight third edge portion 53 of the relevant marking contour 50, which is arranged completely within the imaginary rectangle 60. The fourth rectangle side 64 is associated with a single straight fourth edge portion 54 of the respective marking contour 50, which is arranged completely within the imaginary rectangle 60. The third and fourth edge portions 53; 54 are arranged parallel to each other, wherein they enclose with the measuring direction 11 an angle different from 90 °.

The point 68 at which the third rectangle side 63 coincides with the marking outline 50 is the corner between the third and the second edge portion 53; 52. The point 69 where the fourth rectangle side 64 coincides with the marker outline 50 is the corner between the fourth and first edge portions 54; 51st

As a comparison of FIGS. 2 and 3 shows, the profile of the voltage ratio k over the position x in the region of the 50% values 12 in the second embodiment is significantly less steep than in the first embodiment. The distance 66 or the clear width (No. 67 in FIG. 1) is again selected such that the path distance 13 of the 50% values 12 of the voltage ratio k is as exactly as possible an integer multiple of the first pitch λ.

Fig. 4 shows a rough schematic representation of a portion of a material measure 20 according to a third embodiment of the invention. The imaginary rectangle 60 is shown in FIG. 4 with dashed lines. The single straight first edge portion 51 of the marking contour 50 is located completely on the first rectangle side 61, wherein the first rectangle side 61 is longer than the first edge portion 51. The single straight second edge portion 52 of the marker contour 50 is located entirely on the second rectangular side 62, wherein the second rectangular side 62 is longer than the second edge portion 52.

The third side of the rectangle 63 is associated with a third edge portion 53a of the marking contour 50 that is curved outward. The fourth side of the rectangle 64 is associated with an outwardly curved fourth edge section 54a of the marking outline 50. The third and fourth edge portions 53a; 54a are mirror-symmetrical to each other. The third and fourth edge portions 53a; 54a each have exactly two straight subsections 57, which enclose an angle which is greater than 90 °. The two associated straight subsections 57 adjoin one another in a corner 58. The corners 58 form the points 68; 69, on which the third and the fourth side of the rectangle 63; 64 coincides with the marker outline 50.

The course of the stress ratio k over the position x in the region of the 50% values 12 in the third embodiment is essentially the same as in the second embodiment according to FIG. 3. The distance 66 or the clear width (No. 67 in FIG. 1) is again selected such that the path distance 13 of the 50% values 12 of the voltage ratio k is as exactly as possible an integer multiple of the first pitch λ.

The marking contour 50 according to the third embodiment is formed in total mirror-symmetrical with respect to the center line 25 of the material measure 20. As a result, errors in the scanning of the scale 20 are avoided.

Fig. 5 shows a rough schematic representation of a portion of a material measure 20 according to a fourth embodiment of the invention. This embodiment relates to several further deviations of the actual signal form from the ideal signal form for the signal evaluation. The fourth embodiment of Fig. 5 is a modification of the first embodiment of Fig. 2, but it can also be combined with the second or third embodiment of Figs. 3 and 4, respectively.

In Fig. 5 below, the waveform is drawn with a dashed line, which may result if only the first embodiment of FIG. 2 is used. With a solid line, the waveform is drawn, which results after the compensation measures explained below, and which is particularly suitable for a simple signal evaluation. A total of three types of deviations 14a result between these signal forms; 14b; 15a; 15b; 16, which will be discussed in detail below.

The plateau effect 16 can be observed when the individual coil under consideration is at a great distance from a marking 21 completely above the ferromagnetic material of the material strip 23. The signal amplitude can then be slightly higher than when the individual coil is located at a small distance from a marking 21 completely over the ferromagnetic material of the material strip 23. This plateau effect 16 can be counteracted by auxiliary markings 21a, which are designed to be very narrow compared with the information-bearing markings 21. The auxiliary markings 21a are arranged precisely where there is a plateau effect 16 without auxiliary markings 21a. The width of the auxiliary markers 2 la is just chosen so large that the plateau effect 16 disappears.

The overshoots 14a; 14b can be observed when the individual coil considered shortly before or shortly after a marker boundary 53; 54 is above the ferromagnetic material of the material strip 23. The overshoots 14a; 14b can be counteracted by removing ferromagnetic material in the corresponding region of the material strip 23. For this purpose, a fifth edge portion 55 of the marking contour 50 is provided on the first rectangle side 61 of the auxiliary marking 21a, which is bent outwardly with respect to the measuring direction 11, wherein the second rectangle side 62 at least a sixth edge portion 56 of the marking contour 50 of the auxiliary marker 21 a is assigned with respect to the measuring direction 11 is bent outwards.

The undershoots 15a; 15b can be observed when the individual coil considered shortly after or just before a marking boundary 53; 54 is above the free space of a marker 21. The subjugators 15a; 15b can be counteracted by adding ferromagnetic material in the corresponding region of the material band 23. For this purpose, a fifth edge portion 55 of the marking contour 50 is provided on the first rectangle side 61 of the marking 21, which curve is inwardly bent with respect to the measuring direction 11, wherein the second rectangle side 62 of the marking 21 is associated with at least a sixth edge portion 56 of the marking contour 50 the measuring direction 11 is bent inwards.

The fifth and / or the sixth edge portion 55; 56 may have at least one straight subsection 57a, as shown in FIG. 5 at the overshoot 14b and at the subswinger 15b. The fifth and / or the sixth edge portion 55; 56 may include a kink-free bent subsection 57b, as shown in FIG. 5 at overshoot 14a and at undershoot 15a.

Fig. 6 shows a rough schematic cross section of the position measuring system 10 of FIG. 1, wherein the markings 21 are formed as apertures 22. Accordingly, the markings 21 enforce the entire thickness 26 of the material measure 20. The marking contour 50 is formed substantially constant over the entire thickness 26 of the material strip 23. Deviations can arise due to tolerances due to the preferred production with a photochemical etching process. The openings 22 are preferably etched out of the material strip 23 simultaneously from two opposite sides, so that the etching time is short.

Further, in Fig. 6, the arrangement of the receiver coils 40 and the transmitter coil assembly 41 relative to the measuring scale 20 can be seen. The receiver coils 40 and the transmitter coil assembly 41 are each formed as planar coil arrangements, which are preferably produced by means of a photochemical etching process. In Fig. 6, only a single layer for the receiver coils 40 and the transmitter coil assembly 41 is provided, wherein more layers may be provided to make the number of turns as large as possible. The individual layers are separated from each other by an insulating layer 47, which may for example consist of polyimide. This plastic is electrically non-conductive, withstanding high temperatures. Insofar as the receiver coils 40 and / or the transmitter coil arrangement 41 each have a plurality of layers, these are preferably electrically connected to one another via plated-through holes, the plated-through holes passing through one or more associated insulating layers.

The sensor spacing 17 between the scale body 20 and the assembly, which contains the receiver coils 40 and the transmitter coil arrangement 41, is preferably made small, most preferably smaller than the first pitch λ.

Fig. 7 shows a representation corresponding to Fig. 6, wherein the markings 21 are formed as recesses 22a. The recesses 22 a have a constant depth 22 b, which is equal to, for example, half the thickness 26 of the material strip 23. The recesses 22a are preferably produced by a photochemical etching process, wherein the etching takes place only from one side of the material strip 23. Since the etching depth and therefore the depth 22b of the recesses 22a is difficult to control, the openings according to FIG. 6 are preferred.

Incidentally, reference is made to the comments on Fig. 6, wherein in Fig. 6 and 7 the same or corresponding parts are provided with the same reference numerals.

reference numeral

[0057] <tb> λ <SEP> first pitch <tb> δ <SEP> second pitch <Tb> M <September> measuring voltage <Tb> k <September> tension <tb> x <SEP> Position of a single receiver coil relative to the scale <Tb> <September> <Tb> 10 <September> position measuring system <Tb> 11 <September> measuring direction <tb> 12 <SEP> 50% value of the voltage ratio <tb> 13 <SEP> Distance between the 50% values of the stress ratio <Tb> 14 <September> overshoot <Tb> 14b <September> overshoot <Tb> 15 <September> undershoots <Tb> 15b <September> undershoots <Tb> 16 <September> plateau effect <Tb> 17 <September> Sensor distance <Tb> <September> <Tb> 20 <September> graduation <Tb> 21 <September> Marking <Tb> 21 <September> Auxiliary marker <Tb> 22 <September> breakthrough <Tb> 22 <September> recess <tb> 22b <SEP> Depth of the recess <Tb> 23 <September> material strip <Tb> 24 <September> side bar <Tb> 25 <September> centerline <tb> 26 <SEP> Thickness of the measuring tape <tb> 27 <SEP> Width of the custom tape <Tb> <September> <Tb> 30 <September> scanning <Tb> 31 <September> AC power source <Tb> 32 <September> Analog-to-digital converter <tb> 33 <SEP> programmable digital computer <Tb> 34 <September> evaluation board <Tb> <September> <Tb> 40 <September> receiver coil <Tb> 41 <September> Send Erwin extension arrangement <Tb> 42 <September> Station area <tb> 43 <SEP> Serpentine trace <tb> 44 <SEP> first group <tb> 45 <SEP> second group <tb> 46 <SEP> border between the two groups of serpentine traces <Tb> 47 <September> insulating <Tb> <September> <Tb> 50 <September> mark outline <tb> 51 <SEP> first edge section <tb> 52 <SEP> second edge section <tb> 53 <SEP> third edge section <tb> 53a <SEP> third edge section <tb> 54 <SEP> fourth edge section <tb> 54a <SEP> fourth edge section <tb> 55 <SEP> fifth edge section <tb> 56 <SEP> sixth edge section <tb> 57 <SEP> straight subsection <tb> 57a <SEP> straight subsection <tb> 57b <SEP> kink-free bent subsection <Tb> 58 <September> corner <Tb> <September> <tb> 60 <SEP> imaginary rectangle <tb> 61 <SEP> first rectangle page <tb> 62 <SEP> second rectangle page <tb> 63 <SEP> third rectangle page <tb> 64 <SEP> fourth rectangle page <tb> 65 <SEP> Distance between first and second rectangle sides <tb> 66 <SEP> Distance between third and fourth rectangle sides <tb> 67 <SEP> clear distance between two adjacent rectangles <tb> 68 <SEP> Point at which the third rectangle side coincides with the marking outline <tb> 69 <SEP> Point at which the fourth rectangle side coincides with the marking outline <Tb> <September> <Tb> 70 <September> switching device <tb> 71 <SEP> first switching means <tb> 72 <SEP> second switching means <tb> 73 <SEP> third switching means <tb> 74 <SEP> fourth switching means <tb> 75 <SEP> first signal line <tb> 76 <SEP> second signal line <tb> 77 <SEP> third signal line <Tb> <September> <Tb> 80 <September> Operational Amplifiers <tb> 81 <SEP> first input terminal of the operational amplifier <tb> 82 <SEP> second input terminal of the operational amplifier <tb> 83 <SEP> first output terminal of the operational amplifier <tb> 84 <SEP> second output terminal of the operational amplifier <tb> 85 <SEP> first feedback resistor <tb> 86 <SEP> second feedback resistor

Claims (14)

A dimensional unit (20) for use in a position measuring system (10), the dimensional scale (20) being formed by a strip of material (23) made of a ferromagnetic material, the strip of material (23) being elongated along a measuring direction (11) is formed, along the measuring direction (11) a plurality of markings (21; 21a) are arranged on the strip of material in a row, wherein the markings (21) each formed by openings (22) or by recesses (22a) with a constant depth wherein the markers (21) each have a marking outline (50), wherein at least a part of the markers (21) encodes a binary random number sequence, wherein each marker outline (50) is disposed entirely within an associated imaginary rectangle (60) having first, second, third and fourth rectangle sides (61; 62; 63; 64), the first and second side rectangles (61 62) parallel to the measuring direction (11), the marking outlines (50) each having at least one straight first edge portion (51) coinciding with an associated first rectangle side (61), the marking outlines (50) each at least one straight second one Edge portion (52) coinciding with an associated second side of the rectangle (62), wherein the third and the fourth side of the rectangle (63; 64) coincide at least at one point (68; 69) with the associated marking contour (50) Distance of the third side of the rectangle (63) of two immediately adjacent imaginary rectangles (60) each an integer multiple of a first pitch (λ) is t, characterized in that the clear distance (67) of two immediately adjacent, imaginary rectangles (60) is different from an integer multiple of the first pitch (λ). 2. Massverkörperung according to claim 1, wherein the marking contours (50) in each case completely coincide with the associated imaginary rectangle (60). 3. The measure of claim 1, wherein the third side of the rectangle (63) is associated with a single straight third edge portion (53) of the respective marking contour (50), wherein the fourth side of the rectangle (64) is a single straight fourth edge portion (64) of the respective marking contour (63). 50), wherein the third and the fourth edge portion (53; 54) are arranged parallel to one another, wherein they enclose an angle different from 90 ° with the measuring direction (11). 4. A material measure according to claim 1, wherein the third side of the rectangle (63) is associated with an outwardly or inwardly bent extending third edge portion (53 a) of the marking contour (50), wherein the fourth side of the rectangle (64) curved outwardly or inwardly extending fourth edge portion (54a) of the marker contour (50) is associated. 5. The material measure according to claim 4, wherein the third and the fourth edge portion (53a; 54a) each have two straight subsections (57) which enclose an angle which is greater than 90 °. 6. Massverkörperung according to claim 5, wherein the two associated straight subsections (57) in a corner (58) or in a circle radius adjoin. 7. Mass standardization according to one of the preceding claims, wherein the first and the second side of the rectangle (61; 62) associated edge portions of the marking contour (50) are mirror-symmetrical to each other. 8. Massverkörperung according to any one of the preceding claims, wherein the first side of the rectangle (61) is associated with at least a fifth edge portion (55) of the marking contour (50) which is curved with respect to the measuring direction (11), the second side (62) of the rectangle (62) having at least a sixth edge portion (56) of the marking contour (50) ), which is bent with respect to the measuring direction (11). 9. A material measure according to claim 8, wherein the fifth and / or the sixth edge portion (55; 56) has at least one straight subsection (57a). 10. Massverkörperung according to claim 8 or 9, wherein the fifth and / or the sixth edge portion (55; 56) has at least one buckling bent lower portion (57b). 11. Mass standardization according to one of the preceding claims, wherein the first edge portions (51) of all marking outlines (50) in the measuring direction (11) are arranged in alignment, wherein the second edge portions (52) of all marking outlines (50) in the measuring direction (11) in an escape are arranged. 12. The measure of embodiment according to one of the preceding claims, wherein the distance (66) of the third and the fourth side of the rectangle (63; 64) is between 20% and 50% of the first pitch (λ) greater than the nearest integer multiple of the first pitch (λ). is. 13. Position measuring system (10) with a material measure (20) according to any one of the preceding claims, wherein a scanning device (30) is provided which has at least five receiver coils (40) which are arranged in the measuring direction (11) in a row, wherein the Scanning device (30) has a transmitter winding arrangement (41) which is immovable relative to the receiver coils (40), wherein the scanning device (30) in the measuring direction (11) along the scale (20) is movable, wherein the receiver coils (40) Transmitter winding arrangement (41) and the scale (20) are arranged so that the position of the scale (20) relative to the scanning device (30) influences the inductive coupling between the transmitter winding arrangement (41) and the receiver coils (40). 14. The material measure according to one of the preceding claims, wherein the transmitter winding arrangement (41) delimits a plurality of separate transmitter surfaces (42) which are arranged in the measuring direction (11) in a row, wherein in a transmitter surface (42) arranged at most one associated receiver coil (40) is.