DE102011106940A1 - Position measuring unit for measuring position of measuring scale i.e. broad strip, and sampling unit, has pairs of receiver coils switched in series manner, where distance between pairs of coils is integral multiple of pitch distance - Google Patents

Abstract

The unit (10) has a measuring scale (20) at which measuring marks (21) are periodically arranged along a measuring direction (11). A pair of receiver coils (E11) is arranged within a transmitter coil in the measuring direction. Another pair of receiver coils (E13) is arranged within another transmitter coil in the measuring direction, where the pairs of coils are switched in a series manner. Winding directions of the pairs of coils are equal to or opposite to the transmitter coils, where distance between the pairs of coils is an integral multiple of a pitch distance (lambda).

Description

The invention relates to a position measuring device according to the preamble of claim 1.

From the EP 1 164 358 B1 is a position measuring device known. According to the 16 of the EP 1 164 358 B1 the position-measuring device comprises a material measure and a scanning device. The material measure comprises a multiplicity of mutually identical measuring markings, which are arranged distributed periodically along a measuring direction, wherein they have a pitch λ. The material measure may be, for example, a sheet-metal strip, wherein the measurement marks are formed by rectangular openings in the sheet-metal strip.

The scanning of the EP 1 164 358 B1 is movable in the measuring direction relative to the material measure. It comprises a transmitter winding arrangement, which consists of planar, non-overlapping coils EK1, Es1, Ec1, ..., Esn, Ecn, Ek2, which are connected in parallel. In this case, the material measure influences the electromagnetic field of the transmitter winding arrangement such that electrical voltages are induced in the receiver coil pairs S1- / S1 +,..., Cn + / Cn-1, by means of which it is possible to deduce the relative position between the material measure and the scanner. This is an incremental position-measuring device, ie it must be determined by counting the measuring markings at which point of the material measure the scanning device is located. By contrast, within the pitch λ, the position can be determined absolutely by interpolation.

In the context of this application, a printed conductor arrangement which generates substantially the same electromagnetic field as a coil-shaped or spiral-shaped printed conductor is referred to as an effective coil. This is particularly intended to an embodiment in which a plurality of effective coils are formed by a serpentine conductor track, as for example from the DE 10 2009 042 940 or the US 3 466 580 is known.

In the 10 of the EP 1 164 358 B1 the electromagnetic field of the transmitter winding arrangement is shown roughly schematically. It can be seen on the one hand that two adjacent transmitter coils have an opposite winding direction. It can also be seen that the first and the last transmitter coil generate an electromagnetic field deviating from the other transmitter coils. This effect is in the embodiment according to 16 of the EP 1 164 358 B1 compensated in that in the said outer transmitter coils EK1, EK2 no receiver coil pairs Si- / Si + or Ci- / C + are arranged so that all receiver coil pairs are exposed to a substantially identical transmitter field. Thus, an identical voltage is induced in all receiver coil pairs of the sine and cosine groups, which is added by the series connection of the receiver coil pairs in a group, so that a particularly strong measurement voltage is generated.

The disadvantage of the known position-measuring device is the space requirement of the compensation transmitter coils EK1, EK2, in which no receiver coil pairs are arranged. The object of the invention is to provide a position measuring device in which the edge error of the transmitter field is compensated without separate compensation elements.

This object is achieved according to claim 1, characterized in that a first pair of receiver coils, which is arranged within the transmitter coil located first in the measuring direction, and a last pair of receiver coils, which is arranged within the last in the measuring direction transmitter coil, are connected in series, wherein the winding directions of the the first and last receiver coil pairs and the first and last transmitter coils are either both equal or opposite to each other, the spacing of the first and last receiver coil pairs being an integer multiple of the pitch λ. Accordingly, a receiver coil pair is arranged in each case in the first and the last transmitter coil, so that no installation space for separate compensation transmitter coils is required. The measuring voltages of the first and the last receiver coil pair are added by series connection. The distance of said receiver coil pairs is chosen so that they have the same relative position with respect to the associated measuring mark of the material measure. The claimed winding directions of the transmitter and receiver coils cause the useful portion of the measuring voltage of the first and the last receiver coil pair to be added up. The changed field at the edge of the transmitter winding arrangement generates opposite pole voltage components in the two receiver coil pairs, so that the edge effects cancel out by the series connection. The mentioned field error at the edge is mainly due to the fact that the first and the last effective transmitter coil have only one adjacent transmitter coil, whereas the other transmitter coils have an adjacent transmitter coil on both sides. The amount of error voltage in one of the individual coils of the receiver coil pair depends mainly on the distance of the single coil to the adjacent transmitter coil. For effective compensation it is therefore necessary that in each case two individual coils, which have the same distance from the adjacent transmitter coil, have an opposite interference voltage. The interference voltage is that voltage which is induced by the single adjacent transmitter coil in the single coil of the receiver coil pair. The proposed winding direction of the effective transmitter and the associated effective receiver coils exactly the desired effect is achieved. All other combinations with respect to the winding direction do not lead to the desired effect, ie either the useful voltage components of the first and the last receiver coil pair do not add up or the desired compensation does not take place.

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

The transmitter winding arrangement and / or the receiver coil pairs may each have a first and a second group of conductor tracks whose ends are electrically conductively connected to each other, wherein the conductor tracks of a group each serpentine parallel to each other at a small distance, with the interconnects of the two groups intersect such in that they define several effective coils. An effective transmitter coil is in each case formed by an arc section of the first group of conductor tracks and the associated arc section of the second group of conductor tracks. In this embodiment, all effective coils of the transmitter coil assembly and a receiver coil pair, respectively, are surrounded by the same current. This ensures that, in particular, all effective transmitter coils generate an electromagnetic field that is identical except for a sign difference. Consequently, the inventive compensation of the edge effect is particularly good. It should be noted that in particular the relevant first and last transmitter coils must generate the same electromagnetic field.

This is usually not the case if several of the out of the EP 1 164 358 B1 known individual coils are connected in parallel. The various individual coils have due to manufacturing tolerances significantly different from each other resistive resistors, so that they are traversed by a parallel connection of significantly different currents. The actually desirable series connection of the individual transmitter coils is usually out of the question, since the resulting total resistance of the transmitter winding arrangement would be too great. By contrast, the proposed pairs of serpentine conductor tracks can be connected in any desired series or in parallel in order to set the desired total resistance. This leaves no influence on the uniform current distribution in all effective transmitter coils. It should also be noted that the proposed serpentine patterns can also be applied to the receiver coil pairs to improve their compensation effect on external interference fields.

There may be a plurality of groups of series-connected receiver coil pairs, the group having the first and the last receiver coil pair having a receiver coil pair more than the remaining groups of receiver coil pairs, wherein a receiver coil pair is arranged within all effective transmitter coils. It is fundamentally conceivable not to provide one of the centrally situated effective transmitter coils with a receiver coil pair. However, this would waste space, without this being a technical benefit. It is therefore advantageous to provide all effective transmitter coils with a receiver coil pair. So that the compensation according to the invention results, the group with the first and the last receiver coil pair must have a receiver coil pair more than the other coil groups. Usually, two groups of receiver coil pairs are used whose measuring voltages are phase-shifted by 90 °. However, it is also conceivable to use more than two groups, as this can increase the measurement accuracy. A corresponding position measuring device is the subject of a further patent application, which was filed at the same time by the applicant.

For the pitch distance δ of the transmitter coil arrangement, the relationship n × λ = m × δ holds, where n and m are arbitrarily positive integers. From the EP 1 164 358 B1 the case m = n = 1 is known. However, the position measuring device according to the invention also works in cases where m and n are different. As an example let n = 11 be called with m = 6. The number m also indicates how many groups of receiver pairs connected in series must at least be provided. As far as m is odd, at least m groups of receiver coil pairs must be provided. If m is even, at least m / 2 sets of receiver coil pairs must be provided. In the example above, three groups are required. By separating the series connection of a group, of course, more groups can be generated, but this brings no technical benefit.

One effective transmitter coil each can define a sensing element with the associated effective receiver coil pair, with all sensing elements except the winding direction being substantially identical. Two sensing elements are essentially identical when the effective Transmitter coils generate the same electromagnetic field, the receiver coil pairs react in the same way to this field. In the case of planar coils, it does not matter in particular how different conductor track sections are connected to one another as long as the spatial distribution of the currents remains the same. In the embodiment proposed above, the compensation according to the invention is particularly good, since all the scanning elements have the same electromagnetic behavior.

All sensing elements may be substantially symmetrical with respect to a central axis. The sensing elements are substantially symmetrical about the central axis when the current distribution in the respective tracks is symmetrical to the central axis. In this embodiment, it is ensured that the transmitter coil adjacent to a receiver coil pair to the left and the transmitter coil adjacent to the right have the same effect on the receiver coil pair except for a sign difference. Thus, the compensation according to the invention is particularly good in this embodiment.

The invention will be explained in more detail below with reference to the accompanying drawings. It shows:

1 a rough schematic side view of a position measuring device according to the invention;

2 a rough schematic plan view of the sender winding arrangement of the position measuring device according to 1 ; and

3 a rough schematic plan view of the receiver winding arrangement of the position measuring device according to 1 ,

1 shows a rough schematic side view of a position measuring device according to the invention 10 , The position measuring device 10 includes a material measure 20 and a scanner 30 , The measuring standard 20 consists of a large number of identical measuring marks 21 , which at a constant pitch λ periodically along the measuring direction 11 are arranged. The measuring standard 20 can be formed, for example, by a metal strip extending in the direction of measurement 11 extends, with the measurement marks 21 be defined by rectangular openings in the metal strip. The width of the openings and the width of the intermediate webs is the same size and is therefore λ / 2. Other conceivable embodiments are in the EP 1 164 358 B1 with reference to the local 2 explained.

The scanning device 30 is in measuring direction 11 opposite the measuring standard 20 movable, the position measuring device 10 a scanning signal U ₁ , U ₂ , U ₃ outputs, based on which the relative position of said components 20 . 30 can be determined. The measuring standard 20 is contrary to the representation in 1 considerably longer than the scanner 30 , so that the position measuring device 10 has a sufficiently large measuring path.

At this point it should be noted that the 1 to 3 with respect to the measuring direction 11 drawn to scale. In particular, the position of the various effective coils S _ij , E _ij with respect to the measurement marks 21 represented according to the actual conditions. It should be pointed out in particular that the first receiver coil pair E _{11 has} the same relative position with respect to the associated measuring markings 21 occupies like the last receiver coil pair E ₁₃ . In the direction perpendicular to the measuring direction 11 the size ratios are greatly exaggerated for the sake of clarity. The material measure has, for example, a pitch of 1.0 mm, the thickness of which is, for example, 0.3 mm. The thickness of the various planar trace assemblies in the scanner 30 is for example 0.3 mm.

In 1 is the constant pitch of the scanner 30 namely the distance between two receiver _{coil pairs} E _ij denoted by δ. Between the pitch λ of the material measure 20 and the pitch δ of the scanner 30 applies in the embodiment according to the 1 to 3 the relationship 6 × δ = 11 × λ. In this selection, a scanning device with three groups of receiver coil pairs E _{ij is} realized, wherein between two adjacent receiver coil pairs E _ij each sufficient clearance for the transmitter coil arrangement is present, so that the transmitter and the receiver winding arrangement 40 ; 50 do not overlap. Corresponding to the above connection between the pitches δ and λ, three groups of receiver coil pairs E _{ij are} provided whose scanning signals U ₁ , U ₂ , U ₃ are phase-shifted by 120 °.

2 shows a rough schematic plan view of the transmitter winding arrangement 40 , The transmitter coil arrangement 40 consists of a first and a second group 41 ; 42 of printed conductors, being in 2 only one single trace of each group is shown. In fact, each track group includes 41 ; 42 a plurality of conductor tracks, which are arranged at a small distance parallel to each other. The tracks of each track group 41 ; 42 each run in the form of a rectangular snake line, where they are so cross that define a plurality of effective transmitter coils S _ij . Contrary to the illustration in 2 the tracks run in the crossing area 43 exactly parallel so that the effective transmitter coils S _ij each have exactly the shape of a rectangle. The individual effective transmitter coils S _ij are all essentially identical, so that they all generate the same electromagnetic field. In this case, each effective transmitter coil S _{ij is} mirror-symmetrical to an associated central axis 31 executed. The transmitter winding arrangement thus also defines the pitch δ of the scanning device 30 , The two groups of tracks 41 ; 42 are each arranged in different, electrically isolated layers, so that in the crossing area 31 no electrically conductive connection between the two groups of conductors 41 ; 42 consists. Depending on a conductor track of the first and the second group are via a via 44 electrically conductively connected to each other so that all traces of a single voltage terminal U _S can be powered. The transmitter coil arrangement 40 is supplied during operation with AC voltage having, for example, a frequency of 100 kHz. The required frequency results from the maximum travel speed of the position-measuring device 10 and the pitch λ of the material measure 20 ,

The current direction of the individual effective transmitter coils S _ij is in 2 represented by circular arrows. It should be pointed out that the present interconnect arrangement inevitably has the consequence that two adjacent effective transmitter coils S _ij each have the opposite winding or current direction. The current intensity and thus the field strength of each effective transmitter coil S _ij can be set to any value by means of the number of parallel conductor track. As a rule, you will choose the highest possible transmitter field strength. Thus, the installation space between the receiver coil pairs E _{ij is provided} with the highest possible number of parallel conductor tracks, which can be manufactured with technical safety.

3 shows a rough schematic plan view of the receiver winding arrangement 50 , The receiver winding arrangement 50 comprises a plurality of receiver _{coil pairs} E _ij . Each receiver coil pair E _ij consists of two complementary individual coils En _ij , Ep _ij , ie, the individual coils are made essentially identical, wherein they have an opposite direction of winding. The two individual coils En _ij , Ep _ij have the shape of a rectangular spiral, with their decency λ / 2. The rectangular spirals each have a plurality of Windungsumläufen on, in 3 only one single winding circulation is shown. The opposite winding direction of the individual coils En _ij , Ep _ij is in 3 indicated by rectangular arrows. in 1 For example, a minus sign denotes a winding direction in the counterclockwise direction and a plus sign indicates a winding direction in a clockwise direction. In the present embodiment, all receiver coil pairs have the same winding direction.

It should be noted that in the receiver coil pairs E _ij also the intersecting groups of serpentine tracks can be used, as in the transmitter winding arrangement 40 Find use. However, this promises only a slight technical advantage, since the receiver coil pairs can be easily connected in series in order to obtain the desired summation of the individual voltages. In contrast, the spiral-shaped coils are to be preferred, since a maximum number of winding turns can be accommodated in a predetermined number of printed conductor levels.

The receiver coil pairs E _ij are each connected in series to groups. The first group comprises the receiver coil pairs E ₁₁ , E ₁₂ , E ₁₃ , the second group the receiver coil pairs E ₂₁ , E ₂₂ and the third group the receiver coil pairs E ₃₁ , E ₃₂ . In the 3 Plotted connecting tracks represent the interconnection of the receiver coils in the sense of a circuit diagram correctly, with the rest, no relation to the actual trace course is present. The individual receiver _{coil pairs} E _{ij of} a group each have the same relative position relative to the associated measurement mark 21 or a 180 ° out of phase relative position. The distance of the receiver coil pairs is accordingly an integer multiple of the pitch λ or of λ / 2. Insofar as there is a phase shift, the associated effective transmitter winding arrangement S _{ij has} a reverse winding sense, so that the measurement voltages induced in the receiver coil pairs add up and do not cancel out.

In the present embodiment, the receiver coil pairs E ₁₁ , E ₁₂ and E _{13 are} connected in series to a first group of receiver coil pairs. The receiver coil pairs E ₁₁ and E ₁₃ each have the same relative position to the associated measuring mark, wherein the associated effective transmitter coils S ₁₁ and S _{13 have} the same winding direction. By contrast, the receiver coil pair E ₁₂ is arranged 180 ° out of phase with respect to the associated measuring mark, the transmitter coil S ₁₂ having an opposite winding direction with respect to the transmitter coils S ₁₁ and S ₁₃ . At this point it should be pointed out again that all receiver coils have the same winding direction. The required polarity reversal of the Receiver coil pair E ₁₂ could of course also be generated by reversing its winding direction. However, this is not contemplated in the present embodiment because of the present design of the transmitter coil assembly 40 the winding directions of the individual effective transmitter coils S _{ij is} fixed.

The edge effect that is to be compensated by the compensation arrangement according to the invention is due to the fact that acting on a pair of receiver coils not only the directly associated effective transmitter coil S _ij , but also the adjacent effective transmitter coils. This is mainly due to the immediately adjacent effective transmitter coils, while the effects of the more distant effective transmitter coils can be neglected, since the field strength of an effective transmitter coil decreases rapidly with increasing distance.

In the present scanner 30 have the receiver coil pairs E ₂₁ , E ₃₁ , E ₁₂ , E ₂₂ , E ₃₂ each to the left and to the right side an immediately adjacent effective transmitter coil S _ij . These two adjacent transmitter coils together generate an electromagnetic field with respect to the central axis 31 of the interposed receiver _{coil pair} E _{ij is} symmetrical. In this way, the opposite winding direction of the two individual coils En _ij , Ep _{ij of} a receiver coil _pair E _{ij leads} to the cancellation of the voltages induced by the adjacent transmitter coils.

The first and last receiver coil pairs E ₁₁ and E ₁₃ each have only a single immediate adjacent effective transmitter coil S ₂₁ and S _32, respectively. The effect described above can therefore not come into play. In the mentioned receiver coil pairs E ₁₁ and E ₁₃ therefore an interference voltage is induced, which falsifies the measurement result. With the interconnection of the receiver coil pairs E ₁₁ and E ₁₃ according to the invention, it is achieved that these two interference voltages cancel out exactly, so that there is no longer a falsification of the measurement result. It is assumed that the transmitter coils S ₂₁ and S ₃₂ generate a substantially identical electromagnetic field, so that in the individual coils En _{11 ,} Ep ₁₁ and En ₁₃ , Ep ₁₃ induced voltages only from the distance between the transmitter coils and the Depend on assigned single receiver coils. Accordingly, the effective transmitter coil S ₂₁ induced in the single coil Ep ₁₁ the same magnitude as the transmitter coil S ₃₂ in the single coil En ₁₃ , since both have the same distance. However, the voltages mentioned have an opposite sign, since the individual coils Ep ₁₁ and En _{13 have} an opposite winding direction. By the series connection of the receiver coil pairs E ₁₁ and E ₁₃ , the said voltages extinguish. The individual coils En ₁₁ and Ep _{13 also} have the same distance to the effective transmitter coils S ₂₁ and S ₃₂ , so that here, too, a corresponding cancellation effect occurs. If one reverses the winding direction of the first and / or the last receiver coil pair E ₁₁ , E ₁₃ , this remains without influence on the compensation effect described above, if at the same time the winding direction of the associated effective transmitter coil S ₁₁ and S _{13 is} reversed.

As the above statements show, it is crucial for the compensation effect that all effective transmitter coils S _ij generate the same electromagnetic field. Therefore, the compensation effect according to the invention with that of the EP 1 164 358 B1 known transmitter winding arrangement 40 can not be achieved in practice with several spiral-shaped transmitter coils, since significantly different currents flow in the parallel-connected transmitter coils due to their tolerance-induced different ohmic resistances. The known transmitter coils therefore do not all generate the same electromagnetic field, so that the compensation effect does not occur. Compensation is only possible in practice by a transmitter winding arrangement according to claim 2, which ensures that the same currents flow in all effective transmitter coils. This is again on the DE 10 2009 042 940 the entire contents of which are referred to and incorporated in the present application.

The second and the third group of series-connected receiver coil pairs E ₂₁ , E ₂₂ and E ₃₁ , E ₃₂ each comprise one receiver coil pair less than the first group E ₁₁ , E ₁₂ , E ₁₃ . The resulting difference in the signal strengths must be taken into account in the evaluation of the measuring voltages applied to the terminals U ₁ , U ₂ , U ₃ . The mentioned measuring voltages are sinusoidal signals which have the same frequency as those in the transmitter winding arrangement 40 fed AC voltage, wherein the amplitude of the relative position between the scanning device 30 and material measure 20 depends. The present position measuring device 10 operates incrementally, ie when the scanner 30 is shifted by a pitch λ, the same measurement voltages U ₁ , U ₂ , U _{3 are} output.

It should also be noted that the 1 to 3 are each shown congruent. Ie. mentally the receiver turn arrangement 50 according to 3 via the transmitter winding arrangement 40 according to 2 pushes you get a true proportions corresponding scanner 30 in which the Single coils En _ij , Ep _{ij of} the receiver coil _arrangement 50 completely within the associated effective transmitter coils S _{ij of} the transmitter coil arrangement 40 are arranged. This fact is also 1 to be taken at the perpendicular to the measuring direction sections 43 the transmitter coil arrangement 40 are arranged between the receiver _coil pairs E _ij .

LIST OF REFERENCE NUMBERS

λ

Pitch of the material measure

δ

Pitch of the scanner

S _ij

effective transmitter coil

U _s

Voltage connection of the transmitter winding arrangement

En _ij , Ep _ij

Single coil

E _ij

Receiver coil pair, consisting of the individual coils En _ij

U _i

Voltage connection of the receiver winding arrangement

10

Position measuring device

11

measuring direction

20

Measuring standard

21

measurement mark

30

scanning

31

Center axis of a scanning element

40

Send Erwin extension arrangement

41

first group of tracks

42

second group of tracks

43

perpendicular to the direction of measurement extending section; crossing area

44

via

50

Empfängerwindungsanordnung

51

Distance between the first and last receiver coil pairs

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• EP 1164358 B1 [0002, 0002, 0003, 0005, 0005, 0010, 0012, 0019, 0032]
• DE 102009042940 [0004, 0032]
• US 3466580 [0004]

Claims (6)

Position measuring device ( 10 ) comprising a material measure ( 20 ) and a scanner ( 30 ), whereby at the material measure ( 20 ) along a measuring direction ( 11 ) periodically arranged, mutually identical measuring marks ( 21 ) are provided, which have a pitch λ, wherein the scanning device ( 30 ) relative to the material measure ( 20 ) in the measuring direction ( 11 ) is movable, wherein the scanning device ( 30 ) a transmitter coil arrangement ( 40 ) whose electromagnetic field from the measuring markings ( 21 ) of the material measure ( 20 ), the transmitter winding arrangement ( 40 ) several along the measuring direction ( 11 ), periodically arranged, planar, non-overlapping effective transmitter coils (S _ij ), wherein two immediately adjacent transmitter coils (S _ij ) have an opposite winding direction, wherein within at least a portion of the transmitter coils (S _ij ) each a single planar receiver coil pair (E _ij ) is arranged, which in each case has two effective individual coils (En _ij , Ep _ij ), which are connected in series with opposite winding direction, whereby in the measuring direction ( 11 ) Are staggered with a pitch of λ / 2, where all the effective individual coils (En _ij, Ep _ij) are carried out with the exception of the winding is substantially equal, characterized in that a first receiver coil pair (E _11), which within the measuring direction ( 11 ) first transmitter coil (S ₁₁ ) is arranged, and a last receiver coil pair (E ₁₃ ), which within the direction of measurement ( 11 ) last transmitter coil (S ₁₃ ) is arranged, are connected in series, wherein the winding directions of the first and the last receiver coil pair (E ₁₁ , E ₁₃ ) and the first and the last transmitter coil (S ₁₁ , S ₁₃ ) either both the same or both are opposite, with the distance ( 51 ) of the first and last receiver coil pair (E ₁₁ , E ₁₃ ) is an integer multiple of the pitch λ. Position measuring device according to claim 1, characterized in that the transmitter winding arrangement ( 40 ) and / or the receiver _{coil pairs} (E _ij ) each have a first and a second group ( 41 ; 42 ) of printed conductors whose ends are connected to one another in an electrically conductive manner, the printed conductors of a group ( 41 ; 42 ) in each case run in a serpentine manner with a small distance parallel to one another, wherein the interconnects of the two groups ( 41 ; 42 ) so as to define a plurality of effective coils (S _ij ). Position measuring device according to one of the preceding claims, characterized in that a plurality of groups of series-connected receiver coil pairs (E ₁₁ , E ₁₂ , E ₁₃ , and E ₂₁ , E ₂₂ , and E ₃₁ , E ₃₂ ) are provided, wherein the group with the first and the last receiver coil pair (E ₁₁ , E ₁₃ ) has a receiver coil pair more than the other groups of receiver coil pairs, wherein a receiver coil pair (E _ij ) is arranged within all effective transmitter coils (S _ij ). Position measuring device according to one of the preceding claims, characterized in that for the pitch δ of the transmitter winding arrangement 40 the relationship n × λ = m × δ holds, where n and m are arbitrarily positive integers. Position measuring device according to one of the preceding claims, characterized in that each one effective transmitter coil (S _ij ) with the associated effective receiver coil pair (E _ij ) defines a sensing element, wherein all sensing elements except the winding direction are made substantially identical. Position measuring device according to claim 5, characterized in that all scanning elements substantially symmetrical with respect to a central axis ( 31 ) are executed.

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