DE4430392A1 - Absolute position indicator of turning or translation movement of machine part - Google Patents

Abstract

A mask (1) contains in the direction of movement a number of adjacent scanning areas (2) with intervening gaps (4) to allow the penetration of a sensor beam. Inside are impenetrable or reflective areas (3). Sensor beam transmitter units (5-8) and a receiver are positioned on either side of the mask (1). A processing device is operated by the receiver.Either the mask (1) or the transmitter-receiver is attached to the machine part while the other components remain stationary. A control device pulses the sensor beam transmitter units (5-8) in the direction of movement. The processing device determines the position of the machine part by comparing the on- and off-times of the transmitted pulses.

Description

The invention relates to an absolute encoder for Er setting the position of a rotating or translational Component according to the preamble of claim 1. Derarti ge encoders serve the purpose of rotating the angular position of a the component, e.g. B. a shaft or rotatable with this connected components, or the translation position of a e.g. B. from an associated linear moving actuator Detect component driven by translation.

An absolute angle position encoder of this type is, for example known from DE 41 11 562 A1. As electromagnetic Ab tactile radiation is there z. B. uses visible light that is generated by LEDs. As a structured aperture element elements serve pulse disks on several coaxial Circular rings each coded in a specific way, i. H. With a sequence of translucent and opaque Be rich are provided, e.g. B. in a Gray code. Everyone coded Circular ring represents an information channel, the one LED transmitter on one side of the pulse disc and an associated Photo receiver on the opposite pulse is assigned. Those captured by the photo receivers optical signals are converted into electrical signals and selected in a subsequent electrical circuit  tet. In addition to a gearbox made of pulse disks designed gears, which the detection of multiple allowed rotations, the local encoder has another Ge The usual single pulse disk for determination the angular position within one revolution of the pulse disc rotatably holding shaft, which on the other hand rotates firmly connected to the rotating component to be measured is. The LEDs are switched on continuously in measuring mode tet, and on the receiver side, this is for the respective angle position characteristic pattern of one in the individual Ka existing or missing light transmission as ent speaking bit pattern evaluated. The higher the resolution for the angular position detection should be, the narrower the field the with translucent or opaque area Chen and the more information channels, d. H. bar coded Pulley disk rings are required. The manufacture Technically achievable precision of the generation of the lini adhesive, translucent and opaque area che on the pulse disc and the achievable accuracy when reading the Si resulting from these lines gnale ultimately limits the achievements with this technology clear resolution. The same also applies if instead of this be knew transmitted light arrangement which also be as an alternative Known reflection arrangement is selected in the transmitter and Receiver unit on the same side of the pulse disc are arranged and the latter in fields with one light each casual and a reflective area is divided.

The invention is the technical problem of providing an absolute position encoder of the type mentioned at the beginning the basis with which with a comparatively small construct tion effort can achieve a high resolution.

This problem is solved by an absolute encoder with the Features of claim 1 solved. In contrast to the be Known donors of this type are several transmitters in the Direction of movement of the panel element one behind the other  arranged and consequently the same scanning fields on the Blen associated with the element. These transmitters are not in measuring mode permanently switched on, but are ge via a controller clocks on and off at a definable frequency, the control for the individual transmitters out of phase ben takes place. By time-resolved acquisition of the Blen the element in the case of a transmission arrangement NEN or reflected in the case of a reflection arrangement Radiation, e.g. B. light generated by light emitting diodes, and Ver equal to a related signal with one or more Control signals for the transmitters are therefore possible on the relative position of the transmitter arrangement within the area ei to close the scanning field. This results in a with low construction effort realizable increase in Resolving power in absolute position detection. On place an ever finer structuring of the aperture element There is a specific, temporal discretization of the scanning radiation such that the time course of the received by the receiver unit via the aperture element Radiation clearly from the relative location of the Transmitter arrangement within a scanning field, consisting of one radiolucent and one radiopaque field or reflecting field area. The resolution solution is therefore practically not due to the limited reducer availability of the technically feasible structural dimensions limited to the aperture element, the problem of resolution rather on the electronic, signal generating and signal evaluating page transfers, where a certain resolution solution is comparatively easier to achieve. If about that entire range of motion to be recorded several such scanning fields assigned to the clocked transmitters are arranged one behind the other and therefore each make up only part of the range of motion Advantageously, the encoder also has a conventional level type with bar-coded aperture element and in permanent radiation operation working radiation transmitter and emp catcher unit to the position of the component to be monitored  to determine exactly down to the extent of a scanning field, within which then the encoder part according to the invention completely the exact position is determined. For such a supportive Aperture element coding is not an overly fine structure ren required, so that the design effort is low remains.

In a development of the invention, the single is according to claim 2 summary recording of the total over time including the amount of radiation arriving at the receiver unit seen, so that no sharp local separation and thus Zu order for a respective transmitter for the received beam tion is required, which is also a design effort saves. The training is based on the knowledge that that due to the mutually out of phase clocking The transmitter itself sends the total signal to the receiver radiation incident in its temporal course still clearly from the position of the transmitter arrangement voltage within a scanning field.

A good resolution is a further development of the invention beneficial according to claim 3. This transmitter arrangement causes that only beam in each position of the diaphragm element a total of one transmitter or two adjacent transmitters partially reached the receiver unit, for example from the time difference of this periodically arriving beam to the control clock of a selected transmitter teln, the radiation of which transmitter or which two Transmitter is currently being received, which as a result at the level of the radiation-permeable or radiation reflection ting field area can be recognized horizontally. It is by evaluating the respective share of two transmitters incoming mixed radiation also the detection of intermediate positions possible. A spatial resolution can thus be achieved len, which is usually significantly higher than the dimension of one radiation-transmitting or reflecting scanning field empire. It should be noted that there are several  Scanning fields are not required, all transmitters inside to be arranged in a row half of the same scanning field. Rather, the transmitters can add an arbitrary amount times the extent of a scanning field against each other ver be set, receiving the same functionality remains and otherwise possibly existing difficulties ten should be avoided in the spatial arrangement of the transmitters.

In claims 4 to 6 are three advantageous, alternative Embodiments specified, with claims 4 and 5 on the measurement of rotatable and the claim 6 on the Measurement on components that can be moved. Here the encoder performs the resolution of the rotation according to claim 4 angle measurement within a certain angular range, except for which a position detection by a conventional structure th encoder part can take place while the encoder according to claim 5 of the angle of rotation detection over the entire range of 360 ° serves.

According to claim 7 is advantageously provided that Carry out signal evaluation for position detection, that from a reference point in time, e.g. B. the time of on switching a predetermined reference transmitter, the time period is measured until one of the beams received since then signal dependent on the quantity specified stical limit value. This period is for egg NEN comparatively easy to measure and secondly in one the current position of the ball denelementes dependent on the transmitter arrangement, so that from it a clear statement about the position of the can make coupled, movable component.

In a development of the invention is according to claim 8 Microcontroller provided at a corresponding Output of an internal clock signal to the on control of the transmitter is used, for which a previous Frequency division can be useful. It is understood that  the microcontroller simultaneously other functions in the Donor can meet. So the serves in an advantageous manner Microcontroller in development of the invention according to claim 9 in addition to the evaluation of the measurement data by such is used, which has an internal time counter , with the length of time from the beginning of a bar of the internal clock signal up to a subsequent one Level change one at an associated controller input lying signal is detected. If at this input the from dependent on the radiation incident on the receiver unit microprocessor is capable of applying the evaluation signal the time between the switch-on time is very precise of a particular transmitter that is in sync with the level change of the underlying clock signal, and a signal flank rise of the result of the received radiation renden evaluation signals, z. B. due to an overshoot a predetermined limit according to claim 7, and consequently the position of the moving component to be monitored determine. In addition, the microcontroller can be used if necessary also as an evaluation unit for an additional, conventional one Encoder stage with one or more bar-coded balls act the elements.

Preferred embodiments of the invention are as follows explained in more detail with reference to the drawings, in which:

Fig. 1 is a schematic, plan view of a hälftige arranged in an encoder pulse disc and the associated light transmitter unit,

Fig. 2 is a schematic, side view of the hälftige pulse disc of FIG. 1 with an associated light transmitter and light receiver unit,

A transition signal beitungsstufe Fig. 3 shows the temporal waveforms of the four LEDs of the light emitter unit of Figs. 1 and 2 and of the off in Fig. 4 shown Signalverar,

Fig. 4 is a schematic block diagram of relevant elec tronic components of the encoder of Figs. 1 to 3,

Fig. 5 is a plan view of another example of a pulse disc and an associated arrangement of ge clocked, light-emitting transmitters for an absolute angle encoder and

Fig. 6 is a plan view of a linear rail as a structured diaphragm element and an associated arrangement of four clocked, light-emitting transmitters for a transmitter for detecting the absolute position of a translatable component.

In Fig. 1, a pulse disk ( 1 ) as a structured Blen denelement and a light transmitter arrangement of four LEDs ( 5 , 6 , 7 , 8 ) is shown, which are part of an absolute position sensor for detecting the position of a rotatable component. The rotatable with the monitored, rotatable construction part connectable pulse disc ( 1 ) has a Kreisringbe rich, which is divided into 32 identical scanning field sectors ( 2 ), each consisting of an opaque area ( 3 ) and a translucent area ( 4 ) , these areas being arranged alternately in the direction of rotation. The angular width (b2) of the opaque areas ( 3 ) is three times as large as that (b1) of the translucent areas ( 4 ), so that the angular width (b3 = b1 + b2) of a scanning field ( 2 ) 11.25 °, that (b1) of a translucent area ( 4 ) is a quarter of this value and that (b2) of the translucent areas ( 3 ) is three fourths of this value. The LED transmitters ( 5 to 8 ) are all within this in the scanning fields ( 2 ) subdivided th pulse disc ring on one side of the pulse disc ( 1 ) so arranged in the direction of rotation one behind the other that the projected in the direction of rotation distance (ds) be adjacent transmitter is approximately equal to the angular width (b1) of a translucent field area ( 4 ), so that the entire transmitter arrangement ( 5 to 8 ) extends just over the angular width (b3) of a scanning field ( 2 ). If the spatial arrangement of the four stations shown in Fig. 1 (5 to 8) (2) Difficulties are inner half of the same scanning field due to spatial tightness, so, any of these Sen can instead (5 to 8) at the location shown to a ganzzah The multiple of the scanning field angle width (b3) can be offset within the pulse disk circular ring without changing the mode of operation explained in more detail below. Instead of visible light, e.g. B. Alternatively, infrared radiation can be used.

In the side view of Fig. 2, the transmitter unit ( 5 to 8 ) on the opposite side of the pulse disk ( 1 ) assigned to the receiver unit ( 9 ) can be seen, which contains four individual ne photodiodes ( 10 , 11 , 12 , 13 ), which ei ner LEDs ( 5 to 8 ) are assigned to detect the light generated by the latter if there is a translucent field area ( 4 ) of the pulse disk ( 1 ) in between. The outputs of the four photodiodes ( 10 to 13 ) are combined to form a common signal output ( 14 ), via which a signal is emitted which corresponds to the total of the light received by the four photodiodes ( 10 to 13 ).

The encoder, which includes the components of the pulse disc ( 1 ), light transmitter unit ( 5 to 8 ) and light receiver unit ( 9 ), also has a conventional and therefore not shown and not to be described encoder part, with which the position of the coupled rotary movable component up to the angular width (b3) of a touch panel ( 2 ) is determined, and if necessary the conventional transmitter stage can be constructed such that multiple revolutions of the rotatable component are also detected. For this purpose, the encoder can have a completely separate stage from the one shown in FIGS . 1 and 2, the conventional stage can, however, also be integrated into this stage by using additional circular ring zones with conventional ones on the pulse disk ( 1 ) in a manner not shown Barcode structuring, e.g. B. in a Gray code, are provided, which corresponding conventional light transmitter and light receiver units are assigned, in which light is continuously emitted from the transmitters on the pulse disk in measurement mode.

The encoder part outlined in FIGS . 1 and 2 then, together with the clocked LED control explained below and a suitable evaluation of the signals at the receiver output ( 14 ), provides a more precise resolution of the angle of rotation position within the angular width (b3) of a scanning field ( 2 ). The associated functional principle is explained on the basis of the signal curves in FIG. 3. The four LEDs ( 5 to 8 ) are clocked on and off by a control unit provided for this purpose in accordance with the uppermost four signal curves shown in FIG. 3, the signal ( 25 ) the LED ( 5 ), the signal ( 26 ) the LED ( 6 ), the signal ( 27 ) act on the LED ( 7 ) and the signal ( 28 ) on the LED ( 8 ). Without restricting generality, it is assumed that the high signal level corresponds to an on and the low signal level corresponds to an off LED. As can be seen from FIG. 3, all LEDs ( 5 to 8 ) are driven with the same clock frequency and the same blanking ratio of 1: 1, but the clock signals for the LEDs ( 5 to 8 ) starting from the one in FIG. 1 are the furthest LED ( 5 ) on the left in the direction of rotation progressively shifted from one to the next LED by 90 °, ie a quarter period, phase shifted. Accordingly, if, as shown in Fig. 3, the left LED ( 5 ) is switched on at a reference time t₀ and this switch-on process is repeated after a clock period T at a time t₁ = t₀ + T, then the switch-on times of the other LEDs follow the reference time (t₀) at times t₂ = t₀ + T / 4, t₃ = t₀ + T / 2 and t₄ = t₀ + 3T / 4).

On the receiver side, the total amount of light striking the receiver unit ( 9 ) from the reference point in time (t₀) is detected and subjected to an analysis with an integrating component. The corresponding evaluation signal obtained by processing the receiver output signal ( 14 ) is shown in its temporal course as the lowest signal curve ( 29 ) in FIG. 3. The processing is carried out by means of a proportional and integral signal processing unit, which generates a typically sinusoidal signal from the receiver output signal ( 14 ), followed by a comparator stage. The latter is based on the generation of level changes in the event of limit violations and undershoots of the sinusoidal signal, e.g. B. the same at zero crossings, is provided. For further evaluation, in particular the time (t _e ) of the first level rise of the evaluation signal ( 29 ) is evaluated on the basis of a first zero crossing on the falling flank of the sinusoidal signal after the reference time (t₀). It is ensured that this level increase at time (t _e ) occurs in any case within the given clock period (T), which can be ensured by suitable system adaptation for any angle of rotation position, the arrangement of the transmitters ( 5 to 8 ) being among others can be matched to the sequence of the scanning fields ( 2 ) in such a way that at least the light of one transmitter or respectively light portions of two transmitters always strike the receiver unit ( 9 ).

It is clearly understood from FIGS. 1 and 3 that the position of the point in time (t _e) of the limit value is exceeded, within one transmitter control clock in an unambiguous manner on the instantaneous angular position of the code disc (1) rela tive to the stationary light transmitters (5 to 8) is dependent. If, for example, the pulse disk position shown in FIG. 1 is present, in which the LED ( 5 ) which is first switched on is located in a translucent field area ( 4 ), the entire light of this LED ( 5 ) is already on the receiver unit at the start of a transmitter control cycle ( 9 ), which is why the level change of the evaluation signal ( 29 ) has already been reached at an early point in time (t _e ), which is consequently very close to the reference point in time (t₀). If there is a pulse disc position as an extreme counterexample, in which the LED ( 8 ) on the right in FIG. 1 lies exactly on a light-permeable field area ( 4 ), the other three LEDs ( 5 to 7 ) are largely from an adjacent, light impermeable area ( 3 ) is covered, and consequently it is only after three quarters of a transmitter control cycle period that more light falls on the receiver unit ( 9 ), so that the evaluation signal level change only shortly before the end of a full control cycle for the reference LED ( 5 ) it follows, ie in this case the associated time (t _e ) is very close to the time t₁ = t₀ + T. Between these at the extreme positions, the position of the level change instant (t _e ) within the reference clock period (T) changes visibly steadily with the change in the angular position of the pulse disk ( 1 ) relative to the four transmitters ( 5 to 8 ) within a scanning field angle width ( b3).

A high spatial resolution for the measurement of the rotational angle is also achieved for the positions within a scanning field ( 2 ), without the pulse disk ( 1 ) for this purpose having to have approximately as fine line structures as it corresponds to this achievable resolution. Rather, this resolution is achieved by direct detection and suitable analysis of the phase-shifted light transmitter units ( 5 to 8 ), only a summary detection of the amount of light transmitted on the receiver side is required Lich, without the signals of the individual photodiodes ( 10 to 13 ) being evaluated separately Need to become. The encoder constructed in this way consequently enables a high resolution in the detection of the angle of rotation position with comparatively little design effort.

In Fig. 4, important circuitry components of the encoder for fulfilling the above functions are shown in block diagram form. The central component of this encoder electronics is a microcontroller, e.g. B. of the conventional type 87C51FA from Intel Corporation, which has an internal counting device, so-called "Programmable Counter Array (PCA)". The microcontroller ( 15 ) has an internal clock, whose clock signal is available at an output ( 16 ). A frequency divider ( 17 ) is connected to this output ( 16 ), which divides the clock frequency into a clock frequency desired for the LED control. The divided frequency clock is supplied to an LED control stage ( 18 ), which generates the LED control clock signals shown in FIG. 3, phase-shifted against one another, and acts on the LEDs ( 5 to 8 ).

In addition to the function as a control-generating unit, the microcontroller ( 15 ) also functions as an essential part of the evaluation part. For this purpose, the common output signal ( 14 ) of the four photodiodes ( 10 to 13 ) of the receiver unit ( 9 ) leads to a signal processing stage ( 19 ) which, as described above, processes the receiver output signal ( 14 ) with an integrating property via an integrating and proportional component and this signal is then fed to a comparator, also provided in this stage ( 19 ), for the purpose of recognizing limit violations and underruns, which generates the evaluation signal ( 29 ) on the receiving side shown in FIG. 3, below. This signal is given by the signal processing stage ( 19 ) to an input ( 20 ) of the microcontroller ( 15 ), which is linked to its internal time counter in such a way that this time counter is able to record the length of time that a change in level of the output ( 16 ) output clock signal until a first subsequent edge rise of this signal at the input ( 20 ) passes. This shows that the microcontroller ( 15 ) uses this internal time counter to determine exactly the time between the reference switch-on time (t₀) of the reference LED ( 5 ) and the time (t₃) represented by a signal edge increase of the level change of the receiver-side evaluation signal can The internal microcontroller structure with respect to this time counting device can also be used to the extent that after a detected edge rise and consequently an end to the time counting, the counting result, which represents the time period sought, is immediately placed in a callable register, while the time counter itself simply continues to run , whereby the time counter value is loaded into a register at each reference time (t₀). The micro controller ( 15 ) already has several selectable frequency dividing stages internally, of which expediently one is selected which corresponds to the frequency division of the external frequency divider ( 17 ) or in any case does not share more than this ( 17 ). By forming the difference between the count value stored in the register for the signal edge rise and the count value stored in the register for the reference time (t₀), the microcontroller ( 15 ) determines the desired time shift between the level change time (t₃) and the reference time (t₀) and gives the corresponding value, which is a clear measure of the angular position of the pulse disk ( 1 ) relative to the stationary light transmitters ( 5 to 8 ) within a scanning field ( 2 ), at an output ( 21 ) for display purposes. The use of the internal time counter of the microcontroller ( 15 ) on the one hand eliminates the need for an external timer that is functionally analogous and also provides a highly precise time measurement method, since one and the same time clock serves both to generate the light signal for the control clock and to count the time required for the level change after the start of the reference clock , which automatically prevents corresponding synchronization problems.

The microcontroller ( 15 ) can also be used with multistage ge designed absolute position encoder as an evaluation unit for the conventional angular position detection stages, as illustrated in FIG. 4 for the case that the encoder in addition to the encoder part according to the invention according to FIGS . 1 and 2 beyond a multi-turn encoder stage ( 23 ) and a conventional single revolution stage ( 22 ). The multiple rotation stage ( 23 ) is used for the detection of full 360 ° revolutions of the rotatable component, for which the sensor has, for example, the known, initially mentioned pulse disk transmission together with associated light generating and light receiving units ( 23 ), the receiver-side downstream evaluation units, e.g. B. Schmitt trigger building blocks are connected in a symbolically indicated manner to associated evaluation inputs ( 24 ) of the microcontroller ( 15 ). The conventional single rotation stage ( 22 ) includes a conventional, bar-coded pulse disk, not shown, with which the angular position of the coupled, rotatable component can be determined within one revolution up to the angular width (b3) of a scanning field ( 2 ) according to FIG. 1, for which in turn one conventional pulse disc with comparatively coarse and therefore less expensive bar coding is sufficient. Via a downstream evaluation unit, e.g. B. another Schmitt trigger module, this stage ( 22 ) is connected to associated inputs ( 30 ) of the microcontroller ( 15 ) for evaluation, so that then at the output ( 21 ) of the microcontroller ( 15 ) a the absolute angle of rotation position Coupled component clearly reproducing signal is present, the full revolution portion of the conventional multiple revolution stage ( 23 ), the angular position portion within one revolution up to a scanning field angle width (b3) from the conventional single revolution stage ( 22 ) and its resolution-determining portion within the scanning field angle width ( b3) is provided by the donor part according to the invention.

In Fig. 5 is another example of a pulse disc ( 40 ) with associated LED light transmitter arrangement ( 41 ) on one side of the pulse disc and associated receiver unit, not shown, on the other side of the pulse disc for an encoder with clocked light transmitter arrangement for detecting the absolute angular position of a given rotatable component again. The transmitter arrangement consists of eight equidistant in the direction of rotation over a circular ring area within the expansion of the pulse disk ( 40 ) arranged LEDs ( 41 ). The pulse disc ( 40 ) is completely opaque except for a tangent to this annulus area, translucent strip ( 31 ), the rotational angle distance of the LEDs ( 41 ) and the shape of the translucent strip fens ( 42 ) are matched so that they are always straight one LED completely or two adjacent LEDs partially lie over the area of the translucent strip ( 42 ). The phase-shifted, clocked activation of the eight LEDs ( 41 ) in turn results in the analog effect as in the case of the arrangement of four sensors described above.

In contrast to the arrangement of FIG. 1, the arrangement of FIG. 5 performs the detection of the angle of rotation position over the entire range of a full revolution with a lower resolution overall due to the further selected light transmitter spacing, this full range of revolution for the transmitters ( 41 ) effectively in essentially consists of a scanning field, the effective translucent area of which forms a circle segment ( 43 ). The angular extent of the segment corresponds approximately to twice the angular distance between two adjacent LEDs, while the opaque area of the touch panel makes up the remaining part of a full revolution. The eight transmitters ( 41 ) are in turn not shown in a manner not shown eight separate photodiodes analog to the example above, whose output signal is additively linked and evaluated in the same manner as described above. Based on the time shift of the limit violation based on the respective start of the cycle of a selected reference LED, this encoder can determine the angle of rotation within a full revolution relatively accurately, for which purpose, instead of a highly precise bar coding, only the simple design of the pulse disk shown with a light-through is shown casual stripes in connection with the clocked light transmitter control is required.

In Fig. 6 a structured in the form of a diaphragm member movable in translation in its longitudinal direction linear rail (50) is shown with an associated array of four light transmitters (51). Such an arrangement is for a sensor for detecting the position of a translatable construction part, the z. B. is driven by a servomotor, a settable. The linear rail ( 50 ) is designed to be opaque except for a translucent strip ( 52 ) arranged with a component running transversely to the direction of movement, and the four LEDs ( 51 ) lie in a line one behind the other in the direction of movement, the distance (d1) between two LEDs being approximately corresponds to the effective width (b4) of the translucent strip ( 52 ). As described in the first exemplary embodiment from FIGS . 1 and 2, the four LEDs ( 51 ) on the other side of the linear rail ( 50 ) in turn are assigned a unit unit consisting of four individual photodiodes, not shown. The control of the four LEDs ( 51 ) and the evaluation of the receiver output signal is carried out as described in this example above, so that there is a fully analog operation, with the modification that with this linear position transmitter the translation instead of the angular position of a moving component within of the movement area limited by the two outermost LEDs is detected.

Of course, further modifications are for the expert NEN and combinations of the arrangements described above possible Lich, whereby it is characteristic that several statio radiation emitters in the same structured area of a to the moving component to be monitored  couplable aperture element are assigned and clocked are switched on and off in phase with each other, where the position of the component from the temporal relationship of the receiver-side signal to the transmitter control signals len is determined. It is understood that it le diglich on the relative movement of the aperture element on the one hand and radiation transmitter and receiver on the other hand arrives, so that, alternatively to the above examples, the aperture element stationary and transmitter and receiver units to the moveable che component can be provided coupled.

Claims (10)

1. Absolute position encoder for detecting the position of a rotating or translatable component, with

• - A structured diaphragm element ( 1 ) with one or more, one behind the other in the direction of movement from touch panels ( 2 ), each consisting of a transparent for a given ne scanning radiation ( 4 ) and an opaque or reflective field area ( 3 ), which che in the direction of movement are arranged one behind the other, and
• - A scanning radiation transmitter unit ( 5 to 8 ) and an associated scanning radiation receiver unit ( 9 ) and an evaluation unit ( 19 , 15 ) connected downstream of the receiver unit, wherein either the diaphragm element or the transmitter and the receiver unit can be connected to the rotating or translationally movable component so that it cannot move , while the other component is arranged stationary,

characterized in that

• - The transmitter unit contains at least two spaced transmitters in the direction of movement ( 5 to 8 ) and a Sen deransteuerungseinheit ( 15 , 16 , 17 , 18 ) for periodic switching on and off of the transmitter in measuring mode, wherein
• - The consecutive transmitters in the direction of movement are each switched on and off with a mutual phase shift and
• - The receiver unit ( 9 ) downstream evaluation unit ( 19 , 15 ) generates an evaluation signal dependent on the amount of radiation received by the receiver unit and compares it with that of the on / off control for the transmitter and uses it to compare the position of the movable component within the range From a touchpad determined.

2. Absolute position sensor according to claim 1, further characterized in that the receiver unit ( 9 ) which from the Sen ( 5 to 8 ) emitted and transmitted from the aperture element sene or reflected amount of radiation is summarized. 3. Absolute position sensor according to claim 1 or 2, further characterized in that the transmitter arrangement comprises at least four transmitters ( 5 to 8 ) which are located one behind the other with a distance (ds) projected in the direction of movement, which is approximately between the single and double the value of effective width (b1) of a transmissive or reflective field region ( 4 ) plus any integer multiple of the effective width (b3) of a scanning field ( 2 ) be. 4. Absolute position sensor according to claim 3 for detecting the position of a rotatable component, further characterized in that a pulse disk ( 1 ) is provided as the diaphragm element, which has a ring zone evenly divided into a plurality of scanning fields ( 2 ), with each scanning field from a permeable field area ( 4 ) and an impermeable field area ( 3 ) with approximately three times the width of the permeable field area and the ring zone four transmitters ( 5 to 8 ) are assigned. 5. Absolute position sensor according to claim 3 for detecting the position of a rotatable component, further characterized in that the transmitters ( 41 ) are arranged equidistantly distributed over a circular line and that a pulse disk ( 40 ) is associated with a single scanning field, which as permeable area has a strip ( 42 ) tangential to the circular line of the transmitter arrangement. 6. Absolute position sensor according to claim 3 for detecting the position of a translatable component, further characterized in that a linear rail ( 50 ) is provided with a single scanning field as a structured aperture element, which is a permeable area with a transverse component to the translation direction arranged streak fen ( 52 ), and that the linear rail ( 4 ) in the translation direction are assigned equidistantly one behind the other transmitter ( 51 ), the mutual distance (d1) corresponds approximately to the effective width (b4) of the permeable strip ent. 7. absolute position encoder according to one of claims 2 to 6, further characterized in that in the evaluation unit Limit for one of the since a reference time (t₀) received radiation quantity dependent evaluation signal is given, the time shift of the point in time (t₃) the limit violation compared to the reference time point (t₀) as a measure of the position of the movable component serves. 8. absolute position encoder according to one of claims 1 to 7, further characterized by a microcontroller ( 15 ) with a clock output (T6) and a directly connected to this or via an intermediate frequency division unit ( 17 ) transmitter control stage ( 18 ) which the transmitter ( 5th to 8 ) with mutually phase-shifted on / off clock signals. 9. Absolute position encoder according to claim 8, further characterized in that the microcontroller ( 15 ) via an internal time counting device for detecting the level change of the emitted clock signal ( 16 ) up to a subsequent level change of a signal applied to an associated input ( 20 ) is equipped, with this input ( 20 ) an evaluation signal of a reception-side signal processing stage ( 19 ) is applied, the level change only after a transmitter control reference time (t bei) when a predetermined limit value for the radiation quantity received since he goes.