EP1634841B1 - Elevator system with a device for determining the position of an elevator cabin and method to operate the elevator system - Google Patents

Description

The invention relates to an elevator installation with a cabin and a device for determining a cabin position, and to a method for operating such an elevator installation as defined in the patent claims.

It is known to determine the car position of an elevator installation in order to derive from this information control signals which are further used by the elevator control. This is how the German utility model teaches DE9210996U1 a device for determining the car position with magnetic tape and magnetic head for reading the magnetic tape. The magnetic tape has a magnetic coding and extends along the entire travel distance of the cabin. The magnetic head attached to the cab reads the coding without contact. From the read codes, a car position is determined.

A further development of this device is in the patent WO03011733A1 which also forms the closest prior art for the present invention. According to the teaching of this patent specification, the coding of the magnetic tape consists of a multiplicity of code marks arranged in a row. The code marks are magnetized as either South Pole or North Pole. Several consecutive code marks form a codeword. The code words in turn are in a row as a code mark pattern with arranged binary pseudo-random coding. Each codeword thus represents an absolute cabin position.

For scanning the magnetic fields of the code marks, the device of the patent specification WO03011733A1 a sensor device with multiple sensors, which allows simultaneous scanning of multiple code marks. The sensors convert the different polarity of the magnetic fields into a corresponding binary information. For south poles, they output a bit value "0" and for north poles a bit value "1". This binary information is evaluated by an evaluation unit of the device and processed in an understandable for the elevator control absolute position information and used by the elevator control as control signals.

The patent WO03011733A1 further teaches the use of small 3mm long sensors arranged in two adjacent tracks so that two sensors lie on the length of one code mark. As a result of this twice the periodicity of the sensors as the code marks, the sensors can clearly detect a transition between differently poled code marks as a zero crossing of the magnetic field.

Upon detection of the magnetic field of the code marks, the resolution of the absolute cabin position is equal to the length of a code mark, ie 4mm. When detecting the transition between different poled code marks the resolution of the absolute cabin position is much better and is 0.5mm.

A disadvantage of the device of the patent WO03011733A1 Firstly, the strength of the magnetic field in the normal direction above the code marks decreases rapidly and the sensors must therefore be positioned at a small distance of 3 mm above the code marks. Next disadvantage of this device is that the sensors must be positioned with great accuracy of +/- 1mm centered above the code marks. For sufficiently high security and sufficient reliability of the elevator installation, the sensor device above the code mark pattern must be carried out consuming. This is expensive. Especially at high cabin speeds of 10m / sec, the associated expense is very large.

The present invention has for its object to provide an elevator system with a car and a device for determining the car position and a method for operating such an elevator system, which allows accurate scanning of a code mark pattern by a sensor device with little effort, without the security and reliability affect.

This object is achieved by the invention according to the definition of the claims. The elevator system has at least one car and at least one device for determining a car position. The device has a code mark pattern and a sensor device. The code mark pattern is mounted along the travel distance of the car and consists of a plurality of code marks. The sensor device is mounted on the cabin and scans the code marks with sensors without contact. The code marks are arranged in a single track and the sensors are arranged in a single track.

The advantage of the invention is that the dimensions of the code marks and the track of the sensors are optimally matched to the signal strength of the code marks. By using a single track for the code marks and a single track for the sensors, an efficient and lossless scanning of the code marks by the sensors takes place. The arrangement of the sensors in a single track centrally above the track code marks allows targeted scanning of the code marks in the high signal strength range. Here, it is considered that a given signal strength of the code marks on the one hand decreases toward the edges of the code marks and on the other hand, it decreases away from a certain distance above the code marks. The so efficiently and lossless scanned high signal strengths of the code marks lead to large confidence areas in which the sensors can reliably and reliably scan the code marks with sufficiently strong sensor signals. Thus, it is possible to design the confidence range targeted, and so not to arrange the sensors in a limited by the signal strength distance above the code marks, but in a certain distance determined by the guide effort above the code marks. By increasing the distance of the sensors above the code marks the cost of the leadership of the sensor device is lowered while ensuring high security and reliability of the elevator system.

Advantageously, given the signal strength of the code marks and the given sensitivity of the sensors, the brand dimension of the code marks and / or the track dimension of the track of the sensors is selected such that the sensors can be positioned at the maximum distance above the code marks.

Advantageously, the brand dimension is less than 2.5 and / or the track dimension is smaller than 2.5.

Advantageously, the sensors are guided at a minimum distance of 15 mm, preferably 14 mm, preferably 13 mm, preferably 12 mm, preferably 11 mm, preferably 10 mm, preferably 9 mm, preferably 8 mm, preferably 7 mm, preferably 6 mm, preferably 5 mm, preferably 4 mm above the code marks.

Fig. 1

schematisch eine Aufzuganlage mit einer Kabine und einer Einrichtung zur Ermittlung der Kabinenposition,

Fig. 2

schematisch den Aufbau eines Teils einer Einrichtung zur Ermittlung der Kabinenposition mit Sensorvorrichtung und Kodemarkenmuster aus dem Stand der Technik der Patentschrift WO03011733A1 ,

Fig. 3

schematisch den Aufbau eines Teils einer ersten Ausführungsform einer erfindungsgemässen Einrichtung zur Ermittlung der Kabinenposition mit Sensorvorrichtung und Kodemarkenmuster,

Fig. 4

schematisch den Aufbau eines Teils einer zweiten Ausführungsform einer erfindungsgemässen Einrichtung zur Ermittlung der Kabinenposition mit Sensorvorrichtung und Kodemarkenmuster,

Fig. 5

eine Längssicht der Sensorvorrichtung oberhalb einer Kodemarke einer Einrichtung zur Ermittlung der Kabinenposition aus dem Stand der Technik gemäss Fig. 2,

Fig. 6

eine Längssicht der Sensorvorrichtung oberhalb einer Kodemarke der ersten erfindungsgemässen Einrichtung zur Ermittlung der Kabinenposition gemäss Fig. 3,

Fig. 7

eine Längssicht der Sensorvorrichtung oberhalb einer Kodemarke der zweiten erfindungsgemässen Einrichtung zur Ermittlung der Kabinenposition gemäss Fig. 4,

Fig. 8

eine Quersicht der Sensorvorrichtung oberhalb einer Kodemarke einer Einrichtung zur Ermittlung der Kabinenposition aus dem Stand der Technik gemäss Fig. 2 und 5,

Fig. 9

eine Quersicht der Sensorvorrichtung oberhalb einer Kodemarke der ersten erfindungsgemässen Einrichtung zur Ermittlung der Kabinenposition gemäss Fig. 3 und 6, und

Fig. 10

eine Quersicht der Sensorvorrichtung oberhalb einer Kodemarke der zweiten erfindungsgemässen Einrichtung zur Ermittlung der Kabinenposition gemäss Fig. 4 und 7.

Hereinafter, the invention with reference to embodiments according to the Fig. 1 to 10 explained in detail. It shows:

Fig. 1

schematically an elevator installation with a cabin and a device for determining the cabin position,

Fig. 2

schematically the construction of a part of a device for determining the car position with sensor device and Kodemarkenmuster from the prior art of the patent specification WO03011733A1 .

Fig. 3

1 shows schematically the structure of a part of a first embodiment of a device according to the invention for determining the car position with sensor device and code mark pattern,

Fig. 4

2 shows schematically the structure of a part of a second embodiment of a device according to the invention for determining the cabin position with sensor device and code mark pattern,

Fig. 5

a longitudinal view of the sensor device above a code mark of a device for determining the cabin position according to the prior art Fig. 2 .

Fig. 6

a longitudinal view of the sensor device above a code mark of the first inventive device for determining the cabin position according to Fig. 3 .

Fig. 7

a longitudinal view of the sensor device above a code mark of the second inventive device for determining the cabin position according to Fig. 4 .

Fig. 8

a cross-sectional view of the sensor device above a code mark of a device for determining the cabin position according to the prior art Fig. 2 and 5 .

Fig. 9

a transverse view of the sensor device above a code mark of the first inventive device for determining the cabin position according to Fig. 3 and 6 , and

Fig. 10

a transverse view of the sensor device above a code mark of the second inventive device for determining the cabin position according to Fig. 4 and 7 ,

To the lift: At the in Fig. 1 schematically illustrated elevator system 10, a car 1 and a counterweight 2 are suspended on at least one support cable 3 in a shaft 4 in a building 40. The support cable 4 runs over a guide roller 5 and is driven by a drive 6.2 via a drive pulley 6.1. Deflection pulley 5, traction sheave 6.1 and drive 6.2 can be arranged in a separate machine room 4 ', but they can also be located directly in the shaft 4. By turning left or right of the traction sheave 6, the cabin 1 is moved along a trajectory in or against a travel direction y and serves floors 40.1 to 40.7 of the building 40th

The device for determining the car position: A device 8 for determining the car position has a code mark pattern 80 with code marks, a sensor device 81 and an evaluation unit 82. The code mark pattern 80 has a numerical coding of absolute positions of the car 1 in the pit 4 with respect to a reference point. The code mark pattern 80 is fixedly mounted in the shaft 4 along the entire travel distance of the car 1. The code mark pattern 80 may be mounted freely stretched in the shaft 4, but it may also be attached to shaft walls or guide rails of the elevator installation 10. The sensor device 81 and the evaluation unit 82 are mounted on the car 1. The sensor device 81 is thus moved together with the car 1 and thereby scans the code marks of the code mark pattern without contact. For this purpose, the sensor device 81 is guided at a short distance from the code mark pattern 80. For this purpose, the sensor device 81 is attached to the car 1 via a holder perpendicular to the travel path. According to Fig. 1 If the sensor device 81 is fastened to the car roof, it is, of course, entirely possible to fasten the sensor device 81 laterally or at the bottom to the car 1. The sensor device 81 forwards the sampled information to the evaluation unit 82. The evaluation unit 82 translates the sampled information into an absolute position indication that can be understood by an elevator controller 11. About a suspension cable 9 this absolute position information is forwarded to the elevator control 11. The elevator controller 11 uses this absolute position indication for a variety of purposes. For example. It is used to control the travel curve of the car 1, such as the use of deceleration and acceleration measures. It also serves to Schachtendverzögerung, Schachtendbegrenzung, floor detection, for accurate positioning of the car 1 in floors 40.1 to 40.7 and of course for speed measurement of the car. 1

With knowledge of the present invention, the expert can of course realize other elevator systems with other types of drive such as hydraulic drive, etc. or lifts without counterweight, as well as a wireless transmission of position information to an elevator control.

The Fig. 2 to 4 show the structure of parts of devices 8 for determining the car position with sensor device 81 and code mark pattern 80. During Fig. 2 an embodiment of a device 8 for determining the car position from the prior art of the patent specification WO03011733A1 shows, give the Fig. 3 and 4 a first and a second embodiment according to the invention device 8 for determining the cabin position again.

To the code mark pattern: The code mark pattern 80 is composed of a plurality of code marks 83 applied on a carrier 84. The code marks 83 used in the shown embodiments of the car position determining means 8 are all identical in materials.

Advantageously, the code marks have high coercive field strengths. The carrier 84 is, for example, a plastic band of 1 mm carrier thickness and 10 mm carrier width. The code marks 83 are, for example, from magnetizable material also 1mm brand thickness and a brand width δ = 10mm. The code marks 83 are arranged on the carrier 84 in the longitudinal direction y and form the same length rectangular sections. The longitudinal direction y corresponds to the travel direction y according to Fig. 1 , The code marks 83 are equally spaced. They are magnetized as either South Pole or North Pole. Advantageously, they are 83 magnetized to saturation. For iron as a megnetic material of the code marks, the saturation magnetization is 2.4T. The code marks have a given signal strength, for example, they are manufactured with a certain magnetization of +/- 10mT. A south pole forms a negative magnetic field and a north pole forms a positive oriented magnetic field. Of course, with knowledge of the present invention, differently dimensioned code mark patterns with wider or narrower brand widths as well as thicker or thinner mark thicknesses can be used. In addition to iron as a magnetic material for the code marks also any other industrially proven and inexpensive magnetic materials, such as rare earths such as neodymium, samarium, etc., or use magnetic alloys or oxidic materials or polymer-bonded magnets, etc.

On the Branding Dimension: The differences of the code mark patterns 80 in the embodiments of the car position determining means 8 are that in the embodiment of the prior art Fig. 2 the mark length λ 1 = 4 mm, while in the first embodiment according to the invention Fig. 3 or 4 the brand length λ2 = 6mm and in the second embodiment according to the invention Fig. 4 the brand length λ3 = 7mm. The inventive code marks 83 are thus longer than the code marks 83 from the prior art. The brand dimension MD1, MD2, MD3 of the code marks 83 is determined from the width-to-length ratio of the code marks 83. In the prior art according to Fig. 2 is the brand dimension MD1 = 10/4 = 2.5, while according to the invention according to Fig. 3 the brand dimension MD2 = 10/6 = 1.7 resp Fig. 4 the brand dimension MD3 = 10/7 = 1.4. The inventive brand dimension MD is thus MD2, MD3 <2.5. With knowledge of the present invention, of course, differently dimensioned code mark patterns with smaller brand dimensions MD <= 1.2 or MD <= 1.0 can be used.

The sensor device 81: The sensor device 81 scans the magnetic fields of the code marks 83 as seen in the longitudinal direction y with a large number of sensors 85, 85 'arranged at the same distance from one another. The sensors 85, 85 'used in the three embodiments of the car position detecting means 8 are identical in mechanical dimensions and sensitivity. Preferably, cost-effective and easily controllable and readable Hall sensors are used for the sensors 85, 85 '. The sensors 85, 85 'form the same length rectangular sections with a broad side of 3mm and a narrow side of 2mm. For example. are the sensors 85, 85 'supported sensors in which a carrier limits the broad side and the narrow side and the actual sensor surface 850, 850' has a significantly smaller dimension of eg. 1mm ² . In the case of Hall sensors, the sensor surface 850, 850 'is typically arranged centrally in the center of the sensors. The sensors 85, 85 'detect over the Sensor surface 850, 850 ', the magnetic fields of the code marks 83 as sensor signals. The stronger the signal strength of the code marks 83, the stronger the sensor signal of the sensors 85, 85 '. Typical sensitivities of Hall sensors are 150V / T. The sensors 85, 85 'output binary information for the magnetic marks of the code marks 83 detected as analog voltages. For a south pole, they output a bit value "0" and for a north pole they output a bit value "1". With knowledge of the present invention, however, the skilled person can also use other magnetic sensors such as coils. He can also use different sized sensors with wider or narrower broadsides, as well as wider or narrower narrow sides. Also, the skilled person can use more sensitive, or less sensitive Hall sensors.

For Coding: The code mark pattern 80 has a binary pseudorandom coding. The binary pseudorandom coding is thus a continuous succession of sequences with n bit values "0" or "1". Each farther back of one bit value in the binary pseudorandom coding introduces a new n-ary sequence with bit values "0" or "1". Such a sequence of consecutive bit values is called a codeword. For example. a codeword with a 13-digit sequence is used. With simultaneous scanning of thirteen consecutive code marks 83 of the code mark pattern 80, the 13-digit sequence is read out unambiguously and without repetition of code words. The sensor device 81 for reading the codewords comprises thirteen plus one ie fourteen sensors 85, 85 '. Of course, with the knowledge of the present invention, those skilled in the art will appreciate sensor devices having more or less long codewords and accordingly realize more or fewer sensors. It is also possible to realize a so-called Manchester coding in which, after each South Pole code mark, an inverse North Pole code mark is added and vice versa. Consequently, a zero crossing of the magnetic field takes place in the code mark pattern at the latest after two code marks, which enables a synchronization of the sensors. The codewords are then twice as long and twice as many sensors are needed to sample the codewords. The skilled person can use any known and industrially proven one-way, repetitive absolute coding.

Resolution: In order to achieve a high resolution of 0.5mm of the absolute cabin position, transitions between different poled code marks 83 are measured as zero crossings of the magnetic field. For these purposes, the periodicity of the sensors 85, 85 'is twice that of the code marks 83, i. per brand length λ1, λ2, λ 3 come two sensors 85, 85 'to lie. In this way, each code mark 83 of the code mark pattern 80 is detected by two sensors 85, 85 '. If one of the two sensors 85, 85 'in the vicinity of a Kodemarkenwechsels and provides a sensor signal of approximately zero, then the other sensor 85, 85' is certainly in coverage to a code mark 83 and provides secure information. This embodiment of the car position detection device with two sensors per code mark is convenient for achieving high resolution, but it is not necessarily to practice the invention.

On the track dimension: the differences of the sensor device 81 in the three embodiments of the device 8 for determination the cabin position is that in the embodiment of the prior art according to Fig. 2 the sensors 85, 85 'seen in the longitudinal direction y are arranged in two tracks S1 and S2 with the total track width δ1 = 7mm, while the sensors 85 of the first embodiment according to the invention Fig. 3 Seen in the longitudinal direction y are arranged in a single track with the track width δ2 = 3mm and the sensors 85 of the second inventive embodiment according to Fig. 4 Seen in the longitudinal direction y are arranged in a single track with the track width δ3 = 2mm. In the embodiment according to Fig. 2 If the first track S1 of sensors 85 is formed by the broad side of the sensors 85, the second track S2 of sensors 85 'is formed by the broad side of the sensors 85', both tracks S1, S2 of sensors 85, 85 'are seen in the transverse direction x spaced 1mm apart. In the first embodiment according to the invention Fig. 3 the track width δ2 = 3mm is formed solely by the broad side of the sensors 85. In the second embodiment according to the invention Fig. 4 the track width δ3 = 2mm is formed solely by the narrow side of the sensors 85. The inventive track of sensors 85 is thus narrower than the two tracks S1, S2 of the prior art. The track dimension SD1, SD2, SD3 of the sensors 85, 85 'is determined from the ratio of the track width δ to the length of a sensor 85, 85'. In the prior art according to Fig. 2 is the track dimension SD1 = 7/2, while according to the invention according to Fig. 3 the track dimension SD2 = 3/2 or according to Fig. 4 the track dimension SD3 = 2/3. The track dimension SD according to the invention is thus SD2, SD3 <3.5. With knowledge of the present invention, of course, differently dimensioned sensor devices with even smaller track dimensions SD <= 2/3 or with a track dimension SD = 1 or with larger track dimensions SD> = 2/3.

To the views in the longitudinal direction: The Fig. 5 to 7 show views in the longitudinal direction y of the devices 8 for determining the car position. While Fig. 5 the sensor device 81 and the code mark pattern 80 of the device 8 for determining the car position according to the prior art Fig. 2 shows, give the 6 and 7 a first or second inventive embodiment of the arrangement of the sensor device 81 and the code mark pattern 80 of the device 8 for determining the cabin position according to Fig. 3 and 4 again.

Confidence: The magnetic fields are represented by curved arrows with respect to the normal N. The signal strength of the code marks 83 is strongest in the middle of the code marks 83 and decreases towards the edges of the code marks 83. Also, the signal strength of the code marks 83 decreases away from the code marks 83 a certain distance away. An area with sufficiently strong magnetic fields above the code marks 83, in which the code marks 83 can be scanned reliably and reliably by the sensor device 81, is called a confidence interval. The confidence interval is determined by the signal strength of the code marks 83, the sensitivity of the sensors 85, 85 'and the brand dimensions MD1, MD2, MD3 of the code marks 83 and the track dimensions SD1, SD2, SD3 of the tracks of the sensors 85, 85'. Given the signal strength of the code marks 83 and given sensitivity of the sensors 85, 85 ', the confidence interval is determined solely by the brand dimensions MD1, MD2, MD3 and the track dimensions SD1, SD2, SD3. The sensor surfaces 850, 850 'of the sensors 85, 85' must with a game of, for example, +/- 1mm in Confidence range. The curve Λ1 limits the range of confidence in the longitudinal direction y of the device 8 for determining the cabin position according to the prior art Fig. 2 , The curve Λ2 limits the confidence interval in the longitudinal direction y of the device 8 for determining the car position of the first embodiment according to the invention Fig. 3 , The curve Λ3 limits the confidence interval in the longitudinal direction y of the device 8 for determining the car position of the second embodiment according to the invention Fig. 4 ,

Due to different brand dimension MD1 = 10/4 of the code marks 83 of the embodiment according to Fig. 2 and MD2 = 10/6 of the first embodiment of code marks 83 according to the invention Fig. 3 and MD3 = 10/7 of the second embodiment of code marks 83 according to the invention Fig. 4 the height of the curve Λ1 is lower than the height of the curves Λ2, Λ3. Although the brand width δ = 10mm is identical in all embodiments shown, but the shorter code marks 83 according to the prior art according Fig. 2 a lower effective signal strength and thus a lower confidence level. The losses of the signal strength of the code marks 83 with a short brand length λ2 = 4mm according to Fig. 2 are so high that the sensors 85, 85 'at a low distance of only 3mm above the code marks 83 must be arranged. The arrangement of the sensors 85, 85 'according to Fig. 2 is thus limited by the signal strength, since the sensor surfaces 850, 850 'have to lie with a clearance of +/- 1mm in the confidence interval.

In contrast, in the two embodiments according to the invention Fig. 3 and 4 the brand length λ2 = 6mm or λ3 = 7mm longer and avoids losses of the signal strength of the code marks 83, which manifests itself in a larger confidence range. This large confidence range makes it possible to arrange the sensors 85 not in a limited by the signal strength distance, but in a determined by the guide effort distance above the code marks 83. Thus, the sensors 85, 85 'are arranged at a large distance of 10 mm above the code marks 83. Further extension of the brand length causes no further increase in the confidence interval. This follows from the height of the curves Δ1, Δ2, Δ3 of the confidence intervals in the transverse direction x according to the following Fig. 8 to 10 , which result from a brand width δ = 10mm. With knowledge of the present invention, the expert can thus the sensors by targeted design of the confidence range in a minimum distance of 15mm, preferably 14mm preferably 13mm, preferably 12mm, preferably 11mm, preferably 10mm, preferably 9mm, preferably 8mm, preferably 7mm, preferably 6mm, preferably 5mm , preferably 4mm above the code marks.

To the views in the transverse direction: The Fig. 8 to 10 show transverse views x of the devices 8 for determining the car position. While Fig. 8 the sensor device 81 and the code mark pattern 80 of the device 8 for determining the car position according to the prior art Fig. 2 and 5 shows, give the Fig. 9 and 10 a first or second inventive embodiment of the arrangement of the sensor device 81 and the code mark pattern 80 of the device 8 for determining the cabin position according to Fig. 3 and 6 respectively. Fig. 4 and 7 again.

As already explained, an area with sufficiently strong signal strength of the sensors 85, 85 'above the code marks 83 is called the confidence zone, in which confidence region the code marks 83 can be scanned reliably and reliably by the sensor device 81. The curve Δ1 limits the confidence interval in the longitudinal direction x of the device 8 for determining the car position in accordance with the prior art Fig. 2 , The curve Δ 2 limits the confidence interval in the longitudinal direction x of the first embodiment according to the invention of the device 8 for determining the cabin position Fig. 3 and 6 , The curve Δ3 limits the confidence interval in the longitudinal direction x of the second embodiment according to the invention of the device 8 for determining the cabin position Fig. 4 and 7 ,

Due to the identical brand width of 10mm, the heights of the curves Δ1, Δ2, Δ3 are equal. Both the embodiment of the sensor device 81 according to the prior art Fig. 2 with a track width δ1 = 7 mm as well as the first and second embodiment according to the invention of the sensor device 81 according to the invention Fig. 3 and 4 with track widths δ2 = 3 mm and δ3 = 2 mm lie with their sensor surfaces in the confidence interval of the curves Δ1, Δ2 and Δ3.

Of course, with knowledge of the present invention, those skilled in the art can realize other code mark patterns and correspondingly designed sensor devices. Thus, other physical principles for representing a length coding are conceivable. For example. For example, the code marks may have different dielectric numbers read by a capacitive-effect sensing device. Also, a reflective code mark pattern is possible in which, depending on the value of the individual code marks, more or less reflected light is detected by a sensor device detecting a reflection light.

Claims (6)

1. Lift installation (10) with at least one cage (1) and at least one equipment (8) for detecting a cage position, the equipment (8) comprises a code mark pattern (80) and a sensor device (81), the code mark pattern (80) is mounted along the travel path of the cage (1), the code mark pattern (80) consists of a plurality of code marks (83), and the sensor device (81) is mounted at the cage (1) and contactlessly scans the code marks (83) by sensors (85), wherein the code marks (83) are arranged in a single track and the sensors (85) are arranged in a single track, characterised in that a mark dimension (MD2, MD3), namely the width-to-length ratio, is smaller than 2.5 and/or a track dimension (SD2, SD3), of the track of the sensor (85), namely the ratio of the track width to the length of the sensor, is smaller than 3.5.
2. Lift installation (10) according to claim 1, characterised in that for a given signal strength of the code marks (83) and given sensitivity of the sensors (85) the mark dimensions (MD2, MD3) of the code marks (83) and/or the track dimension (SD2, SD3) of the track of the sensors (85) is or are so selected that the sensors (85) are positionable at maximum spacing above the code marks (83).
3. Lift installation (10) according to one of claims 1 and 2, characterised in that the sensors (85) are guided at a minimum spacing of 6 millimetres, preferably 5 millimetres, preferably 4 millimetres, above the code marks (83).
4. Method of operating a lift installation (10) with at least one cage (1) and at least one equipment (8) for detecting a cage position, the equipment (8) comprises a code mark pattern (80) and a sensor device (81), the code mark pattern (80) is mounted along the travel path of the cage (1), the code mark pattern (80) consists of a plurality of code marks (83), and the sensor device (81) is mounted at the cage (1) and contactlessly scans the code marks (83) by sensors (85), wherein the code marks (83) are arranged in a single track and the sensors (85) are arranged in a single track, characterised in that a mark dimension (MD2, MD3), namely the width-to-length ratio, is smaller than 2.5 and/or a track dimension (SD2, SD3), of the track of the sensor (85), namely the ratio of the track width to the length of the sensor, is smaller than 3.5.
5. Method according to claim 4, characterised in that for a given signal strength of the code marks (83) and given sensitivity of the sensors (85) the mark dimensions (MD2, MD3) of the code marks (83) and/or the track dimension (SD2, SD3) of the track of the sensors (85) is or are so selected that the sensors (85) are positionable at maximum spacing above the code marks (83).
6. Method according to one of claims 4 and 5, characterised in that the sensors (85) are guided at a minimum spacing of 6 millimetres, preferably 5 millimetres, preferably 4 millimetres, above the code marks (83).

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