Encoder and method of operating the encoder

Abstract

To provide an encoder improved in presenting failure probability.SOLUTION: An encoder 10 includes: a scale carrier 12 on which a measurement scale 14 is arranged; at least one position sensor 20 capable of generating a position-dependent measurement signal PS by scanning the measurement scale 14; a processing unit 30 capable of processing the position-dependent measurement signal PS to a position signal P; and an interface unit 40 for communicating with a succeeding electronic device 100 via at least one data transmission channel 45. A monitoring device 60 can be supplied with at least one of operating conditions Ta, I1, I2, VDD, and HM of the encoder. The monitoring device 60 has an evaluation device 62. The evaluation device 62 determines component failure rates AR_K1 and AR_K2 of at least one of components 50, 60 to be monitored depending on the at least one of the operating conditions Ta, I1, I2, VDD, and HM, and determines therefrom an actual operation failure rate AR_B of the encoder 10.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The invention relates to an encoder according to claim 1 and to a method for operating an encoder according to claim 8.

[0002] Encoders are used in machines and equipment in automation technology, for example in machine tools or manufacturing robots. The task of an encoder is to measure the position or the change in position of a moving part. Rotary encoders or angle measuring instruments measure the rotational movement, for example of a rotating shaft. Length measuring instruments, on the other hand, measure the linear displacement of machine parts that are arranged movably relative to one another.

[0003] Machines and installations require that encoders have a high degree of reliability, which on the one hand means error-free functioning (availability) and on the other hand functional reliability, i.e. the ability to reliably recognize occurring functional failures.

[0004] In patent application WO 02 / 04333 the possibility of determining the remaining life of position measuring equipment is described. To do so, operating variables influencing the life are weighted and taken together in order to determine the remaining life. However, this requires a large database, which is often not available. This is because, due to the high quality of the measuring equipment, only a few failed equipment can be investigated. Furthermore, the exact circumstances that led to the failure are often unknown or not reproducible, which makes the analysis of the cause of the failure more difficult. Furthermore, measuring equipment is often replaced before it fails (preventive maintenance).

[0005] Measures to increase functional reliability allow the occurrence of malfunctions of measuring equipment to be recognized and thus to largely avoid hazardous situations resulting from the failure of measuring equipment, i.e. the occurrence of a malfunction must not endanger personnel in the hazardous area of ​​the machine or installation or cause material damage.

[0006] The probability that an undetected fault will still remain despite all implemented error detection measures is indicated by the so-called PFH value ("Probability of a Dangerous Undetected Failure per Hour"). For encoders, the PFH value is usually determined by the manufacturer using a system FMEDA (Failure Modes, Effects and Diagnostics Analysis). The basis for this is application conditions which are based on a typical application profile of such equipment. The PFH value is guaranteed if the encoder is operated within the framework of these application conditions. No consideration is given to possible deviations from these application conditions in the actual implementation of the encoder. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] European Patent Application No. 2273238 Summary of the Invention [Problem to be solved by the invention]

[0008] It is an object of the present invention to provide an encoder with an improved presentation of failure probabilities. [Means for solving the problem]

[0009] This problem is solved by an encoder according to claim 1 below.

[0010] a scale carrier (12) on which a measuring scale (14) is arranged; at least one position sensor (20) capable of generating a position-dependent measurement signal (PS) by scanning the measuring graduation (14); one processing unit (30) capable of processing a position-dependent measurement signal (PS) into a position signal (P), an interface unit (40) for communicating with a subsequent electronic device (100) via at least one data transmission channel (45); In an encoder having The encoder (10) comprises a monitoring device (60) to which at least one operating condition (Ta, I1, I2, VDD, HM) of the encoder can be supplied, the monitoring device (60) comprising an evaluation device (62) which calculates a component failure rate of at least one component (50, 60) to be monitored in dependence on the at least one operating condition (Ta, I1, I2, VDD, HM) and from said calculation calculates an actual operational failure rate of the encoder.

[0011] It is also an object of the invention to provide a method which allows improving the presentation of the failure probability of an encoder.

[0012] This problem is solved by a method for operating an encoder as claimed in claim 8 below.

[0013] a scale carrier (12) on which a measuring scale (14) is arranged; at least one position sensor (20) capable of generating a position-dependent measurement signal (PS) by scanning the measuring graduation (14); one processing unit (30) capable of processing a position-dependent measurement signal (PS) into a position signal (P), an interface unit (40) for communicating with a subsequent electronic device (100) via at least one data transmission channel (45); 1. A method for operating an encoder having a The method, wherein the encoder (10) comprises a monitoring device (60), to which at least one operating condition (Ta, I1, I2, VDD, HM) of the encoder is supplied, the monitoring device (60) comprises an evaluation device (62) which calculates a component failure rate of at least one component (50, 60) to be monitored in dependence on the at least one operating condition (Ta, I1, I2, VDD, HM) and calculates from said calculation an actual operational failure rate of the encoder.

[0014] Further advantageous features of the invention can be seen from the dependent claims of claim 1 or claim 8 and from the description of advantageous embodiments with the aid of the drawings. [Brief description of the drawings]

[0015] [Figure 1] FIG. 2 is a configuration diagram of an encoder according to the present invention. [Diagram 2] FIG. 4 is a block diagram of a further embodiment of an encoder of the present invention; [Diagram 3] FIG. 4 is a block diagram of a further embodiment of an encoder of the present invention; [Figure 4] FIG. 4 is a block diagram of a further embodiment of an encoder of the present invention; DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] 1 shows a block diagram of an encoder 10 according to the invention. The encoder 10 comprises a graduation carrier 12 with a measuring graduation 14, at least one position sensor 20, a processing unit 30 and an interface unit 40 for measuring, processing and outputting position-dependent signals.

[0017] The position sensor 20 is suitably configured for scanning the measuring graduation 14 on the graduation carrier 12. The graduation carrier 12 and the position sensor 20 are then arranged in a known manner so as to be movable relative to one another in the measuring direction, whereby for example the graduation carrier 12 and the position sensor 20 are connected to movable parts of a machine tool, the relative positions of which parts are determined relative to one another. The position sensor 20 and the measuring graduation 14 are configured according to the physical scanning principle applied and used during the position measurement.

[0018] For the purposes of the present invention it is not important whether the encoder is a length measuring instrument or, as shown in Figure 1, an angle measuring instrument (rotary encoder). The scale carrier 12 can therefore be a straight scale with measuring graduations 14 arranged in the scale direction for measuring linear movements, or a circular disc with measuring graduations 14 arranged radially around the disc pivot point D for measuring rotational movements, for example of a shaft.

[0019] A position-dependent position signal PS resulting from the scanning of the measuring graduation 14 is supplied to a processing unit 30. The position signal PS may comprise an analog or digitally coded signal. The processing unit 30 processes the position signal PS into a digital position value P and outputs this to the interface unit 40. This processing is not described in detail here but processing steps such as signal modification, digitization etc. may be carried out. In addition to the position value P, further position-dependent quantities may possibly be determined in the processing unit 30, such as, for example, velocity, acceleration or ruck.

[0020] The role of the interface unit 40 is to transmit data, e.g. the position value P, to the subsequent electronics 100 via a data transmission channel 45. Furthermore, commands and data can also be transferred from the subsequent electronics 100 to the interface unit 40, thereby enabling communication between the subsequent electronics 100 and the interface unit 40 (and thereby between the encoder 10). The subsequent electronics 100 can thereby request data (e.g. the actual position value P) from the encoder 10 by means of a data request command. For data transmission between the subsequent electronics 100 and the encoder 10, preferably a serial interface is used.

[0021] The encoder 10 is provided with at least one integrated circuit (IC). In this embodiment, the integrated circuit 50 contains the electrical circuits of the processing unit 30 and the interface unit 40. The integrated circuit 50 can be an application specific integrated circuit (ASIC) or a programmable integrated circuit (e.g. FPGA). As indicated by the dotted line, the integrated circuit 50 can also contain the position sensor 20. This is particularly advantageous for the optical scanning principle, since the position sensor contains a photodetector which can be manufactured on a semiconductor chip by known manufacturing methods. An integrated circuit which contains both optical structural elements and analog and digital circuit components is also called Opto-ASIC.

[0022] Each functional component of the encoder 10 has a component failure rate, which indicates the probability of failure of the component. The component failure rate is usually expressed in units of FIT (Failure In Time), where 1 FIT = 1 x 10 -9 / h, which is a variable that varies depending on the operating conditions of interest. The operating conditions of interest are those operating conditions that have a significant effect on the component failure rate. In this example, integrated circuit 50 has been assigned a component failure rate AR_K1.

[0023] According to the invention, the encoder 10 comprises a monitoring device 60. The monitoring device 60 is adapted to determine at least one component failure rate in dependence on the operating conditions of the encoder 10 (the failure rate of a system component to be monitored, which is dependent on at least one operating condition) and to determine therefrom an operational failure rate AR_B of the encoder 10. In the present example, attention is focused on the component failure rate AR_K1 of the integrated circuit 50.

[0024] The monitoring device 60 may be a separate integrated circuit, such as a microcontroller, a programmable gate array (FPGA), or an application specific integrated circuit (ASIC), but as indicated by the dashed and dotted lines, the monitoring device 60 may also be integrated within the integrated circuit 50 as a circuit module, thus forming the integrated circuit 50'.

[0025] The operating conditions that affect the component failure rate and therefore the operational failure rate AR_B can be divided into external and internal operating conditions that are captured or determined outside the encoder 10 and can be provided to the monitoring device 60, for example, from the subsequent electronics 100 via the interface unit 40.

[0026] One example of an external operating condition is time information, which includes date and possibly time, allowing the age of the encoder 10 to be determined and, from there, the percentage of the operational failure rate AR_B that is related to the age of use (Anteil) to be determined. This percentage is high at the beginning of the life of the encoder 10, then drops to a low level, and rises again near the end of its life (bathtub curve).

[0027] A further example of an external operating condition is the installation height above sea level. With increasing altitude, cosmic radiation increases, which affects the so-called soft error rate of the integrated circuit. This means that the encoder 10 is exposed to high-energy particle radiation, which increases, among other things, the component failure rate AR_K1 of the integrated circuit 50, which in turn adversely affects the operational failure rate AR_B. A similar effect occurs if the encoder 10 operates around machines that generate high-energy ionizing radiation, for example medical radiation equipment.

[0028] Internal operating conditions are operating conditions that are captured by the encoder 10 itself. Internal operating conditions include operating conditions that act directly on components of the encoder 10 and are therefore advantageously identified where they occur or arise. Sensors can be placed within the housing of the encoder 10 for capture. An example of an internal operating condition is temperature. Temperature, among other things, has a large effect on the failure rate of integrated circuits.

[0029] In this first embodiment, a temperature sensor 70 is provided in the encoder 10. The temperature sensor 70 is arranged together with the integrated circuit 50 in the housing of the encoder 10, for example on a circuit board. By means of the temperature sensor 70, the ambient temperature Ta of the structural elements arranged in the encoder 10, in particular the integrated circuit 50, can thus be measured.

[0030] In addition to the temperature sensor 70, further sensors 72, 74 can be provided to determine further internal operating conditions. For example, the further sensors 72, 74 can include acceleration sensors, vibration sensors, structure-borne sound sensors, humidity sensors, current sensors, voltage sensors, as well as time sensors (operation time measuring devices). The position sensor 20, possibly together with the processing unit 30, can also be considered as a sensor to determine the internal operating conditions, since the position or the position changes (velocity, acceleration) can affect the operational failure rate AR_B. The measured values ​​of the further sensors 72, 74 can also be supplied to the evaluation device 62 and can be considered to determine the component failure rate AR_K1 and therefrom the operational failure rate AR_B.

[0031] Suitable interfaces are provided for connecting the sensors 20, 70, 72, 74 to the monitoring device 60. Depending on whether the sensors are analog or digital, an A / D converter or a digital data interface can be used to provide digital measurements of the captured operating conditions to the evaluation device 62 for further processing.

[0032] In practice, the operational failure rate AR_B is often determined from the component failure rates of a small number of components of the encoder 10. This is the case when a component has a relatively high component failure rate and therefore contributes significantly to the operational failure rate AR_B, or when a component has a high variation in component failure rate under the influence of changing operating conditions. Hereinafter, such components are referred to as components to be monitored. Components with a relatively low component failure rate and / or a roughly constant component failure rate under changing operating conditions may be ignored in determining the operational failure rate AR_B, or their contribution to the operational failure rate AR_B may be considered constant.

[0033] In this example, integrated circuit 50 is the component to be monitored. Integrated circuit 50 has a component failure rate AR_K1.

[0034] In order to determine the operational failure rate AR_B, the following steps are carried out in the evaluation device 62: - Steps to determine relevant operating conditions Identifying a component failure rate AR_K1 for at least one component to be monitored determining an operational failure rate AR_B of the encoder 10 based on the component failure rate AR_Kn; is necessary.

[0035] The operating condition to be looked at in this example is the barrier layer temperature of the semiconductor chip of integrated circuit 50 .

[0036] The starting point for determining the component failure rate AR_K1 is the reference failure rate AR_R1 of the integrated circuit 50, which is determined by the wafer technology (structure width, manufacturing process, etc.) and the reference conditions (in this case the reference temperature of the barrier layer of the semiconductor chip). The reference failure rate AR_R1 is a specification by the manufacturer of the integrated circuit 50. The reference failure rate AR_R1 is based on a reliable database, since it is not very dependent on the internal electric circuit of the integrated circuit 50 and therefore applies to all integrated circuits manufactured using the same wafer technology. Therefore, an analysis of the cause of failure of the failed equipment is no longer necessary. The reference failure rate AR_R1 is stored in a storage device 64 arranged in the monitoring device 60. Deviations from the reference temperature lead to a change in the component failure rate AR_K1 of the integrated circuit 50, which change is determined by the Arrhenius law. If the power consumption of the integrated component 50 is known, the barrier layer temperature of the semiconductor chip of the integrated circuit 50 can be determined based on the ambient temperature Ta, determined using the temperature sensor 70, and the thermal resistance of the housing of the integrated circuit 50.

[0037] The ambient temperature Ta is supplied to an evaluation device 62 arranged in the monitoring device 60. The evaluation device 62 determines the component failure rate AR_K1 of the integrated circuit 50 based on the ambient temperature Ta, and determines the operation failure rate AR_B of the encoder 10 therefrom. For this purpose, a table can be stored in the storage device 64, in which the component failure rate AR_K1 of the integrated circuit 50 depending on the ambient temperature Ta is recorded. Alternatively, the component failure rate AR_K1 of the integrated circuit 50 can be determined by calculation. In the case of temperature, the Arrhenius law can be used for this purpose, and suitable alternative calculation specifications can be used to determine the influence of further operating conditions.

[0038] As mentioned above, external operating conditions can also be taken into account when determining the operational failure rate AR_B. In the example of Fig. 1, the subsequent electronics 100 provides the encoder 10 with an operating height HM, which indicates how high above sea level the encoder 10 operates. The operating height HM is transferred from the interface unit 40 to the monitoring device 60. In the monitoring device 60, an evaluation device 62 determines (again, for example from a table in the storage device 64) the soft error rate SER resulting from the operating height HM. The soft error rate SER, which can also be expressed in units of FIT, is taken into account when determining the component failure rate AR_K1.

[0039] Based on the component failure rate AR_K1 (and possibly further component failure rates), an operational failure rate AR_B of the encoder 10 can then be determined by the evaluation device 62. In the simplest case, the individual component failure rates can be added up. In particular, in the case of component failure rates of electronic structural elements, the operational failure rate AR_B can be determined by Markov analysis.

[0040] The operating height HM can already be transmitted to the encoder 10 at the factory and stored there. This is particularly meaningful if the place of use and thus the operating height HM are already known when ordering the encoder 10. In this case, it is advantageous for the value of the operating height HM to be stored in a write-protected manner, so that only competent personnel can change this value.

[0041] Advantageously, the value of the operating height HM can be read back, i.e. this value can be transmitted to the subsequent electronics 100 via the interface unit 40. In this way this value can be checked in the subsequent electronics 100 for correctness.

[0042] In addition to the operating height HM, further external operating conditions, such as for example time information T (date and possibly time of day), can be supplied to the encoder 10 and taken into account when determining the operating failure rate AR_B.

[0043] The operational failure rate AR_B of the encoder 10 can be used by a user to determine the overall failure rate of the machine or installation in which the encoder 10 is installed. Based on the overall failure rate the availability of the machine or installation can be evaluated. Based on the operational failure rate AR_B and the results of a FMEDA or equivalent method for analysing operational reliability, a so-called PFH value of the encoder 10 can be determined, which represents the functional reliability of the encoder 10. From this a measure of the functional reliability of the entire machine or installation can be derived.

[0044] The determination of the operational failure rate AR_B can be performed continuously or can be initiated by a corresponding command of the subsequent electronics 100. The transmission of the results to the subsequent electronics 100 is performed via the interface unit 40 and the data transmission channel 45.

[0045] In order to facilitate the analysis of the failure rate of the machine or installation for the manager of the machine or installation in which the encoder 10 is installed, it is advantageous for the subsequent electronics 100 to provide start and stop commands for starting and stopping the continuous determination of the operational failure rate AR_B and for the evaluation device 62 to be appropriately configured and to determine the maximum operational failure rate AR_B for a time interval specified by the start and stop commands. In this way, it is possible to check whether the machine or installation has reached the required standards of availability and functional reliability at all times during the work cycle to be monitored. If a given value of the overall failure rate is exceeded or fallen below, appropriate measures can be taken to optimize the operation of the machine or installation with regard to working speed and functional reliability.

[0046] A further embodiment of the inventive encoder 10 is shown in Fig. 2. The components described in connection with the previous embodiment have the same reference numerals. In this embodiment, a better possibility is shown for determining the barrier layer temperature of a semiconductor chip of an integrated circuit 50. Since the temperature has a large influence on the component failure rate AR_K1, the temperature allows a more accurate determination of the component failure rate AR_K1.

[0047] In this embodiment, in addition to the ambient temperature Ta determined by the temperature sensor 70, the actual power consumption of the integrated circuit 50 is also taken into account. The known thermal resistance of the housing of the integrated circuit 50 can then be used to calculate the exact change in the barrier layer temperature of the semiconductor chip. The ambient temperature Ta can then also be used to calculate the actual barrier layer temperature of the semiconductor chip.

[0048] To determine the power consumption of the integrated circuit 50, a current sensor is provided, which is for example embodied as a measuring resistor R1. In this example, the measuring resistor R1 is connected between the ground potential GND of the power supply of the encoder 10 and the earth connection of the integrated circuit 50. The voltage drop across the measuring resistor R1 is also supplied as a sensor value to the evaluation device 62. On the basis of the voltage drop and the value of the measuring resistor R1, the operating current I1 of the integrated circuit 50 can be calculated in the evaluation device 62. From the operating current I1 and the known supply voltage VDD of the integrated circuit 50, the actual power consumption of the integrated circuit 50 is obtained, which, together with the thermal resistance of the housing, is finally used to calculate the temperature rise of the semiconductor chip. The actual barrier layer temperature of the semiconductor chip is then obtained by adding the ambient temperature Ta. In a further embodiment of the method, the fluctuations of the supply voltage VDD can also be taken into account in the calculation by measuring the actual value of the supply voltage in the evaluation device 62. For this purpose, a measuring line can be provided in the evaluation device 62 between the supply voltage VDD and the A / D converter (not shown). This measuring line can be considered as a voltage sensor in the context of the present invention.

[0049] From the actual barrier layer temperature of the semiconductor chip of the integrated component 50, the evaluation device 62 determines (again by calculation or using a table) the component failure rate AR_K1 of the integrated component 50 and therefrom the operational failure rate AR_B of the encoder 10.

[0050] The monitoring device 60 itself has a component failure rate AR_K2, which may affect the operational failure rate AR_B of the encoder 10. The monitoring device 60 may therefore also be a component to be monitored. In particular, if the monitoring device 60 is implemented as an integrated component, the component failure rate AR_K2 may be determined in a similar manner to the component failure rate AR_K1 of the integrated component 50, i.e. on the basis of the ambient temperature Ta and possibly the operating current I2 (which may be determined using the current sensor R2) and the supply voltage VDD. The monitoring device 60 is thus advantageously configured to determine its own component failure rate AR_K2 depending on the relevant operating conditions (in this embodiment the ambient temperature Ta and possibly the operating current I2 and the supply voltage VDD) and to take this into account when determining the operational failure rate AR_B of the encoder 10.

[0051] To summarize, firstly the relevant operating conditions are determined: the ambient temperature Ta, the operating current I1 of the integrated component 50 and possibly also the supply voltage VDD of the integrated component 50. Then the actual component failure rate AR_K1 of the integrated component 50 is determined.

[0052] If the monitoring device 60 is also taken into account, its operating current I2 and possibly also its supply voltage VDD are additionally measured and a component failure rate AR_K2 is determined.

[0053] Finally, the actual operational failure rate AR_B is obtained from the component failure rates AR_K1 and AR_K2.

[0054] A further embodiment of the inventive encoder 10 is shown in Fig. 3. The components described in connection with the previous embodiment are given the same reference numerals. In this embodiment, an alternative possibility for determining the barrier layer temperature of a semiconductor chip of an integrated circuit 50 is shown.

[0055] Here, an on-chip temperature sensor 78 is co-integrated on the semiconductor chip of the integrated circuit 50. This allows the barrier layer temperature of the semiconductor chip to be measured directly, which is more accurate than the indirect determination via the circuitous route of measuring the ambient temperature, the operating current and the supply voltage, and makes the measurement independent of the actual mechanical structure, especially the composition (material, size, etc.) of the housing of the integrated circuit 50.

[0056] To determine the component failure rate AR_K1, the measurement signal of the on-chip temperature sensor 78 is fed to an evaluation device 62 in the monitoring device 60.

[0057] Of course, in this embodiment, additional operating conditions may be captured or considered in determining the component failure rate AR_K1.

[0058] A block diagram of a further embodiment of an encoder 10 of the present invention is shown in Figure 4. Again, functional blocks described in relation to the previous embodiment are numbered the same.

[0059] Whereas in the previously described embodiment it was assumed that the evaluation of the functional reliability of the encoder 10 is carried out in the subsequent electronics 100, in this example the monitoring device 60 is enhanced to determine an indication for the functional reliability of the encoder 10 in the form of a reliability-specific failure rate AR_S. For this purpose, reliability data SD of the encoder 10 are stored in the memory device 64. The reliability data SD are captured by the manufacturer in a FMEDA or equivalent method for verifying the functional reliability of the equipment. The reliability data SD contain information on methods for increasing the functional reliability of individual components (e.g. the integrated circuit 50) as well as on methods for increasing the functional reliability through the interaction of various components. The latter can for example be monitoring functions for internal signals (e.g. the clock signal) as well as the creation of redundancies through parallel signal and measurement paths.

[0060] The reliability-specific failure rate AR_S calculated from the operational failure rate AR_B corresponds to the PFH value of the encoder 10, which is known from reliability technology, and is expressed in units of FIT (Failure In Time), where 1 FIT = 1 × 10 -9 / h, which means in this case that a dangerous undetected error can occur once per billion hours. The failure rate AR_S can also be transmitted to the subsequent electronics 100 via the interface unit 40, which makes it easier for the manager of the machine or plant in which the encoder 10 is operating to determine not only the availability but also an actual indication of the functional reliability for a certain operating situation, without requiring any further information about the encoder 10.

[0061] The embodiment described with reference to FIGS. 1 and 2 can of course also include determining the failure rate AR_S specific to the reliability.

[0062] The invention is not limited to the examples described here: those skilled in the art can develop alternative embodiments without departing from the scope of the claims defined by the claims. The present application relates to the invention described in the claims, but may also include the following configurations as other aspects. 1. a scale carrier (12) on which a measuring scale (14) is arranged; at least one position sensor (20) capable of generating a position-dependent measurement signal (PS) by scanning the measuring graduation (14); one processing unit (30) capable of processing a position-dependent measurement signal (PS) into a position signal (P), an interface unit (40) for communicating with a subsequent electronic device (100) via at least one data transmission channel (45); In an encoder having The encoder (10) comprises a monitoring device (60) to which at least one operating condition (Ta, I1, I2, VDD, HM) of the encoder can be supplied, the monitoring device (60) comprising an evaluation device (62) which calculates a component failure rate of at least one component (50, 60) to be monitored in dependence on the at least one operating condition (Ta, I1, I2, VDD, HM) and from said calculation calculates an actual operational failure rate of the encoder. 2. The encoder described in claim 1, wherein reliability data (SD) can be stored in one memory device (64) of the monitoring device (60), and a reliability-specific failure rate (AR_S), which is an indication of the functional reliability of the encoder (10), can be calculated from the operational failure rate (AR_B) using the reliability data (SD) in the evaluation device (62). 3. The encoder of claim 1 or 2, wherein the encoder has at least one sensor (70, 72, 74, 78, R1, R2), and wherein measurement values ​​of the sensors (70, 72, 74, 78, R1, R2) can be supplied to the monitoring device (60) as operating conditions and / or wherein at least one operating condition can be supplied from the subsequent electronics (100) to the monitoring device (60) via the interface unit (40). 4. 4. The encoder according to any one of claims 1 to 3, wherein at least one component (50, 60) to be monitored is an integrated circuit. 5. The encoder of claim 4, wherein the component failure rate (AR_K1) of the integrated component (50) can be calculated in the evaluation device (62) based on a barrier layer temperature of the semiconductor chip, and the barrier layer temperature of the semiconductor chip can be measured by an on-chip temperature sensor (78) integrated on the semiconductor chip. 6. a component failure rate (AR_K1) of the integrated components (50, 60) can be calculated in the evaluation device (62) based on the barrier layer temperature of the semiconductor chip; the barrier layer temperature of the semiconductor chip is determined by an ambient temperature (Ta), a power consumption of the semiconductor chip, and a thermal resistance of a housing of the semiconductor chip; The ambient temperature (Ta) can be measured by a temperature sensor (70); said power consumption being calculable from the operating current (I1) of said integrated components (50, 60) and a supply voltage (VDD); 5. The encoder according to claim 4, wherein a current sensor (R1) is provided for measuring the operating current (I1). 7. 7. An encoder according to claim 6, wherein the supply voltage (VDD) of the integrated components (50, 60) is also measurable by the evaluation device (62). 8. a scale carrier (12) on which a measuring scale (14) is arranged; at least one position sensor (20) capable of generating a position-dependent measurement signal (PS) by scanning the measuring graduation (14); one processing unit (30) capable of processing a position-dependent measurement signal (PS) into a position signal (P), an interface unit (40) for communicating with a subsequent electronic device (100) via at least one data transmission channel (45); 1. A method for operating an encoder having a The method, wherein the encoder (10) comprises a monitoring device (60), to which at least one operating condition (Ta, I1, I2, VDD, HM) of the encoder is supplied, the monitoring device (60) comprises an evaluation device (62) which calculates a component failure rate of at least one component (50, 60) to be monitored in dependence on the at least one operating condition (Ta, I1, I2, VDD, HM) and calculates from said calculation an actual operational failure rate of the encoder. 9. The method according to claim 8, wherein reliability data (SD) is stored in one memory device (64) of the monitoring device (60), and a reliability-specific failure rate (AR_S), which is an indication of the functional reliability of the encoder (10), is calculated from an operational failure rate (AR_B) using the reliability data (SD) in the evaluation device (62). 10. The method according to claim 8 or 9, wherein the encoder comprises at least one sensor (70, 72, 74, 78, R1, R2), and measurement values ​​of the sensors (70, 72, 74, 78, R1, R2) are supplied to the monitoring device (60) as operating conditions and / or at least one operating condition is supplied from the subsequent electronics (100) to the monitoring device (60) via the interface unit (40). 11. At least one component to be monitored is an integrated circuit (50); 11. The method according to any one of claims 8 to 10, wherein a component failure rate (AR_K1) of the integrated component (50) is calculated in the evaluation device (62) based on a barrier layer temperature of the semiconductor chip, and the barrier layer temperature of the semiconductor chip is measured by an on-chip temperature sensor (78) integrated on the semiconductor chip. 12. At least one component to be monitored is an integrated circuit (50, 60); a component failure rate (AR_K1) of the integrated component (50) is calculated in the evaluation device (62) based on the barrier layer temperature of the semiconductor chip; the barrier layer temperature of the semiconductor chip is determined by an ambient temperature (Ta), a power consumption of the semiconductor chip, and a thermal resistance of a housing of the semiconductor chip; The ambient temperature (Ta) is measured by a temperature sensor (70); said power consumption being calculated from the operating current (I1) of said integrated components (50, 60) and a supply voltage (VDD); 11. The method according to any one of claims 8 to 10, wherein the operating current (I1) is measured by a current sensor (R1). 13. 13. The method according to claim 12, wherein the supply voltage (VDD) of the integrated components (50, 60) is also measured by the evaluation device (62). 14. 14. The method according to any one of claims 8 to 13, wherein the continuous calculation of the operational failure rate (AR_B) is started or stopped by start and stop commands from the connected electronic device. 15. 15. The method of claim 14, wherein the evaluation device (62) determines a maximum operation failure rate within a time interval specified by the start and stop commands. [Explanation of symbols]

[0063] 10 Encoders 12 Scale carrier 14 Measuring scale 20 Position Sensor 30 Processing Unit 40 Interface Unit 45 Data Transmission Channels 50 Integrated Circuits 60 Monitoring equipment 62 Evaluation Equipment 64 Storage device 70 Temperature Sensor 72 More Sensors 74 More Sensors 78 On-chip temperature sensor 100 Subsequent electronic equipment AR_S Reliability specific failure rate AR_B Operation failure rate AR_K1 Component failure rate AR_K2 Component failure rate AR_Kn Component failure rate AR_R1 Standard failure rate D Disk pivot point GND Earth potential HM Operating height I1 operating current I2 operating current P Position value PS position signal R1 Current sensor R2 Current sensor SD Reliability Data T Time information Ta Ambient temperature VDD Supply voltage

Claims

1. a scale carrier (12) on which a measuring scale (14) is arranged; at least one position sensor (20) capable of generating a position-dependent measurement signal (PS) by scanning the measuring graduation (14); one processing unit (30) capable of processing the position-dependent measurement signal (PS) into a position signal (P); an interface unit (40) for communicating with a subsequent electronic device (100) via at least one data transmission channel (45); In an encoder having said encoder (10) comprises a monitoring device (60), to which at least one operating condition (Ta, I1, I2, VDD, HM) of said encoder can be supplied, said monitoring device (60) comprises an evaluation device (62) which calculates at least one component failure rate of the component to be monitored (50) and of the monitoring device (60) in dependence on said at least one operating condition (Ta, I1, I2, VDD, HM) and from said calculation calculates an actual operational failure rate of said encoder, said at least one component to be monitored (50) being an integrated circuit; A component failure rate (AR_K1) of the integrated circuit (50) can be calculated in the evaluation device (62) based on a barrier layer temperature of the semiconductor chip; the barrier layer temperature of the semiconductor chip is determined by an ambient temperature (Ta), a power consumption of the semiconductor chip, and a thermal resistance of a housing of the semiconductor chip; The ambient temperature (Ta) can be measured by a temperature sensor (70); The power consumption can be calculated from an operating current (I1) and a supply voltage (VDD) of the integrated circuit (50); The encoder, wherein a current sensor (R1) is provided for measuring the operating current (I1).

2. The encoder of claim 1, wherein reliability data (SD) can be stored in one storage device (64) of the monitoring device (60), and a reliability-specific failure rate (AR_S), which is an indication of the functional reliability of the encoder (10), can be calculated from the operational failure rate (AR_B) using the reliability data (SD) in the evaluation device (62).

3. 3. The encoder according to claim 1 or 2, wherein the encoder comprises at least one sensor (70, 72, 74, 78, R1, R2), the measured values ​​of which can be supplied to the monitoring device (60) as operating conditions and / or at least one operating condition can be supplied from the subsequent electronics (100) to the monitoring device (60) via the interface unit (40).

4. Encoder according to any one of the preceding claims, wherein a supply voltage (VDD) of the integrated circuit (50) is also measurable by the evaluation device (62).

5. a scale carrier (12) on which a measuring scale (14) is arranged; at least one position sensor (20) capable of generating a position-dependent measurement signal (PS) by scanning the measuring graduation (14); one processing unit (30) capable of processing the position-dependent measurement signal (PS) into a position signal (P); an interface unit (40) for communicating with a subsequent electronic device (100) via at least one data transmission channel (45); 1. A method for operating an encoder having a said encoder (10) comprises a monitoring device (60), to which at least one operating condition (Ta, I1, I2, VDD, HM) of said encoder is supplied, said monitoring device (60) comprises an evaluation device (62) which calculates at least one component failure rate of the component to be monitored (50) and of the monitoring device (60) depending on said at least one operating condition (Ta, I1, I2, VDD, HM) and calculates from said calculation an actual operational failure rate of said encoder, the at least one component to be monitored is an integrated circuit (50); The component failure rate (AR_K1) of the integrated circuit (50) is calculated in the evaluation device (62) based on the barrier layer temperature of the semiconductor chip, the barrier layer temperature of the semiconductor chip is determined by an ambient temperature (Ta), a power consumption of the semiconductor chip, and a thermal resistance of a housing of the semiconductor chip; The ambient temperature (Ta) is measured by a temperature sensor (70); The power consumption is calculated from an operating current (I1) and a supply voltage (VDD) of the integrated circuit (50); The method, wherein the operating current (I1) is measured by a current sensor (R1).

6. 6. The method according to claim 5, wherein reliability data (SD) is stored in one storage device (64) of the monitoring device (60), and a reliability-specific failure rate (AR_S), which is an indication of the functional reliability of the encoder (10), is calculated from the operational failure rate (AR_B) using the reliability data (SD) in the evaluation device (62).

7. 7. The method according to claim 5 or 6, wherein the encoder comprises at least one sensor (70, 72, 74, 78, R1, R2), and wherein measured values ​​of the sensor (70, 72, 74, 78, R1, R2) are supplied as operating conditions to the monitoring device (60) and / or at least one operating condition is supplied from the subsequent electronics (100) to the monitoring device (60) via the interface unit (40).

8. The method according to any one of claims 5 to 7, wherein the supply voltage (VDD) of the integrated circuit (50) is also measured by the evaluation device (62).

9. The method according to any one of claims 5 to 8, wherein the continuous calculation of the operational failure rate (AR_B) is started or stopped by start and stop commands from the subsequent electronics.

10. 10. The method of claim 9, wherein the evaluation device (62) determines a maximum operation failure rate within a time interval specified by the start and stop commands.

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