EP4335033A1

EP4335033A1 - Diagnosable circuit assembly, sensor apparatus having a circuit assembly, and method for diagnosing a circuit assembly and/or sensor apparatus

Info

Publication number: EP4335033A1
Application number: EP22726739.0A
Authority: EP
Inventors: Mohamed ELAMIN; Sascha Staude; Stefan Müller; Florian Eckardt
Original assignee: Valeo Schalter und Sensoren GmbH
Current assignee: Valeo Schalter und Sensoren GmbH
Priority date: 2021-05-06
Filing date: 2022-05-03
Publication date: 2024-03-13
Also published as: WO2022233820A1; DE102021111771A1

Abstract

The present invention relates to a diagnosable circuit assembly (100), a sensor apparatus comprising such a circuit assembly, and to a method for diagnosing such a circuit assembly, wherein: the circuit assembly (100) comprises an electrical contact switch (10), at least one electrically conductive sensor electrode (30) and a control, measuring and evaluation device (20), and the electrical contact switch (10) comprises a first electrical contact element (A) and a second electrical contact element (B); the first electrical contact element (A) is electrically connected via a first electrical connection line (1) to the first connection (3) of the control, measuring and evaluation device (20), and the second electrical contact element (B) is electrically connected via a second electrical connection line (2) to a base potential (GND) or to the second connection (4) of the control, measuring and evaluation device (20); together with a contact element (A, B) of the contact switch (10), the sensor electrode (30) forms a sensor capacitor, and a switching state of the contact switch (10) can be determined by means of the sensor electrode (30); and, depending on the switching state of the contact switch (10), a functional state of the circuit assembly (100) can be determined for diagnosis of the circuit assembly.

Description

Diagnosis-capable circuit arrangement, sensor device with a circuit arrangement and method for diagnosing a circuit arrangement and/or sensor device

The present invention relates to a diagnosable circuit arrangement which has an electrical contact switch, at least one electrically conductive sensor electrode and a control, measuring and evaluation device, the electrical contact switch having at least one first electrical contact element and at least one second electrical contact element, the control The measuring and evaluation device has at least one first electrical connection and at least one second electrical connection, wherein the first electrical contact element is or can be electrically connected to the first connection of the control, measurement and evaluation device via a first electrical connection line and the second electrical contact element is electrically connected or connectable via a second electrical connection line with a base potential or with the second terminal of the control, measuring and evaluation device, and wherein the little At least one electrically conductive sensor electrode is designed and arranged relative to at least one contact element of the contact switch in such a way that it forms a sensor capacitance with at least one contact element of the contact switch.

Furthermore, the present invention relates to a sensor device for an operator input device, wherein the sensor device has a circuit arrangement with a capacitive sensor with at least one electrically conductive sensor electrode and at least one contact switch.

Furthermore, the present invention relates to a method for diagnosing such a circuit arrangement and/or a sensor device as described above.

Circuit arrangements with an electrical contact switch and a control, measuring and evaluation device are known in principle from the prior art, for example from EP 2 001 034 A2 or DE 102020108704.7.

In addition, it is fundamentally known to design circuit arrangements to be diagnosable, ie in particular such that at least one component or at least one function of the circuit arrangement or circuit arrangement can be monitored or at least one malfunction or at least one error state can be detected. For this purpose, it is known, for example, to carry out defined test measurements and then evaluate their measurement results for diagnostic purposes, with the evaluation being carried out, for example, by comparing one or more measured variables recorded with one or more corresponding target variables. If one or more of the recorded measured variables deviate more than intended or permissible from a predefined, corresponding target variable or a corresponding target value, it can be assumed that the circuit arrangement or one or more components of the circuit arrangement are not working properly, for example because at least one component is defective or there is a short circuit or the condition of a component has changed in an undesired manner beyond a desired or permissible level.

Such an undesired change can be, for example, a changed contact transition resistance or the like, which can be attributed to corrosion of an associated contact element, for example.

The more safety-relevant an application is in which a circuit arrangement is used, the more diagnostic measures or options are generally required to achieve the required functional safety of the application or the circuit arrangement.

A classic measure, with which the corresponding diagnostic requirements can often be met, is to provide the respective, safety-relevant components redundantly. However, this is usually complex and expensive, since the relevant components have to be stored twice. In addition, a corresponding space requirement or installation space requirement is also required for the redundant components, which is generally also not available at will.

Generic capacitive sensor devices with at least one electrically conductive sensor electrode and at least one contact switch are also known, for example also from DE 102020108704.7.

It is also known to carry out appropriate diagnoses to check a functional state of the circuit arrangement or the sensor device during the operation of a circuit arrangement or sensor device.

Against this background, it is an object of the present invention to provide an alternative circuit arrangement capable of diagnosis, in particular one with regard to its Diagnosis functionality improved circuit arrangement, which has a high diagnostic capability, in particular with few components, and enables a high level of functional safety.

Furthermore, it is an object of the present invention to provide an alternative sensor device that is improved in particular with regard to its diagnostic capability, which has a high diagnostic capability, in particular with few components, and enables a high level of functional reliability.

A further object of the present invention is to provide an alternative method for diagnosing a circuit arrangement and/or a sensor device, in particular an improved method with which a high functional safety of the circuit arrangement or sensor device can be achieved, in particular due to a good, in particular improved diagnostic capability can.

This object is achieved by a diagnosable circuit arrangement, by a sensor device with such a circuit arrangement, and by a method with the features according to the respective independent patent claims. Advantageous designs and developments of the invention are the subject matter of the dependent patent claims, the description and the figures. The wording of the claims is made part of the content of the description by express reference.

A diagnosable circuit device designed according to the present invention has an electrical contact switch, at least one electrically conductive sensor electrode, and a control, measuring and evaluation device, the electrical contact switch having at least one first electrical contact element and at least one second electrical contact element. The control, measurement and evaluation device has at least one first electrical connection and at least one second electrical connection, the first electrical contact element of the contact switch being electrically connected or connectable to the first connection of the control, measurement and evaluation device via a first electrical connection line and the second electrical contact element of the contact switch is or can be electrically connected via a second electrical connection line to a base potential or the second connection of the control, measuring and evaluation device, and wherein the at least one electrically conductive sensor electrode is designed in this way and relative to at least one contact element of the contact switch is arranged such that it forms a sensor capacitance with at least one contact element of the contact switch. According to the invention, the circuit arrangement is designed in such a way that in at least one state, in particular at least in an open state of the contact switch, the circuit arrangement for at least partial diagnosis of the circuit arrangement by means of the control, measuring and evaluation device is at least temporarily connected to the first contact element and/or the A first defined potential can be applied to the first connection line and at the same time a second defined potential can be applied to the second contact element and/or the second connection line. The control, measuring and evaluation device is also designed to do this while, i.e. while a first defined potential is present at the first contact element and/or the first connecting line and at the same time a second defined potential is present at the second contact element and/or the second connecting line, to detect at least one resultant first voltage occurring on the first contact element and/or in the first connection line and/or in the first connection, and/or during this time at least one on the second contact element and/or in the second connection line and/or to detect a resulting second voltage occurring at the second connection, to use the at least one sensor electrode to determine a switching state of the contact switch, in particular whether the contact switch is open or closed, to evaluate at least one detected voltage, and depending on the using i.e he sensor electrode determined switching state of the contact switch and depending on at least one detected voltage, in particular depending on a detected first voltage and a detected second voltage to determine a functional state of the circuit arrangement, in particular a functional state of the contact switch.

With a circuit arrangement according to the invention, for example, changes in technical parameters of the circuit arrangement, in particular of the contact switch, which have an influence on the evaluation of the contact switch can be detected in a simple manner. This can be, for example, a changed contact resistance, a changed shunt resistance or other errors or malfunctions in other components, such as undesired circuits (e.g. short circuits or the like) or interruptions in an electrical connection in or on a component or between components. For example, interruptions and/or short circuits to supply and/or external voltage potentials can occur in a circuit arrangement, which can be detected particularly easily and reliably with a circuit arrangement using a corresponding, suitably designed method for diagnosing a circuit arrangement.

With a circuit arrangement according to the invention, both variants, i.e. changes over time, or invariant, i.e. changes that do not change over time, high-impedance changes (such as short circuits, electromigration) as well as variants or invariant low-impedance changes can be detected (assuming a corresponding implementation of a method according to the invention for diagnosing the circuit arrangement) .

In particular, changes caused by aging, mechanical, chemical or electrical damage, contamination or the like can be detected, which can lead to an undesirable, faulty evaluation of the contact switch. Influences on the contact switch that change over time can also be determined, such as a loose contact, dew formation, electromagnetic coupling or the like.

By determining the functional state of the circuit arrangement as a function of the switching state of the contact switch, a particularly good, in particular improved diagnostic capability can be achieved. In particular, a particularly high rate of correctly identified functional states. As a result, a particularly robust and functionally reliable circuit arrangement can be provided. In particular, error states of the circuit arrangement can be clearly identified in this way, which are not clearly recognizable as an error state without determining the switching state of the contact switch. For example, a short circuit in the contact switch can be distinguished from a closed contact switch in this way. In this way, the functional safety of the circuit arrangement can be significantly increased.

The capacitive detection of the switching state of the contact switch using an electrically conductive sensor electrode, which forms a sensor capacitance with at least one contact element of the contact switch, has the advantage that a disruptive influence on the contact switch, for example by currents flowing away or disruptive parasitic capacitances, is kept very low, which means that the above-described "undesirable changes" in the circuit arrangement and thus "errors" can be detected particularly well and sensitively.

In particular, such a circuit arrangement can advantageously be used to detect interruptions in the circuit arrangement, for example in the contact element, in the connection lines, and a contact switch that closes incorrectly.

Furthermore, short circuits, for example to the base potential, in particular to ground or +0V (GND) and/or to a reference potential, for example to the supply voltage of the control, measurement and evaluation device or a microcontroller (PC) can be detected.

In addition, with a circuit arrangement according to the invention, a change in the contact resistance and/or a change in the insulation resistance can be detected in the contact switch.

In the context of the present invention, a “control, measurement and evaluation device” is understood to mean a combined control, measurement and evaluation device which is set up at least to control one or more components of the circuit arrangement in such a way that, in particular, a method for diagnosis according to the invention of the circuit arrangement can be carried out, in particular steps a) to g) of a method according to the invention.

The control, measurement and evaluation device can in particular be a microcontroller (PC), in which the components required for this are all integrated, be part of such a microcontroller or also a microcontroller and others that are arranged separately from the microcontroller or outside of it and have trained components that can be connected upstream and/or downstream of one or more microcontrollers. A circuit arrangement according to the invention can also have more than one control, measurement and evaluation device. The at least two contact elements can each be coupled to more than one control, measurement and evaluation device or be assigned to more than one control, measurement and evaluation device and be evaluated by several or different control, measurement and evaluation devices be assigned and each evaluated by different control, measurement and evaluation devices. In other words, for example, a contact element can be evaluated by two different control, measurement and evaluation devices, and two contact elements can each be evaluated by different control, measurement and evaluation devices.

Likewise, a circuit arrangement according to the invention can also have more than one contact switch.

A “connection” within the meaning of the present invention can be, for example, a connection pin of a corresponding plug contact or a connection of a printed circuit board. However, a connection does not have to be a pin or the like, but can in principle be any electrical contact, for example any electrical connection on a printed circuit board, for example a soldering contact or the like. This means that a connection does not necessarily have to represent an input or output. A connection can in particular be a connection contact, whereby a “connection contact” is understood to mean in particular an (electrically) interruptible, i.e. (electrically or galvanically) separable connection, such as in the case of a plug or switch.

The term "diagnosis" is understood in general to mean the determination or determination of a state, in particular the determination of at least one state of at least one component of the circuit arrangement, for example the determination of a state of a connecting line, for example whether it is free of a line break and is therefore in a is in a functional state or has a line break and is therefore in an error state or has a defect.

In a particularly advantageous embodiment of a circuit arrangement according to the invention, the circuit arrangement is also designed in particular to output the determined functional state, in particular in a further step, for example in the form of a corresponding output signal or the like.

In a particularly advantageous embodiment, a circuit arrangement according to the invention is also designed to carry out at least one appropriate measure in the event of a detected faulty functional state of the circuit arrangement, in particular as a function of an output signal characterizing the fault state. Such a measure can be, for example, entering information into an error memory and/or transferring the circuit arrangement and/or a corresponding system using the circuit arrangement to a safe state, for example by switching it off. A circuit arrangement according to the invention can be designed and set up, for example, for use in a control element and/or a control device with at least one contact switch, for example for use in a control input device as described in DE 102020108704.7, already mentioned at the outset, or a corresponding sensor device for a such operator input device. A circuit arrangement according to the invention is particularly suitable for this purpose, since generally no or only a few additional components are required to implement the diagnostic functionality of the circuit arrangement according to the invention.

A circuit arrangement according to the invention is particularly preferably designed for use in a vehicle, in particular for use in an operating element and/or an operating device for a vehicle. A circuit arrangement according to the invention is preferably designed as described above for use in an operator input device as described in DE 102020108704.7 already mentioned at the outset or in a corresponding sensor device for such an operator input device.

In an advantageous embodiment of a circuit arrangement according to the present invention, the electrical contact switch is designed in particular to assume at least two switching states, in particular a first switching state and a second switching state, with the contact switch preferably being open in the first switching state and an electrical connection between the first electrical contact element and the second electrical contact element is separated, and wherein the contact switch is preferably closed in a second switching state of the contact switch and an electrical connection is established between the first electrical contact element and the second electrical contact element.

A simple and advantageous circuit arrangement can be implemented in a particularly simple manner with such a contact switch. Such contact switches are known in principle from the prior art, to which reference is hereby made for further details on the basic functioning of such contact switches, for example from EP 2 001 034 A2 already mentioned at the outset or DE 102020108704.7, also already mentioned at the outset.

In principle, the contact switch of a circuit arrangement according to the invention can also have more than two contact elements, in particular three or more contact elements. The contact switch of a circuit arrangement according to the invention can not only be a changeover switch, but also a changeover switch, button or the like. In particular, a contact switch can be designed as known in principle from the prior art. In particular, the contact switch can be any type of changeover switch, changeover switch or button and have the number of contact elements required for this in each case.

The contact switch can in principle be designed as a so-called NOC contact switch, i.e. as a so-called “normally open contact”, i.e. as a contact switch that is open “normally” or in particular in a non-actuated state and/or in a state of the circuit arrangement that is disconnected from the power supply, which closes when actuated and can therefore also be referred to as a "closer". Or alternatively also as a so-called NCC contact switch (“Normally Closed Contact”), which is closed “normally” or in particular when the contact switch is not actuated and/or when the switching device is disconnected from the power supply and opens when actuated and therefore can also be referred to as an "opener".

In a further advantageous embodiment of a circuit arrangement according to the present invention, the sensor electrode is in particular designed and arranged relative to the contact switch, in particular in such a way relative to at least one contact element of the contact switch, that a change in the sensor capacitance can be brought about by changing the distance between the two contact elements relative to one another . As a result, the switching state of the contact switch can be determined in a particularly simple manner with the aid of an electrically conductive sensor electrode.

In a particularly advantageous embodiment of a circuit arrangement according to the present invention, the circuit arrangement, in particular the control,

Measuring and evaluation device is designed to capacitively detect a distance between the two contact elements and based on the distance between the contact elements to determine a switching state of the contact switch (open or closed).

If the contact switch is designed in such a way that one of the contact elements is arranged to be movable and one is stationary, the sensor electrode preferably forms the sensor capacitance with the movable contact element, in which case the changes in this sensor capacitance can be recorded and evaluated to determine the switching state of the contact switch and the switching state of the Contact element can be evaluated particularly preferably depending on this. As a result, the switching state can be recognized particularly simply and advantageously.

However, the sensor electrode can also form a sensor capacitance with both contact elements, in which case the changes in both sensor capacitances can be recorded and evaluated and used to determine the switching state.

In a possible and advantageous configuration of a circuit arrangement according to the present invention, the sensor electrode is formed separately from the first contact element and separately from the second contact element, with the control, measuring and evaluation device preferably also having a sensor electrode connection via which the sensor electrode is connected by means of a sensor electrode - The connection line is electrically connected or can be connected to the sensor electrode connection of the control, measuring and evaluation device. As a result, the sensor electrode can be integrated into the circuit arrangement in a particularly simple manner. In particular, a circuit arrangement according to the invention based on a circuit arrangement with an electrical contact switch can be constructed particularly easily in this way, or expanded by the sensor electrode.

In an alternative, possible but also advantageous configuration of a circuit arrangement according to the present invention, the at least one sensor electrode is not formed separately from the contact elements of the contact switch, but is formed by the first contact element or the second contact element.

Such a configuration has the advantage that no additional connection is required for the electrical connection of the sensor electrode to the control, measuring and evaluation device. This is advantageous in particular when there is a limited number of available connections or suitable connections. Furthermore, such a circuit arrangement requires fewer components and fewer soldered connections or electrical contacts. The space for the sensor electrode can also be saved or used for other purposes. A circuit arrangement that is simpler in design and less expensive can thus be provided.

In a particularly advantageous embodiment of a circuit arrangement according to the present invention, in particular in a development of the embodiment described above, the other contact element of the contact switch is also designed as an electrically conductive sensor electrode and forms with the (first) as Sensor electrode formed contact element not only the contact elements of the contact switch, but also a capacitive sensor element, in particular a capacitive sensor.

In a preferred configuration of a circuit arrangement according to the present invention, the circuit arrangement therefore also has a second electrically conductive sensor electrode, the first sensor electrode being formed in particular by the first contact element and the second sensor electrode preferably by the second contact element.

In a further advantageous embodiment of a circuit arrangement according to the present invention, in particular in a further development, the circuit arrangement also has in particular at least one electrical resistor, preferably at least one ohmic resistor, with at least one electrical resistor preferably being arranged along a connecting line, i.e. in particular along the Connection line is connected in series or switchable.

A particularly simple and advantageous arrangement of the individual components of the circuit arrangement can thereby be achieved.

In a particularly advantageous embodiment of a circuit arrangement according to the present invention, the circuit arrangement has in particular at least a first electrical resistor and a second electrical resistor, which are particularly preferably each in the form of ohmic resistors, with the first electrical resistor preferably being arranged along the first connection line, in particular such that the first contact element is or can be electrically connected via the first connection line and the first electrical resistance (connected in series) to the first connection of the control, measuring and evaluation device, and wherein the second electrical resistance is in particular along the second connection line is arranged, preferably such that the second contact element via the second connection line and the second (connected in series) electrical resistance to the second terminal of the control, measurement and evaluation teeinrichtung is electrically connected or connectable.

By means of such a series-connected electrical resistance between the contact element and the connection along the respective associated connecting line, the control, measuring and evaluation device can be protected in a simple manner, in particular against an excessively high input current or an excessively high input voltage at the associated connection contact. This allows in many cases in a simple way and In the event of an error in the circuit arrangement or a defect in the circuit arrangement, undesirable states that may arise during operation of the circuit arrangement, such as excessive current flow as a result of a short circuit or the like, can be intercepted without damaging the control, measuring and evaluation device becomes. As a result, functional reliability and the risk of failure of the circuit arrangement can be significantly improved in a simple manner.

The first electrical resistance and the second electrical resistance can have the same nominal resistance or each have different nominal resistances. The use of electrical, in particular ohmic, resistors with the same nominal resistances has the advantage that fewer component variants are required to provide or establish an advantageous circuit arrangement according to the invention.

The use of electrical, in particular ohmic resistors with different nominal resistances, on the other hand, has the advantage that in this way the resulting voltages at the associated connections can be influenced differently in a targeted manner, which can be used specifically for evaluation, whereby further, in particular result in additional and advantageous diagnostic options.

In a further, particularly advantageous embodiment of a circuit arrangement according to the present invention, in particular in a further development, in particular at least one of the connections, in particular at least the first connection and/or the second connection contact, is designed and set up as a switchable connection or as a switchable connection pin. in particular as a so-called multifunction pin or so-called GPIO connection contact, which in particular and depending on the switching state can be operated as an input or output connection and can be optionally assigned different functions or signals depending on the switching state.

In order to optionally assign the desired function or a corresponding signal to the (reversible) connection, the control, measurement and evaluation device is preferably designed and set up accordingly, with the control, measurement and evaluation device also having at least one (to) switchable pin which is electrically connected or connectable to the switchable terminal. The at least one switchable pin can in particular be switched at least between operation as an input pin and operation as an output pin and is particularly preferably designed and set up, depending on the switching state, either to output a voltage, in particular a defined voltage, to detect a voltage, to put the respective associated connection on a potential, in particular on a defined potential, or to switch the associated connection to high impedance.

In this case, the at least one switchable pin can in particular be part of a switchable port which comprises a plurality of pins, in particular a plurality of switchable pins. In particular, the at least one switchable pin can be part of a switchable input port and/or a switchable output port and/or particularly preferably part of a GPIO port.

A so-called "GPIO connection" is understood in the sense of the present invention as a so-called "general purpose input output" connection, which can be optionally assigned different functions or signals depending on the switching state, the control, measurement and evaluation device preferably has at least one input and/or output pin for this purpose, in particular a switchable input and/or output pin, to which the GPIO connection is correspondingly assigned in particular, with at least one input and/or output pin preferably being designed for this purpose and is set up to output a voltage, in particular a defined voltage, to detect a voltage, to apply a respective, associated connection to a, in particular, defined, potential and/or to switch the respective connection to high resistance or low resistance.

In a particularly preferred embodiment of a circuit arrangement according to the invention, the first connection and the second connection are each designed and set up as a switchable connection, in particular as switchable connection pins or respectively as multifunction pins, in particular in each case as a so-called GPIO connection, and preferably in each case optionally and depending on the switching state can be operated as an input or output connection and, depending on the switching status, can be assigned with various functions or signals.

For this purpose, the control, measurement and evaluation device can have in particular at least one first switchable port which is or can be electrically connected to the first switchable connection, and a second switchable port which is or can be electrically connected in particular to the second switchable connection, wherein the first port and the second port are particularly preferred can each be switched between operation as an input port and operation as an output port and are in particular designed and set up, depending on the switching state, either to output a voltage, in particular a defined voltage, to detect a voltage, to set the respective associated connection to a potential increase, in particular to a defined potential, or to apply a potential to the respective connection, in particular a defined potential, or to switch the associated connection to high resistance or low resistance.

Such an embodiment of a circuit arrangement enables a comprehensive diagnostic functionality of a contact switch with only a few connections or connection pins, in particular in the case of two contact elements with only two connections.

In a further advantageous embodiment of a circuit arrangement according to the present invention, the circuit arrangement also has at least one reference capacitance and at least one pull resistor, the reference capacitance being in particular between a connection of the control, measurement and evaluation device and an electrical resistor with a connecting line is electrically connected or connectable, and on the other hand is preferably electrically connected or connectable to a base potential, in particular to a ground potential (GND). The pull resistor is preferably, on the one hand, electrically connected or can be connected between a contact element and an electrical resistor, in particular the aforementioned resistor, with a connection line, in particular with an associated connection line, and on the other hand electrically connected or can be connected to a first reference potential or a base potential is.

As a result, it is possible to use just a few components, especially just one connection line and/or just one associated connection contact, especially in many cases with the components that are already present, especially if the contact switch is combined with at least one capacitive sensor electrode or is part of a capacitive sensor device or a Forming part of a capacitive sensor, it is easy to apply a defined potential to the respective associated contact element and/or the associated connection line.

In the context of the invention, the term “reference capacity” means a capacity of known size that can be charged in a defined manner. A reference capacitance can be formed, for example, by a capacitor of known capacitance. A "pull resistor" within the meaning of the invention is a resistor by means of which a voltage or a potential can be "pulled" to a defined value. “Pull resistors”, in particular what are known as pull-up and pull-down resistors, are known in principle from the prior art, to which reference is hereby made in this regard for further explanations.

In the context of the invention, the term “reference potential” is understood to mean a defined electrical potential which is used in particular to charge a reference capacitance in a defined manner, in particular up to the reference potential or an associated reference voltage. The reference potential can, for example, correspond to the supply potential of the control, measurement and evaluation device, in particular the supply voltage Vcc or Vdd of an associated microcontroller, for example +5V or +3.3V, in particular depending on the control, measurement and evaluation device or depending on the associated one microcontroller.

In the context of the invention, the term “base potential” means a defined electrical potential which is used in particular to discharge a reference capacitance in a defined manner, in particular down to the base potential or an associated base voltage. In particular, the base potential can be a ground potential, for example a potential of +0V, i.e. GND.

In a particularly advantageous embodiment of a circuit arrangement according to the present invention, in particular in a further development, the circuit arrangement has in particular a first reference capacitance and a first pull resistor. The first reference capacitance is preferably electrically connected or can be connected between the first connection of the control, measuring and evaluation device and the first electrical resistance to the first connection line and also electrically connected or can be connected to a base potential. The first pull resistor is preferably electrically connected or connectable to the first connection line between the first contact element and the first electrical resistor and is electrically connected or connectable to a first reference potential or a base potential.

In an even more preferred advantageous embodiment of a circuit arrangement according to the present invention, in particular in a further development, the circuit arrangement particularly preferably also has a second reference capacitance and a second pull resistor. In this case, the second reference capacitance is preferred on the one hand electrically connected or connectable between the second connection of the control, measuring and evaluation device and the second electrical resistance with the second connection line and on the other hand electrically connected or connectable to a base potential. The second pull resistor is preferably electrically connected or connectable to the second connection line between the second contact element and the second electrical resistor and is electrically connected or connectable to a second reference potential or a base potential.

In a further development, in particular in an advantageous embodiment of a circuit arrangement according to the invention, at least one pull resistor, in particular the first pull resistor and/or the second pull resistor, is preferably a pull-down resistor and in particular with a base potential, in particular a ground potential of approx. ±0V=GND, electrically connected or connectable.

As a result, an associated reference capacitance can first be discharged, in particular almost completely discharged, in a simple manner with few components, and then a defined potential can be applied to the associated contact element and/or the associated connection line by defined charging of the reference capacitance.

In an alternative but also advantageous configuration of a circuit arrangement according to the present invention, at least one pull resistor, in particular the first pull resistor and/or the second pull resistor, can also be a pull-up resistor and in particular with a reference potential be electrically connected or connectable, with the reference potential being in particular a supply voltage of the control, measurement and evaluation device, in particular the supply voltage of an associated microcontroller (pC) of the control, measurement and evaluation device, for example a supply voltage Vcc or Vdd of +5V or from +3.3V or the like, depending on the microcontroller used.

As a result, an associated reference capacitance can first be charged to a defined potential in a simple manner using few components and then a defined potential can be applied to the associated contact element and/or the associated connection line using the reference capacitance that has been charged in a defined manner.

Alternatively or additionally, a circuit arrangement according to the invention can also be designed in an advantageous embodiment in such a way that at least one pull resistor can be optionally connected to a switch using a corresponding switch Reference potential, for example a supply voltage of an associated microcontroller, or can be electrically connected to a base potential, for example a ground potential of +0V (GND), for example in a first switching state of an associated switch with a reference potential which corresponds to the supply voltage of a microcontroller of the associated control, Measuring and evaluation device corresponds, and in a second switching state of the associated switch with the base potential of the microcontroller, which is preferably +0V (GND).

As a result, the pull resistor can be operated in a simple manner either as a pull-up resistor or as a pull-down resistor, which increases the flexibility of the circuit arrangement, in particular the associated or resulting evaluation options in the context of diagnosis simple way can be advantageously expanded.

In an alternative but also advantageous configuration of a circuit arrangement according to the present invention, in particular in an alternative configuration to a circuit arrangement with at least one reference capacitance and an associated pull resistor, a circuit arrangement according to the invention, in particular the control, measuring and evaluation device, can also also have at least one further electrical connection which is or can be electrically connected in particular via a further connection line to the first contact element and/or the first connection line or the second electrical contact element and/or the second connection line. The further connection and/or the further connecting line is particularly preferably via a corresponding connection node on or between the associated contact element and an associated electrical resistor, particularly preferably via an associated further electrical resistor which is connected in series along the associated further connecting line electrically connected or connectable to the associated electrical contact element and/or the associated connection line.

By means of such a further connection, in particular in connection with a further connection line, the application of the defined potential, the detection of the resulting voltage that occurs and the evaluation of the voltage can be simplified considerably and thus also the implementation of a diagnosis. In particular, allows a trained and set up as described above Circuit arrangement with at least one further connection and/or at least one further connection line, in particular a diagnosis which is independent of the charging or discharging behavior of a reference capacitance over time or can be carried out independently thereof. In particular, it is no longer absolutely necessary in such a circuit arrangement for a reliable evaluation to detect the resulting voltage over time, ie as a voltage curve, as is however usually required if the respective defined potential using a Reference capacitance is applied by defined discharging or defined charging of the reference capacitance and the voltage that occurs during charging or discharging (changing over time) is recorded.

In a particularly advantageous embodiment of a circuit arrangement according to the present invention, the circuit arrangement has in particular a third electrical connection which is or can be electrically connected in particular via a third connection line to the first contact element and/or the first connection line, and particularly preferably also a fourth electrical connection Connection contact which is or can be electrically connected, in particular via a fourth connection line, to the second contact element and/or the second connection line.

The third connection is particularly preferably electrically connected in particular via a connection node on or between the first contact element and the first electrical resistor, particularly preferably via a third resistor which is connected in series along the third connecting line with the first contact element and/or the first connecting line connected or connectable and the fourth connection in particular via a connection node on or between the second contact element and the second electrical resistor, particularly preferably via a fourth resistor which is connected in series along the fourth connection line.

Such an arrangement makes it possible, for example at the same time, to operate the first connection and/or the second connection as an input or (permanently) form it as an input and to operate the third connection and/or the fourth connection at the same time as an output or (permanently) as an output educate, while on the other hand only a total of two connections are present, ie if only a first connection and a second connection are available, for carrying out a diagnosis must be switched between an output mode and an input mode at the respective terminals.

In a further advantageous embodiment of a circuit arrangement according to the present invention, in particular in a further development of a circuit arrangement with at least one additional electrical connection and one additional connection line, the circuit arrangement, in particular the control, measuring and evaluation device, preferably has at least one that can be operated at least partially as an input or (permanently) designed and set up as an input, which is electrically connected or can be connected to the first electrical connection or the second electrical connection and at least one first output pin that can be operated at least temporarily as an output or is (permanently) designed and set up as an output. Pin that is electrically connected or connectable to at least one other electrical connection.

The at least one input is designed in particular as an analog input. In principle, a digital input is also possible. However, this is not as advantageous for detecting a voltage via this input as an analog input, to which in particular an analog-to-digital converter channel and/or an analog-to-digital converter unit can be connected, which in particular has at least one analog -Can include digital converter channel.

The at least one output, on the other hand, is preferably designed as a digital output. This makes it very easy to create a defined potential.

In a particularly advantageous embodiment of a circuit arrangement according to the present invention, the circuit arrangement, in particular the control, measuring and evaluation device, particularly preferably has at least one first input pin that can be operated at least temporarily as an input or is (permanently) designed and set up as an input is or can be electrically connected to the first electrical connection, a second input pin that can be operated at least temporarily as an input or is designed and configured as an input, which is or can be electrically connected to the second electrical connection, and a second input pin that can be operated at least temporarily as an output or is an output formed and set up first output pin, which is electrically connected or connectable to the third electrical connection, as well as a at least temporarily operable as an output or formed and set up as an output Output pin electrically connected or connectable to the fourth electrical connection.

This enables a diagnosis that is particularly easy to carry out. In particular, a particularly simple application of the defined potentials, a particularly simple detection of the resulting first and second voltage that occurs, a particularly simple evaluation of the detected voltages and a particularly simple determination of a functional state of the circuit arrangement.

In a further advantageous embodiment of a circuit arrangement according to the present invention, the circuit arrangement, in particular the control, measuring and evaluation device, also has a fifth electrical connection which is electrically connected to the first contact element and/or the first connection line in particular via a fifth connection line is connected or connectable, and preferably also a sixth electrical connection contact, which is electrically connected or connectable in particular via a sixth connection line with the second contact element and/or the second connection line. The fifth connection is particularly preferably electrically connected to the first contact element and/or the first connection line via a connection node between the first contact element and the first electrical resistor, particularly preferably via a fifth resistor which is connected in series along the fifth connection line connectable. The sixth connection is particularly preferably electrically connected or can be connected to the second contact element and/or the second connection line via a connection node between the second contact element and the second electrical resistor, particularly preferably via a sixth resistor which is connected in series along the sixth connection line . As a result, the diagnostic options can be advantageously expanded in a simple manner.

In this case, ie in particular in a further development, a circuit arrangement according to the invention particularly preferably also has at least one further third output pin which can be operated at least temporarily as an output or is (permanently) designed and set up as an output and which is electrically connected in particular to the fifth electrical connection or can be connected, as well as preferably also a fourth output pin that can be operated at least temporarily as an output or is (permanently) designed and set up as an output, which is or can be electrically connected to the sixth electrical connection. This allows the Diagnostic options are expanded in a particularly advantageous manner in a simple manner.

In a further advantageous embodiment of a circuit arrangement according to the present invention, the circuit arrangement, in particular the control, measuring and evaluation device, preferably has a first analog-to-digital converter that can be electrically connected or is connected to the first connection and/or the first input pin channel and/or a first analog-to-digital converter unit that can be electrically connected or is connected to the first connection and/or the first input pin, in particular for detecting an on the on the first contact element and/or on the first connecting line and /or resulting voltage set at the first connection, and particularly preferably also a second analog-to-digital converter channel that can be or is electrically connected to the second connection and/or the second input pin and/or a second channel to the second connection and /or analog digit electrically connectable or connected to the second input pin al converter unit, which is designed in particular to detect a resulting second voltage occurring at the second contact element and/or in the second connection line and/or at the second connection. As a result, a resulting voltage that occurs in each case or a corresponding resulting voltage profile that occurs in each case can be detected in a very simple and advantageous manner.

Instead of an analog-to-digital converter unit for detecting the resulting voltage that occurs at one of the contact elements or the associated connecting line or in/on the associated connection, the connection can alternatively or additionally be electrically connected or connectable to a so-called comparator input, A comparator input in the context of the present invention is understood to mean an input which functions in particular according to the comparison principle. A distinction is made as to whether the voltage present at this input is above or below a defined voltage threshold or above or below a defined voltage value, with the result of the comparison usually being a digital value (in particular 0 (below the threshold) or 1 (above the threshold). ). Control, measurement and evaluation device, is adaptable or adaptable in particular with the help of software. In this way, in particular, the evaluation or the determination of the functional state can be simplified or, in particular, already done by the comparator input. If a dataable or adaptable comparator input is used, ie a comparator input with a customizable or applicable threshold value, a particularly high level of flexibility and adaptability of the circuit arrangement to the respective application can be achieved.

A sensor device according to the invention for an operator input device has a circuit arrangement with a capacitive sensor with at least one electrically conductive sensor electrode and at least one contact switch and is characterized in that the circuit arrangement is designed according to the invention. As a result, a particularly advantageous sensor device can be provided, in particular a sensor device with good diagnostic capability. As a result, in turn, a high level of functional reliability of the sensor device can be achieved.

A sensor device according to the invention can be designed in particular for an operator input device, as described in DE 102020108704.7, which has already been mentioned several times, and in particular can have a contact switch, for example, which is designed in such a way that when there is no operator, an electrical connection between the first electrical contact element and the second electrical contact element is separated and by applying an operating force in the direction of actuation that is greater than a defined contact closing force, an electrical connection can be made between the first electrical contact element and the second electrical contact element, wherein by applying an operating force in particular a change in the sensor capacitance can be brought about, the sensor device being designed in particular to detect a change in the sensor capacitance and, depending on this, a switching state of the Ko tact switch to be determined, and also particularly preferably an operating force applied to the operator input.

A method according to the invention for diagnosing a circuit arrangement and/or a sensor device according to the invention is characterized by the steps: a) providing a circuit arrangement according to the invention and/or a sensor device according to the invention, b) determining a switching state of the contact switch of the circuit arrangement using the at least one electrically conductive sensor electrode, c) Application of a first defined potential to the first contact element and/or the first connection line, in particular as a function of the determined switching state of the contact switch, and at the same time d) application of a second defined potential to the second contact element and/or the second connection line, in particular as a function from the determined switching state of the contact switch, and at least temporarily while steps c) and d) are being carried out: e) detecting a resulting first at the first contact element and/or at the first connection line and/or at the first connection voltage and/or a resulting second voltage occurring at the second contact element and/or in the second connecting line and/or occurring at the second connection, f) evaluating at least one detected voltage, and g) determining a functional state of the circuit arrangement, in particular a function z state of the circuit arrangement and/or the contact switch, depending on the switching state of the contact switch detected using the sensor electrode and depending on at least one detected and evaluated voltage.

By determining the functional state of the circuit arrangement depending on the switching state of the contact switch, the ability to diagnose the circuit arrangement can be significantly improved. In particular, error states of the circuit arrangement can be clearly identified in this way, which are not clearly recognizable as an error state without determining the switching state of the contact switch. In this way, for example, a short circuit in the contact switch can be distinguished from a closed contact switch. As a result, the functional safety of the circuit arrangement can be significantly increased. For example, in this way, when a contact switch is open, a short circuit within the contact switch can be detected, which could not be clearly identified without knowledge of the switching state.

The switching state of the contact switch is preferably determined capacitively in a conventional manner known from the prior art, with preferred a change in the sensor capacitance formed between the at least one sensor electrode and at least one of the contact elements is detected and evaluated, in particular a change in the sensor capacitance resulting from a change in the distance between the two contact elements of the contact switch.

The change in the sensor capacitance can be detected, for example, using one of the known CVD methods (capacitive voltage divider method), as described, for example, in "AN1478 - mTouch™ Sensing Solution Acquisition Methods Capacitive Voltage Divider" from Microchip is described, available at the filing date of the present application at http://ww1.microchip.com/downloads/en/Appnotes/01478B.pdf.

A particularly efficient and advantageous embodiment of a method according to the invention results when the switching state of the contact switch is determined using the sensor electrode before a potential is applied in one of steps c) and/or d). This makes it possible to apply the potential in a targeted manner tailored to the respectively detected switching state of the contact switch or to carry out only those diagnostic steps or measurements that enable the functional state to be clearly determined in the respective current switching state of the contact switch.

This allows the diagnosis to be carried out very efficiently and in a targeted manner. This is particularly advantageous when only short periods of time, i.e. short time slots, are available to carry out a diagnosis.

In principle, however, it is also possible to determine the switching state of the contact switch only immediately before determining the functional state. In order to reliably determine the functional status, the switching status of the contact switch should be determined during or shortly before or after the voltages are recorded in order to ensure correct evaluation and classification or assignment of the measured voltage(s) to the switching status of the contact switch enable.

A first defined potential can be applied to the first contact element and/or to the first connection line, for example, in particular if the circuit arrangement has a reference capacitance electrically connected to the first connection line and an associated pull resistor, for example by first charging the reference capacitance in a defined manner or is discharged defined, and then discharged or charged. If the at least one voltage to be detected is detected in particular during discharging or charging, A functional state of the circuit arrangement can be inferred, in particular, from a resultant voltage curve that results and is then compared with the expected target voltage curve for the respectively underlying, defined charge or discharge state.

If the recorded voltage curve does not correspond to the expected voltage curve, for example because the reference capacitance discharges much faster than expected, this indicates a faulty functional state of the circuit arrangement. In this way, for example, a short circuit with a ground potential or a supply potential can be detected, or else a changed resistance behavior of one or more components of the circuit arrangement.

In another embodiment of a circuit arrangement according to the invention, for example if the first contact element and/or the second contact element are/are also electrically connected or can be connected via a further connection and a further connection line to the control, measuring and evaluation device, for example via a third and/or or fourth connection line and a third and/or fourth connection, the respective connection line assigned to the first contact element or the second contact element can be applied to a corresponding potential, for example, by applying the corresponding potential to the associated further connection or the associated further connection line is, for example a supply potential Vcc or Vdd of the control, measuring and evaluation device, in particular an associated microcontroller, or a ground potential, in particular a potential of +0V, i.e. in particular a Grou nd potential, i.e. GND. This can be carried out in a particularly advantageous and simple manner by forming the respective associated further connection as an output or by switching it as an output for the potential application period and in particular by connecting it to a corresponding pole of a respective voltage source.

In a particularly preferred embodiment of a method according to the invention, the at least one resultant first and/or second voltage or the resultant first and/or second voltage curve that occurs in each case is recorded in particular by means of or with the aid of a corresponding one assigned to the respective connection Analog-to-digital converter or the like. This is preferably, at least during the detection, electrically connected to the first terminal or the second terminal, wherein the first Connection and/or the second connection are either (permanently) designed as an input for this purpose, ie in particular high-impedance, or can be operated as an input at least during detection, for example by being designed as GPIO connections and during detection or for detection be switched to high resistance, in particular to a voltage measurement operation, in which they are electrically connected, for example, to the analog-to-digital converter.

The resulting voltage can be recorded either once, i.e. by sampling once, or several times in succession, i.e. by continuous measurement or continuously with the help of an analog input.

In particular, if a defined potential is applied in step c) and/or d) by a defined charging or a defined discharging of a reference capacitance, the resulting voltage that occurs is particularly preferably continuously recorded, i.e. the associated voltage profile is recorded, or at least time-dependent, i.e. the time between two measured voltage values is also recorded. Otherwise, due to the non-constant potential present, it is not possible to reliably determine the functional state of the circuit arrangement.

On the other hand, at least time-dependent, in particular continuous, voltage detection is not required if the defined potential can be applied via a further connection and/or a further connection line, since in this case a constant potential can be applied in a simple manner and in a fault-free state this also results in a constant voltage. A functional state of the circuit arrangement can thus be reliably determined here in particular with just one, in particular with two, measured voltage values.

The evaluation in step f) can in particular include a comparison of the detected voltage or the detected voltage curve with an associated setpoint value or an associated setpoint curve and/or include signal processing or the like and/or error correction and/or compensation, for example to avoid signal noise to reduce and/or to calculate corresponding component, error and/or environmental influences or tolerances or measurement tolerances or the like and thus to improve the detection accuracy or quality of the determination of a functional state of the circuit arrangement or of the contact switch. This can be achieved, for example, with the help of appropriate value windows, threshold values, signal filters, averaging, etc. For example, it is possible in this way to calculate the technically conditioned, respectively existing filter or buffer capacities of individual components.

The functional state of the circuit arrangement can be determined, for example, by comparing the resulting first voltage detected at the first connection with the resulting second voltage occurring in particular simultaneously at the second connection and with the respective voltage at the first contact element or in the first connection line and/or include potentials applied to the second contact element and/or in the second connection line.

In this way, an error condition can be detected, for example, if (with an open contact switch) the first contact element in step c) has been subjected to a first reference potential of, for example, +5V via a third connection and a third connection line, but at the first connection when detecting the resulting first voltage that occurs in the first connection line or at the first connection in step e) only a voltage of +3.5V has been detected instead of an expected voltage of, for example, +4.8V which, taking into account an electrical resistance in of the first connection line and an electrical resistance connected in series in the third connection line should have set.

Likewise, for example, an error state can be concluded if the contact switch is in a first open switching state, a first potential of, for example, +5V is applied to the first contact element in step c), at the same time a potential of, for example, is applied to the second contact element in step d). ±0V is applied, i.e. GND in particular, but a resulting voltage of approx. +4.8V instead of ±0V is still detected at the second connection in step e). This suggests that, for example, there is a short circuit between the contact elements or the second contact element or the second connection line or the second connection is otherwise short-circuited or is electrically connected to the supply potential of the microcontroller, for example.

When carrying out a method according to the invention, it is preferably determined in particular whether one of the contact elements is short-circuited with a potential, for example with a supply potential or a base potential, in particular for example with a supply potential or with a ground potential of an associated microcontroller. Alternatively or additionally, in a particularly preferred embodiment of a method according to the invention, a contact transition resistance and/or an insulation resistance between the contact elements is determined or determined.

This is possible with a circuit arrangement according to the invention or a sensor device according to the invention and in particular with a method according to the invention, since the insulation resistance can only be determined when the contact switch is open, for example, while the contact transition resistance, on the other hand, can only be determined when the contact switch is closed and by the detection according to the invention can each be checked for plausibility or confirmed whether the contact switch is actually open or closed.

The evaluation of at least one detected voltage and/or the determination of a functional state of the circuit arrangement can take place in particular immediately after the voltage(s) have been detected or also at a certain time interval thereafter, in particular depending on the operating state of the contact switch.

The functional state of the circuit arrangement, in particular of the contact switch or the control, measuring and evaluation device, is particularly preferably determined, but only after the resulting first voltage and the resulting second voltage occurring at the second contact element and/or in the second connection line and/or at the second connection have been recorded.

This enables both voltages, i.e. the first voltage and the second voltage, to be taken into account when determining the functional state of the circuit arrangement. The functional state can thus be determined better and more precisely. In other words, the first voltage occurring at the first contact element and/or in the first connecting line and/or at the first connection and the resulting first voltage at the second contact element and/or in the second connecting line and/or are particularly preferred. or the resulting second voltage occurring at the second connection is detected and evaluated, and the functional state of the circuit arrangement is then determined in step f), in particular as a function of the first voltage and as a function of the second voltage.

In a particularly advantageous embodiment of a method according to the invention, the functional status is also subsequently output, in particular in a further one Step, for example in the form of a corresponding output signal or the like, wherein in the case of a detected faulty functional state of the circuit arrangement, at least one corresponding measure is particularly preferably carried out, and in particular as a function of an output signal characterizing the fault state.

Such a measure can be, for example, entering information into an error memory and/or transferring the circuit arrangement and/or a corresponding system using the circuit arrangement to a safe state, for example by switching it off.

To improve the diagnostic quality, the application of the potentials (steps c) and d)) and the detection of the voltage (step e)) can be repeated several times. Likewise the evaluation (step f)) and the determination of the functional state (step g)). In some cases, it can also make sense to repeat the determination of the switching state of the contact switch (step b)) in each case in this context.

In this case, the quality of the diagnosis can be improved in a particularly advantageous manner by carrying out one or more further cycles, each of which includes one or more repetition steps. It has proven to be particularly advantageous if these cycles are each carried out with changed parameters, but preferably in such a way that the result of a previous cycle can be checked for plausibility. This can be achieved, for example, by carrying out multiple diagnostic cycles with different potential values.

If the circuit arrangement is to be tested for a changed contact resistance, for example, several measurements with different potentials, which are applied to the contact elements in the respective cycles, can be carried out and evaluated, with all the results of the individual measurements being used to determine the functional state of the circuit arrangement Cycles can be taken into account and, in particular, compared with one another or otherwise linked to one another or related to one another in order to improve the quality of the determination of the functional state, in particular the accuracy. In principle, all possible variations are conceivable.

In a particularly advantageous embodiment of a method according to the invention, steps b) to e) are first carried out in one cycle. After this first cycle has been carried out, a second cycle is carried out in particular, in which at least steps b) to e) are repeated, ie the steps determining the switching state of the contact switch (step b)), applying a first defined potential (step c)) and a second defined potential (step d)) and detecting the resulting first or second voltages (step e) ) before the detected voltages are evaluated and (step f)) and the functional state of the circuit arrangement is determined in step g).

In the second cycle, in a particularly preferred embodiment of a method according to the invention, in step c) the second defined potential from the first cycle is applied to the first contact element and/or the first connecting line, and at the same time in step d) the first defined potential from the first cycle is applied applied to the second contact element and / or the second connecting line.

During the subsequent evaluation in step f), in particular when determining the functional state in step g), in particular at least one voltage recorded in the first cycle, in particular a first voltage recorded in the first cycle and a second voltage recorded in the first cycle, and at least one in the second Cycle detected voltage is taken into account, in particular a first voltage detected in the first cycle and a second voltage detected in the first cycle.

i.e. In other words, in a particularly advantageous embodiment or embodiment of the method according to the invention, in the second cycle, the potentials from the first cycle are preferably applied in opposite directions to the first contact element or the second contact element or to the associated connection lines before the detected Voltages are evaluated and the functional state of the circuit arrangement is determined, the functional state being determined in particular as a function of the voltages recorded and evaluated in the first cycle and in the second cycle.

As a result, the functional state of the circuit arrangement can be determined even better, in particular more precisely and unambiguously, and the diagnosis of the circuit arrangement can thus be improved. In particular, a significantly higher diagnostic accuracy can be achieved as a result. Above all, the rate of correctly recognizable error states can be increased in this way. Furthermore, any fault or defect that may be present in the circuit arrangement can be better localized or more precisely determined in this way.

Alternatively or additionally, it is also conceivable to carry out the second cycle only after the evaluation of the voltages recorded in the first cycle and/or also only after a functional state of the circuit arrangement has already been determined in step g) on the basis of the voltage(s) detected in the first cycle.

This means that the second cycle can in principle also only be carried out after steps f) and g) have initially been carried out following the first cycle or steps a) or b) or c) to e).

The second cycle can be carried out directly after the first cycle or immediately after step f) or g) or with a defined break in between.

The first cycle and the second cycle can also be repeated as often as you like: alternately or with a changing rhythm, whereby the time intervals between the execution of the individual cycles can be constant or can also be variable, depending on the need, in particular depending on the need for diagnosis or available diagnostic time.

In many applications, it can be advantageous if the diagnosis or the method according to the invention for diagnosing the circuit arrangement is carried out continuously, that is to say is repeated continuously and cyclically. This means that the diagnosis or the method according to the invention for diagnosing the circuit arrangement can be carried out in particular after an associated control unit has been started up and can be repeated cyclically until the control unit shuts down or has shut down again. As a result, particularly good monitoring of the contact switch can be achieved.

Alternatively, the diagnosis can also only be carried out as required, for example only immediately after starting up the circuit arrangement or a system with such a circuit arrangement, for example a sensor system or the like and/or after certain events, in particular triggering or triggering a diagnosis.

In some cases it can be particularly advantageous to repeat the method according to the invention, in particular steps b) to g) and/or only the first cycle and/or the second cycle, if necessary several times, in particular with others, from the first and / or second defined potential different potentials that are applied, resulting in more diagnostic options.

For example, in some cases it can be advantageous if, after a second cycle, a third cycle is also carried out according to the same principle, with In this third cycle, for example, a third potential, in particular a third potential different from the first potential and/or the second potential, is applied to the first contact element and/or the first connection line and/or the first connection and/or the second contact element and/or the second connection line and/or the second connection is created.

In a particularly advantageous embodiment of a method according to the invention, in particular after carrying out steps b) or c) to e) in a second cycle, at least a third cycle is carried out, particularly preferably also a fourth cycle, particularly preferably in the third cycle in each case and/or in the fourth cycle at least steps b) or c) to e) are repeated, in particular before steps f) and g) are carried out. In the first cycle and in the second cycle, the first potential and the second potential are preferably chosen to be different from each other and in the third cycle, in steps c) and d), the first defined potential from the first or second cycle is preferably applied to both the applied to the first contact element and/or the first connection line as well as to the second contact element and/or the second connection line. In the fourth cycle, in steps c) and d), in particular the second defined potential from the first or second cycle is applied both to the first contact element and/or the first connecting line and to the second contact element and/or the second connecting line and when evaluating in step f) or when determining the functional state in step g), particularly preferably at least one voltage recorded in the first cycle, at least one voltage recorded in the second cycle and at least one voltage recorded in the third cycle and/or one voltage recorded in the fourth cycle is taken into account or the functional state is determined as a function of at least all of these, in particular as a function of all of the voltages recorded in the individual cycles.

i.e. In other words, and to put it in simplified terms, that particularly preferably in at least one cycle, for example in a first cycle, two different potentials are applied to the first contact element and the second contact element or the associated connection lines or connection nodes, and particularly preferably a corresponding further cycle , for example a second cycle, is repeated with reversely applied potentials, as it were as a redundant cycle, and also in particular at least one further cycle is carried out, for example a third cycle, by particularly preferably contacting both contact elements or connection lines or connection nodes, the same potentials are applied, such a cycle preferably also being carried out redundantly, but preferably with a further potential.

Particularly preferably, in such a further cycle, for example in a third cycle, a first further potential is applied to both contact elements or the associated connection lines and in a further, for example fourth cycle, a second further potential that differs therefrom. These additional potentials can be the same potentials that are selected as different potentials in a different cycle, ie correspond to the first and second potentials from the first and second cycles, for example, or alternatively be third or fourth potentials with third or fourth potential values.

As a result, the ability to diagnose, in particular the reliability of the diagnosis or the reliability of the determination of the functional state, can be significantly improved. In particular, the detection of the individual voltages can also be checked, for example, whether the analog-to-digital converters used are functioning properly.

The preferred embodiments presented with reference to a diagnosable circuit arrangement according to the invention and the advantages thereof also apply correspondingly to a sensor device according to the invention and to a method according to the invention for diagnosing such a circuit arrangement and vice versa, even if this is indicated in this application, in particular to avoid repetition is not explicitly described again in the relevant places.

Further features of the invention result from the claims, the figures and the description of the figures. All of the features and combinations of features mentioned above in the general description and the features and combinations of features mentioned and/or described below in the description of the figures and/or shown in the figures can be used not only in the combination specified in each case, but also in other combinations and also on their own , provided that this combination or the respective configuration is technically feasible.

The invention will now be explained in more detail on the basis of several non-restrictive exemplary embodiments and with reference to the attached drawings, in which components with the same function are provided with the same reference numbers. show: 1 shows a simplified block diagram of a first exemplary embodiment of a circuit arrangement according to the invention,

2 shows a simplified block diagram of a second exemplary embodiment of a circuit arrangement according to the invention,

3 shows a flowchart for a first exemplary embodiment of a method according to the invention,

4 shows a simplified block diagram of a third exemplary embodiment of a circuit arrangement according to the invention,

5 shows a simplified block diagram of a fourth exemplary embodiment of a circuit arrangement according to the invention,

6 shows a simplified block diagram of a fifth exemplary embodiment of a circuit arrangement according to the invention, and

7 shows a simplified block diagram of a sixth exemplary embodiment of a circuit arrangement according to the invention.

Fig. 1 shows a simplified block diagram of a first exemplary embodiment of a circuit arrangement 100 according to the invention, this circuit arrangement 100 being designed for use in a control element and/or a control device, in particular for use in a control input device in a vehicle, for example in a steering wheel or the like .

According to the invention, the circuit arrangement 100 has an electrical contact switch 10 and a control, measuring and evaluation device 20 . The electrical contact switch 10 has a first electrical contact element A and a second electrical contact element B. The control, measurement and evaluation device 20 , which is formed by a microcontroller (PC) in this exemplary embodiment, has a first electrical connection 3 and a second electrical connection 4 .

The first electrical contact element A is electrically connected to the first connection 3 of the control, measuring and evaluation device 20 via a first connecting line 1 and a first electrical resistor R1, and the second contact element B via a second connecting line 2 and a second electrical resistor R2 with the second connection 4. According to the invention, the circuit arrangement 100 also has an electrically conductive sensor electrode 30, which is designed and arranged relative to at least the contact elements A and B of the contact switch 10 in such a way that it forms a sensor capacitance (not designated in more detail) with them. In this exemplary embodiment, the sensor electrode 30 is formed separately and is electrically connected to the control, measuring and evaluation device 20 via a sensor electrode connection line 31 with a further connection 32 , in particular a sensor electrode connection 32 .

The sensor electrode 30 is arranged relative to the contact switch 10, in particular to its contact elements A and B, that when the distance between the contact elements A and B changes, the sensor capacitance changes, which can be measured, in particular capacitively, detected. This can be used to determine a switching state of the contact switch 10, in particular whether the contact switch 10 is open or closed. In particular, a change in the sensor capacitance can be detected using a capacitive measuring method, for example using a so-called CVD method (capacitive voltage divider method).

According to the invention, in this circuit arrangement 100, in at least one state of the circuit arrangement 100 for at least partial diagnosis of the circuit arrangement 100, the control, measuring and evaluation device 20 can also be used at least temporarily to connect the first connection line 1 and thus also to the first contact element via the first connection 3 A a first defined potential can be applied and at the same time a second defined potential via the second connection 4 to the second connection line 2 and thus also to the second contact element B while the first defined potential and the second defined potential are present, to detect a resulting first voltage occurring at the first terminal 3 and meanwhile to detect a resulting second voltage occurring at the second terminal 4, and to output the detected voltages values, and to determine a functional state of the circuit arrangement 100 as a function of the switching state of the contact switch 10 determined using the sensor electrode 30 and as a function of the detected and evaluated voltages. In order to have only one connection line 1 or 2 between the contact element A and the associated connection 3 on the control, measuring and evaluation device 20 or between the contact element B and the associated connection 4, as in this exemplary embodiment of a circuit arrangement 100 according to the invention, In this exemplary embodiment, the first connection 3 and the second connection 4 of the control, measuring and evaluation device 20 are each connected by so-called Multifunction pins formed and designed as so-called GPIO connections 3 and 4, ie as so-called (re)switchable connections 3 and 4, which can be switched between different operating or functional states, the switching in this embodiment being done electronically , ie at the semiconductor level, w which can be brought about by software within the PC 20, ie internally. To implement this switching function, terminals 3 and 4 are each electrically connected to an internally switchable pin GPI01 or GPI02 of PC 20, with the two pins GPI01 and GPI02 in the exemplary embodiment shown here each being switched between an operating state as an input pin, here symbolized by E1, and can be switched between two different operating states A1 and A2 as the output pin.

In a first switching state, the connections 3 and 4 can each be operated as an input E1, in particular as an analog input E1, with the associated connection 3 or 4 being switched to high resistance and connected to an analog-to-digital converter unit ADC1 or ADC2 is electrically connected. As a result, in this state, an electrical voltage present at the associated connection 3 or 4 can be detected.

In a second switching state, terminals 3 and 4 can each be operated as output A1 or A2, in particular as a digital output, and in this example either with a reference potential (output A1 - here Vcc) or with a base potential (output A2 - here GND) can be electrically connected.

In this example, the reference potential is the positive supply voltage Vcc of the microcontroller or the control, measuring and evaluation device 20, which is +5V in this case, and the base potential is the ground potential of the microcontroller 20 or the control, Measuring and evaluation device 20, ie in this case a potential of ±0V, ie "Ground" or GND. Furthermore, in order to be able to carry out a corresponding diagnosis with only one connecting line 1 or 2 or only one associated connection 3 or 4, respectively, an electrical resistor R1 designed as an ohmic resistor is in each case between the contact element A and B or R2 along the associated connecting line 1 or 2 in series. In addition, the resistors R1 and R2 make it easy to avoid a hard short circuit between the connections 3 and 4 or the connection nodes K3 and K4 in the event of a closed contact switch and thus prevent the PC connections from being overloaded as a result of a Short circuit resulting in uncontrolled, rapid capacitor charge reversal. In addition, each of the contact elements A and B is also electrically connected via the associated connection line 1 or 2 to an associated reference capacitance C1 or C2 and an associated pull-down resistor PD1 or PD2.

In this exemplary embodiment of a circuit arrangement 100 according to the invention, the associated reference capacitance C1 or C2 is electrically connected on the one hand to the base potential or the ground potential GND, i.e. to ±0V, and on the other hand via a connection node K3 or K4 to the respectively associated to connection line 1 or 2, wherein the connection node K3 or K4 between the depending Weil associated electrical resistor R1 or R2 and the associated terminal 3 or 4 is located.

The pull-down resistor PD1 is also electrically connected to the base potential or the ground potential GND, i.e. with ±0V, and on the other hand also via a connection node K1 to the associated connection line 1. However, the connection node K1 is in each case between the contact element A and the electrical resistance R1 and not between this and the connection 3 on the control, measuring and evaluation device 20.

The pull-down resistor PD2 is also electrically connected to the base potential or the ground potential GND, i.e. with ±0V, and on the other hand also via a connection node K3 to the associated connection line 2. However, the connection node K3 is in each case between the associated Contact element B and the electrical resistance R2 and not between this and the associated connection 4 on the control, measuring and evaluation device 20.

By appropriate, suitable pC-internal switching of pins GPI01 and GPI02 or by appropriate, suitable reassignment of connections 3 and 4, it is possible to of such a circuit arrangement 100 in at least one state of the circuit arrangement 100 perform a diagnosis of the circuit arrangement 100 and determine a functional state of the circuit arrangement 100, in particular by means of a method according to the invention, which is explained in more detail below.

3 shows a flowchart of a first exemplary embodiment of a method according to the invention for diagnosing a circuit arrangement according to the invention, for example for diagnosing circuit arrangement 100, with a circuit arrangement according to the invention being provided after a start SO in a first step S1. I.e. the circuit arrangement 100 must be available. In a further step S2, the switching state of the contact switch 10 is then initially determined with the aid of the sensor electrode 30, in particular whether it is open or closed. Then, in step S3, a first defined potential is applied to the first connecting line 1 and, at the same time, in step S4, a second defined potential is applied to the second connecting line 2. At least temporarily and while steps S3 and S4 are being carried out, in step S5 a first connection 3 and/or a resultant second voltage occurring at the second connection 4, which is then evaluated in step S6. In step S7, a functional state of the circuit arrangement 100 is determined as a function of the determined switching state of the contact switch 10 and as a function of the voltage(s) detected, for example whether the circuit arrangement 100 is functioning properly or there is an error, for example a short circuit .

Steps S2 to S7 can each be carried out only once before the method ends in step S8, or they can be repeated individually or together with other steps in the form of one or more further cycles before the method is ended in step S8, which is symbolized by the feedback arrows.

When repeating the individual steps, potentials other than the first or second potential can in principle also be used and/or the first and second potential can be interchanged and/or the first potential and the second potential can be chosen to be the same.

Further steps after S7 can also be carried out. For example, the determined functional state can be output and/or one or more measures can be initiated and carried out. Such a measure can, for example, enter an error in an error memory, display an error message and/or the switching of the circuit arrangement and/or of a system using the circuit arrangement to a safe state, for example switching to emergency operation or switching off the system.

A diagnosis of circuit arrangement 100 can be carried out, for example, in particular using a method according to the invention, in that a current sensor capacitance or a current capacitive coupling between sensor electrode 30 and one or both contact elements A and B is first detected and evaluated using a capacitive measurement, for example, and in Depending on the result, a switching state of the contact switch 10 is determined.

Then, for example, the first connection 3 can be switched as an output and in particular switched or “connected” to the first output A1, so that the reference potential Vcc, in this case +5V, is applied to the first connection 3. Furthermore, for example, the second connection 4 can also be switched as an output at the same time, but this can be switched to the second output A2, for example, so that the base potential of +0V is present at the connection 4.

The first reference capacitance C1 is charged by flattening this state. This state is preferably maintained until the first reference capacitance C1 is charged in a defined manner, in particular completely up to the reference potential Vcc or in this case to +5V.

If the first connection 3 is then switched to input mode by switching the first pin GPI01, i.e. switched to "high impedance", the first reference capacitance C1 begins to discharge. If the first connection 3 is switched over to the input E1 designed as an analog input, the resulting voltage occurring at the first connection 3 can be detected with the first analog-to-digital converter ADC1 or the analog-to-digital converter unit ADC1 , in particular the voltage profile that occurs over time when the first reference capacitance C1 is discharged.

If the detected voltage, ie the measured voltage or the detected voltage curve, deviates by more than a defined as permissible amount from a respective, respectively expected setpoint voltage or the respectively expected setpoint voltage curve, this indicates an error or a undesired changes within the circuit arrangement 100 indicate, for example, an increased resistance at one of the contact elements A, B, a line break, a short circuit, a reduced insulation resistance between the contact elements A and B and/or an increased contact resistance between the contact elements A and B. The expected target voltage or the expected target voltage curve is dependent on the switching state of the contact switch 10. If the first reference capacitance C1 discharges faster than expected when the contact switch 10 is open, ie the detected falls If the voltage drops faster than expected, this indicates a short circuit.

If a detected deviation exceeds a permissible level, an error functional state is determined as the functional state and, in particular, is output for further processing. If the deviation is below the permissible value, in particular below a defined threshold, an error-free functional state is determined as the functional state and is output in particular for further processing.

In which the detected voltage, or in this case particularly preferably the detected voltage curve, is evaluated and in particular compared with an associated defined voltage setpoint or a defined voltage setpoint curve, according to the invention in each case depending on the switching state of the contact switch 10, the is determined according to the invention using the sensor electrode 30, the functional state of the circuit arrangement 100 can be reliably determined in a simple manner.

For a particularly reliable diagnosis of the circuit arrangement 100, analogously to the first cycle, one or more further cycles can be carried out, for example at least one second cycle, in which, for example, instead of a voltage occurring at the first connection 3, a resulting voltage occurring at the second connection 4 is recorded or other potentials are applied to the first connection line or the second connection line.

By varying the initial state or the switching states of the circuit arrangement 100, in particular of the GPIO pins, different potentials can be applied for which different target voltages are expected in each case. Errors or changes in the circuit arrangement 100 can be detected by detecting the resulting voltages or voltage curves that are set in each case for the predefined states and a corresponding comparison of these with the expected setpoint values.

The order of the individual test states or switching combinations in order to create different potentials and potential combinations accordingly Being able to detect as many error states or undesired changes or malfunctions as possible is fundamentally arbitrary and freely variable.

For example, in a second cycle, the first connection 3 can be permanently switched as an output and in particular applied to the second output A2, so that the base potential GND is applied to the second connection 3 and thus to the connection contact K2, while at the same time the second connection 4 is initially connected is electrically connected to the first output A1, so that the reference potential Vcc is applied to the connection contact K4. As a result, the second reference capacitance C2 is now charged to a second defined potential, which is based on the first potential and, in particular, approximately corresponds to the reference potential Vcc at +5V.

If the second reference capacitance C2 is fully charged, analogous to the first cycle, instead of the first connection 3, the second connection 4 is now switched to input operation and in particular connected to the associated input E1 of the connection 4, with the second connection 4 being switched to high resistance for this purpose. In this state, the second analog-to-digital converter ADC2, which is electrically connected to the second connection 4, can be used to detect the resulting voltage occurring at the second connection 4 or the voltage profile resulting from the discharge of the second reference capacitance C2.

If the voltage recorded by means of the second analog-to-digital converter ADC2 or the second analog-to-digital converter unit ADC2 or the recorded voltage profile deviates by more than a degree defined as permissible from the respectively expected setpoint voltage or the If the expected setpoint voltage profile decreases in each case, this also indicates a fault or an undesired change within the circuit arrangement 100, for example an increased resistance at one of the contact elements A, B, a line break, a short circuit, a reduced insulation resistance between the contact elements A and B and or to an increased contact resistance between the contact elements A and B.

If, when determining the functional state of circuit arrangement 100, both the voltages recorded in the first cycle by means of the first analog-to-digital converter ADC1 or the voltage curves recorded over time and the voltages or If the associated voltage curve is taken into account when determining the functional state of the circuit arrangement, the functional state of the circuit arrangement 100 can be determined more reliably than if, for example, only the first Cycle is carried out or only the voltages recorded in this are taken into account. In particular, this enables a plausibility check and/or the detection of additional error states or additional undesired changes in the circuit arrangement 100.

In order to achieve continuous monitoring and determination of the functional state of the circuit arrangement 100, the various cycles can be repeated regularly, in particular alternately and with or without a pause in between. The time between two cycles, i.e. the duration of a pause between two diagnostic cycles, can also be varied or chosen to be constant.

To further improve the diagnosis, in particular to identify further error states or to check error states recognizable based on the first cycle and/or the second cycle for plausibility, at least one further cycle can be carried out, for example a third cycle and a fourth cycle, in particular before determining the functional state of the circuit arrangement 100.

If the first reference capacitance C1 is completely discharged again, for example at the end of the first and/or second cycle, in a third cycle that follows the second, for example, the first connection 3 can be switched (permanently) as an input, i.e. it can be connected to E1, and the second connection 4 are simultaneously switched to the output A1, so that the reference potential Vcc of +5V is applied to the second connection 4 and thus to the second connection line 2, and meanwhile the resulting voltage occurring at the first connection 3 by means of the first Analog-to-digital converter ADC1 is measured. And then evaluated.

Accordingly, in a fourth cycle, for example, when the second reference capacitance C2 is completely discharged, the second connection 4 can be connected to the analog input E1 and at the same time the first connection 3 can be connected to A1, so that the first connection 3 and thus the first connection line 1 the reference potential Vcc of +5V is applied, while the resulting voltage occurring at the second connection 4 is detected by means of the second analog-to-digital converter ADC2.

In particular, it is also possible to select the individual cycles that can be carried out to diagnose the circuit arrangement 100, for example depending on the determined switching state of the contact switch 10. A particularly efficient diagnosis can be carried out as a result. For example, it can be achieved that a check of a contact transition resistance, in particular a diagnostic cycle required for this, is only carried out, for example, when the contact switch 10 is closed, while a measurement or a diagnostic cycle to determine an insulation resistance or to check whether this changes over the term or lifetime of the circuit arrangement 100 has changed, particularly preferably, for example, is only carried out when the contact switch 10 is open.

Fig. 2 shows a simplified block diagram of a second exemplary embodiment of a circuit arrangement 200 according to the invention, this circuit arrangement differing from the circuit arrangement 100 shown in Fig. 1 in that the pull resistors PU1 and PU2 from Fig. 2 are each pull-up resistors are designed instead of as pull-down resistors and instead of having the base potential of +0V, i.e.

GND, in the circuit arrangement 200 are each electrically connected to a reference potential - here Vcc, i.e. +5V.

A diagnosis of this circuit arrangement 200 can be carried out, for example, in particular with a method according to the invention, in that, for example, first the first connection 3 is switched as an output and in particular is switched to the second output A2, as a result of which the base potential, in this case the ground potential of +0V, i.e. GND, is applied to the first connection 3, and the second connection 4 is also switched as an output at the same time, but in particular to the first output A1, so that the reference potential Vcc of +5V is present at the connection 4.

By holding this state, the first reference capacitance C1 is discharged. This state is preferably maintained until the first reference capacitance C1 is discharged in a defined manner, in particular completely down to the base potential or in this case to +0V or GND.

If the first connection 3 is then switched over to input operation by switching over the first pin GPI01, the first reference capacitance C1 begins to charge. If the first connection 3 is switched over to the input E1 designed as an analog input, the resulting voltage occurring at the first connection 3 during the charging of the first reference capacitance C1 can be detected with the first analog-to-digital converter ADC1 connected downstream, in particular the voltage profile that occurs when charging the first reference capacitance C1.

Correspondingly, for example, in a fourth cycle when the second reference capacitance C2 is fully charged, the second connection 4 to the analog input E1 are switched and at the same time the first connection 3 is connected to A2, so that the base potential GND of +0V is present at the first connection 3 and thus in the first connection line 1, with the second analog-to-digital converter ADC2 meanwhile being used to Connection 4 adjusting, resulting voltage is detected.

In the third or fourth cycle, it is not necessary either in the circuit arrangement 100 from FIG. 1 or in the circuit arrangement 200 from FIG.

When choosing the sampling time, i. H. However, particularly when selecting the time for detecting the respective voltage at the respective terminal 3 or 4, the delay that occurs in each case should be taken into account and you should wait until the voltage to be detected is stable. This is only the case when the associated reference capacitance (C1 or C2) has charged via the network of resistors (R1, R2, PD1 and PD2). Alternatively or additionally, the charging curve of the associated capacitor, i.e. the time profile of the voltage during charging, can also be recorded and evaluated for an evaluation. ,

As an alternative to the exemplary embodiments of a circuit arrangement 100 or 200 according to the invention shown in FIGS. 1 and 2, the capacitors C1 and C2 could also be connected to Vcc instead of being connected to the base potential or GND here. Only other, in particular reverse, voltage curves then result. But a diagnosis is basically possible according to the same principle.

Fig. 4 shows a simplified block diagram of a third exemplary embodiment of a circuit arrangement 300 according to the invention, this circuit arrangement 300 differing from the two circuit arrangements 100 and 200 described above in particular in that the contact elements A and B of the contact switch 10 have a plurality of connection lines 1, 5 and 9 or 2, 7 and 12 as well as electrical ohmic resistors R1, R3 and R5 or R2, R4 and R6 connected in series along these connection lines 1, 5 and 9 or 2, 7 and 12 with the control, measuring and evaluation device 20 are electrically connected, and in that the control, measurement and evaluation device 20 also has further connections 6 and 11 and 8 and 13 in addition to a first connection 3 and a second connection 4 . In addition, no pull resistors or reference capacitors C1 or C2 electrically connected to the first or second connecting line 1 or 2 are provided.

Furthermore, in this exemplary embodiment, the first connection 3 and the second connection 4 are not designed as GPIO connections, in particular not as (re)switchable connection contacts, but as permanent input connections 3 or

4 and each permanently electrically connected to a corresponding analog-to-digital converter ADC 1 or ADC 2 . Thus, via the first connection 3 or the second connection 4, only one voltage present at the associated connection 3 or 4 or in the associated connecting line 1 or 2 or at the associated contact element A or applied voltage can be detected, but via this connection 3 or 4 no defined potential can be applied to the associated connection line 1 or 2 and/or the associated contact element A or B.

However, this is possible via the additional connections 6 and 11 as well as 8 and 13, which are each designed as (reversible) switchable connections. However, the connections 6 and 11 as well as 8 and 13 are only designed as switchable output connections. I.e. they cannot be operated as an input.

The third connection 6 and the fourth connection 8 are each designed as digital, switchable outputs that can be connected either to a first defined potential, here the reference potential Vcc (here for example +5V), or to a second defined potential, here the base potential GND (here for example +0V), can be assigned.

However, there is also nothing to be said against a different embodiment of designing connections 6 and 8 like connections 11 and 13, i.e. with 3 switching positions or possible switching states.

The other connections 11 and 13, i.e. the fifth and sixth connections 11 and 13, are also designed only as switchable output connections and can likewise only be switched over between specific output states.

In this case, the connections 11 and 13 are also designed as digital outputs and are each also designed to be optionally assigned the reference potential Vcc or the base potential GND. In addition, the connections 11 and 13 can only be switched to high impedance, ie to "high impedance", which is symbolized by the single circuit without any other connected line. The other connection lines 5 and 9, via which the other connections 6 and 11 are connected to the first contact element A, are not electrically connected directly to the associated contact element A, but rather indirectly via the connection node K1 and the, based on the representation in Fig. 4, left part of the first connection line 1, here additionally denoted by 1a.

The further connection lines 7 and 12, via which the further connections 8 and 13 are connected to the second contact element B, are also not electrically connected directly to the second contact element B, but also via a connection node K2 and an associated, based on the representation in Fig. 4, left part of the second connection line 2, denoted here by 2a.

Circuit arrangement 300 is also designed to carry out a diagnosis using a method according to the invention, circuit arrangement 300 being able to be operated for this purpose in particular in a manner similar to inventive circuit arrangements 100 and 200 described above, which are illustrated in FIGS.

A diagnosis of the circuit arrangement 300 can be carried out, for example, in particular with a method according to the invention, by first connecting the connection 6 to Vcc, i. H. to +5V, for example, and at the same time connection 8 is connected to GND, and meanwhile the resulting voltage that occurs at the first connection 3 or at the second 4 is measured by means of the respective associated analog-to-digital converter ADC 1 or ADC 2 is detected, and then the detected voltages are evaluated and a functional state of the circuit arrangement 300 is determined.

If the circuit arrangement 300 is error-free and functions properly and has no short circuit or undesirably changed internal resistances, for example, and if the contact switch 10 is open, the first voltage U1 recorded at the first connection 3 by means of the first analog-to-digital converter ADC1 should be +5V and the second voltage U2=0V detected at the second connection 4 by means of the second analog/digital converter ADC2.

If, on the other hand, the contact switch 10 is closed but the circuit arrangement 300 is still error-free, the voltage detected at the first connection 3 and the voltage detected at the second connection 4 should each change according to the following equation have set. If at least one of the voltages measured by means of the first analog-to-digital converter ADC1 or by means of the second analog-to-digital converter ADC2 or at least one combination of the voltage values detected at the connections 3 and 4 deviates from the previously described voltage values U1, U2 or If the combinations of voltage values U1, U2 described above, which should be present in the case of an open contact switch 10 or a closed contact switch, deviate by more than a degree defined as permissible, this indicates a fault condition. In this case, as in the case of the circuit arrangements 100 and 200 described above, an error functional state is also determined as the functional state and, in particular, is output for further processing.

If the deviation is below the permissible value, in particular below a defined threshold, an error-free functional state is determined as the functional state and is output in particular for further processing.

With the help of the information as to which of the recorded voltage values deviates, i. H. For example, a voltage detected by the first analog-to-digital converter ADC1 at the first connection 3 or, for example, a voltage detected by the second analog-to-digital converter ADC2 at the second connection 4, the possible cause of the error or the location of the error can be inferred, which can also be evaluated and taken into account when determining the functional status.

To improve the diagnostic quality, in particular to improve the diagnostic accuracy or to check the detected voltage values for plausibility or to check the detected fault status, the further connections 6 and 8 can be subjected to a different potential combination or each to a different potential in a second, subsequent cycle are applied or a different potential is applied to them compared to the first cycle and during which the resulting voltages that occur at the terminals 3 and 4 are recorded, then evaluated and a functional state of the circuit arrangement 300 is determined as a function of these, in particular taking into account or also depending on the voltages recorded in the first cycle.

For example, in a second cycle, the third connection 6 can be connected to the base potential GND and the fourth connection 8 to the reference potential Vcc. If the circuit arrangement 300 is error-free and works properly and has no short circuit or undesirably changed internal resistances, for example, and if the contact switch 10 is open, the first voltage U1 recorded at the first connection 3 by means of the first analog-to-digital converter ADC1 should be +0V and the second voltage U2=+5V detected at the second connection 4 by means of the second analog/digital converter ADC2.

If, on the other hand, the contact switch 10 is closed but the circuit arrangement 300 is still error-free, the voltage detected at the first connection 3 and the voltage detected at the second connection 4 should each change according to the following equation have set.

As described above, the first cycle and the second cycle can also be repeated regularly in this circuit arrangement 300, in particular alternately, with or without corresponding pauses in between, it being possible for the pauses in between to have a time-constant or variable length. Additional cycles and variations can be used to detect additional error states, for example by applying corresponding potentials via the additional connections 11 and 13 and the connection lines 9 and 12 and via the connections 3 and 4 and the associated analog-to-digital converters ADC1 and ADC2 adjusting voltage are recorded and compared with the respectively expected voltages.

Fig. 5 shows a simplified block diagram of a fourth exemplary embodiment of a circuit arrangement 400 according to the invention, with this circuit arrangement 400 having two electrically conductive sensor electrodes 30A and 30B on the one hand, and these are not formed separately, but are each formed by the contact elements A and B or .these form. Like the circuit arrangement 300 from FIG. 4 , this circuit arrangement can be diagnosed, but has the advantage that no sensor electrode connection line 31 and in particular no additional sensor electrode connection 32 are required. Such a configuration is therefore particularly suitable when the number of connections is not sufficient.

FIG. 6 shows a simplified block diagram of a fifth exemplary embodiment of a circuit arrangement 500 according to the invention, which requires even fewer parts or components than the circuit arrangement 400 from FIG. 5, in particular considerably fewer connections on the control, measurement and evaluation device 20. Instead of having various connections on the control, measurement and evaluation device 20, the second contact element B or the second sensor electrode 30B is here only connected to the base potential GND via the second connecting line 2 electrically connected.

A circuit arrangement of this type has a reduced scope of diagnostics or a reduced diagnostic capability compared to the circuit arrangements described above. In some cases, however, this can still be sufficient, in particular if the safety requirements for a circuit arrangement are not too high.

However, this circuit arrangement 500 is very compact and can be implemented inexpensively. It also requires very few connections to a control, measurement and evaluation device 20.

Fig. 7 shows a simplified block diagram of a sixth exemplary embodiment of a circuit arrangement 600 according to the invention, this circuit arrangement 600 differing from the circuit arrangement 400 described with reference to Fig. 5 in particular in that further connections 6 and 11 and 8 and 13 each have their own separate connection lines 5 and 9 or 7 and 12 and in each case an ohmic resistor R3 or R5 or R4 or R6 connected in series along these are electrically connected directly to the first contact element A or the second contact element B.

In this way, all connection lines 1, 2, 5, 9, 7 and 12 can be monitored over their entire length for possible interruptions or line breaks, as well as the contact elements A and B themselves. I.e. with the circuit arrangement 600, even when the contact switch 10 Detect interruptions within the contact elements A and B, which is not possible with the circuit arrangement 400 from FIG. 4, for example. When the contact switch 10 is open, the circuit arrangement 400 from FIG. 5 also does not allow detection of an interruption in the section of the first connection line 1 or the second connection line 2 between the associated contact element A or B and the connection node K1 or K2.

An even better diagnostic capability can thus be achieved with a circuit arrangement 600 according to FIG. 7 .

For further explanations on the individual diagnostic options or diagnostic cycles and the voltages or voltage curves to be expected for the individual circuit arrangements described herein, reference is hereby made to DE 102021111734.8, which contains extensive explanations in this regard.

reference list:

100, 200, 300, 400 circuit arrangement according to the invention 500, 600 1 first connection line

1a left part of the first connection line

2 second connection line

2a left part of the second connection line

3 first connection

4 second connection

5 third connection line

6 third connection

7 fourth connection line

8 fourth connection

9 fifth connection line

10 contact switch 11 fifth connection 12 sixth connection line 13 sixth connection 20 control, measuring and evaluation device/microcontroller

30, 30A, 30B electrically conductive sensor electrode

31 sensor electrode connection cable

32 sensor electrode connector

A first contact element

A1 , A2 output pin

ADC1 first analog to digital converter unit

ADC2 second analog to digital converter unit

B second contact element

C1 first reference capacitance

C2 second reference capacitance

E1 input pin

GND base potential / ground potential

GPI01 , GPI02 GPIO pin / multifunction pin K1 , K4 connection node PD1 , PD2 pull down resistor

PU1 , PU2 pull-up resistor

R1 first electrical resistance

R2 second electrical resistor

R3 third electrical resistor

R4 fourth electrical resistance

R5 fifth electrical resistor

R6 sixth electrical resistance

SO,.., S8 method steps Vcc positive supply voltage

Claims

patent claims

1. Diagnosable circuit arrangement (100, 200, 300, 400, 500, 600), having an electrical contact switch (10), at least one electrically conductive sensor electrode (30, 30A, 30B), and a control, measuring and evaluation device (20 ), wherein the electrical contact switch (10) has at least one first electrical contact element (A) and at least one second electrical contact element (B), the control, measuring and evaluation device (20) having at least one first electrical connection (3) and at least has a second electrical connection (4), wherein the first electrical contact element (A) is or can be electrically connected to the first connection (3) of the control, measuring and evaluation device (20) via a first electrical connection line (1) and that second electrical contact element (B) via a second electrical connection line (2) with a base potential (GND) or the second connection (4) of the control, measurement and evaluation te device (20) is or can be electrically connected, and wherein the at least one electrically conductive sensor electrode (30, 30A, 30B) is designed and arranged relative to at least one contact element (A, B) of the contact switch (10) in such a way that it is connected to at least a contact element (A, B) of the contact switch (10) forms a sensor capacitance, characterized in that the circuit arrangement (100, 200, 300, 400, 500, 600) is designed in such a way that in at least one state of the circuit arrangement (100, 200 , 300, 400, 500, 600) for at least partial diagnosis of the circuit arrangement (100, 200, 300, 400, 500, 600) by means of the control, measuring and evaluation device (20) at least temporarily to the first contact element (A) and /or the first connection line (1) a first defined potential (Vcc, GND) can be applied, and at the same time a second defined potential (Vcc, GND) to the second contact element (B) and/or the second connection line (2) can be applied, and the control, measuring and evaluation device (20) is designed for this purpose, while at least one is located on the first contact element (A) and/or one is located in the first connection line (1) and/or one is located on to detect the resulting first voltage that occurs at the first connection (3) and/or during this at least one voltage that occurs at the second contact element (B) and/or one that occurs in the second connection line (2) and/or one that occurs at the second connection (4), to detect the resulting second voltage, to use the at least one sensor electrode (30, 30A, 30B) to determine a switching state of the contact switch (10), in particular whether the contact switch (10) is open or closed, to evaluate at least one detected voltage, and as a function to determine a functional state of the circuit arrangement (100, 200, 300, 400, 500, 600) from the switching state of the contact switch (10) determined using the sensor electrode (30, 30A, 30B) and at least as a function of a detected and evaluated voltage.

2. Circuit arrangement (100, 200, 300, 400, 500, 600) according to claim 1, characterized in that the electrical contact switch (10) is designed to assume at least two switching states, in a first switching state of the contact switch (10) one electrical connection between the first electrical contact element (A) and the second electrical contact element (B) is separated, and wherein in a second switching state of the contact switch (10) an electrical connection between the first electrical contact element (A) and the second electrical contact element (B ) is made.

3. Circuit arrangement (100, 200, 300, 400, 500, 600) according to claim 1 or 2, characterized in that the sensor electrode (30, 30A, 30B) is designed and arranged relative to the contact switch (10) that by a Change in the distance between the two contact elements (A, B) relative to each other, a change in the sensor capacitance can be effected.

4. Circuit arrangement (100, 200, 300) according to one of claims 1 to 3, characterized in that the sensor electrode (30) is formed separately from the first contact element (A) and separately from the second contact element (B) and the control, measurement - and evaluation device (20) further a sensor electrode Connection (32), wherein the sensor electrode (30) via a sensor electrode connection line (31) and the sensor electrode connection (32) with the control, measuring and evaluation device (20) is electrically connected or connectable.

5. Circuit arrangement (400, 500, 600) according to any one of claims 1 to 3, characterized in that the sensor electrode (30A, 30B) is formed by the first contact element (A) or the second contact element (B).

6. Circuit arrangement (400, 500, 600) according to Claim 5, characterized in that the circuit arrangement (100, 200, 300, 400, 500, 600) also has a second electrically conductive sensor electrode (30B), the first sensor electrode (30A) is formed by the first contact element (A) and the second sensor electrode (30B) by the second contact element (B).

7. Circuit arrangement (100, 200, 300, 400, 500, 600) according to one of the preceding claims, characterized in that the circuit arrangement (100, 200, 300, 400, 500, 600) also has a first electrical resistor (R1) and has a second electrical resistor (R2), the first electrical resistor (R1) being arranged along the first connecting line (1) in such a way that the first contact element (A) via the first connecting line (1) and the first electrical resistor (R1) is or can be electrically connected to the first connection (3) of the control, measuring and evaluation device (20), and wherein the second electrical resistor (R2) is arranged along the second connection line (2) in such a way that the second contact element (B ) via the second connecting line (2) and the second electrical resistor (R2) with the second terminal (4) of the control, measuring and evaluation device (20) is electrically connected or connectable.

8. Circuit arrangement (100, 200) according to one of the preceding claims, characterized in that at least one of the connections (3, 4) is designed and set up as a switchable connection (3, 4), wherein the control, measuring and evaluation device (20) also has at least one switchable pin (GPI01, GPI02) which is or can be electrically connected to the switchable terminal (3, 4) and which is at least between operation as an input pin and operation as an output pin can be switched over and is designed and set up to either output a voltage, to detect a voltage, to apply the respective associated connection (3, 4) to a potential (Vcc, GND) or to switch the associated connection (3, 4) to high or low resistance.

9. Circuit arrangement (100, 200) according to claim 8, characterized in that the circuit arrangement (100, 200) further comprises at least one reference capacitance (C1, C2) and at least one pull resistor (PD1, PU1; PD2, PU2), wherein the reference capacitance (C1, C2) is or can be electrically connected between a connection (3) of the control, measuring and evaluation device (20) and an electrical resistor (R1) with a connecting line (1) and with a base potential (GND) is or can be electrically connected, and wherein the pull resistor (PD1, PU1) is or can be electrically connected between a contact element (A, B) and an electrical resistor (R1) with a connecting line (1) on the one hand, and on the other hand another is electrically connected or connectable to a first reference potential (Vcc) or a ground potential (GND).

10. Circuit arrangement (300, 400, 500, 600) according to one of claims 1 to 7, wherein the control, measuring and evaluation device (20) further has: a third electrical connection (6) which is connected via a third connection line (5th ) is or can be electrically connected to the first contact element (A) and/or the first connection line (1), and a fourth electrical connection (8) which is connected to the second contact element (B) and/or via a fourth connection line (7). the second connection line (2) is electrically connected or connectable.

11 . Circuit arrangement (300, 400, 500, 600) according to Claim 10, the control, measuring and evaluation device (20) also having: a first input pin that can be operated at least temporarily as an input or is designed and set up as an input, which is or can be electrically connected to the first electrical connection (3), a second input pin that can be operated at least temporarily as an input or is designed and set up as an input, the is or can be electrically connected to the second electrical connection (4), a first output pin that can be operated at least temporarily as an output or is configured and set up as an output, which is or can be electrically connected to the third electrical connection (6), a first output pin that is at least temporarily used as a Output operable or designed and furnished as an output second output pin which is electrically connected or connectable to the fourth electrical connection (8).

12. Circuit arrangement (300, 400, 500, 600) according to claim 10 or 11, wherein the control, measuring and evaluation device further comprises: a fifth electrical connection (11) via a fifth connecting line (9) to the first contact element (A) and/or the first connecting line (1) is or can be electrically connected, a third output pin which can be operated at least temporarily as an output or is designed and set up as an output and which is or can be electrically connected to the fifth electrical connection (11), a sixth electrical connection (13) which is or can be electrically connected to the second contact element (B) and/or the second connecting line (2) via a sixth connecting line (12), and an at least temporarily operable or configured as an output and furnished fourth output pin which is electrically connected or connectable to the sixth electrical connection (13).

13. Circuit arrangement (100, 200, 300, 400, 500, 600) according to any one of claims 1 to 12, wherein the control, measuring and evaluation device (20) further comprises: one with the first connection (3) and / or the first input pin electrically connectable or connected first analog-to-digital converter channel and/or a first analog-to-digital converter unit (ADC1 ), and a with the second connection (4) and / or the second input pin electrically connectable or connected second analog-to-digital converter channel and / or with the second connection (4) and / or the second input pin electrically connectable or connected second analog-to-digital converter unit (ADC2).

14. Sensor device for an operator input device, wherein the sensor device has a circuit arrangement (100, 200, 300, 400, 500, 600) with a capacitive sensor with at least one electrically conductive sensor electrode (30, 30A, 30B) and at least one contact switch (10). , characterized in that the circuit arrangement (100, 200, 300, 400, 500, 600) is designed according to one of claims 1 to 13.

15. A method for diagnosing a circuit arrangement (100, 200, 300, 400, 500, 600), which is designed according to any one of claims 1 to 13, or for diagnosing a sensor device according to claim 14, characterized by the steps of: a) providing a Circuit arrangement (100, 200, 300, 400, 500, 600), which is designed according to one of Claims 1 to 13 or a sensor device according to Claim 14, b) determining a switching state of the contact switch (10) of the circuit arrangement (100, 200, 300 , 400, 500, 600) using the at least one electrically conductive sensor electrode (30, 30A, 30B), c) applying a first defined potential (Vcc, GND) to the first contact element (A) and/or the first connection line (1) , and at the same time d) applying a second defined potential (Vcc, GND) to the second contact element (B) and/or the second connection line (2), and at least temporarily while steps c) and d) are carried out: e) detecting one himself first en contact element (A) and / or in the first connection line (1) and / or at the first connection (3) adjusting, resulting voltage and / or at the second contact element (B) and / or in the second connection line (2) and/or a resulting voltage occurring at the second connection (4), f) evaluating at least one detected voltage, and g) determining a functional state of the circuit arrangement (100, 200, 300, 400, 500, 600) depending on the switching state of the contact switch (10) determined using the sensor electrode (30, 30A, 30B) and depending on the at least one detected and evaluated voltage.