Device having a communication apparatus for data transfer via a data-transfer bus, and data-transfer system having devices of this kind

Abstract

The invention relates to a device (1) having a communication apparatus (10) and having a connecting apparatus (20) for connecting the device (1) to a data-transfer bus (2), wherein the connecting apparatus (20) comprises electrical contacts (K1-K5) which can be connected in pairs to corresponding bus-side electrical contacts (K1'-K5') of a bus-side connecting apparatus (20') provided on the bus (2) in order to connect the device (1) to the bus (2), and wherein the electrical contacts (K1-K5) comprise at least one data contact (K1, K2) for transferring a data signal (CANL, CANH), a first supply contact (K3) for transferring a first supply potential (GND), and a second supply contact (K4) for transferring a second supply potential (VS) which differs from the first supply potential. The aim of the invention is to enable simple and reliable address allocation for a plurality of devices (1) connected to the data-transfer bus (2). This aim is achieved in that: the electrical contacts (K1-K5) also comprise an additional contact (K5); the device (1) has a voltage meter (30) in order to measure a potential (POT) across the additional contact (K5, K5'); and the communication apparatus (10) allocates an address to the device (1), which address is selected from a plurality of different specified addresses according to the potential (POT) measured across the additional contact (K5). The invention also relates to a corresponding data-transfer system comprising devices (1) of this kind.

Description

[0001] Description

[0002] Device with a communication device for data transmission via a data transmission bus, and data transmission system with such devices

[0003] The present invention relates to a device having a communication device for data transmission via a data transmission bus and to a data transmission system having at least one such device.

[0004] According to a first aspect, the invention is based on a device with a communication device for sending and / or receiving data (data transmission) via a data transmission bus and with a device-side connection device (e.g., plug-in connector) for connecting the device to the data transmission bus, wherein the device-side connection device has electrical contacts which, in order to connect the device to the data transmission bus, can be connected in pairs to corresponding bus-side electrical contacts of a bus-side connection device (e.g., mating plug-in connector) provided on the data transmission bus, wherein the electrical contacts comprise at least one data contact for transmitting a data signal, a first supply contact for transmitting a first supply potential (e.g., ground potential), and a second supply contact for transmitting a different second supply potential (e.g., supply voltage).

[0005] Such devices and the data transmission systems implemented with them are known in a variety of designs from the prior art. One example is a data transmission system often used in vehicles with a so-called CAN ("Controller Area Network") bus (data transmission bus), to which one or more control units and a plurality of other devices, e.g., each having at least one actuator and / or at least one sensor, are connected. These devices are each equipped with a CAN transceiver including a CAN interface (communication device) to send and / or receive data via the CAN bus.

[0006] In such a data transmission system, each device connected to the data transmission bus requires a unique address (identification), i.e. one that is only assigned once in the data transmission system, in order to use this address to identify the sending device (sender) when sending data and / or the device intended for receiving data (receiver).

[0007] One known prior art option for such address assignment involves installing devices with a suitable predefined address or one preset prior to installation in the data transmission system at the respective designated locations (e.g., in a vehicle). A predefined address of a device can, for example, correspond (in a specific assignment) to a component identification, such as a "part number," which is usually already defined for the device for logistical reasons.

[0008] However, this known approach is disadvantageous, for example, when several essentially identical devices, e.g., a specific sensor model, are to be installed at several different locations in one and the same data transmission system. If these devices have an identical part number, the disadvantage arises that the addresses of these devices cannot be specified according to the part number. On the other hand, if the devices are provided with different component identifications to solve this problem, this is unsatisfactory for logistical reasons.

[0009] In order to be able to install several copies of a specific device (e.g. sensor model or actuator model) with identical part numbers in different positions, it is also possible to provide an additional contact on the device, to which the first supply potential or the second supply potential or no potential at all is applied by means of the bus-side connection device, depending on the specific installation position of the device, whereby each device then selects its own address from three different predefined addresses by means of suitable device-side detection.

[0010] The disadvantage of this design, however, is that a maximum of three devices can be connected to the data transmission bus. Furthermore, correct address assignment may fail if there is a cable break and / or a short circuit to one of the two supply potentials in the area of ​​the connection of one of the additional contacts.

[0011] US Pat. No. 8,930,506 B2 discloses a system and method for automatically assigning addresses to devices connected to a data transmission bus. In this prior art, each device measures a parameter (e.g., a supply voltage), the value of which depends on the physical location of the device. The devices then communicate the measured parameters at specific times to a central control unit, which calculates the parameters based on the respective measurement results. Finally, the central control unit assigns addresses to the individual devices based on the communicated parameters and communicates these addresses to the individual devices for storage.

[0012] A disadvantage here is, for example, the requirement for a central control unit to assign the individual device addresses. Furthermore, implementing the aforementioned communication of the measured parameters as well as the assigned addresses via the data transmission bus requires a certain amount of effort and / or adaptations to the communication devices in the devices and the central control unit, which are not provided for, for example, according to common data transmission standards.

[0013] It is an object of the present invention to show a novel way by which a simple and reliable address assignment for several devices of the type mentioned above connected to a data transmission bus can be ensured.

[0014] According to the first aspect of the invention, this object is achieved in a device of the type mentioned at the outset in that the electrical contacts further comprise an additional contact, that the device has a voltage measuring device which is designed to measure a potential applied to the additional contact with respect to the first supply potential and / or with respect to the second supply potential, and that the communication device is designed to assign an address to the device for sending and / or receiving the data via the data transmission bus, which address is selected by the communication device from a plurality of different predetermined addresses depending on the potential measured at the additional contact.

[0015] The invention advantageously enables automatic assignment of addresses to individual devices (e.g., sensor devices) on a data transmission bus (e.g., CAN bus), particularly for multiple identically configured devices with identical part numbers. Advantageously, a larger number of devices can be used, and no central authority is involved in the allocation and assignment of individual device addresses. Rather, allocation and assignment are handled autonomously by the individual devices. The devices can advantageously determine their own addresses immediately after being connected to the data transmission bus and use them normally from the outset. In particular, no special "startup procedures" or prior, adapted communications via the bus are required. The invention is therefore very universally applicable.

[0016] In one embodiment, the data transmission bus is a CAN bus. However, the invention can also be used for any other data transmission system that provides addressable data transmission, i.e., with device addresses.

[0017] Depending on the accuracy of the device-side measurement of the potential applied to the additional contact, the invention can advantageously be used to assign a large number of different addresses and thus to use a large number of identical devices in a data transmission system.

[0018] In a preferred embodiment of the invention, for example, it is provided that the communication device is designed to select the address from at least four different predetermined addresses.

[0019] Here's an example: Suppose five identical sensors are each to measure one or more values ​​at five different locations in the exhaust system of a motor vehicle and communicate via a CAN bus to a central control unit of the vehicle. In this case, each sensor must have its own CAN address, which is uniquely defined by its respective installation position. Each sensor can automatically set the CAN address required for the respective installation position according to its position. To do this, each sensor measures the potential at the additional contact and then selects its address from several different predefined addresses based on the measured potential.

[0020] A simple way to provide the potential (hereinafter also referred to as "POT") at an additional contact of a device in a defined manner is to divide the supply voltage VS - GND (hereinafter also referred to as VBAT) already provided by the first supply potential (hereinafter also referred to as "GND") and the second supply potential (hereinafter also referred to as "VS") by means of a voltage divider formed from two or more resistors, wherein at least one resistor of this voltage divider is arranged on the bus side.

[0021] With regard to the term "resistance" used here in connection with the formation of voltage dividers, it should be noted that this term can generally and fundamentally also include direct electrical line connections with a resistance value that is negligible in practice (R = 0 Q).

[0022] Each device can then, for example, measure the voltage between the auxiliary contact and the first supply contact and thus determine the potential POT, for example, as a proportion of VBAT. In the above example of five devices, five differently set potentials POT1 to POT5 can be provided as follows:

[0023] POT1 = 0% VBAT (corresponding to GND)

[0024] POT2 = 25% VBAT

[0025] POT3 = 50% VBAT

[0026] POT4 = 75% VBAT

[0027] POT5 = 100% VBAT (corresponding to VS)

[0028] Depending on the measured potential POT at the additional contact, each device can then select its respective address ADR (in the example: CAN-ID) from 5 different predefined addresses ADR1 to ADR5 based on the corresponding stored voltage thresholds as follows:

[0029] POT = POT1 : Selection of ADR = ADR1

[0030] POT = POT2: Selection of ADR = ADR2

[0031] POT = POT3: Selection of ADR = ADR3

[0032] POT = POT4: Selection of ADR = ADR4

[0033] POT = POT5: Selection of ADR = ADR5

[0034] In the above example, in which POT1 and POT5 each correspond to one of the two supply potentials GND, VS, the disadvantage arises that if there is a short circuit of an additional contact to one of the two supply potentials GND, VS, both correct address assignment and meaningful error diagnosis can fail. In an embodiment of the invention that is advantageous in this respect, it is therefore provided that the communication device is designed to evaluate a case in which the measured potential POT corresponds to the first supply potential GND or the second supply potential VS as an error case. In other words, in this embodiment, the values ​​of the supply potentials GND, VS are not possible (permissible) values ​​for the potential POT.

[0035] In a corresponding modification of the above example of five devices, for example, five differently set potentials POT1 to POT5 could be provided as follows:

[0036] POT1 = 50% VBAT

[0037] POT2 = 60% VBAT

[0038] POT3 = 70% VBAT

[0039] POT4 = 80% VBAT

[0040] POT5 = 90% VBAT

[0041] In one embodiment of the invention, it is provided that the communication device is designed to select the address (ADR) to be assigned to the device according to an assignment table, by means of which non-overlapping and preferably spaced-apart sub-areas within the potential range between the first supply potential (GND) and the second supply potential (VS) as well as addresses respectively assigned to these sub-areas are defined.

[0042] In the above example, such non-overlapping and spaced-apart sub-areas and the address assignment could be provided, for example, as follows:

[0043] 48% VBAT < POT < 52% VBAT: Selection of ADR = ADR1

[0044] 58% VBAT < POT < 62% VBAT: Selection of ADR = ADR2

[0045] 68% VBAT < POT < 72% VBAT: Selection of ADR = ADR3

[0046] 78% VBAT < POT < 82% VBAT: Selection of ADR = ADR4

[0047] 88% VBAT < POT < 92% VBAT: Selection of ADR = ADR5 If a device measures a potential POT that is not within one of the specified sub-ranges (in the example above, for example, 55% VBAT), this represents an error and correct address assignment is then not possible.

[0048] In a further development of the embodiment, it is provided that the communication device is designed to evaluate a case in which the measured potential (POT) is not within one of the predetermined subranges as an error case (and, for example, to send an error case message via the data transmission bus using an error case address predefined in the device).

[0049] In one embodiment of the invention, it is provided that the manner of providing the potential POT (e.g. the values ​​of the resistors used to form the aforementioned voltage dividers) in conjunction with the sub-areas is such that one, two or all three of the following errors can be detected and differentiated from one another on the basis of a then resulting (faulty) potential POT: Error 1: Short circuit of the additional contact to GND; Error 2: Additional contact open; Error 3: Short circuit of the additional contact to VBAT.

[0050] As mentioned above, the potential POT can be provided at the additional contact of each device using a voltage divider composed of resistors. At least one resistor of the voltage divider must be located on the bus side, i.e., outside the device. This is done to implement a voltage division for each device, the result of which (divided voltage or potential POT) depends on the position of the device. Thus, a different address ADR can be selected for each position.

[0051] Since the device according to the invention is provided for connecting the device to the data transmission bus by connecting the device-side connection device to a corresponding bus-side connection device, said at least one resistor of the relevant voltage divider can advantageously be formed in particular in the relevant bus-side connection device.

[0052] The accommodation of the (at least one) resistor in the bus-side connection device has the advantage that no additional electrical connection (e.g. additional cable or additional line in a data transmission bus line arrangement) is required which connects the resistor to the bus-side connection device.

[0053] However, within the scope of the invention, it should not be excluded that in a voltage divider (at least) one bus-side resistor is arranged outside the relevant bus-side connection device (e.g. a connector of this connection device) and is connected via an additional line connection to the relevant bus-side connection device (and the additional bus-side contact located there).

[0054] In one embodiment of the invention, it is provided that the device-side connection device has one or more electrical connectors (e.g. "plugs" or "sockets") which can be connected in pairs to corresponding bus-side electrical (counter-)connectors (e.g. "sockets" or "plugs") of the bus-side connection device in order to connect the device to the data transmission bus.

[0055] In this case, the said at least one bus-side resistor can thus advantageously be formed in particular in a plug connector (mating connector) of the relevant bus-side connection device in order to connect the bus-side additional contact to the bus-side first supply contact or to the bus-side second supply contact.

[0056] Two resistors can also be formed in the relevant bus-side connection device or in a connector thereof, of which one resistor (also referred to below as "third resistor") connects the bus-side additional contact to the bus-side first supply contact and the other resistor (hereinafter also referred to as "fourth resistor") connects the bus-side additional contact to the bus-side second supply contact.

[0057] The fact that at least one resistor of the aforementioned voltage divider must be located on the bus side, i.e., outside the device in question, in no way precludes the possibility of at least one resistor of a resistor arrangement forming the voltage divider also being located in the device, and in particular, for example, in its device-side connection device. In many cases, the latter even offers particular advantages, for example, with regard to the possibilities and significance of fault diagnostics.

[0058] In one embodiment of the invention, for example, it is provided that the device has a first resistor, via which the additional contact is connected to the first supply contact, and / or a second resistor, via which the additional contact is connected to the second supply contact. The first resistor and / or the second resistor of the device can advantageously be arranged, in particular, within the device-side connection device.

[0059] According to a further aspect of the present invention, the object set out at the outset is achieved by a data transmission system comprising: a data transmission bus (e.g. CAN bus) having at least one data line for transmitting a data signal, a first supply line for transmitting a first supply potential and a second supply line for transmitting a different second supply potential, at least one device of the type described here connected to the data transmission bus, for each device connected to the data transmission bus, a bus-side connection device with bus-side electrical contacts provided on the data transmission bus,which are connected in pairs to the corresponding electrical contacts of the device-side connection device of the respective device for connecting the respective device to the data transmission bus and comprise at least one bus-side data contact for transmitting the data signal, a bus-side first supply contact for transmitting the first supply potential, a bus-side second supply contact for transmitting the second supply potential, and a bus-side additional contact, wherein the data transmission system further comprises for each of the at least one bus-side connection device provided on the data transmission bus: a resistor (hereinafter also referred to as "third resistor"), via which the bus-side additional contact of the respective bus-side connection device is connected to the bus-side first supply contact of the respective bus-side connection device,and / or a resistor (hereinafter also referred to as "fourth resistor"), via which the bus-side additional contact of the respective bus-side connection device is connected to the bus-side second supply contact of the respective bus-side connection device, wherein, in the case of several bus-side connection devices provided on the data transmission bus, the respective resistor arrangements formed from a respective third resistor and / or a respective fourth resistor all differ from one another.

[0060] The embodiments and special configurations described here for the device according to the invention can, individually or in any combination, also be provided in an analogous manner as embodiments or special configurations of the data transmission system according to the invention, and vice versa.

[0061] In one embodiment, it is provided that the at least one bus-side connection device has one or more bus-side electrical connectors which can be connected in pairs to corresponding electrical connectors of the device-side connection device of the respective device in order to connect the respective device to the data transmission bus.

[0062] In one embodiment, it is provided that the resistor arrangement formed from the third resistor and / or the fourth resistor is formed at least partially, in particular completely, in the relevant bus-side connection device.

[0063] The device-side and bus-side connection devices can each have one or more electrical connectors that can be connected in pairs to connect the respective device to the data transmission bus. In one embodiment, the device-side and bus-side connection devices provided for each device connected to the data transmission bus are each implemented by a single connector. In this case, these connectors each contain (at least) all of the electrical contacts required within the scope of the invention, i.e., the at least one data contact, the first supply contact, the second supply contact, and the additional contact.

[0064] In another embodiment, the connection devices to be interconnected for each device are each implemented by multiple connectors or, alternatively, by a connector and at least one other type of electrical connection device. In particular, for example, the connection between the first supply contacts (potential GND) and / or the connection between the second supply contacts (potential VS), it is possible to implement these structurally separately from the other contact connections of the data transmission system.

[0065] For example, in a vehicle in particular, an on-board electrical system for distributing a supply voltage (e.g., battery voltage) may be provided, which has lines for distributing a first supply potential and / or a second supply potential. In this respect, such an on-board electrical system can, if necessary, supply one or more devices used within the scope of the invention with the GND potential and / or the VS potential and thus represent a functional component of the data transmission bus within the meaning of the invention. Furthermore, in the event that the GND potential is identical to a "ground potential" distributed in a vehicle, e.g., via a (metallic) body, it should not be ruled out that one or more of the devices are supplied with the GND potential via an electrical connection directly to an adjacent part of this body.

[0066] In one embodiment, it is provided that the data transmission system further comprises a control unit connected to the data transmission bus with a communication device for transmitting and / or receiving data via the data transmission bus, wherein the resistor arrangement formed from the third resistor and / or the fourth resistor for each bus-side connection device provided on the data transmission bus is formed at least partially, in particular completely, in the control unit and is connected to the relevant bus-side connection device via an additional line.

[0067] A preferred use of the devices within the scope of the invention is, for example, for a data transmission system in a vehicle. In vehicles, the devices provided according to the invention can represent or comprise, for example, sensors (e.g., for exhaust gas aftertreatment, battery monitoring, hydrogen measurement, etc.) and / or actuators (e.g., for operating mechanically adjustable interior or exterior components, pumps such as coolant pumps, fans, etc.).

[0068] The invention will be further described below using exemplary embodiments with reference to the accompanying drawings. They schematically depict:

[0069] Fig. 1 shows a device according to a first embodiment,

[0070] Fig. 2 shows a device according to a second embodiment,

[0071] Fig. 3 shows a connection device of a device according to a third embodiment,

[0072] Fig. 4 shows a data transmission bus including a bus-side connection device for connecting a device, according to a first embodiment,

[0073] Fig. 5 shows a data transmission bus including a bus-side connection device for connecting a device, according to a second embodiment,

[0074] Fig. 6 is a flowchart of a method for automatically assigning an address after connecting a device to a data transmission bus, according to a first embodiment, and

[0075] Fig. 7 is a flowchart of the method for automatically assigning the address according to a second embodiment.

[0076] Fig. 1 shows a device 1 with a communication device 10 for sending and / or receiving data via a data transmission bus (not shown in Fig. 1) and with a device-side connection device 20 for connecting the device 1 to the data transmission bus. In the example shown, the device 1 is a sensor device implemented by means of a microcontroller and used in a vehicle, having a sensor 40 for measuring one or more specific measured values ​​at a point in the vehicle (e.g. measuring exhaust gas parameters in the exhaust system of a motor vehicle), wherein the communication device 10 is designed as a CAN transceiver with a CAN interface in order to communicate the measured values ​​via the data transmission bus, which in this case is designed as a CAN bus, to other devices and / or a central control unit of the vehicle that is also connected to the data transmission bus.The CAN transceiver and its CAN interface can be implemented using software and viewed as functional components of the microcontroller mentioned.

[0077] However, in contrast to the example shown, the communication device 10 and accordingly the data transmission bus could be provided according to a different data transmission standard or data transmission protocol.

[0078] The device-side connection device 20, for example an electrical connector connected to an assembly comprising the components 10 and 40 via an electrical line arrangement (e.g. connecting cable piece) as symbolized in Fig. 1, has in the example shown electrical contacts K1 -K5 which, in order to connect the device 1 to the data transmission bus, can be connected in pairs to corresponding bus-side electrical contacts (not shown in Fig. 1) of a bus-side connection device provided on the data transmission bus (see e.g. 20' in Fig. 4).

[0079] The device-side connection device 20 (connector), symbolized only schematically as a single block in Fig. 1, can generally be implemented within the scope of the invention by one or more electrical connectors and / or one or more other types of electrical connection devices. The only essential requirement is the pairwise connection of the electrical contacts K1-K5 with corresponding bus-side electrical contacts. In the example, these are the following contacts provided according to the CAN standard:

[0080] K1 : first data contact for transmitting a data signal CANL

[0081] K2: second data contact for transmitting a data signal CANH

[0082] K3: first supply contact for the transmission of a first

[0083] Supply potential GND K4: second supply contact for transmitting a second supply potential VS different from GND (and thus a supply voltage VBAT = VS - GND)

[0084] In addition, the connection device 20 has another contact:

[0085] K5: Additional contact for transmitting a potential POT

[0086] The device 1 further comprises a voltage measuring device 30, which is preferably structurally combined with components 10 and 40, e.g., provided on a common "device circuit board." At least during start-up of the device 10, the potential POT applied to the additional contact K5 is measured with respect to the first supply potential GND by means of the voltage measuring device 30.

[0087] The communication device 10 is designed to assign an address to the device 1 for sending and / or receiving data (data transmission), here in particular for sending the measurement data acquired by the sensor 40, via the data transmission bus. This address is independently determined by the communication device 10. This address is selected from several different predefined addresses depending on the potential POT measured at the additional contact K5. For this purpose, these predefined addresses are stored in a memory device of the communication device 10, for example in the form of a lookup table (assignment table). Preferably, the communication device 10 is designed to select the address to be assigned to the device 1 from at least four different predefined addresses.

[0088] The functioning of such an address assignment in the device shown in Fig. 1 is explained by way of example for the case in which the device 1 is connected together with other identically designed devices (not shown) to a data transmission bus shown in Fig. 4.

[0089] Fig. 4 shows a data transmission bus 2 with a bus-side

[0090] Connection device 20' for connecting a device of the type described here. It is assumed below, by way of example, that the bus-side connection device 20' shown in Fig. 4 is intended for connecting the device 1 shown in Fig. 1. For the sake of simplicity of illustration, only a single connection device 20' is shown in Fig. 4, i.e. the additional bus-side connection devices present in practice for connecting additional devices to the data transmission bus 2 are not shown in Fig. 4.

[0091] In compatibility with device 1 (here: CAN standard), data transmission bus 2 has the following lines:

[0092] L1 : Data line for transmitting the data signal CANL

[0093] L2: Data line for transmitting the data signal CANH

[0094] L3: first supply line for transmitting the first

[0095] Supply potential GND

[0096] L4: second supply line for transmitting the second

[0097] Supply potential VS

[0098] The bus-side connection device 20' has electrical contacts K1 '-K4' electrically connected to these lines as well as an additional contact K5', which are connected in pairs to the corresponding electrical contacts K1 -K4 and K5 of the device-side connection device 20 when the two connection devices 20, 20' are connected together (K1 ' with K1, K2' with K2, etc.).

[0099] In order to provide a predetermined potential POT for the device 1 or for the shown position on the data transmission bus 2 at the additional contact K5 in a defined manner, the supply voltage (VBAT = VS - GND) provided by the two supply potentials GND and VS is divided by means of a voltage divider, which in the described example is formed from two resistors R3, R4.

[0100] In the example of Fig. 4, both resistors R3, R4 are accommodated in the bus-side connection device 20' as shown, wherein the resistor R3 is arranged between the additional contact K5' and the first supply contact K3' and the resistor R4 is arranged between the additional contact K5' and the second supply contact K4'.

[0101] The potential POT applied to the additional contact K5' and thus also to K5 is thus POT = (R3 / (R3 + R4)) x VBAT and can therefore be specified as desired within the interval [GND, VS] by appropriately selecting the resistance values ​​of R3 and R4.

[0102] The further bus-side connection devices not shown in Fig. 4 for connecting further devices to the data transmission bus 2 can each be designed, for example, in the same way as the connection device 20' shown, but the respective resistor arrangements (voltage dividers) formed from a respective third resistor (R3) and / or a respective fourth resistor (R4) all differ from one another in such a way that the respective predetermined potentials (POT) also all differ from one another.

[0103] As already explained above for device 1, all other devices (not shown) connected to the data transmission bus 2 can then independently assign the address required for sending and / or receiving data based on the result of a measurement of the respective potential POT.

[0104] Termination at the ends of the respective data transmission bus, which is required in many applications, e.g., a 120 ohm termination of the CANL and CANH lines at the beginning (e.g., formed by a control unit) and at the end of the CAN line, can be provided, for example, in the relevant bus-side connection devices (e.g., connectors) for the two devices in question. Alternatively, it is possible to equip all devices with suitable terminations, which can be individually activated or deactivated on each device using a respective switch device.

[0105] In the following description of further exemplary embodiments, the same reference numerals are used for components with equivalent functions, each supplemented by a lowercase letter to distinguish the specific embodiment. In doing so, only the differences from the previously described exemplary embodiment(s) will be discussed, and otherwise, explicit reference is hereby made to the description of previous exemplary embodiments.

[0106] Fig. 2 shows a device 1a with a communication device 10a for sending and / or receiving data via a data transmission bus (not shown in Fig. 2) and with a device-side connection device 20a for connecting the device 1a to the data transmission bus.

[0107] A special feature of the device 1 a compared to the already described device 1 (Fig. 1 ) is that the device 1 a further comprises a resistor R1 , via which the additional contact K5 is connected to the first supply contact K3, and a resistor R2 , via which the additional contact K5 is connected to the second supply contact K4.

[0108] In the example of Fig. 2, both resistors R1, R2 are structurally combined with the components 10a, 30a, 40a as symbolized in Fig. 2, for example accommodated on a circuit board provided for these components.

[0109] The functioning of the automatic address assignment in the device 1 a shown in Fig. 2 is again explained by way of example for the case in which the device 1 a is connected together with other identically designed devices (not shown) to the data transmission bus 2 shown in Fig. 4.

[0110] In this case too, the potential POT predetermined at the additional contact K5 for the device 1a or for its position on the data transmission bus 2 is provided by dividing the supply voltage (VBAT = VS - GND) by means of a voltage divider, which in this case, however, is formed from a total of four resistors R1, R2, R3, R4.

[0111] The potential POT applied to the additional contact K5 is:

[0112] POT = (R1 x R3 / (R1 + R3)) / ((R1 x R3 / (R1 + R3)) + (R2 x R4 / (R2 + R4))) x VBAT

[0113] The potential POT can be understood more clearly in this way, for example, that on the device side, any arbitrarily predeterminable "base potential" with the value (R1 / (R1 + R2)) x VBAT within the interval [GND, VS] is specified by the voltage divider R1, R2, which, however, is still "shifted" due to the parallel connection of the bus-side voltage divider R3, R4 (and thus different for each of the individual devices).

[0114] Preferably, by appropriately selecting the resistance values ​​of R1 and R2, a "base potential" is provided which lies in a "middle range" of the interval [GND, VS] and is, for example, at least 5% VBAT, in particular at least 10% VBAT and, for example, a maximum of 95% VBAT, in particular a maximum of 90% VBAT.

[0115] In this case, by appropriately selecting the resistance values ​​of R3 and R4, the "shifted base potential" (potential at the additional contact K5) caused by the effect of the parallel-connected bus-side voltage divider R3, R4 can be specified arbitrarily within the interval [GND, VS].

[0116] Here's an example: By selecting resistor values ​​of R1 = 1 kΩ and R2 = 3 kΩ, a "base potential" of 25% VBAT is obtained (identical for all devices). If the resulting potential POT for a specific device or its position is to be, for example, 35% VBAT, this can be achieved by selecting resistor values ​​of R3 = 12 kΩ and R4 = 4 kΩ. If the resulting potential POT for another device is to be, for example, 40% VBAT, this can be achieved by selecting resistor values ​​of R3 = 1 kΩ and R4 = 1 kΩ.

[0117] In contrast to the example described above using two bus-side resistors (R3, R4), the base potential can also be shifted as desired using just one of the two resistors shown (R3, R4). If the base potential (e.g., 25% VBAT) is to be shifted to a lower value (e.g., 20% VBAT), a correspondingly sized resistor R3 is sufficient. If the base potential is to be shifted to a higher value (e.g., 30% VBAT), a correspondingly sized resistor R4 is sufficient.

[0118] Finally, it should be noted in this context that for the special case in which the potential POT for a specific device (or its position) should be exactly equal to the base potential, two options exist: One option is to choose the values ​​of the bus-side resistors R3, R4 such that their ratio to each other corresponds to the ratio of the values ​​of the device-side resistors R1, R2. Another option is to not provide any bus-side resistors R3, R4 for this device (so that the potential POT is determined solely by the voltage division across the resistor arrangement R1, R2).

[0119] Here's an example: On the device side, e.g., on the circuit boards of the respective devices (e.g., "sensor board"), a voltage divider (consisting of resistors R1, R2) is designed to provide a base potential in a medium potential range, e.g., 25% VBAT. To shift this base potential as desired within the interval [GND, VS], a single additional resistor in each bus-side connection device (vehicle power connector) is sufficient, for example:

[0120] Device position 1 : Additional contact K5' electrically conductive (R3 = 0 Q) to GND

[0121] POT = 0% VBAT = GND

[0122] Device position 2: Additional contact K5' open

[0123] POT = 25% VBAT

[0124] Device position 3: Additional contact via R4 high resistance to VBAT

[0125] POT = 50% VBAT

[0126] Device position 4: Additional contact K5' via R4 low resistance to VBAT

[0127] POT = 75% VBAT

[0128] Device position 5: Additional contact K5' electrically conductive (R4 = 0 (1) on VBAT

[0129] POT = 100% VBAT = VS

[0130] Here is a modified example with regard to the individual values ​​of the potential POT:

[0131] Device position 1 : Additional contact via R4 high resistance to VBAT,

[0132] POT = 50% VBAT

[0133] Device position 2: Additional contact K5' via R4 medium resistance to VBAT

[0134] POT = 60% VBAT

[0135] Device position 3: Additional contact K5' via R4 medium-low resistance to VBAT

[0136] POT = 70% VBAT

[0137] Device position 4: Additional contact K5' via R4 low resistance to VBAT

[0138] POT = 80% VBAT

[0139] Device position 5: Additional contact K5' via R4 very low resistance to VBAT

[0140] POT = 90% VBAT

[0141] In both of the above examples, the resistors R3 and R4 can each be arranged in the respective bus-side connection device or, for example, arranged in a control unit and connected to the respective device or the respective device-side connection device via an additional line (e.g. cable).

[0142] In the second example above, the following errors can be easily identified:

[0143] Error 1 : Additional contact short circuit to GND, recognizable by POT = 0% VBAT.

[0144] Error 2: Additional contact open, recognizable by POT = 25% VBAT.

[0145] Error 3: Additional contact short circuit to VBAT, detectable by POT = 100% VBAT. If a device detects such an error (illegal value of POT), it can be configured, for example, for the device to register with an additional "error case" address not used for normal data transmission and send corresponding error information (e.g., error code). This error information further specifies the error (e.g., through the measured value of POT). This way, another device connected to the data transmission bus (e.g., a diagnostic or control unit) can immediately register the error.

[0146] Fig. 3 illustrates a modification of the device 1a of Fig. 2. For the sake of simplicity, Fig. 3 only shows the device-side connection device 20b for connecting the device to the data transmission bus. The modification compared to the previously described device 1a (Fig. 2) consists in the fact that the resistors R1 and R2, which form the device-side voltage divider, are arranged in the region of the device-side connection device 20b, for example, in an electrical connector.

[0147] Fig. 5 shows a data transmission bus 2a with a bus-side connection device 20a' for connecting a device of the type described here, for example the device 1 shown in Fig. 1.

[0148] In compatibility with the device 1 (here: CAN standard), the data transmission bus 2a again has the lines L1 -L4 already described above with reference to Fig. 4 for transmitting the signals CANL, CANH and potentials GND, VS, and the bus-side connection device 20a' has the electrical contacts KT-K4' electrically connected to these lines L1 -L4 as well as the additional contact K5' for providing the potential POT for a device (not shown in the figure) connected to the connection device 20a'.

[0149] Furthermore, Fig. 5 shows a control unit 50a with a communication device 60a, which is also connected to the data transmission bus 2a as shown and represents, for example, a central control unit in a vehicle and, in this context, performs control tasks in the vehicle, for example by controlling actuator devices connected to the bus 2a and / or by querying measured values ​​from sensor devices connected to the bus 2a. In contrast to the control unit 50a described with reference to Fig.4, the resistors R3, R4 forming a bus-side voltage divider are not accommodated in the bus-side connection device 20a', but (in this example both) as shown in the control unit 50a, wherein the resistor R3 is arranged between an additional line L5 and the first supply line L3 and the resistor R4 is arranged between the additional line L5 and the second supply line L4, and wherein the additional line L5 runs along the remaining bus lines L1 -L4 (parallel to these) up to the point of the connection device 20a' and from there further into the connection device 20a' and is electrically connected there to the additional contact K5'.

[0150] Not shown in Fig. 5 for the sake of simplicity of illustration is a possibly provided connection device of the device 50a with the corresponding electrical contacts for connection to the lines of the bus 2a (in this case, the resistors R3, R4 can also be arranged between the corresponding respective contacts of such a connection device).

[0151] For the sake of simplicity of illustration, the additional bus-side connection devices for connecting additional devices to the data transmission bus 2a, which are present in practice, have again been omitted in Fig. 5. In this context, it should be noted that resistors R3, R4 forming a respective bus-side voltage divider for such additional bus-side connection devices can also be accommodated in the control unit 50a and can be connected to the respective additional bus-side connection device and the additional contact provided therein by a respective additional electrical connection, such as an additional line (e.g., running parallel to the other bus lines).

[0152] A plurality of devices of the type described here, such as, for example, a plurality of devices according to one of the exemplary embodiments in Figs. 1, 2 and 3, together with an associated data transmission bus to which these devices (and optionally independently of this, at least one additional device such as, in particular, a control unit with, for example, a fixed device address) are connected, form a data transmission system in which the devices can advantageously assign themselves an address for communication via the data transmission bus. An advantageous use of the invention arises, for example, in a vehicle or other machine with an internal combustion engine, wherein an exhaust gas aftertreatment system with several different catalysts is installed and there is a need to measure variables such as, for example,to measure the NOx content and / or lambda at up to five consecutive points in the exhaust gas path and to communicate this information to a control unit. The devices designed as sensor devices in this case can be required, for example, at the following points: (1) point at the beginning of the exhaust gas path (raw emissions), (2) point downstream of the pre-catalyst, (3) point downstream of the storage catalyst, (4) point downstream of the first SCR catalyst, (5) point downstream of the second SCR / lock catalyst. By means of the invention, completely identically designed sensor devices (with correspondingly, for example, the same part numbers) can advantageously be used at such different points in the exhaust gas path.

[0153] Since in practice cables could break, resistors could be damaged, etc., it is advantageous within the scope of the invention if a controller (e.g. the control unit mentioned above) checks the plausibility of the automatically assigned addresses of the individual devices. If the individual devices are sensor devices, such a plausibility check can be carried out, for example, on the basis of the measured values ​​supplied by the sensors in question. If several devices are, for example, identically designed sensor devices arranged at different locations in a vehicle (e.g. different locations along an exhaust gas path), a plausibility check can be carried out, for example, based on a temperature measured by each of the devices (provided, for example, that different temperatures are to be expected at the different locations). Modeling (taking physical variables such as temperature, heating output, etc. into account) can also be carried out in a controller, for example.) to predict such measured values, whereby a plausibility check can then also be carried out by comparing measured values ​​with modelled values.

[0154] Fig. 6 shows an example of a possible sequence of a method for automatically assigning an address to a device of the type described here, the operation of which is carried out by control software running in the device.

[0155] The method begins with a step SO with the connection of a respective device to a data transmission bus and supply of the device with the supply potentials GND, VS and thus a supply voltage VBAT (= VS - GND).

[0156] In step S1, the device is initialized and the control software is booted. In step S2, the potential POT is measured at the additional contact of the device-side connection device, implemented, for example, as a voltage measurement relative to the first supply potential GND. In step S3, in this example, the ratio "ratio" between the potential difference POT - GND (result of the voltage measurement in step S2) and the supply voltage VBAT (= VS - GND) is determined: ratio = (POT - GND) / (VS - GND)

[0157] In step S4, a check is made to determine whether the value of "ratio" falls within a permissible range. If so, processing proceeds to step S5, where, depending on this value, the correct address ADR is assigned to the device. Then, processing proceeds to step S6, where the device begins data transmission using the previously set device address ADR.

[0158] However, if the value of "ratio" does not fall within a permissible range, processing returns to step S1.

[0159] Fig. 7 shows an example of an address assignment method that is modified from the example in Fig. 6. Steps S0 to S6 correspond to the steps S0 to S6 already described with reference to Fig. 6.

[0160] In contrast, however, in the event that the value of "ratio" checked in step S4 does not fall within a permissible range, it is provided that, based on the result of a check in a step S7, the processing only proceeds back to step S1 until a predetermined number of times (e.g. in the range between 1 and 10) of reaching step S7, otherwise (i.e. if step S7 has been reached again after this number of times) the processing proceeds to a step S8.

[0161] In step S8, a predetermined "error case" address is assigned to the device, and then, in step S9, a predetermined "Error Case" message is sent using the previously set error case address. In one embodiment, the error case message contains information about at least one detail of the error case in question, such as, in particular, one or more values ​​of the "ratio" determined by the device.

[0162] By receiving and evaluating the error message by another device connected to the data transmission bus, be it a device connected dedicated to error diagnosis or a control unit of the type explained above, the occurrence of the error can advantageously be detected immediately after the device in question is connected.

[0163] With the invention and the described embodiments, data transmission systems with autonomous address assignment on the device side can be advantageously implemented. Such systems and the data transmission bus used therein, e.g., CAN bus, are advantageously used in vehicles or other technical devices such as machines.

[0164] In summary, the invention proposes a device (1) with a communication device (10) and with a connection device (20) for connecting the device (1) to a data transmission bus (2), wherein the connection device (20) has electrical contacts (K1 - K5) which, in order to connect the device (1) to the bus (2), can be connected in pairs to corresponding bus-side electrical contacts (K1'-K5') of a bus-side connection device (20') provided on the bus (2), and wherein the electrical contacts (K1-K5) comprise at least one data contact (K1, K2) for transmitting a data signal (CANL, CANH), a first supply contact (K3) for transmitting a first supply potential (GND) and a second supply contact (K4) for transmitting a different second supply potential (VS).In order to enable simple and reliable address assignment for a plurality of devices (1) connected to the data transmission bus (2), it is provided that the electrical contacts (K1-K5) further comprise an additional contact (K5), that the device (1) has a voltage measuring device (30) for measuring a potential (POT) present at the additional contact (K5, K5'), and that the communication device (10) assigns the device (1) an address which (10) is selected from a plurality of different predetermined addresses depending on the potential (POT) measured at the additional contact (K5). Furthermore, the invention proposes a corresponding data transmission system comprising such devices (1).

Claims

Patent claims 1. Device (1) with a communication device (10) for sending and / or receiving data via a data transmission bus (2) and with a device-side connection device (20) for connecting the device (1) to the data transmission bus (2), wherein the device-side connection device (20) has electrical contacts (K1-K5) which can be connected in pairs to corresponding bus-side electrical contacts (K1'-K5') of a bus-side connection device (20') provided on the data transmission bus (2) for connecting the device (1) to the data transmission bus (2), wherein the electrical contacts (K1-K5) comprise at least one data contact (K1, K2) for transmitting a data signal (CANL, CANH), a first supply contact (K3) for transmitting a first supply potential (GND), and a second supply contact (K4) for transmitting a different second supply potential (VS), characterized by: - that the electrical contacts (K1 - K5) also include an additional contact (K5), - that the device (1 ) has a voltage measuring device (30) which is configured to measure a potential (POT) applied to the auxiliary contact (K5, K5') with respect to the first supply potential (GND) and / or with respect to the second supply potential (VS), and - that the communication device (10) is designed to assign an address to the device (1) for sending and / or receiving data via the data transmission bus (2), which is selected by the communication device (10) from several different predefined addresses depending on the potential (POT) measured at the auxiliary contact (K5).

2. Device (1) according to claim 1, wherein the communication device (10) is configured to select the address from at least four different predefined addresses.

3. Device (1) according to one of the preceding claims, wherein the communication device (10) is configured to evaluate a case in which the measured potential (POT) corresponds to the first supply potential (GND) or the second supply potential (VS) as a fault case.

4. Device (1) according to one of the preceding claims, wherein the communication device (10) is configured to select the address to be assigned to the device (1) according to an assignment table, by which non-overlapping and preferably spaced-apart sub-areas within the potential range between the first supply potential (GND) and the second supply potential (VS) are defined, as well as addresses assigned to each of these sub-areas.

5. Device (1) according to one of the preceding claims, wherein the device-side connection device (20) has one or more electrical connectors which can be connected in pairs to corresponding bus-side electrical connectors of the bus-side connection device (20') for connecting the device (1) to the data transmission bus (2).

6. Device (1) according to one of the preceding claims, wherein the device (1) further comprises: a first resistor (R1) via which the auxiliary contact (K5) is connected to the first supply contact (K3), and / or a second resistor (R2) via which the auxiliary contact (K5) is connected to the second supply contact (K4).

7. Data transmission system comprising a data transmission bus (2) comprising at least one data line (L1, L2) for transmitting a data signal (CANL, CANH), a first supply line (L3) for transmitting a first supply potential (GND) and a second supply line (L4) for transmitting a different second supply potential (VS), and at least one device (1) connected to the data transmission bus (2) according to one of claims 1 to 6. For each device (1) connected to the data transmission bus (2), a bus-side connection device (20') provided on the data transmission bus (2) with bus-side electrical contacts (K1 '-K5') which are connected in pairs to the corresponding electrical contacts (K1 - K5) of the device-side connection device (20) of the respective device (1) for connecting the respective device (1) to the data transmission bus (2) and at least one bus-side data contact (K1 K2') for transmitting the data signal (CANL, CANH), a bus-side first supply contact (K3 1 ) for the transmission of the first supply potential (GND), a bus-side second supply contact (K4) 1 ) for the transmission of the second supply potential (VS), and a bus-side additional contact (K5) 1) comprising, and further comprising for each of the at least one bus-side connection device (20') provided on the data transmission bus (2): a third resistor (R3), via which the bus-side auxiliary contact (K5) 1 ) the relevant bus-side connection device (20') with the bus-side first supply contact (K3) 1 ) the relevant bus-side connection device (20'), and / or a fourth resistor (R4), via which the bus-side auxiliary contact (K5) 1 ) the relevant bus-side connection device (20') with the bus-side second supply contact (K4) 1) of the relevant bus-side connection device (20'), wherein in the case of several bus-side connection devices (20') provided on the data transmission bus (2) the respective resistor arrangements formed from a respective third resistor (R3) and / or a respective fourth resistor (R4) are all different from each other.

8. Data transmission system according to claim 7, wherein the at least one bus-side connection device (20') has one or more bus-side electrical connectors which can be connected in pairs to corresponding electrical connectors of the device-side connection device (20) of the respective device (1) for connecting the respective device (1) to the data transmission bus (2).

9. Data transmission system according to claim 7 or 8, wherein the resistor arrangement formed from the third resistor (R3) and / or the fourth resistor (R4) is formed at least partially, in particular completely, in the relevant bus-side connection device (20').

10. Data transmission system according to claim 7 or 8, further comprising a control unit (50a) connected to the data transmission bus (2a) with a communication device (60a) for sending and / or receiving data via the data transmission bus (2a), wherein the resistor arrangement formed from the third resistor (R3) and / or the fourth resistor (R4) for each bus-side connection device (20') provided on the data transmission bus (2) is at least partially, in particular completely, formed in the control unit (50a) and is connected to the respective bus-side connection device (20') via an additional line (L5).

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