Single-wire bus system for devices such as sensor buttons

Abstract

The present invention relates to a proprietary electrical interface and control system based on the LIN interface.

Description

Technical FieldThe invention relates to a proprietary electrical interface and control system that is optimized for use in vehicles. It provides an alternative to existing solutions such as the LIN bus system by providing reduced complexity in hardware, design and manufacture, resulting in a cost reduction. In addition, a distinction between subscribers of the same type in a bus system is possible.Prior ArtA LIN bus-based network for motor vehicles is disclosed in EP 1594262 A2.SUMMARY OF THE INVENTIONThe object of the invention is to design a bus system for vehicles which offers reduced complexity in hardware, development and production.This object is achieved by a device according to claim 1. Advantageous embodiments of the invention are specified in the dependent claims.The system is characterized by a simplified electrical interface that requires only three wires (preferably 0 V, 24 V and a bus signal). At the center of the system is an aggregator signal, which acts as a master and translates the signals between different buttons and the door control unit.A particular feature of the system is the enhanced functionality that allows individual signal transmission for each function of each button. This includes the detection of whether the button has been actuated by an interior space, from the outside or by a wheelchair user. The individual function of the buttons can optionally be assigned by a "teaching" procedure in which the aggregator signal is placed in a special mode and each button is actuated in a fixed order or in accordance with the functionality. This procedure reduces the variety of buttons required, since the assignment of the functions is flexible and not fixed on the hardware side.An essential feature of the system is the auto-detection function. In this case, unique, e.g. 32-bit addresses of the buttons are read out for initialization or after loss of communication via a special method and managed by the master. The buttons are addressed by a search command from the master, the devices being requested by an "adaptive broadcast" for the simultaneous transmission of their addresses. A collision occurring in this case is recognized by dominant and recessive signal levels. This is the state of the art and does not form part of this invention.In order to minimize the transmission time between the actuation of a button and the message of the master to the control unit, the query is adapted depending on the size of the address space and the number of installed buttons. If it is expected that a plurality of buttons will be operated in the interrogation period, the addresses are determined in advance. If, on the other hand, few actuations and their notification are to be assumed, then the address is determined spontaneously.Finally, the system enables later integration into other control units according to a specification to be created. This flexibility allows the system to adapt to the needs of various types of vehicles and applications.The present invention relates to a proprietary electrical interface and control system that relies on the LIN interface, but has significant improvement by the invention. In particular, the system is characterized by simplified hardware, lower depth of development and manufacturing complexity, which leads to a cost reduction compared to conventional LIN solutions. In addition, the invention makes it possible to operate a plurality of similar devices on a bus without this leading to faults such as in the case of LIN. The system comprises a signal aggregator with a master function and enables the individual control and assignment of the functions of buttons within a vehicle by means of a "teaching" procedure or by means of a predefined function of the individual devices.DESCRIPTION OF THE DRAWINGSThe invention is described below by way of example without limiting the general concept of the invention on the basis of exemplary embodiments with reference to the drawings. FIG. 1 shows the basic design of a device according to the invention FIG. 2 shows the right-hand part of FIG. 1 in enlarged form FIG. 3 shows the right-hand part of FIG. 1 in enlarged formFIG. 1 shows an apparatus according to the invention.Various input / output devices, such as buttons and / or indicators, are coupled via a signal aggregator to a bus having at least 2 and preferably 3 lines. Communication with further buttons or displays can take place via the bus.References included in the specificationThis list of documents cited by the applicant has been produced in an automated manner and is only included for the better information of the reader. The list is not part of the German patent application or utility model application. The DPMA does not take any adhesion for any faults or omissions.Patent Literature citedEP 1594262 A2

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Claims

A bus system based on at least 2 lines, having a ground line, a bidirectional communication line and an optional supply line, wherein a DC voltage of 12V or 24V, for example, can be applied to the supply line.Bus system according to Claim 1, characterized in that it is configured in such a way that a signal aggregator takes over the master function and translates the signals between pushbuttons and door control units.Bus system according to one of the preceding claims, characterized in that it has an extended functionality, in which signals for each function of each button can be transmitted individually via the bus, including the differentiation as to whether the button has been actuated by an interior space, by the outside or by a wheelchair user.Bus system according to one of the preceding claims, characterized in that the bus system comprises a "teaching" procedure in order to assign the functions of the push buttons once as a function of their position in the vehicle, as a result of which the multiplicity of push buttons required is reduced and the operation of many push buttons of the same type on a bus is made possible.Bus system according to one of the preceding claims, characterized in that the bus system contains an auto detection function in which the push buttons transmit their unique addresses to the master via a special method.Bus system according to one of the preceding claims, characterized in that it is configured in such a way that it selects for minimizing the latency time between the use of a previously determined address table or spontaneous addressing.Bus system according to one of the preceding claims, characterized in that it is configured in such a way that the buttons are addressed by means of a search command from the master, the buttons responding simultaneously with their preferably 32-bit address, and the device first sends the bit itself for each bit and then its complement.Bus system according to one of the preceding claims, characterized in that the system comprises a branching and selection mechanism in which the master first selects the path with the bit value 0 at a branch (two devices with different bits at the same point).Bus system according to one of the preceding claims, characterized in that the system enables integration into other control units according to a specification (for example specified by CAPTRON), as a result of which forwarding to superordinate systems can be realized analogously to LIN solutions.

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