Abstract:
A method for managing event entries (ABC, XYZ), which are assigned to events, by means of a digital tachograph ( 1 ) electronically records personal data concerning the operation of a commercial vehicle. Conventional methods are very limited in their capabilities, particularly with regard to influencing by a user. A solution for this is provided by virtue of the fact that events of basic components (BK 1 , BK 2 , BK 3 ) are entered in a central event memory ( 2 ) with a priority (P 1 , P 2 ), and an event module ( 3 ) selects events and furnishes them to a subsequent processing.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]     This application is a U.S. national stage application of International Application No. PCT/EP2005/053797 filed Aug. 3, 2005, which designates the United States of America, and claims priority to German application number DE 10 2004 042 940.5 filed Sep. 2, 2004, the contents of which are hereby incorporated by reference in their entirety. 
     
    
     TECHNICAL FIELD  
       [0002]     The invention relates to a method for managing event entries, which are assigned to events, by means of a digital tachograph for electronically recording personal data which relates to the operation of a utility vehicle.  
       BACKGROUND  
       [0003]     During the operation of a tachograph, the main objective is to record a vehicle velocity as a function of time and to record activities in relation to one or more persons. The significant element here is to monitor driving times, rest periods etc. in order to monitor compliance with legal requirements. In this context, several events may occur, for example faults in the recording, cyclical transmission of a measured value, correlated to the velocity, to the recording element, or the activation of operator-controlled elements for controlling the recording process. In the days of mechanical tachographs, such events were essentially processed independently of one another, and the operator frequently created a dependence directly at the level of the recording. In addition, the functional quality of the mechanical device permitted only a less differentiated measurement of, for example, system faults or measurement errors and the user was only provided with a selection of functions which was restricted to the essentials. When an event occurred which made it necessary for the user to intervene in the recording device, the recording device or the tachograph merely gave the user an undifferentiated message so that the details of the rest of the operator-controlled process had to be determined by the user by virtue of his operating competence. Compared to the conventional devices, the new, digital generation of tachographs makes available a much more differentiated functionality. Dedicated fault messages and action instructions direct the user through a menu-prompted operator control system when corresponding events occur. In particular, in terms of the possibilities for evaluating the recordings, the driver of the utility vehicle is provided with completely new functions so that, for example, he is alerted automatically to the need for a break time according to legal stipulations. Furthermore, novel safety mechanisms reliably prevent illegitimate attempts at tampering from being successful. The highly extended functional scope and the increased complexity of the entire arrangement composed of the tachograph, velocity sensor and further connected devices increases the vulnerability to events which can be taken into account.  
         [0004]     The velocity sensor is a wheel speed sensor, generally referred to as a motion sensor, which supplies pulses as a measure of the wheel speeds from which the tachograph calculates the distance covered by the vehicle by means of a constant value for the circumference of the wheels, and determines the velocity therefrom at defined time intervals.  
       SUMMARY  
       [0005]     The invention therefore has the object of providing a method which feeds events of the abovementioned type to a means for taking them into account, in particular further processing, in a way which is appropriate chronologically and in accordance with priorities.  
         [0006]     According to an embodiment, a method for managing event entries which are assigned to events, by means of a digital tachograph for electronically recording personal data which relates to the operation of a utility vehicle, may comprise the steps of: 
        entering events with a priority in a central event memory as event entries of basic components,     searching the event memory by an event module at regular time intervals for the event entry with the highest priority, and selecting the event entry with the highest priority,     assigning a control parameter by the event module to the event of the selected event entry by means of a control parameter table, and     as a function of the control parameter     initiating a memory entry, assigned to the event of the event entry, in a vehicle memory, or     transmitting control signals to another component by means of a car area network, or     preparing an output at a printer, or     initiating representation on a display, or     bringing about data transmission to an external data memory.       
 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0016]     The invention will be described in more detail below for the sake of clarity by means of an exemplary embodiment and with reference to a drawing, in which:  
         [0017]      FIG. 1 : is a schematic illustration of the method by means of a flowchart. 
     
    
     DETAILED DESCRIPTION  
       [0018]     Event entries within the sense of the invention are to be understood as electronic recordings which are entered using a predefined naming convention, in particular with specification of the event time in an electronic memory, specifically the central event memory. The entry process is carried out here by basic components which virtually independently of one another register events, for example the transmission of a measured value from a rotational speed sensor or movement sensor or recording error or safety infringements or the requirement for a breaktime and enter these events as event entries in the event memory. In this context, the events are preferably assigned a priority by the basic components, said priority resulting from a superordinate priority convention as a function of the type of event. An event module which is implemented using software cyclically searches the event memory for event entries and selects that event entry with the highest priority in order to provide it with a control parameter. The event entry is further processed as a function of the control parameter in such a way that a memory entry which is assigned to the event used as the basis is initiated or generated from the event entry in a vehicle memory, or control signals are transmitted to a connected component by means of a car area network, or outputting can be initiated at an attached printer, or representation on a display is initiated, or data transmission to an external data memory is brought about. The particular advantage of the embodiments is that events are taken into account at any time without the highly loaded main processor of the tachograph being burdened at an inappropriate time, and in a way which puts stability at risk, with the processing of the processes initiated by the events. The central event memory acts here as a time buffer and permits controlled and planned execution of the processes which are initiated by means of the events, particular synergy effects, which reduce the utilization factor of the central processor of the tachograph to the minimum necessary, occurring by virtue of the prioritization according to an embodiment when the event entries are stored in the event memory.  
         [0019]     One particularly embodiment provides for the control table to contain control parameters as a function of an event reference number which is assigned to the event entry. The event reference number can comprise here merely a designation of the event entry or an attribute which is assigned to the event entry or the event. In the case of changes in the further processing of event entries, particular flexibility is found to occur since here only entries in the control table have to be changed. The method according to an embodiment can advantageously provide that the basic components access an assignment function which assigns a priority to the event entries. This assignment function is preferably here a subject of the central access so that changes relating to the priority of the handling of an event or event entry can be implemented with minimum expenditure, without having to make changes to the basic components.  
         [0020]     In order to minimize the expenditure when searching the event memory for the event entry with the highest priority, it is expedient if the central event memory has a uniquely defined assignment of memory locations for event entries to priorities. In this way, the event entries of the basic components are performed by the assignment function in accordance with the priority at only one specific memory location of the event memory, and the event module searches the memory locations only once more in a sequential fashion with decreasing assigned priority for the first allocation of an event entry without firstly having to compare all the event entries with respect to their priority. As a result of the fixed memory location of an event which is defined by their priority, a specific event is always written into the same memory location. Owing to the fixed assignment of priorities to memory locations, no priority conflicts can occur. In addition, this provides the possibility that the message can easily be ignored if an event with a duration is signaled repeatedly while it has not yet ended. If the same event is signaled again after it has already been ended, this is registered by incrementing the event counter. In no case must the basic component wait until the memory location becomes free again.  
         [0021]     Events or event entries with the same priority are thus fed to further processing, or provided with a control parameter, in a chronological sequence of their occurrence by the event module.  
         [0022]     The method according to an embodiment is particularly expediently developed if the event module assigns attributes to the event entries as a function of the memory location by means of an attribute table. The assigned attributes can pass on supplementary information to subsequent processing steps, for example to printing out or outputting on a display.  
         [0023]     In particular within the scope of the application according to an embodiment it is important that the memory entries to be made according to legal requirements satisfy stability criteria which apply to the vehicle memory or to a chip card so that it is advantageous if the event module initiates the entry of a memory entry which is assigned to the event of the event entry in the vehicle memory in which it transfers the event entry to a memory module which enters a memory entry, assigned to the event, into a vehicle memory.  
         [0024]     It is also of particular importance for the application within the scope of a digital tachograph to record events with a duration during which the basic component which is entered into the event memory enters the start of the event and the end into the event memory, and the event module assigns the same time value to the end of the event as to the start if an end has not been entered by the basic components because specific events do not have any duration according to their definition. A particular advantage of the assignment of the same time value to the start and to the end is the avoidance of subsequent errors.  
         [0025]      FIG. 1  shows the basic sequence and the interaction between various components according to the method. A tachograph  1  is symbolized by means of a system limit which is provided with the reference symbol  1 . Various basic components BK 1 , BK 2 , BK 3  have writing access to an event memory  2  in which the basic components BK 1 , BK 2 , BK 3  make an event entry ABC, XYZ in the event memory  2  when an event, for example the request for a representation on a display, occurs. The event entry ABC, XYZ is provided here with a priority P 1 , P 2  by the basic components by accessing an assignment function ZuFu.  
         [0026]     The basic components BK 1 , BK 2 , BK 3  enter events as event entries ABC, XYZ in the central event memory  2  as “pending” when they occur, and as “terminated” when they end. Here, each event entry XYZ, ABC is composed of a status, an event counter and a starting time marker and an end time marker. The event counter is used for statistical purposes. The status includes the bit flags “pending”, “terminated”, “event active”, “start-LCD”, “active-LCD” and “cyclic event”.  
         [0027]     An event module  3  searches the event memory  2  for the event entry ABC, XYZ with the highest priority P 1 , P 2 . The event entries ABC, XYZ in the event memory  2  have a uniquely defined assignment to a memory location  4 ,  5  as a function of their priority P 1 , P 2  so that the event module  3  passes through the individual memory locations  4 ,  5  only in the sequential sequence of decreasing priority P 1 , P 2  and feeds the event entry ABC, XYZ of the first occupied memory location  4 ,  5  to further processing.  
         [0028]     In the scope of the further processing the event module  3  assigns the event entry ABC, XYZ a control parameter  6  from a control parameter table  7  and attributes  8  from an attribute table  9 .  
         [0029]     The event entry ABC, XYZ which is expanded with attributes  8  and a control parameter  6  is fed by the event module  3  to an output means, a storage means, a transfer means or a further processing means. If the control parameter  6  provides for outputting, the expanded event entry ABC, XYZ is transferred to an output module  20  which also comprises a memory module  21  which controls storage of a memory entry, based on the event entry ABC, XYZ, in a vehicle memory  23  or a map memory  24 ,  25 . The map memories  24 ,  25  are both components of the tachograph  1  and are embodied as merely virtual chip cards, that is to say memory areas in the tachographs  1  are occupied by identical data entries, like an actual chip card which is introduced into the tachograph  1  for the purpose of recording. If an event is to be output on a printer  27 , the output module  20  feeds the expanded event entry ABC, XYC to the printer  27  a corresponding actuation. In addition, the output module  20  permits a data download by means of a connected download module  28 . The data can be transmitted from the event module  3  to other components  30  by means of the car area network CAN. Furthermore, the event module  3  permits outputting on a display  31  of the tachograph  1 . The possibility of connecting further output devices  34  is provided by an info module  35  which is connected to the event module  3 . By means of a warning module  36  the event module  3  can output warning messages, for example on a combination instrument  37 .