GB2119095A - Data processing systems for motor vehicles - Google Patents

Abstract

A data processing and recording system for a motor vehicle comprising data processing means, providing part of the system fitted to a motor vehicle and connected to sensors 23 to 26 on the vehicle. The data processing means 1 processes sensor signals and records the processed data on a cartridge 2 forming another part of the system. The recorded data on the cartridge is transferred to a data collection means 3. The data processing means requires calibration data, unique to the vehicle in which it is fitted, to process the sensor signals correctly. The calibration data is generated by the data collection means and transferred to the data processing means by the cartridge. Reference data, also unique to the vehicle, is transferred in the same way. <IMAGE>

Description

SPECIFICATION Improvements in and relating to data processing systems for motor vehicles The invention relates to a data processing system for a motor vehicle.

Current legislation has led to the fitting of tachographs in commercial heavy goods vehicles, A tachograph records details of vehicle speed, distance covered, and driver's activity, as a means of monitoring the time spent by a driver in driving the vehicle in order to ensure that statutory limits as to the lengths of a driver's work periods are complied with.

It has been found that data on vehicle usage and driver work load can be useful to the vehicle operator in planning his vehicle schedules.

The present invention provides a data processing system which is suitable for collecting data useful in planning commercial motor vehicle operations.

According to the invention, a data processing system for a vehicle comprises data processing means (the first means) for processing vehicle data in the form of signals received from at least one vehicle sensor, means (the second means) for recording calibration data to be used by the first means in processing data, wherein the first means is capable of being installed in the vehicle to receive the vehicle data and to process the data in dependence on the calibration data, and the second means is operatively connectible to the first means to transfer the calibration data to the first means.

The first means may be capable of memorising the calibration data and returning it to the second means in order to allow checking of the data memorised by the first means against original calibration data.

The second means may receive the calibration data returned to it by the first means at a location different from that at which it recorded that data in order to allow checking of the data memorised by the first means by comparison of the two sets of calibration data in the second means.

The data processing system may include means (the third means) capable of generating the calibration data, the second means being operatively connectiable to the third means to record the calibration data. The third means may be capable also of performing the task of checking the calibration data memorised by the first means and returned to the second means. The calibration operation is repeated if the calibration data memorised by the first means fails the check.

The first means may be capable of detecting an interruption in its power supply and, in the absence of the second means, of adopting default calibration values on restoration of the supply. Thus, the first means is capable of adopting default calibration values for its data processing operations in a situation in which its calibration data would have been corrupted or lost. The default calibration value is set at 1 metre per pulse for processing signals from a sensor which provides a pulse each time the vehicle travels a set distance. The data processed by the use of the default calibration value can be reprocessed elsewhere using true calibration data. Values otherthan 1 metre per pulse may be used.

The third means may, additionally, be capable of removing calibration data from the second means. This permits the clearing of the calibration data from the second means on completion of the calibration of the first means and the use of the cleared second means for recording data processed by the first means, thereby permitting operation of the system in a calibration mode and a recording mode with a single type of recording means.

The first means may be capable of transferring its calibration data to the previously cleared second means and of memorising the data transferred by it to the second means so that, in the recording mode, the first means can re-establish its calibration data following a power supply interruption that would have led to the curruption or destruction of its calibration data. The second means includes a battery which prevents the loss of its data during transfer between the first and third means and, consequently, the second means is not affected by power supply interruptions when connected to the first means. The second means used for recording may be that used for calibration of the first means and cleared subsequently, or the second means may be a different recording means altogether.

The third means may be capable also of collecting data recorded by the first means. In practice, a control console located at a vehicle operator's premises performs all the functions of the third means.

Also, the system may use reference data such as an identifying code for each vehicle and the vehicle odometer reading to assist in its management, the reference data will be transferred, memorised and checked in the same way as the calibration data, and default reference values, including an odometer reading of zero, will be available.

The first means may be capable of sensing removal of the second means and of an orderly closing of data transfers and shut-down before separation of the means.

Means connecting the first means to the second means may be capable of signalling the said removal of the second means.

The second means may be a cartridge insertable into the first and/or third means, respectively.

The second means may be a semiconductor data store insertable into the first means.

The first means may be provided with its own display apparatus to permit the display of processed data.

The invention provides a method of processing and recording vehicle data stored by a data processing means installed in a vehicle, the vehicle data being in the form of signals received by the processing means from at least one vehicle sensor, wherein the method comprises supplying calibration data to the processing means prior to it receiving the data to be processed, storing vehicle data in the processing means in dependence on the calibration data and recording that data.

A recording means may be connected to the processing means to record the processed data and is subsequently disconnected.

The recording means may record the calibration data and is then connected to the processing means to transfer that data to the processing means.

The invention provides a method of transferring data between two separable means, including the step of detecting initial separation of the two means and effecting an orderly closing of data transfers and shut-down before separation of the two means.

The orderly closing of data may be effected by limiting data transfer operations to a period shorter than a nominal time-for-separation.

A data processing and recording system in accordance with the present invention will now be described, by way of example only, and with reference to the accompanying drawings in which: Figure lisa block diagram representation of the components of the data processing and recording system.

Figures 2-11 are flow chart representations of the operations carried out by a data processing means forming part of the data processing and recording system.

Referring to Figure 1, a data processing and recording system includes a data processing module 1, a recording cartridge 2, and a data collection console 3. A host computer 5, a printer 6, and a visual display unit 7 may be connected to the data collection console 3 by way of a bus system 4.

The data processing module 1 is arranged for installation in a vehicle. The data processing module 1 has a power supply input port 45 for connection to a vehicle power supply and a plurality of signal input ports 10, 11, 12 and 13 for connection to sensors 23, 24, 25 and 26 fitted to the vehicle. The data processing module 1 has signal input ports 10, 11 and 12 for connection to respectively a speed sensor 23, a G-sensor 24, and a tachograph interface system 25, and has additional input ports 13 for connection to additional sensors, for example, load and fuel level sensors 26, as required.

The data processing module 1 includes a microprocessor 18. The various signal input ports of the data processing module 1 are connected, by way of respective filters 14, 15, 16 and 17, to data input ports of the microprocessor 18. The microprocessor 18 includes its own programme and data stores and is arranged to process data signals applied to its input ports in accordance with the respective states of its programme store elements, to store the processed data in its data stores, and to present the stored data, by way of an output port, to a multiway connector 19.

Data signals applied to the input ports of the microprocessor 18 are required to be in digital form and could be provided, for example, by electrical contact closures by means of which a normally high value falls to a low value in the presence of some limit of the function monitored by a particular sensor. The speed sensor 23, for example, could be arranged to provide a pulse of at least 1 mS duration each time the vehicle covers a set distance in the range .35 to 2.6 metres per pulse.

A supply level sense circuit 33 is connected to the RESET input port of the microprocessor 18. The supply level sense circuit 33 operates when the supply voltage level falls to a level at which the microprocessor 18 operates unreliably. The supply level sense circuit 33 operates when there is a temporary interruption of the electrical supply to the data processing module 1 and, of course, when there is disconnection of the vehicle battery. The supply level sense circuit 33 resets the microprocessor 18.

A power supply filter 20 and a voltage regulator 21 provide the necessary voltage supplies for the microprocessor 18. An optional back-up battery 22 is shown.

The microprocessor 18 is a Type 8048 manufactured by Intel Corporation. The Type 8048 microprocessor is described in detail in an Intel Corporation publication entitled: 8748 Microprocessor: Intel MCS-48 Microcomputer Users' Manual (1978). The Type 8048 microprocessor employs a multiplexed data/address bus arrangement which reduces the number of system communication leads required.

The data processing module may include a display device arranged to display processed data on command. No display device is shown in Figure 1.

The recording cartridge 2 has a connector arrangement 35 which is complementary to the connector 19 of the data processing module 1. The recording cartridge 2 is connectible to the data processing module 1 by means of the connector 35.

The recording cartridge 2 includes a read/write memory 27, an address latch 28, and an internal clock 29.

Data ports of the read/write memory 27 are connected to the connector 35 by means of a data/address bus 46. The address ports of the read/write memory 27 are connected to the data/address bus 46 and to a bus 47 in order to accommodate the multiplexed address/data arrangement of the microprocessor 18. The address latch 28 holds the part of the address which has to be latched. The read/write memory 27 also records the time provided as signals by the clock 29 by way of the microprocessor 18. The address latch 28 holds the part of the address which has to be latched. The read/write memory 27 also records the time provided as signals by the clock 29 by way of the microprocessor 18. Other components included in the recording cartridge 2 are an indicator 30, a power supply filter 32 and a battery 34.

Cartridge removal detection means, shown as a block 31, are provided for sensing disconnection of the recording cartridge 2 from the data processing module 1. The cartridge removal detection means 31 takes the form of a shortened pin on the connector 35. The shortening of the pin on the connector 35 is of the order of 1 mm so as to provide a time delay of at least 1001lS between the time of separation of the shortened pin from its contact in the complementary connector 19 of the data processing module and the time of disconnection of the other pins and contacts on the connectors 19 and 35, when the recording cartridge 2 is being disconnected from the data processing module 1. The shortened pin lies mid-way along the connector 35 so as to minimise the effects of twisting of the cartridge 2 during disconnection.The microprocessor 18 of the data processing module 1 senses the separation of the shortened pin from its contact and halts after completing the operation cycle on which it was engaged when the said separation was first sensed. This achieves an orderly transfer of data to the recording cartridge 2 at disconnection of the cartridge 2 from the data processing module 1.

The data collection console 3 includes a microprocessor 36, a keyboard 37 and keyboard controller 38, a master clock 39, a read/write memory 40, a receiver/transmitter 41, a display and display controller 42, and a power supply 44. The components of the data collection console 3 communicate with one another by means of an internal bus system 48. The internal bus system 48 connects to an input/output port 49 which is arranged to permit connection of the recording cartridge 2 to the bus system 48.

The microprocessor 36 includes programme and data stores connected to a Type 8085A processing device. The Type 8085A device is manufactured by Intel Corporation and described in detail in an Intel Corporation publication entitled MCS-85 User's Manual (1978). The microprocessor 36 controls the functions of the console 3, the microprocessor 36 operating under the control of its programme store.

The keyboard 37 is a sixteen-key keypad by means of which an operator instructs the microprocessor 36.

The keyboard controller 38 acts as an interface between the keyboard 37 and the bus system 48.

The display 43 and display controller 42 provide a display of entries made by the keyboard 37.

Data reaching the bus system 48 by way of the input port 49 is stored in the data store 40 which has the capacity to hold data from several recording cartridges 2. The data stored in the data store 40 is transferred, as required, to the host computer 5 by way of the receiver/transmitter 41 and the bus system 4.

The master clock 39 provides accurate time information including data (1 to 31), day (as a number 1 to 7), month (as a number 1 to 12), and time of day.

The system is operable in a management mode as well as in a normal mode.

The management mode provides facilities for setting the system to work. A data processing module 1 installed in a vehicle is set to work by the entering into it of calibration data essential for its data processing operations. Calibration data may include a parameter of the vehicle transmission system which permits an assessment of the vehicle speed according to the number of signal pulses received in a set time from a movement sensor which provides a pulse each time some part of the transmission system makes one revolution, say. Alternatively, or additionally, the calibration data may be relevant to fuel consumption and permit an assessment of the fuel consumption rate according to signals from a fuel level sensor or the number of pulses received from a fuel flow sensor in some set time.The calibration data is entered into the data processing module 1 by installing a cartridge 2 in the control consol 3, setting the control console 3 to its management mode, and using the keyboard 37 to transfer calibration data already stored in the control console 3 to the cartridge 2. A vehicle number code and the odometer reading for the vehicle are also transferred to the cartridge 2 at the time of transferring the calibration data. Also during the operation leading to the transfer of the calibration data to the cartridge 2, the control console 3 transfers to the cartridge 2 a code which marks the cartridge 2 as a "calibration" cartridge. The cartridge 2 will, of course, have been cleaned by the control console 3 before the entry of any data. The cartridge 2 is then removed from the control console 3 and inserted into the data processing module 1 in the vehicle.The data processing module 1 recognises the "calibration" cartridge code and reads the calibration data from the cartridge 2. The data processing module also accepts any additional data, for example, vehicle code and odometer reading, as reference data. The data processing module 1 records, on the "calibration" cartridge 2, the calibration data it took from the cartridge 2, but at a different address from that used by the control console 3. The cartridge 2 is then re-inserted into the control console 3 and the console 3 instructed to check that the calibration data entered into the cartridge 2 by the data processing module is the same as that entered originally by the control console 3. The system can be made to check the vehicle code and odometer data in the same way as the calibration data. The calibration operation is repeated if the verification check fails.

When a data processing module is "powered up" forthe first time, it loads its own default calibration data and uses this default data in its data processing operations until the default value is corrected by a calibration procedure. The data processing module will also use default values after a power supply interruption if no calibration data is available on the return of power.

The control console 3 is used in the normal mode to effect day to day use of the system by facilitating the preparation of cartridges for drivers' use and for accepting data from cartridges used in recording the drivers' activities. When the control console 3 is in the normal operating mode, its use by a driver begins with the insertion of a cartridge 2 into it, and the operation of a key marked D. This clears and initialises the cartridge 2 and marks it as suitable for recording data. The cartridge 2 could be the same one as used in the calibration procedure set out above. The system employs only one type of cartridge 2. The driver then operates the appropriate keys on the control console 3 to enter, into the cartridge 2, by way of the control console 3, operational information such as a driver code, a depot code, and/or a journey code.The control console 3 checks that the cartridge clock 29 is correct to within 1 minute of the console clock date and time and updates it if necessary.

The "ready-for-use" cartridge 2, set up for recording, is taken by the driver and installed in the vehicle he is to operate.

When the recording cartridge 2 is presented to the vehicle data processing module 1, the vehicle data processing module 1 records its resident calibration data in the recording cartridge 2. The data processing module 1 treats the recording cartridge 2 as a source of calibration data if a vehicle power supply interruption occurs and reloads calibration data from the recording cartridge 2 following a vehicle power supply interruption. The data processing module 1 transfers its vehicle identification data to the cartridge 2 as it does with its calibration data. While the recording cartridge 2 is present, the data processing module 1 is able to record in it, details of distance travelled, vehicle speed, vehicle and driverfunctions, and times at which changes take place. The times are obtained from the recording cartridge clock 29.The recording cartridge 2 records the time at which it is detached from the data processing module 1 to within 1 minute.

After detaching the recording cartridge 2 from the data processing module 1, the driver presents the recording cartridge 2 to the data collecting console 3 which copies the stored data and marks the recording cartridge 2 as now having "old" data. In the normal mode, the control console 3 will not read again a cartridge 2 marked as "old", but, in the management code, the control console 3 will read a cartridge 2 marked as "old". The cartridge 2 marked as "old" is cleaned and initialised when it is next inserted into the control console, with the console in the normal mode, and the D key is operated, thereby completing the operating cycle.

A cartridge 2 may be used by a driver in more than one vehicle. The cartridge 2 will accommodate up to 64 insertions which may be made on the same vehicle or on several vehicles. It should be apparent that management mode operation of the control console 3 is available only to selected personnel. The operations carried out by the data processing module 1 are represented in Figure 2.

Referring to Figure 2, the controlling microprocessor 18 in the data processing module 1 reacts to a RESET condition, i.e. when first powered up or on the return of power following an interruption, by clearing its internal temporary-storage registers (step 1). A check is then made as to whether or not a cartridge is connected to the module (step 2). If a cartridge is fitted (decision YES), a check is made as to whether or not it carries compensation, i.e. calibration and reference data for the vehicle (step 3), and if calibration and reference data is present (decision YES) the calibration and reference data is accepted by the microprocessor 18 (step 4). If no calibration and reference data is present on the cartridge (decision NO), or there is no cartridge (decision NO at step 2), the microprocessor 18 takes on "default" data (step 5).After loading calibration and reference data, the microprocessor sets the speed output value to zero, starts an interval timer, and activates an input port which permits its timer to interrupt data processing (step 6). Operation then continues with the sensor input ports being activated (step 7), and a further check being made for the presence of a cartridge (step 8). If a cartridge is present (decision YES), the cartridge clock 29 is set up to provide signals at 1/2 second intervals for interrupting data processing (step 9). When an interrupt signal is received (decision YES, step 10), a check is made as to whether the cartridge is a calibration cartridge or a data cartridge (step 11).If the cartridge is a calibration cartridge, i.e. carrying only calibration and reference data (decision YES, step 12) the calibration and reference data is accepted by the data processing module (step 13) and reloads the data into the cartridge at a location different from that used by the control console to permit verification of the calibration operation by means of the control console.

If the cartridge has been marked as suitable for recording data, the operation proceeds toA in Figure 2.

Operation now proceeds to A in Figure 3. The calibration and reference data present in the data processing module is recorded in the data cartridge (step 17) along with vehicle identification data (step 18). The system is so arranged that initial disconnection of the data cartridge from the data processing module results in an orderly transfer, to the data cartridge, of the available data at the time of removal (step 19). Also recorded on the cartridge is data obtained from the various sensors and the time at which the data was recorded (step 20). At this stage in the operating sequence a light emitting diode indicator is switched on (step 21) to indicate to the driver that the system is functional and ready.The operation continues with a check for the continued connection of a cartridge (step 23), the clearing of all addresses from the latch (28 Figure 1) which controls the cartridge memory (27 Figure 1) (step 24), a further comparison of the static module and cartridge data that should remain the same, for example, the vehicle code (step 25). If the fixed data is still the same (decision YES, step 25) the dynamic data, e.g. speed, is checked (step 26), and action taken to update the dynamic data (step 27). The address of the next vacant memory is also updated (step 28). A check is then made for the zero speed condition (step 29). If a non-zero speed is detected (decision NO, step 29), the LED indicator is switched off and processing continues to C of Figure 3, otherwise time along is recorded (step 31) and the LED indicator is switched on before C of Figure 3 is reached.If, at step 25, the static data held by the cartridge and the processing module, respectively, were not the same (decision NO, step 25) the operation returns to step 1 (Figure 2) to reload the static data.

Operation after C in Figure 3 continues from C in Figure 4. The next step in the data processing operation checks the sensor inputs (step 33) and records, on the cartridge, the time and new value if there has been a change (step 34). Whether or not there has been any change in the sensor signals, the operations starting at step 22 are repeated unless 71/2 seconds has elapsed since step 6 was completed (step 15). If 7 seconds has elapsed, the operation moves on with a check of the driver function (step 36) and, if there has been a change in the driverfunction, a check for whether or not the change took place within 71/2 seconds of the start of the last function (step 37).If a change did occur, but not within 71/2 seconds of the start of the last function, the new function is held in the data processor module without disturbing the recording of the previous function (step 41) in the data processor module. If a change occurred within 71/2 seconds of the start of the last function, then the new function data replaces the previous function data (step 38). The 71/2 second timer is then restarted and the data held in the data processor module for the last 71/2 seconds is transferred to the cartridge (step 39). Speed histogram data held in the data processor module is updated with the speed data for the previous 71/2 seconds (step 40) and operation is returned to step 22 (Figure 3).

Figure 5 represents, in flow chart form, the generation of the various time intervals required by the data processing system. As shown in Figure 5, the TIMER operations provide marker signals at 1/2 and 71/2 seconds respectively, for operations at 1/2 and 71/2 second intervals as described with reference to Figure 2 to 4, and also marker signals at 1 minute intervals are used in the detection of zero speed of the vehicle.

Figure 6 also in flow chart form represents the operations carried out by the data processing module in writing data into the recording cartridge. As shown in Figure 6, the WRITE operation starts with a check to confirm the connection of a recording cartridge to the data processing module. A successful check for the presence of the recording cartridge is followed by a determination of the amount of unused memory space remaining in the recording cartridge (for that particular class of data), then a WRITE step. The data written is then verified, a check is made that there is still unused memory space, and further WRITE steps carried out until all the relevant data is transferred or there is no more unused memory space.Steps are included for repeating WRITE steps to correct errors during a WRITE step, and for setting an indication of an error after two unsuccessful attempts to achieve correct data recording or when the recording cartridge runs out of memory space.

Figure 7 represents, in flow chart form, the transfer of data, taken from sensors, from the data processing module to the recording cartridge. As with the WRITE operation of Figure 6, the sensor data is restricted to specific memory locations in the recording cartridge memory, and the sensor data recording operation includes steps for keeping a check on the unused memory space specific memory locations in the recording cartridge memory, and the sensor data recording operation includes steps for keeping a check on the unused memory space reserved for the sensor data. There is also a step available for verifying written data and rewriting it if the verification steps show data errors.

Figure 8 represents, in flow chart form, the steps executed in obtaining time and data data from the clock included in the recording cartridge. The operation begins with a check for the presence of the recording cartridge and, if the cartridge is present, is foilowed by the transfer of one byte (8 bits) from the cartridge clock to the data processing module. The time/date data is checked for errors and the step is repeated if an error is found. An error can occur if the cartridge clock updates during the transfer operation. Otherwise, the transfer steps are continued until all the clock data is transferred to the data processing module. The clock data is later recorded in the recording cartridge memory.

Figure 9 represents, in flow chart form, the reading of reference data from a cartridge to the data processing module. As shown in Figure 9, reading proceeds a byte at a time once it is confirmed that a cartridge is present in the data processing module.

Figure 10 represents, in flow chart form, a REMOVAL operation which achieves the recording, in the recording cartridge, of data present in the data processing module at any time that the recording cartridge is removed. The REMOVAL operation is initiated when a shortened pin on the recording cartridge connector (described with reference to Figure 1 above) loses contact with the complementary connector of the data processing module. The REMOVAL operation begins with the step of loading a "chop" address (step 1) in the data processing module up to which data transfer can take place reliably before separation of the data connections between the cartridge and the data processing module. The data to be transfered, i.e. up to the "chop" address, is loaded into a buffer area in the data processing module (step 1) and the data start-address in the cartridge is noted.

A WRITE step follows (step 2). The written data block is verified (step 3) and rewritten (step 4) if necessary.

A record of the start addresses for still unused memory space in the recording cartridge is also transferred to the recording cartridge (step 5) to permit continued system operation on the return of the recording cartridge to the data processing module. The REMOVAL operation achieves an orderly transfer of processed data from the data processing module to the recording cartridge just prior to separation of the two components. The provision of a means for detecting the start of separation of the components and of a REMOVAL routine reduces the chances of corrupt data being transferred to the recording cartridge because of the action of removing the cartridge from the data processing module.

Figure 11 represents, in flow chart form, the operations performed by the data processing module in respect of the vehicle speed. This operation is treated as an "external interupt" since the movement sensor is arranged to interrupt data processing every x metres of vehicle travel. xis one of the calibration values stored in the data processing module. A timer runs for the intervals between consecutive movement sensor interruptions. The speed is calculated from the ratio of the value of x to the time taken for the vehicle to cover the distance x. The value xis also added to a running total of distance travelled, at each movement since interruption, until the running total reaches 1 metre, when 1 is added to the "odometer" total and the running total is returned to zero. As shown in Figure 11, a "drive" timer is also included in the speed analysis operations. The "drive" timer provides 1 minute markers. Speed is logged at these 1 minute intervals and a record kept of the time in minutes spent in any speed band. The speeds are classified in 5 KPH bands for this purpose.

The speed information is processed and stored both as a speed histogram setting out the total times spent in the various speed bands and as a speed trace giving the vehicle speed profile over its journey time, but the speed trace is restricted to the most recent few minutes while the vehicle speed exceeds 5 KPH. The said last few minutes at speeds in excess of 5 KPH is frozen once the vehicle speed falls below 5 KPH.

In the operation of the system as descibred, the last 2 minutes of speed data at speeds in excess of 5 KPH will be held once the vehicle stops and will be overwritten as soon as the vehicle speed again exceeds 5 KPH.

In the event of an accident, therefore, the last 2 minutes of speed data will be available while the vehicle remains stationary, following the accident, but will be lost when the vehicle moves again. The loss of this speed information can be prevented by removal of the recording cartridge. Alternatively, a G-sensor may be fitted to detect deceleration consistent with emergency braking, and the G-sensor signal arranged to store the potentially valuable speed data, preceding emergency braking, at a location where it will not be overwritten. The G-sensor may be located within the data processing module.

In the system described, the data processing module may be connected to the statutory tachograph as the means of sensing vehicle and driverfunctions. Since, however, the statutory tachograph depends on the driver entering vehicle and driver functions by means of switches, the sensing of vehicle and driver functions from the statutory tachograph depends on the driver's conscientiousness for fidelity. The fidelity of the system described could be assured by incorporating sensors adapted to signal vehicle and driverfunctions independently of the statutory tachograph, for example, the G-sensor referred to above could be used to detect vehicle motion independently of the tachograph driver function switch.

In the system described, the data stored on each Data Cartridge includes: (i) Date stored as Day 1 to 31 Day No. - 1 to 7 (Mon. to Sun.) Month - 1 to 12 (Jan. to Dec.) The date is automatically corrected for 28, 30, 31 day months and leap years.

(ii) Vehicle number - six digits (iii) Driver code - six digits (iv) Depot code - two digits (v) Day start time - when the data cartridge is inserted the insertion time is automatically logged as an indication of day start.

(vi) day end time - when the data cartridge is extracted from the Vehicle Module the last logged time is retained by the cartridge. This updating takes place every 71/2 seconds.

(vii) Driver function - up to 128 changes in driver function can be logged in any driver day. The time that any transition takes place is automatically logged.

(viii) Vehicle function - up to 256 changes in vehicle function can be logged on any combination of the vailable six truck functions.

(ix) Distance traveiled - four digits of distance travelled.

(x) Speed analysis - speed is logged at 71/2 minutes intervals and stored in bands of speed data as 5 KPH bands.

(xi) Accident Log - speed at 0.5 second intervals is logged for the past 98 seconds. The date is continuously updated and the record 'frozen' and retained when zero speed is detected. Thus, a speed and deceleration profile prior to the vehicle stopping can be plotted.

In the event of an accident when the data is required to be retained, the cartridge would have to be withdrawn to prevent overwriting when (or if) the vehicle was again moved.

(xii) Multiple truck usage - The unit will log the appropriate date, start and stop times for multiple vehicle usage using the same cartridge. Up to 64 insertions can take place.

Suitable components for the data cartridge are: (a) The data store (RAM) - a type MM 6116LP3 2Kx 8 memory integrated circuit (Hitachi): (b) The address latch - a type 74C373 Octel D-Type Latch integrated circuit (National Semiconductors): (c) The clock - a type MM 58174 clock integrated circuit (National Semiconductors).

The data stored on each Data Cartridge may be printed out as follows: Driver code = 100000 Total time 13:51 Date = 10/12 Truck code = 081405 Journey code = 67 Start odo = 00317 Finish odo= 000380 Distance = 00063 Total duty 01:15 Longest duty 00:29 Drive Passive Rest Active A B C D E Longest drive 00:29 Total drive 01:15 20:41 0:00 20:41 0:00 20:41 0:00 20:41 0:25 20:59 0:00 Start 20:41 20:41 0:01 20:41 0:01 20:41 0:01 00:49 0:00 00:58 0:00 Finish 10:32 20:42 0:05 20:44 0:01 20:44 0:01 01:13 0:00 10:08 0:00 20:47 0:20 20:45 0:01 20:45 0:01 01:13 0:00 10:09 0:00 21:07 3:42 20:46 0:00 20:46 0:00 10:03 0:29 10:11 0:00 135 0.0 00:49 0:25 20:46 0:20 20:46 0:20 10:30 0:29 10:13 0:00 130 0.0 01:14 8:49 21:06 3:43 21:06 3:43 10:19 0:00125 0.0 10:03 0:29 00:49 0:00 00:49 0:00 10:26 0:00 120 0.0 10:32 00:49 0:00 0:49 0:00 115 0.0 00:49 0:24 00;49 0:24 110 0.1 01:13 0:00 01:12 0: :00 01:13 8:48 01:13 8:48 10:02 0:00 10:02 0:00 10:02 0:00 10:02 0:00 10:02 0:00 10:02 0:00 10:03 0:00 10:03 0:00 10:03 0:00 10:03 0:00 10:03 0:00 10:03 0:00 10:03 0:00 10:03 0:11 10:15 0:00 10:15 0:00 10:15 0:00 10:15 0:00 10:15 0:17 10:15 0:17 01:15 00:00 12:36 00:00

Claims (30)

1. A data processing system for a vehicle comprising data processing means (the first means) for processing vehicle data in the form of signals received from at least one vehicle sensor, means (the second means) for recording calibration data to be used by the first means in processing data, wherein the first means is capable of being installed in the vehicle to receive the vehicle data and to process the data in dependence on the calibration data, and the second means is operatively connectible to the first means to transfer the calibration data to the first means.

2. A data processing system as claimed in claim 1, wherein the first means is capable of memorising the calibration data and returning it to the second means.

3. A data processing system as claimed in claim 2, wherein the second means receives the calibration data returned to it by the first means at a location different from that at which it recorded that data.

4. A data processing system as claimed in anyone of claims 1 to 3, and including means (the third means) capable of generating the calibration data, wherein the second means is operatively connectible to the third means to record the calibration data.

5. A data processing system as claimed in claim 4, as dependent on claim 2 or claim 3, wherein the third means is capable of checking the calibration data returned to the second means by the first means against the calibration data transferred by it to the second means.

6. A data processing system as claimed in any one of claims 1 to 5, wherein the first means is capable of detecting an interruption in its power supply and, in the absence of the second means, of adopting default calibration values on restoration of the supply.

7. A data processing system as claimed in any one of claims 4 to 6, wherein the third means is capable of removing calibration data from the second means.

8. A data processing system as claimed in claim 7, wherein the or another second means without calibration data is capable of recording data processed by the first means.

9. A data processing system as claimed in claim 8, wherein the first means is capable of transferring its calibration data to the or another second means without calibration data.

10. A data processing system as claimed in claim 9, wherein the first means is capable of detecting an interruption in its power supply and of memorising the calibration data transferred by it to the or another second means on restoration of the supply.

11. A data processing system as claimed in any one of claims 8 to 10, wherein the third means is capable of collecting processed data recorded by the second means.

12. A data processing system as claimed in any one of claims 4 to 11, wherein the second means is capable of recording reference data, and the first, second and third means are capable of handling the reference data in the same way as the calibration data.

13. A data processing system as claimed in any one of claims 8 to 12, wherein the first means is capable of sensing removal of the second means and of an orderly closing of data transfers and shut-down before separation of the means.

14. A data processing system as claimed in claim 13, wherein means connecting the first means to the second means is capable of signalling the said removal ofthe second means.

15. A data processing system as claimed in any one of the preceding claims, wherein the second means is a cartridge insertable into the first and/or third means, respectively.

16. A data processing system as claimed in any one of the preceding claims wherein the second means is a semiconductor data store insertable into the first means.

17. A data processing system as claimed in any one of the preceding claims wherein the first means include display means.

18. A data processing system substantially as herein described with reference to, and as illustrated by, the accompanying drawings.

19. A data processing system as claimed in any one of the preceding claims, and in which the first means is substantially as herein described with reference to Figures 1 to 11 of the accompanying drawings.

20. A data processing system as claimed in any one of the preceding claims, and in which the second means is substantially as herein described with reference to Figure 1 of the accompanying drawings.

21. A data processing system as claimed in any one ofthe preceding claims, and in which the second means is substantially as herein described with reference to Figure 1 of the accompanying drawings.

22. A data processing means for a data processing system as claimed in any one of the preceding claims.

23. A vehicle including a data processing means as claimed in claim 22.

24. A method of processing data which includes the use of a data processing system as claimed in any one of claims 1 to 21.

25. A method of processing and recording vehicle data stored by a data processing means installed in a vehicle, the vehicle data being in the form of signals received by the processing means from at least one vehicle sensor, wherein the method comprises supplying calibration data to the processing means prior to it receiving the data to be processed, storing vehicle data in the processing means in dependence on the calibration data and recording that data.

26. A method of processing and recording data as claimed in claim 25, wherein a recording means is connected to the processing means to record the processed data and is subsequently disconnected.

27. A method of processing and recording data as claimed in claim 25, wherein a recording means records the calibration data and is then connected to the processing means to transfer that data to the processing means.

28. A method of transferring data between two separable means, including the step of detecting movement apart of the two means and effecting an orderly closing of data transfers and shut-down before separation of the two means.

29. A method as claimed in claim 28, wherein orderly closing of data is effected by limiting data transfer operations to a period shorterthan a nominal time-for-separation.

30. Data recording means including connection means permitting connection to and disconnection from data processing means with complementary connection means, wherein the connection means has a plurality of connection pins and one pin is shorter than the remaining pins so as to permit sensing by the data processing means of movement apart of the data recording and data processing means.