Abstract:
A vehicle-mounted meter system includes: an inputting and outputting circuit for data measured to show a condition of the vehicle, a control circuit for controlling the system as a whole and for procession of the data, a meter main body, and a control unit detachably attached to the meter main body. The data inputting and outputting circuit is arranged on the meter main body, and the control circuit is arranged on the control unit. Preferably, the meter main body has a random bus structure corresponding to the data inputting and outputting circuit, and the bus structure has a buffer through which communication is allowed between the data inputting and outputting circuit and the control circuit.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     1. Field of the Invention  
         [0002]     The present invention relates to a meter system applicable to meters mounted in an automotive vehicle.  
         [0003]     2. Background Art  
         [0004]     A conventional vehicle-mounted meter is disclosed in Japanese Patent Application Laid-open No. 2003-194595.  FIG. 8  is an exploded perspective view showing a construction of the conventional meter. The meter has a dial plate  101 , a light guiding plate  102 , a bearing plate  103 , a fore cover  104 , a circuit board  105 , and a rear cover  106 . The dial plate  101  is elongated in a transverse direction to comply with a combination meter including meters for vehicle speed, engine revolution speed, fuel quantity, and cooling water temperature, etc. The dial plate  101  is provided with a meter scale pattern  111   a  for vehicle speed, engine revolution speed, fuel quantity, and cooling water temperature, a winker indication pattern  111   b , a warning indication pattern  111   c,  etc. The meter pattern  111   a  is provided for a speed meter, a tachometer, a fuel meter, and a water temperature meter. The light guiding plate  102  guides light emitted from a light source element to illuminate a rear face of the dial plate  101  for the speed meter and the fuel meter. The fore cover  104  is shaped like a saucer and transversely elongated to fit the dial plate  101 . The fore cover  104  is combined with the rear cover  106  so as to sandwich the circuit board  105  therebetween.  
         [0005]     The circuit board  105  has a transversely elongated shape in the same way as the dial plate  101 . The circuit board  105  has a front face arranged with a plurality of LEDs (Light Emitting Diodes)  152  to supply light for a pointer  113  and electronic parts  151  including an IC chip. The circuit board  105  has a rear face arranged with a movement  153  turning the pointer  113 . The movement  153  has a pointer shaft  153   a  penetrating through the circuit board  105  to extend forward. Similarly, another movement  153  (not shown) is provided for the fuel meter, the tachometer, and the water temperature meter respectively. The rear cover  106  has an elongated saucer shape like the fore cover  104 .  
         [0006]      FIG. 9  is a block diagram showing a general electric configuration of a meter mounted in an automotive vehicle. In  FIG. 9 , a vehicle-mounted combination meter  200  has a micro computer  201 , input terminals  202  to  205 ,  206   a  to  206   n , I/O (input/output) circuits  207  to  210 , drivers  211 ,  216 ,  220 , a speed meter  212 , a tachometer  213 , a fuel meter  214 , a water temperature meter  215 , LEDs  217   a  to  217   n , an LCD (Liquid Crystal Display)  221 , an EEPROM (Electrically Erasable Programmable Read-only Memory)  222 , etc.  
         [0007]     The micro computer  201  controls the combination meter  200  as a whole. The micro computer  201  receives vehicle speed signals (SPD) through the input terminals  202  and the I/O circuit  207 . The micro computer  201  also receives engine revolution signals (TACHO) through the input terminal  203  and the I/O circuit  208 . The micro computer  201  further receives signals of a remaining fuel quantity (FUEL) and a water temperature (TEMP) through the input terminals  204  and  205 , an I/O circuit  209 , and an A/D converter  201   a . The micro computer  201  further receives various warning signals, operation signals (PRNDL) of an automatic shift lever, etc. via the input terminals  206   a  to  206   n.    
         [0008]     The micro computer  201  controls the driver  211  to operate the speed meter  212 , the tachometer  213 , the fuel meter  214 , and the water temperature meter  215  respectively in response to input signals of vehicle speed (SPD), engine revolution speed (TACHO), remaining fuel quantity (FUEL), and cooling water temperature (TEMP), so that each meter may indicate a value corresponding to each signal. Furthermore, the micro computer  201  controls the driver  216  to turn on or off the LEDs  217   a  to  217   n  in response to signals for various warning, automatic shift lever operation (PRNDL), etc.  
         [0009]     Electric circuits for control of the micro computer  201  are incorporated in an integrated circuit board like the circuit board  105  shown in  FIG. 8  to operate each meter. The circuits are desirably connected to the meters to operate them.  
         [0010]     Meanwhile, for standardization of parts, another conventional in-vehicle combination meter has a control section such as a micro computer to control meters. The control section is separated from an indication section of vehicle speed, engine revolution speed, etc., and multiplex communication is applied for signal transmission between the control section and the indication section. Such combination meters are disclosed in Japanese patent preliminary publication No. H5-53367, Japanese patent application laid-open No. 2001-356031, and Japanese patent application No. 2002-142720.  
         [0011]      FIG. 10  is an illustration showing a configuration of a vehicle mounted combination meter disclosed in Japanese patent preliminary publication No. H5-53367. The combination meter has a main body  301  and a control circuit section  302  which are separately constructed and disposed in the vehicle.  
         [0012]     The combination meter main body  301  has a vehicle speed meter  311 , an engine revolution speed meter  312 , a cooling water temperature meter  313 , a fuel meter  314 , and a case  315  accommodating the meters. The vehicle speed meter  311 , the engine revolution speed meter  312 , the cooling water temperature meter  313 , and the fuel meter  314  have cross-coil movements  311   a  to  314   a , pointers  311   b  to  314   b , dial plates  311   c  to  314   c , and drive circuits  311   d  to  314   d  respectively. The drive circuits  311   d  to  314   d  are sequentially connected one another. The drive circuit  313   d  positioned at one end of the combination meter is connected to the control circuit section  302  through a signal cable  313 , so that data of driving signals are supplied from the control circuit section  302  to the drive circuit  313   d.    
         [0013]     The control circuit section  302  receives signals of vehicle speed, engine revolution speed, cooling water temperature, and remaining fuel quantity through electrical wires  341  to  344  from sensors (not shown) each desirably positioned in the vehicle. Based on the signals, driving data is supplied to the combination meter main body  301  through a signal cable  303 .  
         [0014]      FIGS. 11 and 12  are respectively a sectional view and a block diagram showing a configuration of a vehicle mounted combination meter disclosed in Japanese patent application laid-open No. 2001-356031. In  FIG. 11 , the combination meter has an indicator board  401 , a vehicle speed meter  402 , a tachometer  405 , a fuel meter  408  indicating a remaining quantity of fuel such as gasoline, and a water temperature meter  411 . Each meter is attached on a fore surface  401   a  of the indicator board  401 .  
         [0015]     The vehicle speed meter  402  is constituted by a stepper motor  403  and a pointer  404 . The stepper motor  403  moves the pointer  404  in response to data of vehicle speed. The tachometer  405  is constituted by a stepper motor  406  and a pointer  407 . The stepper motor  406  moves the pointer  407  in response to data of engine revolution speed. The fuel meter  408  is constituted by a fuel meter  409  and a pointer  410 . The fuel meter  409  moves the pointer  410  in response to data of remaining fuel quantity. The water temperature meter  411  is constituted by a stepper motor  406  and a pointer  407 . The stepper motor  406  moves the pointer  407  in response to data of cooling water temperature. Between each stepper motor and each pointer, there is disposed a dial plate (not shown) provided with scales, numerals, letters, or symbols to complete the meter.  
         [0016]     In the combination meter, the vehicle speed meter  402  is connected to an infrared receiver element  414  via a stepper motor driver and infrared commutation IC  415 ; the tachometer  405  is connected to an infrared receiver element  416  via a stepper motor driver and commutation IC  417 ; the fuel meter  408  is connected to an infrared receiver element  418  via a stepper motor driver and infrared commutation IC  419 ; and the water temperature meter  411  is connected to an infrared receiver element  420  via a stepper motor driver and infrared commutation IC  421 .  
         [0017]     The combination meter also has a control module  422  attached on a rear surface  1   b  of the indication board  430 . The control module  422  includes a base board on which there are disposed an IC  424  (including an interface IC  424   b , a micro computer IC  424   c , and an infrared commutation IC  424   d ) and an infrared emitting element  425  connected to each other. The IC  424  has an interface IC  424   b , a micro computer IC  424   c , and an infrared commutation IC  424   d . The control module  422  is detachably mounted on the indicator board  401  with two fasteners  423 .  
         [0018]     In  FIG. 12 , an input terminal  424   a  receives values, for example of serial data, measured by various sensors (not shown) in regard to vehicle speed, engine revolution speed, fuel temperature, and engine room temperature. The measured values are input in the micro computer IC  424   c  via the interface circuit  424   b . The micro computer IC  424   c  processes the measured values to generate data having identification codes. The data is input into the infrared communication IC  424   d  and transmitted from the infrared emitting element  425  as infrared signals.  
         [0019]     The infrared signals transmitted from the infrared emitting element  425  are received by infrared receiver elements  414 ,  416 ,  418 , and  420  to be supplied into the stepper motor driver and infrared commutation ICs  415 ,  417 ,  419 , and  421  of the stepper motors. Each of stepper motor driver and infrared commutation ICs  415 ,  417 ,  419 , and  421  selectively provides each data of vehicle speed, engine revolution speed, fuel quantity, and engine room temperature to each of the vehicle speed meter  402 , the tachometer  405 , the fuel meter  408 , and the water temperature meter  411  together with an identification code.  
         [0020]     Thus, the control module  422  is a control section that controls the various types of meters indicating measured values of the vehicle. The control module control module  422  is commonly used for the meters. The control module  422  outputs infrared commutation signals. On the indicator board  401 , there are mounted the infrared receiver elements and the infrared commutation ICs of the meters.  
         [0021]     The stepper motors  403 ,  406 ,  409 , and  412  of the vehicle speed meter  402 , the tachometer  405 , the fuel meter  408 , and the water temperature meter  411  are respectively connected to the stepper motor driver and infrared commutation ICs  415 ,  417 ,  419 , and  421 , so that the meters are controlled in response to the infrared signals supplied from the control module  422 .  
         [0022]      FIGS. 13 and 14  are respectively a block diagram and a general constitutional view of a combination meter proposed in Japanese patent application No. 2002-142720. In  FIG. 13 , the combination meter has a plurality of display units  500  and a control unit  600 . The display unit  500  is provided with a receiver  511  for receiving measurement information showing a condition of the vehicle and a driving control device  530  for controlling a driving device  540  in response to the measurement information supplied from the display side receiver  511 . The control unit  600  is provided with a transmitter  631  transmitting the measurement information to the plurality of display units  500  and a control device  611   a  for controlling transmission of the transmitter  631 , an additional information storing device  614 , a receiver  633 , and a warning device  640 .  
         [0023]     The display unit  500  further has a response signal generating device  550   a , a responding device  550   b , and a transmitter  514 . The response signal generating device  550   a  generates driving information for the driving device  540  in response to reception of the measurement information. The display side transmitter  514  transmits the driving information to the control unit  600 . The control unit  600  further has a receiver  633  and a decision device  611   b . The receiver  633  receives the driving information supplied from the display side transmitter  514 . The decision device  611   b  determines whether the driving device  540  can be controlled or not based on comparison of the driving information received by the receiver  633  with the measurement information transmitted from the control device  611   a . The control device  611   a  operates based on the determination of the decision device  611   b.    
         [0024]     As shown in  FIG. 14 , the display units  500  correspond to a vehicle speed meter, a tachometer indicating engine revolution speeds, a fuel meter indicating a remaining fuel quantity, a temperature meter indicating an engine room temperature, etc. The control unit  600  controls indication of all the display units  500 .  
         [0025]     The combination meters disclosed or proposed as mentioned above have configurations different from each other. However, each of the combination meters has a system configuration designed specifically for each car maker or for each type of cars. Thus, the combination meter requires a special design for each application, increasing a development cost. Or, minimization of the development cost decreases flexibility of meter design. Furthermore, when multi-display design with LEDs is applied for a combination meter, users cannot select freely the design of the combination meter, because the meter is specifically designed for each car.  
         [0026]     In view of the above-mentioned situation, the present invention provides a vehicle-mounted meter system having a standardized common part regardless of car types to decrease a manufacturing cost and to improve design flexibility for customization of users.  
       SUMMARY OF THE INVENTION  
       [0027]     A vehicle-mounted meter system of a first aspect of the invention includes: 
        an inputting and outputting circuit for data measured to show a condition of the vehicle,     a control circuit for controlling the system as a whole and for procession of the data, the control circuit separated from the data inputting and outputting circuit,     a meter main body having at least one measured value indication device a driving device for the indication device, and     a control unit detachably attached to the meter main body.        
 
         [0032]     The data inputting and outputting circuit is arranged on the meter main body, and the control circuit is arranged on the control unit.  
         [0033]     A vehicle-mounted meter system of a second aspect of the invention includes: 
        an inputting and outputting circuit for data measured to show a condition of the vehicle,     a control circuit for controlling the system as a whole and for procession of the data, the control circuit separated from the data inputting and outputting circuit,     a meter main body having at least one measured value indication device and a driving device for the indication device, and     a control unit detachably attached to the meter main body.        
 
         [0038]     The data inputting and outputting circuit is arranged on the control unit, and the control circuit is arranged on the meter main body.  
         [0039]     In the first and second aspect of the invention, preferably, the meter main body has a random bus structure corresponding to the data inputting and outputting circuit, and the bus structure has a buffer through which communication is allowed between the data inputting and outputting circuit and the control circuit. Thereby, signals are smoothly transmitted between the meter main body and the control circuit.  
         [0040]     A vehicle-mounted meter system of a third aspect of the invention includes: 
        a meter main body having at least one measured value indication device and a driving device for the indication device, the measured value indication device showing a measured data of a condition of an automotive vehicle, and     a control unit for controlling the system as a whole and for processing the measured data, the control unit detachably mounted on the meter main body.        
 
         [0043]     The control unit has a memory and a control circuit, the memory storing and rewriting a software program to control the system as a whole and to process the measured data, the control circuit operated by the software program.  
         [0044]     A vehicle-mounted meter system of a fourth aspect of the invention includes: 
        a meter main body having an inputting and outputting circuit for data measured by various types of sensors to know a condition of the vehicle, at least one measured value indication device for indicating the measured data, and a driving device for the indication device, and     a control unit for controlling the system as a whole and for processing the measured data, the control unit detachably mounted on the meter main body.        
 
         [0047]     The control unit has a memory and a control circuit, the memory used for storing and rewriting a software program to control the system as a whole and to process the measured data, the control circuit operated by the software program.  
         [0048]     A vehicle-mounted meter system of a fifth aspect of the invention includes: 
        a meter main body having at least one measured value indication device and a driving device for the indication device, the measured value indication device showing a measured data of a condition of the vehicle, and     a control unit detachably mounted on the meter main body.        
 
         [0051]     The control unit has a data inputting and outputting circuit and a memory, the data inputting and outputting circuit transmitting data measured by various types of sensors to know a condition of the vehicle, the memory used for storing and rewriting a software program to control the system as a whole and to process the measured data. The meter main body has a control circuit operated by the software program so that the control circuit controls the system as a whole and to process the measured data.  
         [0052]     Preferably, wire or wireless signal transmission is applied between the meter main body and the control unit.  
         [0053]     Preferably, the control unit is a card-typed one, which can be handled with ease.  
         [0054]     Preferably, the card-typed unit is a PC card in which a software program can be easily rewritten by a computer.  
         [0055]     In the first and second aspects of the invention, the data inputting and outputting circuit is arranged on the meter main body as an independent circuit, while the control circuit is arranged on the control unit detachably attached to the meter main body. Thus, the circuit board mounted on the meter main body is simplified in layout without a control circuit, decreasing a manufacturing cost. Furthermore, the control unit separately arranged from the meter main body, allowing standardized multi-types of control units having different functions even for a combination meter of a higher quality.  
         [0056]     In the third to fifth aspects of the invention, vehicle-mounted meter systems are designed so as to have a common part or device to decrease a development cost of the vehicle-mounted meter systems. Furthermore, the meter main body can have an indication pattern to comply with user&#39;s request, and many types of vehicle-mounted meter systems even of a high grade or design can be provided with a less cost. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0057]      FIG. 1  is a general constitutional view showing a vehicle-mounted meter system according to the present invention;  
         [0058]      FIG. 2  is a general configuration showing a vehicle-mounted meter system particularly with electrical configuration according to the present invention;  
         [0059]      FIG. 3  is a block diagram showing an electrical configuration of a PC card according to the present invention;  
         [0060]      FIG. 4  is a block diagram showing a detailed electrical configuration of a vehicle-mounted meter system according to the present invention;  
         [0061]      FIG. 5  is a block diagram showing a detailed electrical configuration of another vehicle-mounted meter system according to the present invention;  
         [0062]      FIG. 6  is a block diagram showing a detailed electrical configuration of further another vehicle-mounted meter system according to the present invention;  
         [0063]      FIG. 7  is a block diagram showing a detailed electrical configuration of further another vehicle-mounted meter system according to the present invention;  
         [0064]      FIG. 8  is an exploded perspective view showing a conventional combination meter mounted in an automotive vehicle;  
         [0065]      FIG. 9  is a block diagram showing a general electrical configuration of a vehicle-mounted conventional combination meter;  
         [0066]      FIG. 10  is an illustration showing another conventional combination meter mounted in an automotive vehicle;  
         [0067]      FIG. 11  is a sectional view showing a constitution of further another conventional combination meter mounted in an automotive vehicle;  
         [0068]      FIG. 12  is a block diagram showing the conventional combination meter of  FIG. 11 ;  
         [0069]      FIG. 13  is a block diagram showing a general configuration of a vehicle-mounted combination meter precedently proposed by the same applicant as the present application; and  
         [0070]      FIG. 14  is a block diagram showing the combination meter of  FIG. 13 . 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0071]     Referring to the accompanied drawings, embodiments of a vehicle-mounted meter system according to the present invention will be discussed.  
         [0072]      FIG. 1  is a general constitutional view showing a vehicle-mounted meter system according to the present invention. A vehicle-mounted meter system  1  according to the present invention has a combination meter main body (meter unit)  2 . In a front side of the combination meter unit  2 , there are arranged a plurality of meters and a display  7  of LED (liquid crystal display) or the like. The meters includes a vehicle speed meter  3 , a tachometer  4  indicating an engine revolution speed, and a fuel meter  5  indicating a remaining quantity of a fuel like gasoline. Furthermore, in the front side of the combination meter unit  2 , a connector  8  is provided under the display  7  for detachable connection with a control unit  10 .  
         [0073]     The control unit  10  is a card type one such as a PC card of an ATA standard. The PC card complies with a PC card standard agreed by JEIDA and PCMCIA. The PC card is an information medium applicable to a compact information unit like a note-type personal computer  11 . The PC card is the same size as a credit card. ATA (AT attachment) is a standard of ANSI (American National Standards Institute), which is associated with E-IDE (Enhanced Intelligent Drive Electronics) standard of a hard disk. Hereafter, the control unit  10  is called as PC card  10 .  
         [0074]     The PC card  10  serves to control operation of the combination meter unit  2  as a whole. The PC card  10  is inserted into the connector  8  to enable indication of each meter of the combination meter unit  2 . The PC card  10  is drawn out from the connector  8  and can be rewritten in specifications selectable for users by a personal computer  11 . Meanwhile, basic functions of the meters are sets not to be rewritten.  
         [0075]      FIG. 2  is a general configuration showing a vehicle-mounted meter system particularly in electrical configuration according to the present invention. In a rear side of the combination meter unit  2 , there is arranged a mother board  12 . The mother board  12  has a connector  8 , a wiring harness connector  14 , and an EEPROM (Electrically Erasable, Programmable, Read-only Memory)  13 . The mother board  12  also has circuits for electrical connection from the connector  8  to the vehicle speed meter  3 , the tachometer  4 , the fuel meter  5 , the water temperature meter  6 , the EEPROM  13 , a display  15 , and an LED  16 .  
         [0076]      FIG. 3  is a block diagram showing an electrical configuration of the PC card  10  according to the present invention. The PC card  10  includes a micro computer (hereafter called as CPU)  10   a  of a control means, a flush memory  10   b  of a storage means, interface switching circuits  10   c ,  10   f , a meter interface circuit  10   d , a PC interface circuit  10   e , and a connector  10   g . The flash memory  10   b  stores and rewrites functional specifications of the combination meter unit  2  with a software program so that the CPU  10   a  controls operation of the meter system  1  as a whole. The operation includes indication of each meter.  
         [0077]     The PC card  10  can switch interface circuits for the personal computer  11  and the combination meter unit  2  by a hand switch or an automatic switch. The automatic switch operates in response to insertion of the card into the connector  8  or to reception of associated code signals.  
         [0078]     Insertion of the PC card  10  into the connector  8  of the combination meter unit  2  switches the interface switching circuits  10   c ,  10   f  to connect to the meter interface circuit  10   d , so that the CPU  10   a  can control each meters. Disengagement of the PC card  10  from the connector  8  switches the interface switching circuits  10   c ,  10   f  to correspond to the PC interface circuit  10   e , and the PC card  10  is received in a connector of the personal computer  11  so that the personal computer  11  can modify data indication of each meter.  
         [0079]     Thus, the flash memory  10   b  of the PC card  10  can be rewritten for another meter function so that the same PC card  10  can be applied to another vehicle-mounted meter system. This reduces a manufacturing cost and shortens a delivery time of vehicle-mounted meter system, providing an advantage in market competition of the vehicle-mounted meter system. Users can select desirably modifications or functional developments of meter display patterns, improving the vehicle-mounted meter system in quality.  
         [0080]      FIG. 4  is a block diagram showing a detailed electrical configuration of a vehicle-mounted meter system according to the present invention. In  FIG. 4 , a PC card  10  is the same as that of  FIG. 3 . The combination meter unit  2  has a bus line  20  for signal transmission with the connector  10   g  of the control unit  10 , commutation and driving circuits  21  to  26  communicating with the bus line  20 , a communication I/O circuit  27 , an A/D conversion and communication circuit  28 , and an EEPROM  13 .  
         [0081]     The communication and driver circuit  21  supplies vehicle speed data to drive the vehicle speed meter  3 . The communication and driver circuit  22  supplies engine revolution speed data to drive the tachometer  4 . The communication and driver circuit  23  supplies remaining fuel quantity data to drive the fuel meter  5 . The communication and driver circuit  24  supplies cooling water temperature data to drive the temperature meter  6 . The communication and driver circuit  25  supplies subsidiary information to the display  15 . The communication and driver circuit  26  supplies data for various warnings and for operation step indication of an automatic shift lever to LEDs  16   a  to  16   n.    
         [0082]     The communication I/O circuit  27  transmits measured data to the bus line  20 . The data includes signals measured by various types of desirably arranged sensors. The data is converted in digital data with regard to vehicle speed (SPD), engine revolution speed (TACHO), etc. The data transmitted from the communication I/O circuit  27  is input to the CPU  10   a  from the bus line  20  via the connector  10   g , the interface switching circuit  10   f , the meter interface circuit  10   d , and the interface switching circuit  10   c . The data is processed to be changed into indication data. The indication data of vehicle speed is transmitted from the CPU  10   a  to the communication and driver circuit  21  via the interface switching circuit  10   c , the meter interface circuits  10   d , the interface switching circuit  10   f , the connector  10   g , and the bus line  20 . The indication data of engine revolution speed is transmitted from the CPU  10   a  to the communication and driver circuit  22  via the interface switching circuit  10   c , the meter interface circuit  10   d , the interface switching circuit  10   f , the connector  10   g , and the bus line  20 .  
         [0083]     The A/D conversion and communication circuit  28  converts measured data to transmit it to the bus line  20 . The data includes information of remaining fuel quantity (FUEL) and cooling water temperature (TEMP). The data transmitted from the A/D conversion and communication circuit  28  is input to the CPU  10   a  from the bus line  20  via the connector  10   g , the interface switching circuit  10   f , the meter interface circuit  10   d , and the interface switching circuit  10   c . The data is processed to become data for indication.  
         [0084]     The indication data of remaining fuel quantity (FUEL) is transmitted from the CPU  10   a  to the communication and driver circuit  23  via the interface switching circuit  10   c , the meter interface circuit  10   d , the interface switching circuit  10   f , the connector  10   g , and the bus line  20 . The indication data of cooling water temperature (TEMP) is transmitted from the CPU  10   a  to the communication and driver circuit  24  via the interface switching circuit  10   c , the meter interface circuit  10   d , the interface switching circuit  10   f , the connector  10   g , and the bus line  20 .  
         [0085]     Next, operation of thus configured vehicle-mounted meter system  1  will be discussed. The flash memory  10   b  of the PC card  10  stores a basic data and a software program to operate meters arranged in the combination meter unit  2 . The basic data and the software program are preliminarily stored in the PC card  10  from the personal computer  11  ( FIG. 1 ) via the PC interface circuit  10   e , while the PC card  10  is received in the personal computer  11 . The personal computer  11  can switch the interface switching circuits  10   c ,  10   f  toward the PC interface circuit  10   e.    
         [0086]     Then, the PC card  10  having stored the basic data and the software program is inserted in the connector  8  of the combination meter unit  2 . The insertion of the PC card  10  can automatically switch the interface switching circuits  10   c  and  10   f  toward the meter interface circuit  10   d.    
         [0087]     Consequently, digital input signals of vehicle speed, engine revolution speed, remaining fuel quantity, cooling water temperature, etc. are transmitted into the CPU  10   a  of the PC card  10  by means of multiple communication via the bus line  20  and the communication I/O circuit  27  or the A/D conversion and communication circuit  28 . Similarly, subsidiary information and warning signals showing vehicle conditions are transmitted into the CPU  10   a  of the PC card  10  by means of multiple communication from the connector  10   g  via the bus line  20  and the communication and driver circuit  26 .  
         [0088]     The CPU  10   a  processes the digital input signals of vehicle speed, engine revolution speed, remaining fuel quantity, cooling water temperature, etc. The processed signals are output respectively to the communication and driver circuits  21  to  24  via the bus line  20  for indication of each of the meters 3 to 6. The subsidiary information showing vehicle conditions is processed by the CPU  10   a , and the processed date is output to the communication and driver circuit  25  via the bus line  20  for indication in the display  15 . The warning signals are processed by the CPU  10   a , and the processed date is output to the communication and driver circuit  26  via the bus line  20  so that each of LEDs  16   a  to  16   n  lights for warning in response to each of the signals.  
         [0089]     Thus configured vehicle-mounted meter system  1  shown in  FIG. 4  has the PC card  10  (control unit) provided with control circuits and input/output circuits. The PC card  10  is electrically connected to the drivers and I/O circuits arranged in the combination meter unit  2 . Some of the measured signals are transmitted to some of the meters as digital ones via the communication I/O circuit  27 , while the others are transmitted to the other meters via the A/D converter and communication circuit  28 .  
         [0090]      FIG. 5  is a block diagram showing a detailed electrical configuration of another vehicle-mounted meter system according to the present invention. In  FIG. 5 , a control unit  10  has a configuration the same as that of  FIG. 3 . The combination meter unit  2  has an I/O system  30  for signal transmission with the connector  10   g  of the control unit  10 , a bus line  20  of a random bus construction corresponding to I/O circuits, commutation and driving circuits  21  to  27 , and an EEPROM  13 .  
         [0091]     The I/O system  30  has I/O circuits  31   a  to  31   n  and an A/D converter  29  to serve as input/output means. The I/O circuits  31   a  to  31   n  transmit signals between the connector  10   g  and the bus line  20 . The I/O circuits  31   a  to  31   n  also output driving signals to the communication and driver circuits  21  to  26  and input digital signals to the connector  10   g  via the communication I/O circuit  27 . The A/D converter  29  converts analogue signals of remaining fuel quantity, cooling water temperature, etc. to digital ones to supply them to the connector  10   g.    
         [0092]     Thus configured vehicle-mounted meter system  1  shown in  FIG. 5  has the PC card  10  (control unit) provided with control circuits (CPU  10   a ) and the user setting memory  10   b . The vehicle-mounted meter system  1  also has the combination meter unit  2  provided with the I/O system  30 . The I/O system  30  includes the A/D converter  29  and the I/O circuits  31   a  to  31   n . The I/O system  30  is positioned in the combination meter unit  2  and separated from the CPU  10   a  of the control unit  10 , so that the CPU  10   a  can have more flexibility than that of  FIG. 4 .  
         [0093]      FIG. 6  is a block diagram showing a detailed electrical configuration of further another vehicle-mounted meter system according to the present invention. In  FIG. 6 , a control unit  10  has an I/O system  30  in addition to the PC card of  FIG. 3 . A combination meter unit  2  has a CPU  10   a , a bus line  20 , driving circuits  21  to  26 , a communication I/O circuit  27 , an I/O circuit  32 , a vehicle speed meter  3 , and an EEPROM  13 .  
         [0094]     The I/O system  30  includes I/O circuits  31   a  to  31   n  and an A/D converter  29 . The I/O circuits  31   a  to  31   n  transmits signals between the connector  10   g  and the bus line  20 . The A/D converter  29  converts analogue signals of remaining fuel quantity, cooling water temperature, etc. to digital ones to supply them to the connector  10   g.    
         [0095]     That is, the vehicle-mounted meter system shown in  FIG. 6  has the card unit  10  provided with I/O circuits.  
         [0096]     In the aforementioned embodiments, the vehicle-mounted meter systems are designed so as to have a common part or device to decrease a development cost of the vehicle-mounted meter systems. Furthermore, the combination meters can have indication patterns to comply with users&#39; requests, and many types of vehicle-mounted meter systems even of a high grade or design can be provided with a less cost.  
         [0097]     The present invention is not limited in the embodiments discussed above but may be modified variously.  
         [0098]     For example, wireless transmission may be applied between the combination meter unit  2  and the control unit  10  in place of the wire transmission of the embodiments discussed above.  
         [0099]      FIG. 7  is a block diagram showing a detailed electrical configuration of further another vehicle-mounted meter system according to the present invention. In  FIG. 7 , a control unit  10  has a radio transmission section  40  in place of the connector  10   g , and the combination meter unit  2  has a radio transmission section  50  in place of the connector  8 . The radio transmission section  40  includes an antenna  40   a , an I/O circuit  40   b  with modulation capability, a register  40   c , and a battery  40   d  such as a solar cell. The radio transmission section  50  includes an antenna  50   a , an I/O circuit  50   b  with modulation capability, and a register  50   c.    
         [0100]     In this configuration, wireless transmission supplies various signals from the combination meter unit  2  to the control unit  10  via the register  50   c , the I/O circuit  50   b , and the antenna  50   a . The transmitted signals are received by the radio transmission section  40  of the control unit  10  to be delivered to a CPU  10   a  via the I/O circuit  40   b  and the register  40   c.    
         [0101]     Meanwhile, signals that have been processed by the CPU  10   a  return from the control unit  10  to the combination meter unit  2  via the register  40   c , the I/O circuit  40   b , and the antenna  40   a  by wireless transmission. The processed signals are received by the radio transmission section  50  of the combination meter unit  2  and then are supplied to each of the communication and driver circuits via the antenna  50   a , the I/O circuit  50   b , and the register  50   c.    
         [0102]     The wireless data transmission between the combination meter unit  2  and the control unit  10  allows the control unit control unit  10  to be freely positioned. The control unit  10  can advantageously handled when rewritten with a software program.