Patent Publication Number: US-2011072176-A1

Title: Meter system with master/slave meters

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a meter system, and more particularly, to a meter system with master/slave meters. 
     2. Description of the Prior Art 
     Generally, a conventional digital meter often utilizes a serial peripheral interface (SPI) bus to transmit data. Because each device coupled to the SPI bus has to be set an address by the manufacturer, when the device, such as a digital meter, needs to be modified or a vehicle needs to be exchanged the digital meter, the address of the digital meter is utilized unfavorably and inconveniently. Besides, the SPI bus is limited to the SPI communication protocol, so that the SPI bus is unable to transmit a great quantity of data and only transmits a common control signal, such as the control signal for EEPROM, Flash, a clock, an AD inverter, and so on. The SPI bus does not have a flow control function, which means a host can not detect whether a salve device coupled to the SPI bus is in busy or in free. Additionally, the SPI bus does not have an ACK responding mechanism. Therefore, the SPI bus is mainly used to a single meter system and unsuitable to a multi-meter system. 
     In addition, the meter system including a built-in communication network system is developing, such as a vehicle communication network utilized in a vehicle meter system. Furthermore, the meter system trends toward a digital system. The manufacturer of the meter system has to set not only parameters as mentioned above, but also resolution of sensing signals, configuration of meter parameters, specification of a sensing signal, and so on before the meter system leaves the factory. Therefore, the meter system is manufactured and designed complicatedly. 
     SUMMARY OF THE INVENTION 
     The present invention provides a meter system with master/slave meters for solving above drawbacks. 
     According to the claimed invention, the meter system includes a controller area network bus (CAN-Bus) for transmitting a CAN-Bus signal, a master meter coupled to the CAN-Bus, a slave bus coupled to the master meter, and a slave meter. The master meter includes a first controller area network (CAN) module coupled to the CAN-Bus for receiving the CAN-Bus signal transmitted from the CAN-Bus and for transforming the CAN-Bus signal into a message signal, a master instrument panel, a master communication interface, and a master processor coupled to the first CAN module, the master instrument panel, and the master communication interface for receiving the message signal to control the master instrument panel to show information corresponding to the message signal or to transmit the message signal to the master communication interface. The slave bus is for receiving the message signal transmitted from the master communication interface of the master meter. The slave meter includes a slave communication interface coupled to the slave bus for receiving the message signal transmitted from the slave bus, a slave instrument panel, and a slave processor coupled to the slave communication interface and the slave instrument panel for receiving the message signal transmitted from the slave communication interface and for controlling the slave instrument panel to show the information corresponding to the message signal. 
     According to the claimed invention, the meter system further includes a processing device coupled to the master mater and the slave meter for setting parameters of the master meter and the slave meter. The processing device utilizes a parameter setting bus to set initial functional parameters and application layer protocol parameters of the master meter and the slave meter via a parameter setting interface. 
     According to the claimed invention, the meter system utilizes the CAN-Bus to transmit the signal between the master meter and the slave meter and sets the parameters with the parameter setting interface of the processing device. Therefore, the meter system is compatible with meters with different specifications so as to form a complete meter system with master/slave meters. 
     These and other objectives of the present invention will no doubt become obvious to those of ordinary skill in the art after reading the following detailed description of the preferred embodiment that is illustrated in the various figures and drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a diagram of a meter system according to a preferred embodiment of the present invention. 
         FIG. 2  is a diagram of connection between a master instrument panel and a slave instrument panel according to the preferred embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION 
     Please refer to  FIG. 1 .  FIG. 1  is a diagram of a meter system  10  according to a preferred embodiment of the present invention. The meter system  10  can be suitable for various transportation, such as vehicles and carriers having meters. The meter system  10  includes a controller area network bus (CAN-Bus)  12  for transmitting a CAN-Bus signal, and a master meter  14  coupled to the CAN-Bus  12 . The master meter  14  includes a first CAN module  16  coupled to the CAN-Bus  12  for receiving the CAN-Bus signal transmitted from the CAN-Bus  12  and for transforming the CAN-Bus signal into a message signal, a master instrument panel  18 , a master communication interface  20 , and a master processor  22  coupled to the first CAN module  16 , the master instrument panel  18 , and the master communication interface  20  for receiving the message signal to control the master instrument panel  18  to show information corresponding to the message signal or to transmit the message signal to the master communication interface  20 . The meter system  10  further includes a slave bus  24  coupled to the master communication interface  20  of the master meter  14  for receiving the message signal transmitted from the master communication interface  20  of the master meter  14 , and a slave meter  26  coupled to the slave bus  24 . The slave meter  26  includes a slave communication interface  28  coupled to the slave bus  24  for receiving the message signal transmitted from the slave bus  24 , a slave instrument panel  30 , and a slave processor  32  coupled to the slave communication interface  28  and the slave instrument panel  30  for receiving the message signal transmitted from the slave communication interface  28  to control the slave instrument panel  30  to show the information corresponding to the message signal. The master communication interface  20  of the master meter  14  can conform to an inter-integrated circuit (I 2 C) communication interface. The master processor  22  of the master meter  14  can control an input/output pin to simulate a I 2 C signal so as to simulate a function of the I 2 C communication interface. 
     In addition, the meter system  10  can further include a processing device  34  coupled to the master mater  14  and the slave meter  26  for setting parameters of the master meter  14  and the slave meter  26 . The processing device  34  sets the parameters of initial functions and application layer protocol of the master meter  14  and the slave meter  26  with a parameter setting interface  36 . The processing device  34  includes a memory module  38  for storing the parameters of the master meter  14  and the slave meter  26  so as to provide the parameters for the parameter setting interface  36  to set the master meter  14  and the slave meter  26 . The parameter setting bus  36  can conform to a CAN-Bus communication interface, the inter-integrated circuit communication interface, or a universal asynchronous receiver-transmitter interface. 
     The master meter  14  can further include at least one signal slot  40  coupled to at least one sensor  42  for receiving a sensing signal of the sensor  42  and for transmitting the sensing signal of the sensor  42  to the master processor  22 . The sensing signal of the sensor  42  can be an analog signal, a digital signal, a frequency signal, a phase signal, and so on. The master meter  14  can further include a master memory module  44  coupled to the master communication interface  20  for storing vehicle driving data. The master instrument panel  18  of the master meter  14  includes a screen  46  for showing a graph or a numeral so as to represent the information corresponding to the message signal. The master instrument panel  18  of the master meter  14  can further include an indicator mechanism  48  driven by a stepping motor for utilizing a pulse width modulation signal to drive the stepping motor. The master instrument panel  18  of the master meter  14  can further include a light emitting diode unit  50  for showing the information corresponding to the message signal by varying intensity of colors. Methods of showing the information by the master instrument panel  18  are not limited to the above-mentioned embodiment and depend on actual demand. 
     The slave meter  26  can further include a slave memory module  52  coupled to the slave processor  32  for storing an identification code. The slave processor  32  is for reading the identification code so as to analyze the received message signal. The slave communication interface  28  of the slave meter  26  can conform to an I 2 C communication interface. The slave processor  32  of the slave meter  26  can control an input/output pin to simulate an I 2 C communication interface signal so as to simulate a function of the I 2 C communication interface. The salve instrument panel  30  of the slave meter  26  includes a screen  54  for showing a graph or a numeral so as to represent the information corresponding to the message signal. The slave instrument panel  30  of the slave meter  26  further includes an indicator mechanism  56  driven by a stepping motor for utilizing a pulse width modulation signal to drive the stepping motor. The slave instrument panel  30  of the slave meter  26  can further include a light emitting diode unit  58  for showing the information corresponding to the message signal by varying intensity of colors. Methods of showing the information by the slave instrument panel  30  are not limited to the above-mentioned embodiment and depend on actual demand. 
     In addition, the meter system  10  can further include a vehicle communication network  60  and a second CAN module  62  coupled to the vehicle communication network  60  and the CAN-Bus  12 . The second CAN module  62  can transform a signal transmitted from the vehicle communication network  60  into the CAN-Bus signal and transmit the CAN-Bus signal to the CAN-Bus  12 . The vehicle communication network  60  can conform to a vehicle communication protocol network, such as a media oriented system transport (MOST) network, a X-by-Wire network, a local interconnect (LIN) network, and so on. The vehicle communication network  60  can be substituted by a vehicle wireless system module, such as a global position system (GPS) unit, a Zigbee wireless network unit, and so on. The vehicle communication network  60  can further be substituted by an on board diagnostics module, and so on. 
     As mentioned above, because the vehicle communication network  60  transmits the signal to the CAN-Bus  12  with the second CAN module  62 , the master meter  14  can receive the CAN-Bus signal corresponding to data generated by the vehicle communication network  60  with the first CAN module  16  coupled to the CAN-Bus  12 , and transform the CAN-Bus signal into the corresponding message signal to control the master instrument panel  18  to show the information corresponding to the message signal. Besides, the master meter  14  can receive a general sensing signal of the sensor  42  coupled to the signal slot  40  and control the master instrument panel  18  to show the information corresponding to the sensing signal of the sensor  42 . The master instrument panel  18  can show the information generated by the vehicle communication network  60  and the sensor  42  via the CAN-Bus  12  and the signal slot  40 . 
     Furthermore, when the master processor  22  analyzes that the signal transmitted from the CAN-Bus  12  or the signal slot  40  does not conform to a specification of the master instrument panel  18 , the master communication interface  20  can transmit the signal to the slave communication interface  28  of the slave meter  26  via the slave bus  24  and control the slave instrument panel  30  to show the information corresponding to the signal transmitted from the CAN-Bus  12  or the signal slot  40 . The meter system  10  can utilize the parameter setting interface  36  of the processing device  34  to set the parameters corresponding to different master/slave meters, such as meter parameters, manufacturer data, communication port, CAN parameters, and so on, via a parameter setting bus  39 . The function module connected to the CAN-Bus  12  and the slave bus  24  of the present invention are not limited to the above-mentioned components, the function module capable of transmitting the signal via the CAN-Bus  12  and the slave bus  24  is within the scope of the present invention. 
     Please refer to  FIG. 1  and  FIG. 2 .  FIG. 2  is a diagram of connection between the master instrument panel  18  and the slave instrument panel  30  according to the preferred embodiment of the present invention. The master meter  14  can transmit the CAN-Bus signal by coupling to the CAN-Bus  12  and transmit the sensing signal of the sensor  42  by coupling to the signal slot  40 . Therefore, the master meter  14  can show the information corresponding to part of the signal on the master instrument panel  18  and transmit the other CAN-Bus signal or the sensing signal to the slave meter  26  via the slave bus  24 , so that the slave instrument panel  30  can show the corresponding information. The master instrument panel  18  can be selected from a group consisting of a speedometer, a tachometer, a fuel level meter, a coolant water temperature meter, an oil pressure meter, a voltmeter, an ammeter, a vacuum gauge, an alarm indicator, and combination thereof. The salve instrument panel  30  can be selected from a group consisting of a speedometer, a tachometer, a fuel level meter, a coolant water temperature meter, an oil pressure meter, a voltmeter, an ammeter, a vacuum gauge, an alarm indicator, and combination thereof. Collocation of the master instrument panel  18  and the slave instrument panel  30  can be designed according to the actual demand. 
     Comparing to the prior art, the master meter of the meter system of the present invention not only can utilize the CAN-Bus to transmit the CAN-Bus signal, but also can utilize the signal slot to transmit the sensing signal of the sensor, so as to transmit signals effectively and to solve drawbacks of information exchange of conventional electronic modules. The master meter and the slave meter have the communication interfaces with same specification and couple to the slave bus, respectively, so that the master meter and the slave meter can transmit the signal with each other via the slave bus. In addition, the meter system of the present invention can set the parameters of the master meter and the slave mater with the parameter setting interface of the processing device, so as to decrease complexity of the post production of the meter system and working hours of assembly and setting. 
     Those skilled in the art will readily observe that numerous modifications and alterations of the device and method may be made while retaining the teachings of the invention.