JP2011151622A - Communication system, communication device, and communication method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a communication system, device and method, allowing the communication devices to have the same configuration without giving identification information peculiar to each communication device, and reducing man-hours. <P>SOLUTION: Each of input/output devices 2a, 2b, 2c cuts off switches 201a, 201b, 201c of first paths of connection switching parts 20a, 20b, 20c, measures a current value I in input current values I<SB>1</SB>, I<SB>2</SB>, I<SB>3</SB>and each resistor R in the state where switches 202a, 202b, 202c connected to the resistor R connected to a second path in parallel with the first path are connected, and determines a self-address from the current value. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a communication system including a plurality of communication devices, and in particular, a communication system, a communication device, and a communication device that can be identified without giving unique identification information to each communication device, have the same configuration, and can reduce man-hours. It relates to a communication method.

  In recent years, control systems that control a large number of devices and realize various functions as a whole have become widespread. A control device for controlling each device is connected to each device, and each control device is provided with a communication means to exchange data with each other so that each control device does not perform independent control, but other control devices, etc. It is realized as a communication system that executes control in cooperation, such as controlling a device to be controlled corresponding to itself based on data obtained through the network, and is used in various fields.

  In such a system, as the function increases, the number of devices to be controlled increases, and the number of devices such as sensors that acquire or measure data used for control also increases. Especially in the field of vehicles, a lot of devices such as actuators or sensors corresponding to various functions are arranged in the vehicle, and an ECU (Electronic Control Unit) is arranged corresponding to each as a control device for controlling each device. Operates by sending and receiving data to and from each other.

  In a communication system in which a large number of control devices each have a communication function and cooperate as a communication device, unique identification information is set in advance and stored in its own memory, and when each communication device transmits data, It has been configured to transmit identification information. Thereby, when each communication device transmits data, it transmits both its own identification information stored as the transmission source and the identification information of the destination device. Thereby, it is possible to determine whether each device is data addressed to itself and to recognize the identification information of the device that is the data transmission source.

  However, in the conventional method, it takes time to set and store unique identification information in advance. In addition, when a large amount of control devices are required, unique identification information must be set for each, and the information amount of the identification information becomes enormous.

  Therefore, in Patent Document 1, a plurality of communication devices connected in a ring type or daisy chain type connection form can specify mutual addresses without setting their own identification information. The invention is disclosed. In this invention, a plurality of communication devices are composed of one master and a plurality of slaves. When the master transmits an arbitrary address value X, each slave adds a fixed value to the address value X and transfers it. Thereby, each apparatus recognizes it as its own address value based on the received address value or the transmitted address value. Also, the master can recognize the number of slaves based on the address value after being transmitted to all devices. Thereby, even if the identification information is not set in advance, the plurality of communication devices can recognize each other. Therefore, the communication device can be manufactured with the same configuration, and is suitable for mass production.

  Non-Patent Document 1 discloses identification when a single-wire serial bus protocol such as DSI or ASRB2.0 or a half-duplex communication protocol is used between a plurality of communication devices including one master and a plurality of slaves. A method for setting information is disclosed. In order to eliminate the need for fixed information as identification information (ID) of each slave, the master is connected in a chained manner, and the ID is assigned according to the connection order.

Japanese Patent Laid-Open No. 3-72740

freescale, “DSI Bus Standard”, ver.2.02, March 29, 2005, [online], [search August 7, 2009], Internet <URL: http://www.freescale.com/files /analog/doc/support_info/dsibusstandard.pdf>

  According to the inventions disclosed in Patent Literature 1 and Non-Patent Literature 1, connection processing is sequentially performed in a state after each communication device is actually connected to a communication line without setting unique identification information in advance. By performing data transmission / reception processing, identification information can be given to each communication device and used during communication.

  However, sequential processing such as connection processing or data transmission / reception processing is required. There is a demand for further simplification of communication devices, and it is desirable that the steps can be omitted as much as possible in order to reduce costs.

  The present invention has been made in view of such circumstances. A communication system, a communication apparatus, and a communication that can be identified without giving unique identification information to each communication apparatus, have the same configuration, and can reduce man-hours. It aims to provide a method.

  A communication system according to a first aspect of the present invention is a communication system in which one master communication device and a plurality of slave communication devices communicate in a daisy chain connection with the master communication device as a base, and each slave communication device has a first switch. Including the first path and the other adjacent communication devices connected by the parallel circuit of the second path, one end of which is connected to the other end of the resistor connected to the fixed potential via the second switch. The connection point, the switching means for complementarily switching the connection and disconnection of the first and second switches, and the first switch is in the disconnected state and flows to the input terminal of the slave communication device when the second switch is in the connected state A measuring means for measuring a first current value and a second current value flowing through the resistor, and a decision to determine identification information of itself based on the measured first current value and second current value. And means, the resistance value of the resistance of each slave communication device is characterized in that substantially equal.

  In the communication system according to a second aspect of the present invention, the master communication device includes a means for transmitting a detection instruction and a means for outputting a predetermined current value, and when each slave communication apparatus receives the detection instruction, the switching is performed. The first switch is disconnected by means, the second switch is connected, and the identification information is determined by measuring the first current value and the second current value.

  In the communication system according to the third invention, the determining means of each slave communication device is means for calculating a value obtained by dividing the first current value by the second current value, and subtracting the calculated value from a predetermined value. The determined value is determined as identification information.

  A communication system according to a fourth aspect of the present invention is a communication system in which one master communication device and a plurality of slave communication devices are connected in a daisy chain manner with the master communication device as a base, and the plurality of slave communication devices are respectively A switching means for switching connection and disconnection of the switch, comprising a connection point with each of other adjacent communication devices connected by a parallel circuit of a first path including a switch and a second path including a capacitor; Means for measuring the potential difference in the capacitor caused by the voltage supplied from the master communication device side and the potential at the contact point, and determining the identification information of itself based on the measured potential difference and potential And the capacities of the capacitors of the slave communication devices are substantially equal. To.

  In a communication system according to a fifth aspect, the master communication device includes means for transmitting a detection instruction to each slave communication device and means for outputting a predetermined voltage value, and each slave communication device receives the detection instruction. In this case, the switch is disconnected by the switching means and the potential difference and potential are measured to determine the identification information.

  In the communication system according to the sixth aspect of the invention, the determining means of each slave communication device identifies a value obtained by dividing the measured potential by the potential difference, and a value obtained by subtracting the calculated value from a predetermined numerical value It is characterized by being determined as information.

  According to a seventh aspect of the present invention, there is provided a communication device including: a first path including a first switch; and a second path parallel circuit having one end connected to a fixed potential connected to a fixed potential via the second switch. A connection point with each of the other connected communication devices, a switching means for complementarily switching connection and disconnection of the first and second switches, a first switch in a disconnected state, and a second switch in a connected state Based on the measurement means for measuring the first current value flowing through the second path and the second current value flowing through the resistor at a certain time, and its own identification information is determined based on the measured first current value and second current value. Means.

  According to an eighth aspect of the present invention, there is provided a communication device that switches connection and disconnection between a connection point with each of other communication devices connected by a parallel circuit of a first path including a switch and a second path including a capacitor. Switching means; means for measuring a potential difference in the capacitor when the switch is in a disconnected state; and a potential at the contact; and a determination means for determining identification information of itself based on the measured potential difference and potential. It is characterized by.

  In the communication method according to the ninth aspect of the present invention, one master communication device and a plurality of slave communication devices are daisy chain connected with the master communication device as a base point, and each of the plurality of slave communication devices includes a first switch. And a connection point with each of the other adjacent communication devices connected by the parallel circuit of the second path, the other end of which is connected to the other end of the resistor connected to the fixed potential via the second switch. The resistance of each slave communication device is substantially equal, and the communication device performs communication based on its own identification information determined, wherein the plurality of slave communication devices are connected to a first switch and connected to the first switch. 2 The switch is disconnected, the master communication device transmits a detection instruction to the connected slave communication device, outputs a predetermined current value, and each slave communication device According to the instruction, the first switch is disconnected, the second switch is connected, the first current value flowing through the second path and the second current value flowing through the resistor are measured, and the measured first current value and second current value are measured. Based on the above, it is characterized by determining its own identification information.

  In the communication method according to the tenth aspect of the present invention, one master communication device and a plurality of slave communication devices are daisy chain connected with the master communication device as a base point, and the plurality of slave communication devices each include a first path including a switch, and Each having a connection point with each of the other adjacent communication devices connected by the parallel circuit of the second path including the capacitor, the capacity of the capacitor of each slave communication device is substantially equal, and each communication device is determined A communication method for performing communication based on identification information, wherein the plurality of slave communication devices are connected to the switch, and the master communication device transmits a detection instruction to the connected slave communication device, A predetermined voltage value is output, and each slave communication device disconnects the first switch according to the received detection instruction, the potential difference in the capacitor, and Measuring the potential at the contact, based on the measured potential difference and the potential, and determines the own identification information.

In the present invention, a master communication device and a plurality of slave communication devices are connected in a daisy chain type with the master communication device as a base point, and each slave communication device is connected to the master communication device or another slave communication device. Provide contacts. The two contacts for connecting to the outside are also connected to each other via two parallel paths (first path and second path). The first path includes a first switch for switching the connection or disconnection, and one end of a resistor having a resistance value substantially equal to that of another slave communication device having the same configuration is connected to the second path. One switch is connected to a fixed potential through a second switch that is in a complementary relationship.
As a result, while switching to the connection by the first switch (while the second switch is disconnected), the two contacts are directly connected internally, and the master communication device and the plurality of slave communication devices as a whole As a chain connection. While the first switch is switched to disconnection, the second switch is connected, the other end of the resistor connected in parallel to the second path is connected to a fixed potential, and the current to the slave communication device is supplied to the second path. Part of which flows through the resistor.

Therefore, in the present invention, when the first switch is disconnected and the second switch is connected, the first current value of the current including the current to the slave communication device connected next through the second path is measured. Then, the second current value to the resistor whose other end is grounded is measured. That is, when the first switch is disconnected and the second switch is connected in all the slave communication devices, the resistance having substantially the same resistance value with respect to the master communication device is equivalent to the number of slave communication devices. It becomes the structure connected only in parallel. Therefore, the second current value flowing through the resistance of any slave communication device is the same, but the slave current communication device having a larger number of slave communication devices passing through the slave communication device has a smaller first current value flowing through its second path. . Each slave communication device determines the identification information using a first current value that varies depending on the device and a second current value that is the same for all devices.
Although the resistance values of the resistors are substantially the same or substantially the same, variations in resistance as a product are allowed. Further, even if the degree of variation is exceeded, if the error is such that the identification information can be determined, it is substantially the same.

  In the present invention, each slave communication device is triggered by a detection instruction from the master communication device, disconnects the first switch, connects the second switch, measures the first current value and the second current value, and identifies the identification information. decide. During the period when the identification information does not need to be determined, the first switch is connected, the second switch is disconnected, and the first switch is connected in a chained manner. It is also possible to execute communication.

  In the present invention, the first current value measured by each slave communication device is the sum of the current values supplied from the master communication device side to the slave communication device and the subsequent slave communication devices. The second current value measured by the resistance is a value shunted according to the number of slave communication devices. Thus, by dividing the first current value by the second current value, a value corresponding to the number of slave communication devices passing from the master communication device is obtained. In this case, the first current value is larger as the number of vias is smaller. By subtracting the calculated value from a numerical value given in advance, the closer the value is to the master communication device, the smaller the value. Each slave communication device determines the value as identification information. As a result, the closer to the master communication device, the smaller the number corresponding to the connection order can be used as the identification information.

In the present invention, a master communication device and a plurality of slave communication devices are connected in a daisy chain type with the master communication device as a base point, and each slave communication device is connected to the master communication device or another slave communication device. Provide contacts. The contact for connecting to the outside is also connected to the inside via two parallel paths (first path and second path). The first path includes a switch for switching the connection or disconnection, and the second path includes a capacitor in series with the same capacity as that of other slave communication devices.
Thereby, while the switch is connected, the two contact points are directly connected inside, and the master communication device and the plurality of slave communication devices are connected in a chain. While the switch is switched to disconnection, a voltage is applied to the second path.

Therefore, in the present invention, the potential difference at each capacitor and the potential at any electrode or contact are measured with respect to the voltage supplied from the master side when the switch is disconnected. While all the slave communication devices are switched off, capacitors having the same capacity in circuit are connected in series by the number of slave communication devices. Therefore, although the potential difference in the capacitor of each slave communication device is the same, the potential at any one of the contacts is lower as the slave communication device has a larger number passing through the slave communication device from the master communication device. Each slave communication device can calculate a value according to the number of slave communication devices passed from its own master communication device using a potential that differs depending on the device and an equal potential difference in all devices, and identification information can be obtained based on the value. decide.
In addition, although the capacity | capacitance of each capacitor | condenser was substantially the same or substantially equal, the variation as a product of a capacitor | condenser is accept | permitted. Further, even if the degree of variation is exceeded, if the error is such that the identification information can be determined, it is substantially the same.

  In the present invention, each slave communication device cuts off the switch in response to a detection instruction from the master communication device, measures the potential difference in the capacitor and the potential at any one of the contacts, and determines the identification information. During the period when the identification information does not need to be determined, a switch is connected and directly connected internally, and communication can be performed via each contact and the first path using the chain connection. Is possible.

  As described above, according to the present invention, when the switch is disconnected, capacitors having the same capacity in circuit are connected in series by the number of slave communication devices. Therefore, the output of the constant voltage from the master communication device is divided by each slave communication device, and the potential measured by the slave communication device is lower as the number of slave communication devices passing from the master communication device is larger. Thus, by dividing the potential in each slave communication device by each potential difference, a value corresponding to the number of slave communication devices passing from the master communication device is obtained. By subtracting the calculated value from a numerical value given in advance, the closer the value is to the master communication device, the smaller the value. Each slave communication device determines the value as identification information. As a result, the closer to the master communication device, the smaller the number corresponding to the connection order can be used as the identification information.

  In the case of the present invention, identification information unique to each slave communication device is set in advance, each slave communication device notifies its own identification information to the master communication device, and the master communication device identifies each slave communication device. Processing can be made unnecessary. Each slave communication apparatus can simultaneously determine identification information by itself according to the output of a constant current or a constant voltage from the master side after being connected to the system. Each slave communication device does not need to set unique identification information in a fixed manner, and sequential processing is also unnecessary, so that the number of man-hours for setting processing can be reduced. Slave communication devices can be manufactured with exactly the same standard, and the design of the system can be flexibly changed.

1 is a configuration diagram showing a configuration of an in-vehicle communication system in a first embodiment. 2 is a block diagram showing an internal configuration of an ECU and an input / output device in the in-vehicle communication system according to Embodiment 1. FIG. 3 is a configuration diagram illustrating an internal configuration of a connection switching unit of an input / output device that is a slave communication device according to Embodiment 1. FIG. 3 is a flowchart illustrating an example of a processing procedure in which identification information of each person is determined by an ECU and an input / output device that configure the in-vehicle communication system according to the first embodiment. 6 is an explanatory diagram illustrating a state when a current value is measured by the connection switching unit of the input / output device according to Embodiment 1. FIG. 2 is a circuit diagram schematically showing a circuit configuration in an in-vehicle communication system when an address is determined by each input / output device in Embodiment 1. FIG. 6 is a configuration diagram illustrating a configuration of an in-vehicle communication system according to Embodiment 2. FIG. 6 is a block diagram showing an internal configuration of an ECU and an input / output device in an in-vehicle communication system according to Embodiment 2. FIG. 6 is a configuration diagram illustrating an internal configuration of a connection switching unit of an input / output device that is a slave communication device according to Embodiment 2. FIG. 10 is an explanatory diagram illustrating a state when a potential and a potential difference are measured by a connection switching unit of the input / output device in Embodiment 2. FIG. 6 is a circuit diagram schematically showing a circuit configuration in an in-vehicle communication system when an address is determined by each input / output device in Embodiment 2. FIG.

  Hereinafter, the present invention will be specifically described with reference to the drawings showing embodiments thereof. In the following embodiment, the communication system according to the present invention is applied to an in-vehicle communication system in which a large number of actuators, sensors, and ECUs mounted on a vehicle communicate data with each other to realize various functions. An example will be described.

(Embodiment 1)
FIG. 1 is a configuration diagram showing the configuration of the in-vehicle communication system in the first embodiment. The in-vehicle communication system according to Embodiment 1 includes an ECU 1, input / output devices 2a, 2b, and 2c, various sensors or actuators 31 to 39 connected to the input / output devices 2a, 2b, and 2c, the ECU 1, and the input / output device 2a. , 2b, 2c are connected to the communication line 4.

  As shown in FIG. 1, the ECU 1 and the input / output devices 2a, 2b, and 2c are connected in a daisy chain type with the ECU 1 as a base point. The ECU 1 controls the operation of the actuator based on data obtained from various sensors. Each of the input / output devices 2a, 2b, and 2c performs communication on the communication line 4 of data input / output by each sensor or actuator 31-39. Sensors or actuators 31 to 39 are installed inside and outside the vehicle and operate based on control information from ECU 1 or another ECU (not shown).

  The input / output device 2a is connected to a left turn SW (switch) 31 for turning on the left direction indicator when turning left, a right turn SW 32 for turning on the right direction indicator, and a map lamp 33. The input / output device 2a receives signals from the left turn SW31 and the right turn SW32 and transmits information on the switch state to the ECU 1 via the communication line 4, and also turns on / off the map lamp 33 from the ECU 1; Control information such as brightness is received, a control signal is generated based on the received control information, and is output to the map lamp 33.

  The input / output device 2b is connected to a driver door SW sensor 34 that detects opening and closing of the door on the driver's seat side, a right turn signal 35 that flashes when turning right, and a right headlight 36. The input / output device 2b inputs a signal indicating the open / closed state from the driver door SW sensor 34, transmits the open / closed state to the ECU 1 via the communication line 4, and targets the right turn signal 35 or the right headlight 36 from the ECU 1. Control information such as ON / OFF, brightness, or blinking interval is received, a control signal is generated based on the received control information, and is output to the right turn signal 35 or the right headlight 36.

  The input / output device 2c is connected to an assistant door SW sensor 37 that detects opening and closing of the door on the passenger seat side, a left turn signal 38 that flashes when turning left, and a left headlight 39. The input / output device 2c inputs a signal indicating the open / closed state from the assistant door SW sensor 37, transmits the open / closed state to the ECU 1 via the communication line 4, and targets the left turn signal 38 or the left headlight 39 from the ECU 1. A control signal such as ON / OFF, brightness, or blinking interval is received, a control signal is generated based on the received control information, and is output to the left turn signal 38 or the left headlight 39.

  As described above, the sensors or actuators 31 to 39 are not directly connected to the ECU 1, but are connected to the input / output devices 2 a, 2 b, 2 c, and the input / output devices 2 a, 2 b, 2 c are connected to the ECU 1. By adopting a configuration that performs transmission and reception, the input / output devices 2a, 2b, and 2c can communicate data with each other at a suitable transmission / reception timing, thereby reducing the load on the ECU 1. is there.

  The communication between the ECU 1 and the input / output devices 2a, 2b, and 2c is executed by a method controlled by the master communication device based on the master / slave method, although the communication protocol is not limited. Specifically, in the first embodiment, the ECU 1 serves as a master communication device in order to transmit / receive data input / output by the sensors or actuators 31 to 39 between the ECU 1 and the input / output devices 2a, 2b, 2c. The communication by the input / output devices 2a, 2b, 2c operating as devices is controlled.

  FIG. 2 is a block diagram showing an internal configuration of the ECU 1 and the input / output device 2a in the in-vehicle communication system according to the first embodiment. Since the internal configuration of the input / output devices 2b and 2c is the same as the internal configuration of the input / output device 2a, detailed description thereof is omitted.

  The ECU 1 includes a control unit 10, a connection unit 11, a communication unit 12, and an output unit 13. The control unit 10 uses a CPU (core) to execute processing for controlling each sensor or actuator 31 to 39 based on a program stored in a memory (not shown). You may implement | achieve in hardware by the combination of a circuit. The connection unit 11 is an interface to which the communication line 4 is connected, and inputs and outputs signals on the communication line 4. The connecting portion 11 is also connected to the body ground as a fixed potential. Based on an instruction from the control unit 10, the communication unit 12 performs processing to transmit and receive communication signals from the connection unit 11 according to a predetermined protocol. Specifically, a process for formatting the control information given from the control unit 10 according to the protocol or a process for extracting status information from the received signal output from the connection unit 11 according to the protocol is performed. In response to an instruction from the control unit 10, the output unit 13 outputs a predetermined fixed voltage V via the connection unit 11 so as to supply the communication line 4 as described later.

  The input / output device 2a includes a connection switching unit 20a, a communication control unit 21a, an address determination unit 22a, a self address storage unit 23a, a reception address storage unit 24a, a transmission cycle storage unit 25a, an input / output setting storage unit 26a, and input / output data storage. A unit 27a, an arithmetic processing unit 28a, and an input / output unit 29a. The input / output device 2a is configured by an ASIC (Application Specific Integrated Circuit) in which the above-described components are formed. An FPGA (Field Programmable Gate Array) may be used. It should be noted that the function of each component may be realized by software processing by a microcomputer.

  The connection switching unit 20a is connected to the ECU 1 and the input / output device 2b via the communication line 4, respectively. As will be described later, the connection switching unit 20a includes a circuit that switches a connection relationship with the communication line 4 therein, and operates according to an instruction from the communication control unit 21a. The communication control unit 21a is connected to the connection switching unit 20a, and not only outputs a switching instruction to the connection switching unit 20a but also communicates with the ECU 1 and other input / output devices 2b via the communication line 4 by the connection switching unit 20a. Realize communication. In addition, the communication control unit 21a stores information received from the ECU 1 via the communication line 4 with its own address storage unit 23a, reception address storage unit 24a, transmission cycle storage unit 25a, input / output setting storage unit 26a, and input / output data storage. Processing for writing in the unit 27a is performed.

  The own address storage unit 23a is configured using a register, and stores information written by the communication control unit 21a as described above. The own address storage unit 23a stores the own address (identification information) for identifying itself in order to determine whether or not the input / output device 2a itself is the destination when information is received, or to notify the transmission source. The In the first embodiment, in any of the input / output devices 2a, 2b, and 2c, the own address (identification information) for identifying itself is not set in advance. Initially, invalid information is stored in the own address storage unit 23a, and an address determined by processing by an address determination unit 22a described later is written.

  The reception address storage unit 24a is similarly configured using a register and stores information written by the communication control unit 21a. The reception address storage unit 24a stores information (reception address) for identifying which information of various types of information to be received is to be received. The communication control unit 21a stores the reception address in the reception address storage unit 24a based on the received setting information in the setting process described later, and extracts information based on the reception address of the reception address storage unit 24a at the time of transmission / reception. .

  The transmission cycle storage unit 25a is similarly configured using a register and stores information written by the communication control unit 21a. The transmission cycle storage unit 25a stores a transmission cycle for transmitting switch state information extracted from signals input from the left turn SW31 and the right turn SW32 connected to the input / output device 2a. The communication control unit 21a extracts the transmission cycle corresponding to the sensor or actuator 31 to 33 connected to itself from the setting information received in the setting process described later, and stores it in the transmission cycle storage unit 25a. When transmitting / receiving information, the communication control unit 21a reads and transmits input / output data stored in an input / output data storage unit 27a (to be described later) according to the transmission cycle of the transmission cycle storage unit 25a.

  The input / output setting storage unit 26a is similarly configured using a register, and stores information written by the communication control unit 21a. Invalid information is initially stored in the input / output setting storage unit 26a, and information indicating what sensors or actuators 31 to 39 are connected to the input / output device 2a is stored by a process described later. Is done. Specifically, the identification number (bit position) of each of the left turn SW31, right turn SW32, and map lamp 33, the number of bits of control information for controlling each sensor or actuator 31 to 33, the number of bits of state information, and the like. Remembered.

  The input / output data storage unit 27a is configured using a register, and stores information written by the communication control unit 21a or the arithmetic processing unit 28a. Initially, invalid information is stored in the input / output data storage unit 27a, and control information or state information is stored by processing to be described later. Specifically, the switch state information in the left turn SW31 or the right turn SW32 acquired by the arithmetic processing unit 28a via the input / output unit 29a, the control for controlling the map lamp 33 received from the ECU 1 by the communication control unit 21a. Information is written.

  The arithmetic processing unit 28a recognizes that the left turn SW31, the right turn SW32, and the map lamp 33 are connected to the input / output unit 29a based on the setting information stored in the input / output setting storage unit 26a. Then, the arithmetic processing unit 28a executes the processing contents based on the setting information on the information input from the left turn SW31, the right turn SW32 or the map lamp 33 via the input / output unit 29a, and the input / output data storage unit 27a. Processing such as writing to. In addition, the arithmetic processing unit 28a reads the control information written by the communication control unit 21a in the input / output data storage unit 27a based on the setting information in the input / output setting storage unit 26a, creates a control signal, and generates the input / output unit 29a. The control signal is output to the map lamp 33 via

  The input / output unit 29a is an interface to which sensors or actuators 31 to 39 are connected. You may be comprised so that D / A conversion and A / D conversion can be performed. The input / output unit 29a acquires information from the input signal from the left turn SW31 or the right turn SW32 and notifies the arithmetic processing unit 28a, or converts the control information from the arithmetic processing unit 28a into a control signal to convert the map lamp 33. Process to output to.

  A communication method between the ECU 1 and the input / output devices 2a, 2b, and 2c configured as described above will be described. In order to perform communication, the ECU 1 that is the master communication device identifies the input / output devices 2a, 2b, and 2c that are slave communication devices, and each of the input / output devices 2a, 2b, and 2c is the destination. It is necessary to recognize whether or not. That is, an address is required as identification information for identifying each. However, as described above, each input / output device 2a, 2b, 2c, which is a slave communication device, is not set with its own address (identification information) for identifying itself. Therefore, each address is determined by the configuration of the connection switching units 20a, 20b, and 20c as described below, and the processing of the connection switching units 20a, 20b, and 20c and the communication control units 21a, 21b, and 21c, and is used for subsequent communication. It is done.

  FIG. 3 is a configuration diagram illustrating an internal configuration of the connection switching units 20a, 20b, and 20c of the input / output devices 2a, 2b, and 2c that are the slave communication devices according to the first embodiment. Hereinafter, the connection switching unit 20a of the input / output device 2a will be mainly described, and the connection switching units 20b and 20c of the input / output devices 2b and 2c will be denoted by the same reference numerals as those of the connection switching unit 20a, and detailed description thereof will be omitted. .

  The connection switching unit 20a includes a first path connected via the switch 201a and a current measuring element 203a in series, and one end of the resistor R connected to the body ground via the current measuring element 204a and the switch 202a. It includes two connection points 205a and 206a connected by the second path connecting the other end. Note that the current measuring element 203a in the first embodiment is included in series on the upstream side (master communication device side) in terms of the circuit with respect to the contact with the resistor R in the second path. It may be connected to the downstream side. In addition, as the resistor R, the input / output devices 2a, 2b, and 2c having the same resistance value are used. The switches 201a and 202a are complementarily controlled so that when one is connected, the other is disconnected, and when one is disconnected, the other is connected.

  The switch 201a in the connection switching unit 20a is normally connected, and the switch 202a is disconnected. The same applies to the other input / output devices 2b and 2c, and the communication line 4 is treated as a single communication line during normal operation. At this time, the communication control unit 21a extracts information transmitted / received from the signal on the communication line 4 when the switch 201a is connected.

  Then, a current detection instruction is transmitted through the communication line 4 so as to determine each address as an initial process from the ECU 1 as the master communication device to the input / output devices 2a, 2b, and 2c as the slave communication devices. To do.

  The input / output device 2a receives the current detection instruction transmitted to the communication line 4 with the switch 201a connected, disconnects the switch 201a and connects the switch 202a to determine its own identification information, that is, an address. Execute the process.

  FIG. 4 is a flowchart illustrating an example of a processing procedure in which identification information of each person is determined by the ECU 1 and the input / output devices 2a, 2b, and 2c constituting the in-vehicle communication system according to the first embodiment. In the following description, processing executed by the ECU 1 and the input / output device 2a will be described. Since the processing in the input / output devices 2b and 2c is the same as the processing in the input / output device 2a, detailed description thereof is omitted.

  When power is supplied to the ECU 1 and the input / output devices 2a, 2b, and 2c in a state where the ECU 1 and the input / output devices 2a, 2b, and 2c are connected by the communication line 4, the processing of the ECU 1 is triggered as an initial process. The following processes are executed respectively. It is executed at the time of inspection such as a vehicle assembly process or at the time of vehicle inspection.

  In ECU1 which is a master communication apparatus, according to the instruction | indication from the control part 10, the communication part 12 transmits a detection instruction | indication from the connection part 11 (step S101). In the ECU 1, the output unit 13 outputs a constant voltage V from the connection unit 11 in accordance with an instruction from the control unit 10 (step S102).

  On the other hand, in the input / output device 2a, when the supply of power is started with the switch 201a connected, the communication control unit 21a first monitors the communication line 4 to determine whether or not a detection instruction has been received. (Step S103). If the communication control unit 21a determines that the detection instruction has not been received (S103: NO), the process returns to step S103 and waits until the detection instruction is received.

  When the input / output device 2a determines that the detection instruction is received in step S103 (S103: YES), the input / output device 2a disconnects the switch 201a in the first path (step S104). At this time, the switch 202a connected to the resistor R connected to the second path is connected. Then, according to an instruction from the communication control unit 21a, the connection switching unit 20a performs current measurement using the current measuring element 203a and the current measuring element 204a (step S105). As a result, the value of the current flowing through the upstream side (the side connected to the ECU 1) from the point where the resistor R is connected in the second path where the resistor R is connected via the switch 202a, and the resistor R are The flowing current value is measured. At this time, the switches 201b and 201c are also disconnected in the other input / output devices 2b and 2c, and the switches 202b and 202c are connected.

  In the input / output device 2a, two current values measured by the connection switching unit 20a are acquired by the address determination unit 22a. The address determination unit 22a calculates a value corresponding to the number of slave communication devices passing from the ECU 1 as the master communication device from the two current values (step S106), and sets the calculated value to a predetermined value N (preliminarily set). The value is subtracted from the value (step S107), and the subtraction result is determined as an address (step S108). Further, the address determination unit 22a stores (stores) the determined address in the own address storage unit 23a (step S109).

  After determining the address in this way, in the input / output device 2a, the communication control unit 21a detects that the information of the valid address is stored (stored) in its own address storage unit 23a, and instructs the connection switching unit 20a. Switch S201a is connected (step S110). Thereby, communication via the communication line 4 is resumed.

  Thereafter, the communication control unit 21a starts a setting process including communication with another communication device based on the own address stored in the own address storage unit 23a (step S111), and determines the own address along with the end of the setting process. End the process. As described above, the setting process receives the setting information addressed to itself transmitted from the ECU 1 serving as the master communication device, and appropriately receives the reception address storage unit 24a, the transmission cycle storage unit 25a, and the input / output setting storage unit 26a. This is a process of storing (storing).

  On the other hand, in the ECU 1 as the master communication device, after outputting the constant voltage V in step S102, the transmission of the current detection instruction is distributed to the input / output devices 2a, 2b, 2c, and is sent to the input / output devices 2a, 2b, 2c. The switch 201a, 201b, 201c is disconnected and waits for a predetermined time until the switch 202a, 202b, 202c is connected, and the total amount of current output to output a constant voltage V is measured ( Step S112). In the ECU 1, the control unit 10 calculates the total number of input / output devices connected to itself based on the measured total amount of current (step S113).

  Next, the ECU 1 creates setting information based on information such as what is connected to each of the input / output devices 2a, 2b, and 2c set in advance from the outside (step S114). The contents of the setting information are input / output settings such as which number of devices or actuators 31 to 39 are connected to each other as described above, and the number of bits of information input / output by each sensor or actuator 31 to 39. The information stored in the storage unit 26a, the information stored in the transmission cycle storage unit 25a, which is the cycle to be transmitted, or the address of the transmission source device of the information to be received by each of the input / output devices 2a, 2b, 2c Information to be stored in the received address storage unit 24a shown.

  In accordance with the instruction from the control unit 10, the ECU 1 transmits the created setting information from the connection unit 11 (step S115), and determines whether the setting process is completed (step S116). At this time, the ECU 1 may transmit the setting information after determining whether or not the communication with each of the input / output devices 2a, 2b, and 2c has been resumed. In addition, when the connection of the switches 201a, 201b, and 201c is resumed and the response is received from the farthest input / output device 2c among the input / output devices 2a, 2b, and 2c in the communication resumed state, the setting process is completed. to decide.

  If the control unit 10 determines that the setting process has not been completed (S116: NO), the ECU 1 returns the process to step S116 and waits. If the ECU 1 determines that the setting process has been completed (S116: YES), the ECU 1 ends the process.

  By executing the processing procedure shown in the flowchart of FIG. 4, the addresses for identifying the input / output devices 2a, 2b, 2c are determined by themselves. And each input / output device 2a, 2b, 2c receives the information addressed to itself among the setting information transmitted from ECU1 by communication control part 21a, 21b, 21c based on the determined address. Then, in the reception address storage units 24a, 24b, 24c, the transmission cycle storage units 25a, 25b, 25c, and the input / output setting storage units 26a, 26b, 26c, which initially store invalid information, respectively, are set. Information is stored (stored). As a result, transmission / reception processing and input / output processing by the communication control units 21a, 21b, and 21c and the arithmetic processing units 28a, 28b, and 28c can be started.

  Next, the measurement of the current value in step S105 and the address determination method based on the measured current value will be described in detail.

  FIG. 5 is an explanatory diagram showing a state when current values are measured by the connection switching units 20a, 20b, and 20c of the input / output devices 2a, 2b, and 2c in the first embodiment. 5 corresponds to the configuration diagram of FIG.

As shown in FIG. 5, in each of the input / output devices 2a, 2b, and 2c, the switches 201a, 201b, and 201c are disconnected, and the switches 202a, 202b, and 202c are connected. Then, in this state, the connection switching section 20a of the input-output device 2a, the current value I ₁ of the previous branching to the resistance R between the connection points 205a and the connection point 206a is measured by the current measuring element 203a, the branch The current value I flowing through the subsequent resistor R is measured by the current measuring element 204a. Similarly, in the connection switching section 20b of the input-output device 2b, the current value I ₂ before branching to the resistance R between the connection points 205b and the connection point 206b is measured by the current measuring element 203b, the resistance R after branching The flowing current value I is measured by the current measuring element 204b. The connection switching section 20c of the input-output device 2c, a current value I ₃ before branching to the resistance R between the connection points 205c and the connection point 206c is measured by a current measuring element 203c, the current value I flowing through the resistor R after branching Is measured by the current probe 204c.

  The circuit configuration of the in-vehicle communication system in a state where the switches 201a, 201b, and 201c of the input / output devices 2a, 2b, and 2c are disconnected and the switches 202a, 202b, and 202c are connected to determine the address is shown in FIG. 6 is equivalent to the circuit shown in the circuit diagram of FIG. FIG. 6 is a circuit diagram schematically showing a circuit configuration in the in-vehicle communication system when addresses are determined by the input / output devices 2a, 2b, and 2c in the first embodiment.

  The state in which the switches 201a, 201b, and 201c of the input / output devices 2a, 2b, and 2c are disconnected and the switches 202a, 202b, and 202c are connected is output from the ECU 1 that is the master communication device as shown in FIG. With respect to the voltage V, resistors R having the same resistance value are connected in parallel by the number of input / output devices 2a, 2b, 2c which are slave communication devices. Since the resistance values of the resistors R are substantially equal in the input / output devices 2a, 2b, and 2c, they are divided approximately equally and the current value I flows through each resistor R.

  Therefore, the relationship between the current values measured by the current measuring elements 203a, 204a, 203b, 204b, 203c, and 204c shown in FIG. 5 is expressed by the following equations 1a to 1c.

I ₁ = I + I ₂ = 2I + I ₃ = 3I (1a)
I ₂ = I + I ₃ = 2I (1b)
I ₃ = I (1c)

The address determination units 22a, 22b, and 22c of the input / output devices 2a, 2b, and 2c use the current values I ₁ , I ₂ , and I ₃ measured by the current measuring elements 203a, 203b, and 203c in the second path as currents, respectively. The number divided by the current value I flowing through the resistance R measured by the measuring elements 204a, 204b, and 204c (that is, a value corresponding to the number of passing through the slave communication device, but the larger the number of passing through, the larger) is calculated.

  As a result, the address determination unit 22a of the input / output device 2a is “3” from the above equation, the address determination unit 22b of the input / output device 2b is “2” from the above equation, and the address determination unit 22c of the input / output device 2c is the above described. “1” is calculated from the following equation.

  Next, the address determination units 22a, 22b, and 22c of the input / output devices 2a, 2b, and 2c subtract each calculation result from the predetermined value N as shown in the flowchart of FIG. The predetermined value N may be set in advance so that the address determination units 22a, 22b, and 22c can refer to the input / output devices 2a, 2b, and 2c, or transmitted together with a current detection instruction from the ECU 1. May be. Here, as the predetermined value N, a number obtained by adding 1 to the total number of input / output devices 2a, 2b, 2c, which are slave communication devices connected to the ECU 1, is set to N = “4” in the first embodiment. As a result, “1” (= 4-1) is obtained by the address determination unit 22a of the input / output device 2a, and “2” (= 4-2) is obtained by the address determination unit 22b of the input / output device 2b. The address determination unit 22c calculates “3” (= 4-1) as the subtraction result.

  Therefore, the address determination units 22a, 22b, and 22c of the input / output devices 2a, 2b, and 2c determine their own addresses as “1”, “2”, and “3”, respectively, and their own address storage units 23a, 23b, and 23c. Store (memorize).

  In summary, the address determination units 22a, 22b, and 22c of the input / output devices 2a, 2b, and 2c each use a predetermined value N that is set in advance, and determine their own addresses as shown in Equation 2 below.

Address (value) = N-current value I flowing through resistor R / input current value I _m (2)
(M = 1, 2, 3)

  In this manner, the input / output devices 2a, 2b, and 2c can be identified without setting unique identification information in advance to the input / output devices 2a, 2b, and 2c. Thereafter, when the ECU 1 serving as the master communication device transmits information to each of the input / output devices 2a, 2b, and 2c, by adding a number corresponding to the connection order as a destination address, the input / output devices 2a, 2b , 2c recognizes whether or not it is information for itself, and the information relevant to itself is received by the communication control units 21a, 21b and 21c and stored (stored) in the input / output data storage units 27a, 27b and 27c. be able to.

As shown in FIG. 5 and FIG. 6, since the current I flows through the entire system by the number of slave communication devices, the ECU 1 as the master communication device has a total current amount I ₁ , a voltage V and Based on the current value I determined from the resistance value of the resistor R, the number “3” of the input / output devices 2a, 2b, 2c, which are slave communication devices, can be calculated. By setting the number of input / output devices “3” (= N−1) connected to the ECU 1 in advance, it is determined whether or not all the input / output devices 2a, 2b, 2c are normally connected. Is possible.

4 to 6, the address determination units 22a, 22b, and 22c of the input / output devices 2a, 2b, and 2c use the measured current values I ₁ , I ₂ , and I ₃ as resistance R The result of subtracting the number divided by the current value I flowing through the predetermined value N was determined as an address. However, the present invention is not limited to this, and the result of division may be determined as an address as it is, or the result of adding or multiplying a predetermined numerical value may be determined as an address. Since different values can be obtained for the respective input / output devices 2a, 2b, and 2c depending on the result of the division, a method for determining an address for the value thereafter is arbitrary as long as it can be obtained as information that can be distinguished from each other.

  In the in-vehicle communication system shown in the first embodiment, the connection switching units 20a, 20b are used in the input / output devices 2a, 2b, 2c without giving specific identification information to the input / output devices 2a, 2b, 2c in advance. , 20c by switching / disconnecting the switches 201a, 201b, 201c, 202a, 202b, and 202c and performing the process of measuring the current value, respectively, to determine the address. At this time, even if the respective input / output devices 2a, 2b, and 2c are not sequentially processed, they can be determined by the process of cutting the switches 201a, 201b, and 201c and measuring their own current values, and the man-hours can be reduced.

(Embodiment 2)
In the second embodiment, a capacitor is used as the internal configuration of the connection switching unit of each input / output device. FIG. 7 is a configuration diagram showing the configuration of the in-vehicle communication system in the second embodiment. The in-vehicle communication system according to the second embodiment includes an ECU 5, input / output devices 6a, 6b, and 6c, various sensors or actuators 31 to 39 connected to the input / output devices 6a, 6b, and 6c, the ECU 5, and the input / output device 6a. , 6b, 6c are connected to the communication line 4.

  As described above, the second embodiment is different from the first embodiment in the internal configuration of the connection switching unit of the input / output device. The connection form of ECU 5 and input / output devices 6a, 6b, 6c, the function of ECU 5, and the functions of input / output devices 6a, 6b, 6c are the same as those of ECU 1 and input / output devices 2a, 2b, 2c in the first embodiment. is there. Hereinafter, configurations different from those of the first embodiment will be described in detail, and corresponding configurations will be denoted by corresponding reference numerals, and detailed description thereof will be omitted.

  FIG. 8 is a block diagram showing internal configurations of the ECU 5 and the input / output device 6a in the in-vehicle communication system according to the second embodiment. Since the internal configuration of the input / output devices 6b and 6c is the same as the internal configuration of the input / output device 2a, detailed description thereof is omitted.

  The ECU 5 includes a control unit 50, a connection unit 51, a communication unit 52, and an output unit 53. The functions of the control unit 50, the connection unit 51, the communication unit 52, and the output unit 53 are almost the same as the functions of the control unit 10, the connection unit 11, the communication unit 12, and the output unit 13 of the ECU 1 in the first embodiment. Corresponding reference numerals are assigned and detailed description is omitted.

  The input / output device 6a includes a connection switching unit 60a, a communication control unit 61a, an address determination unit 62a, a self address storage unit 63a, a reception address storage unit 64a, a transmission cycle storage unit 65a, an input / output setting storage unit 66a, and input / output data storage. A unit 67a, an arithmetic processing unit 68a, and an input / output unit 69a. Connection switching unit 60a, communication control unit 61a, address determination unit 62a, own address storage unit 63a, reception address storage unit 64a, transmission cycle storage unit 65a, input / output setting storage unit 66a, input / output data storage unit in the second embodiment Each function of 67a, the arithmetic processing unit 68a, and the input / output unit 69a is basically the same as the function of each component of the input / output device 2a in the first embodiment. Therefore, the components corresponding to the components of the input / output device 2a according to the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  However, the internal configuration of the connection switching unit 60a in the second embodiment and the address determination method using the connection switching unit 60a are the same as the internal configuration and address determination of the connection switching unit 20a of the input / output device 2a in the first embodiment. Different from the method. Hereinafter, differences will be mainly described.

  FIG. 9 is a configuration diagram illustrating an internal configuration of the connection switching units 60a, 60b, and 60c of the input / output devices 6a, 6b, and 6c, which are slave communication devices according to the second embodiment. Hereinafter, the connection switching unit 60a of the input / output device 6a will be mainly described, and the connection switching units 60b and 60c of the input / output devices 6b and 6c will be denoted by the same reference numerals as those of the connection switching unit 60a and detailed description thereof will be omitted. .

  The connection switching unit 60a includes two connection points 603a and 604a connected by a first path connected via the switch 601a and a second path including the capacitor 602a in series. The capacity of the capacitor 602a is the same as that of the input / output devices 6a, 6b, 6c.

  The switch 601a in the connection switching unit 60a is connected during normal operation. The same applies to the other input / output devices 6b and 6c, and the communication line 4 is a single communication line during normal operation. At this time, the communication control unit 61a extracts information to be transmitted / received from the signal on the communication line 4 when the switch 601a is connected.

  Then, as an initial process, an instruction is transmitted via the communication line 4 from the ECU 5 serving as a master communication device to the input / output devices 6a, 6b, and 6c serving as slave communication devices in order to determine their own addresses.

  The input / output device 6a receives the instruction transmitted to the communication line 4 in a state where the switch 601a is connected, transfers the instruction to the other input / output device 6b adjacent thereto, disconnects the switch 601a, and identifies its own identification information, that is, an address Execute the process to determine.

  The processing procedure by which the identification information is determined by the ECU 5 and the input / output devices 6a, 6b, and 6c is the same as the processing procedure by the ECU 1 and the input / output devices 2a, 2b, and 2c shown in the flowchart of FIG. Since it is substantially the same except for the detailed processing, it will be described with reference to FIG. The processing in the input / output devices 6b and 6c is the same as the processing in the input / output device 6a, and thus detailed description thereof is omitted.

  The ECU 5 transmits a potential detection instruction (S101) and outputs a constant voltage V (S102).

  In the input / output device 6a, it is determined whether or not a potential detection instruction has been received by the communication control unit 61a (S103). If it is determined that the instruction has not been received (S103: NO), the process proceeds to step S103. Returned.

  In the input / output device 6a, when the communication control unit 61a determines that the detection instruction has been received (S103: YES), the switch 601a is disconnected (S104), and one of the electrodes in the capacitor 602a is instructed by the communication control unit 61a. And the potential difference between the electrodes are measured (S105).

  Then, the address determination unit 62a calculates a value corresponding to the number of slave communication devices passing from the ECU 1 as the master communication device based on the potential difference measured in step S105 (S106), and calculates the calculated value to a predetermined value N Subtract from (preset value) (S107), determine the subtraction result as an address (S108), and store (store) it in its own address storage unit 63a (S109).

  After determining the address in this way, in the input / output device 6a, the communication control unit 61a detects that the information of the valid address is stored (stored) in its own address storage unit 63a, and instructs the connection switching unit 60a. Then, the switch S601a is connected (S110), the communication via the communication line 4 is resumed, the setting process is started (S111), and the process of determining its own address is completed together with the end of the setting process.

  On the other hand, even in the ECU 5, which is the master communication device, after a constant voltage V is output in step S102, transmission of a potential detection instruction is distributed to the input / output devices 6a, 6b, 6c, and the input / output devices 6a, 6b, 6c are transmitted. Then, the switches 601a, 601b, 601c are disconnected, and a predetermined time is waited until the capacitors 602a, 602b, 602c become stable, and the total amount of current output to output the constant voltage V is measured (S112). In the ECU 5, the control unit 50 calculates the total number of input / output devices connected to itself based on the measured total current amount (S113).

  Then, the ECU 5 creates the setting information in the same manner as in the first embodiment (S114), transmits the created setting information to each of the input / output devices 6a, 6b, 6c in which communication has been resumed (S115), and the setting process is performed. It is determined whether or not the process is completed (S116). If it is determined that the process is not completed (S116: NO), the process returns to step S116. If it is determined that the process is completed (S116: YES), the process ends. To do.

  By executing such a processing procedure, an address for identifying each input / output device 6a, 6b, 6c is determined. Each input / output device 6a, 6b, 6c receives information addressed to itself among the setting information transmitted from the ECU 5 based on the determined address by the communication control units 61a, 61b, 61c. As in the first embodiment, the reception address storage units 64a, 64b, and 64c, the transmission cycle storage units 65a, 65b, and 65c, and the input / output setting storage unit 66a, which initially store invalid information, respectively. Setting information is stored (stored) in each of 66b and 66c. As a result, transmission / reception processing and input / output processing by the communication control units 61a, 61b, 61c and the arithmetic processing units 68a, 68b, 68c can be started.

  Next, details of the measurement of the potential and the potential difference in the capacitors 602a, 602b, and 602c in step S106, and the address determination method based on the measured potential and the potential difference will be described in detail.

  FIG. 10 is an explanatory diagram illustrating a state when the potential and the potential difference are measured by the connection switching units 60a, 60b, and 60c of the input / output devices 6a, 6b, and 6c according to the second embodiment. 10 corresponds to the configuration diagram of FIG.

As shown in FIG. 10, in each input / output device 6a, 6b, 6c, the switches 601a, 601b, 601c are disconnected. In this state, the connection switching unit 60a of the input / output device 6a measures the potential V ₁ at the connection point 603a and the potential difference V _{0 at} the capacitor 602a between the connection point 603a and the connection point 604a. Similarly, in the connection switching unit 60b of the input / output device 6b, the potential V ₂ at the connection point 603b and the potential difference V _{0 at} the capacitor 602b between the connection point 603b and the connection point 604b are measured. In the connection switching unit 60c of the input / output device 6c, the potential V ₃ at the connection point 603c and the potential difference V _{0 at} the capacitor 602b between the connection point 603c and the connection point 604c are measured. The potentials V ₁ , V ₂ , and V ₃ are the same as the electrodes on the ECU 5 side (upstream side) of the capacitors 602a, 602b, and 602c.

  The circuit configuration of the in-vehicle communication system in a state where the switches 601a, 601b, and 601c of the input / output devices 6a, 6b, and 6c are disconnected in order to determine the address is the same as the circuit shown in the circuit diagram of FIG. Become. FIG. 11 is a circuit diagram schematically showing a circuit configuration in the in-vehicle communication system when addresses are determined by the input / output devices 6a, 6b, 6c in the second embodiment.

When the switches 601a, 601b, and 601c of the input / output devices 6a, 6b, and 6c are disconnected, as shown in FIG. 11, the capacitor 602a having the same capacity with respect to the voltage V output from the ECU 1 that is the master communication device. , 602b, 602c are connected in series by the number of input / output devices 6a, 6b, 6c which are slave communication devices. Capacitors 602a, 602b, volume of 602c is input and output devices 6a, 6b, from being substantially equal composed 6c, pressurized substantially equally divided, the capacitors 602a, 602b, the potential difference V ₀ at 602c is output from the ECU1 The constant voltage V is equal to a value obtained by dividing the constant voltage V by the number of the input / output devices 6a, 6b, 6c.

Therefore, the relationship between the potentials V ₁ , V ₂ and V _{3 at the} connection points 603a, 603b and 603c shown in FIG. 10 and the potential difference V _{0 at} the capacitors 602a, 602b and 602c is expressed by the following equations 3a to 3c. .

V ₁ = 3V ₀ (3a)
V ₂ = 2V ₀ (3b)
V ₃ = V ₀ (3c)

The address determination units 62a, 62b, and 62c of the input / output devices 6a, 6b, and 6c are numbers obtained by dividing the potentials V ₁ , V ₂ , and V ₃ measured by the respective potential differences V ₀ (that is, slave communication devices). The value corresponding to the number of vias (however, the smaller the number of vias, the larger).

  As a result, the address determination unit 62a of the input / output device 6a is “3” from the above formula, the address determination unit 62b of the input / output device 6b is “2” from the above formula, and the address determination unit 62c of the input / output device 6c is the above described. “1” is calculated from the following equation.

  Next, the address determination units 62a, 62b, and 62c of the input / output devices 6a, 6b, and 6c subtract each calculation result from the predetermined value N. The predetermined value N may be set in advance so that the address determination units 62a, 62b, and 62c can refer to the input / output devices 6a, 6b, and 6c in the same manner as in the first embodiment. May be transmitted together with the detection instruction. Here, as the predetermined value N, a number N = “4” obtained by adding 1 to the total number of input / output devices 6a, 6b, 6c, which are slave communication devices connected to the ECU 5, is set. As a result, “1” (= 4-1) is obtained in the address determination unit 62a of the input / output device 6a and “2” (= 4-2) is obtained in the address determination unit 62b of the input / output device 6b. The address determination unit 62c calculates “3” (= 4-1) as the subtraction result.

  Accordingly, the address determination units 62a, 62b, and 62c of the input / output devices 6a, 6b, and 6c determine their own addresses as “1”, “2”, and “3”, respectively, and their own address storage units 63a, 63b, and 63c. Store (memorize).

  In summary, the address determination units 22a, 22b, and 22c of the input / output devices 6a, 2b, and 2c each use a predetermined value N set in advance, and determine their own addresses as in the following Expression 4.

Address (value)
= N-potential V _{m at the} upstream connection point / potential difference V _{0 at the} capacitor (4)
(M = 1, 2, 3)

  In this manner, also in the second embodiment, the input / output devices 6a, 6b, and 6c can be identified without setting unique identification information in the input / output devices 6a, 6b, and 6c in advance. Thereafter, the ECU 5, which is the master communication device, transmits setting information or control information to each of the input / output devices 6a, 6b, 6c by adding a number corresponding to the connection order as a destination address. The output devices 6a, 6b, and 6c recognize whether or not they are information for themselves, and receive the relevant information by the communication control units 61a, 61b, and 61c and send them to the input / output data storage units 67a, 67b, and 67c. It can be stored.

In the processing described with reference to FIGS. 10 and 11, the address determination units 62a, 62b, and 62c of the input / output devices 6a, 6b, and 6c use the measured potentials V ₁ , V ₂ , and V ₃ , respectively. The result obtained by subtracting the number divided by the potential difference V ₀ in the capacitors 602a, 602b, and 602c from the predetermined value N was determined as an address. However, the present invention is not limited to this, and the result of division may be determined as an address as it is, or the result of adding or multiplying a predetermined numerical value may be determined as an address. Since different values can be obtained for the respective input / output devices 6a, 6b, and 6c depending on the result of the division, a method for determining an address for the values thereafter is arbitrary as long as it can be obtained as information that can be distinguished from each other.

  Even in the in-vehicle communication system shown in the second embodiment, the connection switching units 60a, 60b are provided in the input / output devices 6a, 6b, 6c without giving specific identification information to the input / output devices 6a, 6b, 6c in advance. , 60c by switching the disconnection / connection of the switches 601a, 601b, and 601c, and performing the process of measuring the potential and the potential difference, respectively, the address can be determined. At this time, even if the input / output devices 6a, 6b, and 6c are not sequentially processed, they can be determined by cutting the switches 601a, 601b, and 601c and measuring their own potential and potential difference, thereby reducing man-hours. .

  In the first and second embodiments, the configuration of the connection switching unit to which the communication line 4 is connected is configured as described above to determine the address of the input / output device that is each slave communication device. However, the present invention is not limited to this, and a signal line for determining an address is used separately from the communication line 4, and the master communication device and the slave communication device are connected in a daisy chain type by the signal line, and the signal line is connected. The address may be determined by connecting to the switching unit. Further, a power line connected to each input / output device may be used instead of the communication line 4. At this time, the PLC may be realized on the power line.

  Further, in the first and second embodiments, the configuration using the resistor R and the configuration using the capacitor have been described. In the present invention, each address may be determined by mixing a configuration using the resistor R and a configuration using a capacitor.

  The disclosed embodiments should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

1 ECU (master communication device)
2a, 2b, 2c I / O device (slave communication device)
20a, 20b, 20c connection switching unit 201a, 201b, 201c switch (first switch)
202a, 202b, 202c switch (second switch)
203a, 203b, 203c Current measuring element 204a, 204b, 204c Current measuring element 205a, 206a, 205b, 206b, 205c, 206c Connection point 4 Communication line 5 ECU (master communication device)
6a, 6b, 6c I / O device (slave communication device)
60a, 60b, 60c Connection switching unit 601a, 601b, 601c Switch 602a, 602b, 602c Capacitor 603a, 604a, 603b, 604b, 603c, 604c Connection point

Claims (10)

In a communication system in which one master communication device and a plurality of slave communication devices communicate with each other by daisy chain connection with the master communication device as a base point,
Each slave communication device
The first path including the first switch, and another adjacent communication connected by the parallel circuit of the second path having one end connected to the other end of the resistor connected to the fixed potential via the second switch A connection point with each device,
Switching means for complementarily switching connection and disconnection of the first and second switches;
Measuring means for measuring a first current value flowing through the input terminal of the slave communication device and a second current value flowing through the resistor when the first switch is in a disconnected state and the second switch is in a connected state;
Determining means for determining its own identification information based on the measured first current value and second current value;
The resistance value of the said resistance of each slave communication apparatus is substantially equal. The master communication device is
Means for transmitting a detection instruction;
Means for outputting a predetermined current value,
Each slave communication device
When the detection instruction is received, the switching means disconnects the first switch and connects the second switch, and measures the first current value and the second current value to determine the identification information. The communication system according to claim 1. The determining means for each slave communication device is:
Means for calculating a value obtained by dividing the first current value by the second current value;
The communication system according to claim 1 or 2, wherein a value obtained by subtracting the calculated value from a numerical value given in advance is determined as identification information. In a communication system in which one master communication device and a plurality of slave communication devices are connected in a daisy chain manner with the master communication device as a base point to communicate,
Each of the plurality of slave communication devices is
A connection point with each of the other adjacent communication devices connected by a parallel circuit of a first path including a switch and a second path including a capacitor;
Switching means for switching connection and disconnection of the switch;
Means for measuring a potential difference in the capacitor caused by a voltage supplied from the master communication device side when the switch is in a disconnected state, and a potential at the contact;
Determining means for determining its own identification information based on the measured potential difference and potential,
A communication system characterized in that the capacities of the capacitors of the slave communication devices are substantially equal. The master communication device is
Means for transmitting a detection instruction to each slave communication device;
Means for outputting a predetermined voltage value,
Each slave communication device
5. The communication system according to claim 4, wherein when the detection instruction is received, the switch is disconnected by the switching unit and the potential difference and the potential are measured to determine identification information. The determining means for each slave communication device is:
Means for calculating a value obtained by dividing the measured potential by the potential difference;
The communication system according to claim 4 or 5, wherein a value obtained by subtracting the calculated value from a numerical value given in advance is determined as identification information. Each of the other communication devices connected by the parallel circuit of the first path including the first switch and the second path connected to the other end of the resistor whose one end is connected to the fixed potential via the second switch. A connection point with
Switching means for complementarily switching connection and disconnection of the first and second switches;
Measuring means for measuring a first current value flowing through the second path when the first switch is disconnected and the second switch is connected; and a second current value flowing through the resistor;
Means for determining its own identification information based on the measured first current value and second current value. A connection point with each of the other communication devices connected by a parallel circuit of a first path including a switch and a second path including a capacitor;
Switching means for switching connection and disconnection of the switch;
Means for measuring a potential difference in the capacitor when the switch is in a disconnected state, and a potential at the contact;
A communication device comprising: determining means for determining its own identification information based on the measured potential difference and potential. One master communication device and a plurality of slave communication devices are daisy chain-connected with the master communication device as a base point. Each of the plurality of slave communication devices includes a first path including a first switch, and one end includes a second switch. Via a second path parallel circuit connected to the other end of the resistor connected to the fixed potential via each other adjacent communication device, the resistance of each slave communication device is The communication device is a communication method for performing communication based on its own identification information determined,
The plurality of slave communication devices connect the first switch and disconnect the second switch,
The master communication device is
Send a detection instruction to the connected slave communication device,
Output a predetermined current value,
Each slave communication device
Disconnect the first switch and connect the second switch according to the received detection instruction,
Measuring a first current value flowing through the second path and a second current value flowing through the resistor;
A communication method characterized by determining its own identification information based on the measured first current value and second current value. One master communication device and a plurality of slave communication devices are daisy chain connected with the master communication device as a base point, and each of the plurality of slave communication devices includes a parallel circuit of a first path including a switch and a second path including a capacitor. A communication point that has a connection point with each of the other adjacent communication devices connected by each other, the capacitors of each slave communication device have substantially the same capacity, and each communication device performs communication based on its own identification information determined A method,
The plurality of slave communication devices are connected to the switch,
The master communication device is
Send the detection instruction to the connected slave communication device,
Output a predetermined voltage value,
Each slave communication device
The first switch is disconnected by the received detection instruction,
Measure the potential difference at the capacitor and the potential at the contact,
A communication method characterized by determining its own identification information based on a measured potential difference and potential.

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