JP2003152741A - Communication system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a communication system by which an operator can normally set an ID to each slave without being conscious of respective installed positions of a plurality of the slaves. SOLUTION: Each of a plurality of slave devices 11, 21 and 31 has a switch 12 turning ON/OFF a power line 1 configuring a bus in series with the power line 1, a master device 10 sequentially sets an ID of a connected position in the closer order of the slave devices to the master device on the basis of each connection sequence and each ID of the slave device stored in advance, and the slave device to which the ID is set sequentially turns on the switch to apply bus connection to the slave device of the next stage.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a communication device in which a plurality of slave devices are connected to a bus with respect to a master device, and more particularly to a communication device suitable for an obstacle detection device for vehicles.

[0002]

2. Description of the Related Art As a conventional example of this type, ultrasonic sensors (slave) are provided on, for example, the left side, the front side, and the right side of a vehicle bumper, and a controller (master) is provided based on reflected wave detection signals from the ultrasonic sensors. ), There is known an obstacle detection device which detects at which position there is an obstacle and issues an alarm. In this obstacle detection device, the master 10 shown in FIG. 12 has a plurality of slaves 11, 21 and 31 at individual positions (left, front of the bumper,
The ID corresponding to the right or the like) is set, and the ID is set to each of the slaves 11, 21, and 31. When installed in a vehicle, each slave 1
1, 21, and 31 are masters 1 in their respective positions
0 is connected to the bus via a power supply line 1, a communication line 3, and a GND line 2. Then, the master 10 collects information from each of the slaves 11, 21, and 31 in which individual IDs are set in advance by a polling / selecting method or the like.

[0003]

However, in the above-mentioned conventional example, the slaves 11 and 2 in which individual IDs have already been set.
If 1 and 31 are erroneously connected and installed at a position different from the original position, in the case of an obstacle detection device, the master 10 cannot give an alarm at a position with an obstacle and gives an alarm at a position without an obstacle. There is a problem.

In view of the above-mentioned problems of the conventional example, the present invention provides a communication device which allows a worker to normally set an ID for each slave without being aware of the individual installation positions of the plurality of slaves. The purpose is to do.

[0005]

In order to achieve the above object, the present invention provides a switch for turning on / off a connection between a bus and a slave device at a next stage for each of a plurality of slave devices arranged at individual predetermined positions. And an ID corresponding to each arrangement position of a plurality of slave devices which is stored in advance by the master device.
To the first slave device via the bus based on its ID
After setting, the slave device to which the ID is set sequentially turns on its switch to connect the slave device at the next stage to the bus, and the master device sends the ID to the slave device at the next stage connected to the bus. It is characterized by setting. According to the above configuration, since the ID corresponding to each connection order is automatically set to the plurality of slave devices sequentially from the master device, the worker does not have to be aware of the individual installation positions of the plurality of slaves and assigns them to the individual slaves. On the other hand, the ID can be set normally.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION <First Embodiment> An embodiment of the present invention will be described below with reference to the drawings. 1 is a block diagram showing an obstacle detection device for a vehicle as a first embodiment of a communication device according to the present invention, FIG. 2 is a block diagram showing a configuration of a master shown in FIG. 1, and FIG. 3 is a configuration of a slave shown in FIG. 4 is an explanatory diagram showing the format of the communication frame between the master and slaves in FIG. 1, FIG. 5 is a flow chart for explaining the operation of the master and slaves in FIG. 1, and FIG. 6 is the master in FIG. 3 is a timing chart showing a communication sequence between slaves.

The master 10 in FIG. 1 is, for example, a control device that constitutes a vehicle obstacle detection device, and IDs corresponding to the left, front, and right of the bumper are set in advance in a non-volatile memory (not shown). . Slave 1
Reference numerals 1, 21, and 31 are ultrasonic sensors that form an obstacle detection device for a vehicle, and are sequentially installed in this order from a position closer to the master 10 on the left, front, and right of a vehicle bumper. The above IDs are not set in advance in the slaves 11, 21, and 31 before installation in the vehicle.

In the master 10, as shown in detail in FIG.
The controller 10a is supplied with power from the vehicle-mounted battery + B via the ignition switch IG. Also,
One end of the switch 10b is connected to the in-vehicle battery + B via the ignition switch IG, and the other end is connected to the power supply line 1. As shown in FIG. 3, the slave 11 (and 2
1, 31) are provided with a switch 12, a power supply circuit 13 and a controller 14. The power supply line 1 drawn from the master 10 is connected in series via each switch 12 in the slaves 11, 21, 31. That is, one end of each switch 12 in the slaves 11, 21, 31 is connected to the upstream side, and the other end is connected to the downstream side.

In the slave 11 (and 21, 31), the power supply circuit 13 also includes one end of each switch 12 and the master 10.
The controller 14 is connected to the GND line 2 drawn out from to generate power for the controller 14. The controller 14 is the master 10
It is directly connected (bus connection) to the GND line 2 and the communication line 3 drawn from the switch, and also controls the switch 12.

FIG. 4 shows a master 10-slave 11, 21,
The format of the communication frame between 31 is shown, and one frame is a start of frame (SOF) and a destination,
The message type, ID, frame length, error check code (ECC), and end of frame (EOF) fields are included.

When the communication frame is an ID setting message for setting an ID from the master 10 to the slaves 11, 21, and 31, a broadcast address is set in the destination field and "ID setting" is set in the message type field. Is set, and the setting ID is set in the ID field. If the communication frame is an ID setting completion message returned from the slaves 11, 21, 31 to the master 10, the master address is set in the destination field, and “ID setting complete” is set in the message type field. A setting ID is set in the ID field.

Next, the ID setting operation will be described with reference to FIGS. First, the controller 10a of the master 10 (hereinafter simply referred to as the master 10) starts when the vehicle ignition switch IG is turned on and power is supplied from the vehicle battery (step S1), and the switch 10b is turned on to turn on the power supply line. Supply power to 1 (step S
2). As a result, only the controller 14 of the slave 11 at the next stage (hereinafter, simply slave 11) is supplied with power and starts (step S11).

The master 10 then sets the setting ID to the initial value (I
D = 1) (step S3) and then its ID
The ID setting message in which is set is transmitted to the communication line 3 (step S4), and the ID setting completion message is waited for (step S5). The slave 11 starts when the ignition switch IG of the vehicle is turned on and is supplied with power from the vehicle-mounted battery, and when the ID setting message is received in step S12, the slave 11 determines whether the ID setting message ignore flag F is set. (Step S
13) If it is not set, the process proceeds to step S14. On the other hand, if it is set, the received message is ignored and this process ends. Here, the ID setting message ignore flag F has an initial value of F = 0,
It is a flag that the slave set to set F = 1.

In step S14, the ID in the received ID setting message is stored, and then the ID setting completion message in which the setting ID is set is transmitted (step S1.
4) and then turn on the switch 12 (step S1
5) Next, the ID setting message ignore flag F is set (step S16), and then the process ends. This allows
The slave 21 in the next stage starts by being supplied with power, and the slave 11 having completed the ID setting ignores the ID setting message for the slaves 21 and 31 in the subsequent stages.

In step S5, the master 10 determines whether or not the ID setting completion message is received. If the ID setting completion message is received, the process proceeds to step S6, while if not received, the process branches to step S9. In step S6, the ID in the transmitted ID setting message is compared with the ID in the received ID setting completion message, and if they match, the process proceeds to step S7.
Branch to 9. In step S9, it is determined that the ID setting is defective and the power supply line 1 is turned off. Then, the process returns to step S2 and the power supply line 1 is turned on again.
Start over. As a result, erroneous ID setting due to engine noise or the like can be prevented.

In step S7, it is determined whether or not the ID setting up to the last slave 31 has been completed. If not completed, the process proceeds to step S8 to set the setting ID to the next ID (ID
= ID + 1), and then returns to step S4 to send an ID setting message in which the ID is set to the communication line 3 to set the ID of the slave 21 in the next stage. ID up to the last slave 31 in step S7
If the setting is completed, the process proceeds to step S10 to start communication for collecting information from each slave 11, 21, 31 to which the individual ID is set by the polling / selecting method or the like.

Therefore, according to the first embodiment, the power supply line 1 drawn from the master 10 is connected to the slaves 11 and 2.
Connected in series via each switch 12 in 1 and 31 (GN
The D line 2 and the communication line 3 are always connected to the bus), and the power line 1 is turned on by each switch 12 to set the ID in order from the slave close to the master 10 side. The ID can be normally set for each slave 11, 21, 31 without being aware of the installation position of 31.

<Second Embodiment> In the first embodiment,
Connect the power supply line 1 in series via each switch 12,
Although the D line 2 and the communication line 3 are always connected to the bus, in the second embodiment, the communication line 3 is the slave 1 as shown in FIG.
The power source line 1 and the GND line 2 are always connected to the bus via the switches 12 of 1, 21, and 31 in series. In the second embodiment, when the master 10 turns on the power supply line 1, all the slaves 11, 21 and 31 are in the operating state, but the slaves closer to the master 10 side sequentially.
Since the communication line 3 is turned on by each switch 12 and the bus is connected to set the IDs of the slaves 11, 21 and 31, the worker does not have to be aware of the installation positions of the slaves 11, 21 and 31 and the individual slaves. IDs can be normally set for 11, 21, and 31.

<Third Embodiment> In the third embodiment,
As shown in FIG. 8, the GND line 2 is connected in series via each switch 12, and the power supply line 1 and the communication line 3 are always bus-connected. In the third embodiment, the GND is set by the switches 12 sequentially from the slave close to the master 10 side.
Turn on line 2 to connect to the bus and set slaves 11, 21, 3
Since the ID of 1 is set, the worker can
It is possible to normally set the ID for each slave 11, 21, 31 without being aware of the installation positions of 1, 21, 31.

<Fourth Embodiment> In the fourth embodiment,
As shown in FIGS. 9 and 10, the power supply line 1, the GND line 2 and the communication line 3 are bus-connected, and the ID setting lines 7, 8 and 9 are between the master 10 and the slave 11 and the slave 11-, respectively.
21 and the slaves 21-31 are connected in series. When the ID setting lines 7, 8 and 9 are high-active and the slaves 11, 21 and 31 are in the high-active state and the above-mentioned ID setting message ignore flag F is not set, the ID setting message on the communication line 3 is set. To set the ID, and set the next ID setting lines 8 and 9 to
It is configured to activate.

Therefore, as shown in FIG.
When the master 10 changes the ID setting line 7 from L to H (high-active) and transmits an ID setting message with ID = 1 set to the communication line 3, only the slave 11 sends the communication line 3
Capture the ID setting message above and set the ID
The D setting completion message is transmitted to the communication line 3. Further, the ID setting line 8 of the next stage is set to H and the ID setting message ignore flag F is set. When the master 10 receives the ID setting completion message on the communication line 3 and transmits the next ID setting message to the communication line 3, only the slave 21 in the next stage performs the same operation as the slave 11 in the previous stage.

Therefore, according to the fourth embodiment, the master 10 and the slaves 11 and 21 sequentially set the ID setting lines 7, 8 and 9 to H to set the IDs of the slaves 11, 21 and 31, respectively. Have multiple slaves 11, 2
The ID can be normally set for each slave 11, 21, 31 without being aware of the individual installation positions of 1, 31.

[Brief description of drawings]

FIG. 1 is a block diagram showing a vehicle obstacle detection device as a first embodiment of a communication device according to the present invention.

FIG. 2 is a block diagram showing a configuration of a master shown in FIG.

FIG. 3 is a block diagram showing a configuration of a slave of FIG.

FIG. 4 is an explanatory diagram showing a format of a communication frame between the master and the slave in FIG.

5 is a flowchart for explaining the operation of the master and slave of FIG.

6 is a timing chart showing a communication sequence between the master and the slave in FIG.

FIG. 7 is a block diagram showing a configuration of a slave of the second embodiment.

FIG. 8 is a block diagram showing a configuration of a slave according to a third embodiment.

FIG. 9 is a block diagram showing a communication device of a fourth exemplary embodiment.

10 is a block diagram showing a configuration of a slave of FIG.

11 is a timing chart showing a communication sequence between the master and slave in FIG.

FIG. 12 is a block diagram showing a conventional communication device.

[Explanation of symbols] 1 power line 2 GND line 3 communication lines 10 Master 11, 21, 31 slaves 12 switches

Claims (6)

[Claims] 1. A communication device in which a plurality of slave devices arranged at respective predetermined positions are connected to a master device via a bus, wherein each of the plurality of slave devices has the bus and a slave device at the next stage. The master device has a switch for turning on and off the connection, and sets the ID to the first slave device via the bus based on the ID stored in advance in the master device according to each arrangement position of the plurality of slave devices. Later, I
The slave device set to D sequentially turns on the switch to connect the slave device of the next stage to the bus, and
A communication device, wherein the master device sets an ID for a slave device at a next stage connected to a bus. 2. Each of the plurality of slave devices is configured to turn on / off a connection between a power supply line forming the bus and a slave device at a next stage, and a slave device having an ID set switches the switch. The power supply line is connected to the slave device of the next stage by bus connection when turned on.
The communication device according to 1. 3. Each of the switches of the plurality of slave devices is configured to turn on / off the connection between the communication line forming the bus and the slave device of the next stage, and the slave device to which the ID is set switches the switch. 2. The communication line is connected to the slave device of the next stage by bus connection when turned on.
Or the communication device according to 2. 4. Each of the switches of the plurality of slave devices is configured to turn on / off the connection between the ground line forming the bus and the slave device of the next stage, and the slave device to which the ID is set switches the switch. 2. The ground line is connected to the slave device at the next stage by bus connection when turned on.
5. The communication device according to any one of 1 to 3. 5. A communication device in which a plurality of slave devices arranged at respective predetermined positions are connected to a master device via a bus, wherein the master device and the plurality of slave devices are independent of the bus. The IDs are connected in series via an ID setting line, and the IDs are stored based on the IDs stored in advance by the master device according to the respective arrangement positions of the plurality of slave devices.
After turning on the setting line and setting its ID to the first slave device via the bus, the slave devices to which the ID is set sequentially turn on the ID setting line to the slave device of the next stage, A communication device, wherein the master device sets an ID for a slave device at a next stage in which the ID setting line is on. 6. An obstacle detection sensor in which each of the plurality of slave devices is arranged at each appropriate position of a vehicle, wherein the master device responds to the arrangement position when an ignition switch of the vehicle is turned on. The communication according to any one of 1 to 5, characterized in that an ID is set in the obstacle detection sensor and the position of the obstacle is detected based on the ID of the obstacle detection sensor that has detected the obstacle. apparatus.