JP3178206B2 - Multiplex communication device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention
The present invention relates to a multiplex communication device using a transmission rate conversion device that enables communication between two multiplex communication networks.

[0002]

2. Description of the Related Art When a multiplex communication system is applied to a vehicle or the like, a multiplex communication network connecting between units for vehicle control, such as an engine control unit and an automatic transmission control unit, is required to realize rapid processing. It is necessary to perform high-speed communication. In the case of such high-speed communication, it is necessary to use an expensive optical fiber, shielded wire, or the like for the transmission line in order to prevent adverse effects such as radio wave interference and interference. However, if this transmission line is applied to sensors and switches that do not change relatively and actuators that do not need high-speed control,
Especially when they are present at the end, the cost becomes enormous, and the advantage of using the multiplex communication system is reduced. For this reason, a relatively inexpensive AV line or twisted pair line is used for the transmission line at such a terminal portion, and instead, measures are taken to prevent a radio wave disturbance or interference by drastically reducing the transmission speed. However, such a difference in transmission speed makes it impossible to directly perform transmission and reception between a node on the high-speed communication network and a node on the low-speed communication network. In order to solve the above-mentioned problem, a conventional method for realizing communication between communication networks having different transmission speeds is disclosed in
-254249. In this method, a transmission rate conversion device is provided between a high-speed communication network and a low-speed communication network, and the transmission rate is converted for transmission / reception. For example, when a multiplex node on a high-speed communication network issues a transmission request to a multiplex node on a low-speed communication network, the transmission rate converter stores in advance the data of the multiplex node on the low-speed communication network in a storage unit via a transmission path. If there is a transmission request from a multiplex node on the high-speed communication network to a multiplex node on the low-speed communication network, the corresponding data is read from the storage means and data conversion is performed. Send to With this configuration, nodes on the high-speed communication network can communicate with nodes on the low-speed communication network as if they were communicating with nodes on the high-speed communication network.

[0003]

However, in the conventional multiplex communication system as described above, in order for the master station on the high-speed communication network to communicate with any of the slave stations on the low-speed communication network, a transmission rate conversion device is required. Requires data storage means for the number of slave stations on the low-speed communication network.
Thus, for example, when a RAM is used, the data area to be secured increases in proportion to the number of slave stations.
Further, the contents of this storage means must be updated periodically in preparation for a transmission request from the master station. Therefore,
When a slave station is added, not only does the memory need to be added in some cases, but also the data updating procedure is increased by the number of the added slave stations, so that there is a problem that control software needs to be replaced. Such a problem becomes a greater problem when the transmission rate converter is entirely controlled by hardware, for example, by using a custom IC for cost reduction. That is, it is necessary to change the specifications of the transmission rate converter every time a slave station is added, and the circuit scale of the buffer as the storage means increases with the increase in the number of slave stations.

The present invention has been made to solve the above-mentioned problems of the prior art. Even when nodes on a network are added, it is necessary to add storage means and change control software in a transmission rate converter. An object of the present invention is to provide a multiplex communication device that does not need to be provided.

[0005]

Means for Solving the Problems In order to achieve the above object, the present invention is configured as described in the claims. That is, in the first aspect of the present invention, the transmission rate conversion device stores at least one data in the first storage area for storing transmission data from the master station and at least one data from the slave station on the second multiplex communication network. And a storage unit having a second storage area for storing data for each station, and wherein the transmission rate conversion device transmits data to a slave station on the second multiplex communication network when the master station transmits the data to the slave station on the second multiplex communication network. When the transmission data is output on the line, the transmission data is stored in the first storage area, and after completion of the reception of the transmission data, the data stored in the first storage area is stored on the transmission line of the second multiplex communication network. Output at a specified transmission rate, output data stored in the second storage area on a transmission line of the first multiplex communication network at a specified transmission rate, and transmit data from a master station. Storing the reply data from the slave station on the second multiplex communication network to the second storage area, it is configured so as.

[0006] The invention described in claim 2 is the invention according to claim 1.
Wherein the transmission rate conversion device includes a first reception circuit that receives a signal on a transmission line, and a first reception circuit that temporarily holds the reception data.
, A first transmitting circuit for outputting data of the first buffer onto a transmission line, a second receiving circuit for receiving a signal on the transmission line, and a second receiving circuit for temporarily storing the received data.
, A second transmitting circuit for outputting the data of the second buffer onto the transmission line, and a command discriminator for discriminating that the transmission signal of the master station is a command for a slave station on a second multiplex communication network. A first receiving circuit, a first buffer, and a first transmitting circuit connected in order from the first multiplex communication network to the second multiplex communication network, and A second receiving circuit, a second buffer, and a second transmitting circuit are connected in this order toward the first multiplex communication network, and a determination output of the command determining circuit is connected to the first receiving circuit and the first buffer. And a reception completion signal output of the first reception circuit is connected to the first transmission circuit and the second transmission circuit. Note that the first multiplex communication network corresponds to, for example, the high-speed multiplex communication network 103 or the high-speed multiplex communication network 513 in the embodiment of FIG. 1 or FIG. Network 10
5 or a low-speed multiplex communication network 515.
The storage means also corresponds to the memory 110 or the buffers 506 and 507.

[0007]

According to the first aspect, the master station on the first multiplex communication network transmits the transmission data to the slave station on the second multiplex communication network onto the transmission line on the first multiplex communication network side. If output, the transmission rate conversion device provided between the two networks stores this data in the first storage area of the storage means, and after completion of reception, the transmission data of the master station stored in the first storage area. Is output on the transmission line on the second multiplex communication network side, and the data stored in the second storage area of the storage means is output on the transmission line on the first multiplex communication network side. The data is stored in the second storage area of the storage means. As described above, in the present invention, when the master station transmits to the slave station on the second (low-speed) multiplex communication network, the reply from the slave station is to the previous transmission.
That is, instead of immediately transmitting a reply from the slave station to the current transmission, the next transmission to the second multiplex communication network (for example, several times of transmission and reception with the slave station on the first multiplex communication network is completed). Done after
You will get this reply. With the above-described configuration, the storage means can store any reply for one transmission from the master station, regardless of the number of slave stations on the low-speed side. The first storage area for storing transmission data from the master station and the second storage area for storing data for one station from the child station on the second multiplex communication network. Only the area is required, and the number of slave stations is not affected. Also, it is not necessary to change control software by adding a slave station. Claim 2 describes a specific configuration of the transmission rate conversion device according to claim 1. According to this configuration, one custom IC can be used without software control.
It can be realized by.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings.
FIG. 1 is a block diagram of one embodiment showing the overall configuration of the present invention. In FIG. 1, a high-speed multiplex communication network 1
Reference numeral 03 includes a master station 101 and a plurality of slave stations 102, and performs communication at a relatively high transmission rate. The low-speed multiplex communication network 105 includes only a plurality of slave stations 104 and communicates at a relatively low transmission speed. The high-speed multiplex communication network 103 and the low-speed multiplex communication network 105 are connected via a transmission speed converter 106. The transmission rate conversion device 106 includes transmission control units 107 and 108 composed of a transmission / reception circuit for controlling signals on a transmission line and a communication IC, and a memory 110 for storing control software and data of a CPU.
And a CPU 109 for controlling a transmission control unit and a memory and processing data. The memory 110 as the storage means has an area for storing transmission data from the master station 101 on the high-speed multiplex communication network 103 (master station data storage area) and a slave station 104 on the low-speed multiplex communication network 105. An area (slave station data storage area) for storing data from one station for one station is secured.

In each multiplex communication network, as shown in FIG. 2, a communication system is used in which the master station transmits to the slave station and the slave station responds accordingly. And FIG. 3 is an example diagram of a communication format in a transmission signal of the master station. As shown in FIG. 3, the communication format is a transmission start signal 3
01, a command frame 302 for specifying an operation mode,
A command frame 3 includes an address frame 303 for designating a transmission target node, a data frame 304 indicating specific command contents, and a transmission end signal 305.
02 contains contents indicating whether transmission is to a slave station on a high-speed or low-speed multiplex communication network.

Next, the operation of the present invention will be described. FIG. 4 shows the signals on each of the multiplex communication networks 103 and 105 in FIG.
FIG. 7 is a diagram showing the contents of two data areas secured in the first embodiment.
First, when the master station 101 performs transmission 403 to one of the slave stations 104 on the low-speed multiplex communication network 105,
When the transmission rate converter 106 determines from the command frame 302 that this signal is to be transferred to the low-speed multiplex communication network 105, the transmission rate converter 106 stores the received data in the master station data storage area of the memory 110 (data 408). Next, when the reception is completed, the transmission rate converter 106 outputs the data 408 stored in the master station data storage area onto the low-speed multiplex communication network 105 at the designated transmission rate (414), and stores the slave station data. The data 410 stored in the area is output to the high-speed multiplex communication network 103 at the specified transmission rate (40).
4). The data 410 stored in the slave station data storage area is data corresponding to the slave station reply 413 to the previous transmissions 401 and 412 for the low-speed multiplex communication network, and the slave station response to the current transmissions 403 and 414. When there is a reply 415, the content is updated (4
11). Further, after receiving transmissions 405 and 416 for the next low-speed multiplex communication network, the return data 411
At the designated transmission rate on the high-speed multiplex communication network 103 (406). That is, when the master station 101 has transmitted to the slave station 104 on the low-speed multiplex communication network 105, the current reply from the slave station 104 is to the previous transmission. After several times of transmission and reception with the slave station 102 on the high-speed multiplex communication network 103, when the next transmission to the low-speed multiplex communication network 105 is made, this reply is obtained. Therefore, the control software for controlling the master station is
Consider that there is no relation between the current command of the master station 101 and the reply signal obtained immediately after that, and that the current reply signal was transmitted by the slave station 104 which was the target of the previous command. To create. With the above configuration, regardless of the number of slave stations on the low speed side,
Since it is only necessary to have a capacity for storing one reply for one transmission from the master station, an area to be provided in the memory 110 is a master station data storage area for storing transmission data from the master station 101. And a slave station data storage area for storing one station of data from the slave station 104 on the low-speed multiplex communication network 105, and is not affected by the number of slave stations. In addition, it is not necessary to change control software by adding a slave station.

Next, FIG. 5 shows the transmission rate converter 1 of FIG.
FIG. 10 is a block diagram of an embodiment configured so that software control is not required by replacing part 06 with one custom IC. In FIG. 5, the transmission rate conversion custom IC 501 is configured as follows. First, receiving circuits 502 and 503 for receiving signals on a transmission line, buffers 506 and 507 for temporarily storing the received data,
Transmission circuits 504 and 50 for outputting the data on a transmission line
5 are provided, and are connected in order according to the signal flow between the respective networks of “high speed → low speed” and “low speed → high speed”. The master station 511 on the high-speed multiplex communication network 513 received by the receiving circuit 502
Is provided, a command discriminating circuit 508 for discriminating that the transmitted signal is a command for the slave station 514 on the low-speed multiplex communication network 515, and an output 509 of the command discriminating circuit 509 is provided.
02 and the buffer 506. further,
The reception completion signal 510 output from the reception circuit 502 is
The signals are input to two transmission circuits 504 and 505.

Next, the operation will be described. The basic operation is the same as that described with reference to FIG. That is, the master station 5
11 is a slave station 514 on the low-speed multiplex communication network 515
Command is sent to one of the
08 determines from the command frame that the signal received by the receiving circuit 502 is to be passed to the low-speed multiplex communication network 515, and generates an output 509. The buffer 506 receiving the output 509 holds the data received by the receiving circuit 502. Similarly, receiving circuit 502 receiving output 509 of command discriminating circuit 508 outputs reception completion signal 510 when reception is completed. In response to the signal 510, the transmission circuit 504 outputs the data held in the buffer 506 to the low-speed multiplex communication network 515 at the specified transmission speed, and the transmission circuit 505 multiplexes the data held in the buffer 507 at a high speed. The data is output to the communication network 513 at the specified transmission speed. When a reply is received from the slave station, the contents of the buffer 507 are updated by the receiving circuit 503. Furthermore, the next low-speed multiplex communication network 5
The transmission circuit 505 that has received the reception completion signal 510 of the reception circuit 502 at the time of transmission for
7 is output on the high-speed multiplex communication network 513 at the designated transmission speed.

FIG. 6 is a block diagram showing an example in which the present invention is applied to a multiplex communication system for vehicles. In FIG. 6, a high-speed multiplex communication network 601 includes a master station that is the center of vehicle control such as an engine control unit 602, an automatic transmission control unit 603, and an anti-lock brake control unit 604, and an actuator that requires high-speed control. Slave station 606 with
Is configured as a main node. In addition, the two low-speed multiplex communication networks 608 and 610 are configured with, as main nodes, slave stations having terminal switches and sensors, actuators that do not require high-speed control, and the like. Each of the low-speed multiplex communication networks 608 and 610 and the high-speed multiplex communication network 601 are connected to the transmission rate converter 6 respectively.
11 and 612. These transmission rate converters 611 and 612 have the configuration of 106 in FIG. 1 or 501 in FIG. As described above, each of the control units 602 to 605, which are master stations on a plurality of high-speed multiplex communication networks, sequentially obtains the transmission right by the token passing method, and gives the respective slave stations 606, 608, and 609 to be controlled. On the other hand, communication by the bowling selecting method is performed.

[0014]

As described above, according to the present invention, when a master station on a high-speed multiplex communication network transmits to a slave station on a low-speed multiplex communication network,
A transmission rate conversion device provided between the networks stores the transmission data in the first storage area, and after completion of reception, transmits the transmission data of the master station stored in the first storage area on the low-speed multiplex communication network. By transmitting the data stored in the second storage area to the high-speed multiplex communication network while transmitting the data to the slave station, and storing the reply data of the slave station in the second storage area, Regardless of the number of slave stations on the low-speed side, it is sufficient if there is enough capacity to store one reply for one transmission from the master station. There is no need to add storage means or change control software or the like in the conversion device, and it is possible to obtain the effect that the cost can be easily reduced by using a custom IC or the like.

[Brief description of the drawings]

FIG. 1 is a block diagram of an embodiment showing an overall configuration of the present invention.

FIG. 2 is a diagram showing an example of a communication procedure used in the present invention.

FIG. 3 is a diagram showing an example of a communication format used in the present invention.

FIG. 4 is a multiplex communication network 103, 105 of FIG. 1;
The above signal and the memory 11 in the transmission speed conversion device 106
The figure which shows the content of two data areas ensured to 0.

FIG. 5 is a block diagram of another embodiment of the present invention.

FIG. 6 is a block diagram showing an application example of the present invention.

[Explanation of symbols]

Reference Signs List 101: master station 102: slave station of high-speed multiplex communication network 103: high-speed multiplex communication network 104: slave station of low-speed multiplex communication network 105: low-speed multiplex communication network 106: transmission speed conversion device 107, 108: transmission control unit 109: CPU Reference numeral 110: memory 401: previous transmission signal of the master station 402: return signal of the transmission speed conversion device for the previous transmission of the master station The data is the last two times 403: transmission signal of the current master station 404: transmission of the current master station The return signal data of the transmission rate converter is the previous one 405... The next transmission signal of the master station 406... The return signal data of the transmission rate converter for the next transmission of the master station is this time 407. … Current transmission data of the master station 409… Response data of the previous slave station 410… Response data of the previous slave station 411: current return data of the slave station 412: transmission signal of the previous transmission rate converter 413: return signal of the slave station in response to the previous transmission of the transmission rate converter 414: transmission signal of the current transmission rate converter 415: this time A return signal of the slave station in response to the transmission of the transmission rate converter 509: Command discrimination circuit output 510: Reception completion signal

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H04L 12/28

Claims (2)

(57) [Claims] 1. A transmission line serving as a communication medium for connecting one or more master stations, a plurality of first slave stations for replying to the transmission of the master station, and the master station and the slave station group. And a plurality of second slave stations, and a transmission line connecting the slave stations, and perform communication at a transmission rate lower than that of the first multiplex communication network. A second multiplex communication network to be performed, and a transmission rate conversion device connected between a transmission line of the first multiplex communication network and a transmission line of the second multiplex communication network; The transmission rate conversion device returns a response to the transmission of the master station through the transmission line of the multiplex communication network, and the transmission speed conversion device performs the transmission through the transmission line of the second multiplex communication network. The above Wherein the transmission rate conversion device comprises: a first storage area for storing transmission data from the master station; and a second storage area for storing transmission data from the master station. And a second storage area for storing data from at least one of the slave stations, and wherein the transmission rate conversion device is characterized in that the master station is a slave station on the second multiplex communication network. Data for the first
When the transmission data is output on the transmission line of the multiplex communication network, the transmission data is stored in the first storage area of the storage means, and after the transmission data is completely received, the transmission data is stored in the first storage area. The data is output on the transmission line of the second multiplex communication network at a designated transmission rate, and the data stored in the second storage area of the storage means is output on the transmission line of the first multiplex communication network. It is configured to output at a designated transmission rate and store return data from a slave station on the second multiplex communication network in response to transmission from the master station in a second storage area of the storage means. A multiplex communication device, comprising: 2. The transmission rate conversion device according to claim 1, wherein the transmission rate conversion device includes a first reception circuit for receiving a signal on the transmission line, a first buffer for temporarily storing the received data, A first transmitting circuit for outputting, a second receiving circuit for receiving a signal on the transmission line, a second buffer for temporarily storing the received data, and a second buffer for outputting the data of the second buffer to the transmission line. And a command discriminating circuit for discriminating that the transmission signal of the master station is a command for a slave station on the second multiplex communication network. The first receiving circuit, the first
Buffer, the first transmission circuit, the second reception circuit, the second buffer, and the second transmission from the second multiplex communication network toward the first multiplex communication network. Circuits, the determination output of the command determination circuit is connected to the first reception circuit and the first buffer, and the reception completion signal output of the first reception circuit is connected to the first transmission circuit. The multiplex communication apparatus according to claim 1, wherein the multiplex communication apparatus has a configuration connected to the second transmission circuit.