JPH03216041A - Communication system - Google Patents

Abstract

PURPOSE:To implement the processing of establishing an identification code of each slave station between a master station and a slave station at initializing and to enhance a communication efficiency after initializing by adjusting a signal propagation delay time between the master station and each slave station as soon as the identification number is given. CONSTITUTION:An initializing signal detection means 14 of each slave station detects an initializing signal received from a master station via a reception means 5 and a random data means 15 in response thereto receives the initializing signal and generates a random data as a reply time till the reply to the master station and sets the data to a reply delay means 8 and generates and sends the random data as a slave station identification number of its own station. Thus, while the adjustment of the signal propagation delay time between the master station and each slave station is not implemented yet, the identification number is given efficiently so that the reply signal from each slave station is not in duplicate and the identification number realizes a high communication efficiency.

Description

[Detailed Description of the Invention] [Summary] Regarding a communication system in which a master station and a plurality of slave stations are connected by a transmission path, the signal propagation delay time between the master station and each slave station has not yet been adjusted. To efficiently assign an identification number to a slave station whose identification number has not been set in a state where there is no identification number so that response signals from each slave station will not be duplicated, and to achieve high communication efficiency with the identification number. The main station and multiple slave stations are connected by a transmission path.
In a communication system in which a timing signal is given from a master station to each slave station, and the slave stations given the timing signal respond to the master station, the master station has a transmitting means for transmitting a signal to the slave stations. a receiving means for receiving a signal from a slave station; an initialization broadcasting means for controlling the initialization signal to be transmitted in a broadcast format to a connected slave station during initialization; and a receiver for transmitting from the slave station in response to the initialization signal. slave station identification number detection means for detecting a slave station identification number that has been received; and a slave station number assigning means for assigning and storing the slave station number, and at the time of initialization, upon receiving a response from each slave station to the initialization signal, the transmitting means transmits the slave station identification number and the slave station number to the slave station. and each slave station includes a transmitting means for transmitting a signal to the master station, a receiving means for receiving a signal from the master station, and an initialization signal detection means for detecting reception of an initialization signal from the master station. , a slave station number storage means for receiving and storing the slave station number at the time of initialization, and a response to be sent to the master station when a timing signal with the slave station number assigned to the own station is received from the master station. response data generation means for generating data; response delay means for delaying transmission of the response data by a set time; and upon reception of the initialization signal, for responding to the main station after receiving the initialization signal. random data means for generating random data as a response time and setting it in the response delay means, and generating and controlling random data as a slave station identification number of its own station to transmit. Configure.

[Industrial Application Field] The present invention relates to a communication system in which a main station and a plurality of slave stations are connected by a transmission path.

As shown in Figure 8, in a communication system in which a master station and a plurality of slave stations are connected by transmission paths, in order to communicate between the master station and each slave station, the main The station needs to distinguish and recognize each k of the plurality of slave stations. In other words, when transmitting a signal from the master station to each slave station, the master station needs to add an identification code (address) indicating the target slave station, and when a slave station sends a signal to the master station. , each slave station needs to add its own identification code (address).

In particular, in the case of a communication system in which the identification code of each slave station is not established between the master station and the slave station in the initial state, or the connection/disconnection of each slave station to the system, the ON/OFF of the power supply, etc. In the case of a communication system in which there is a possibility of changes, it is possible to efficiently establish the identification code of each slave station between the master station and the slave station at the time of initialization, and improve the communication efficiency after initialization. Technology was required.

Furthermore, when each slave station outputs a signal addressed to the master station in the time slot assigned to it according to the signal from the master station, and the signals are multiplexed on the transmission path and transmitted to the master station, The delay time of each slave station as seen from the master station must be constant.

[Prior Art and Problems to be Solved by the Invention] Conventionally, as shown in FIG. 8, in a communication system that connects a master station and a plurality of slave stations, there is a In order to establish the identification code of each slave station, the master station outputs an initialization signal to each slave station, and each slave station generates a random number in response to this signal to identify itself. Then, when the master station transmits a signal to the target slave station, this number is given as an identification code to each slave station.

However, conventionally, when exchanging signals between the master station and the slave stations for assigning identification codes to each slave station at the time of the above-mentioned initialization, the signal propagation delay time between the master station and each slave station is Since this adjustment has not yet been made, there has been a problem in that the signals returned from each slave station to the master station overlap with each other in response to the above-mentioned initialization signal from the master station.

In addition, in order for each slave station to identify each slave station by a randomly generated number, the random number must have a considerable number of bits, and this number is used as the identification number of each slave station in subsequent communications. However, there was a problem in that doing so reduced communication efficiency.

Furthermore, at the time of initialization, as described above, the signal propagation delay time between the main station and each slave station has not yet been adjusted, so it is necessary to perform this adjustment. Conventionally, adjustment of the signal propagation delay time between a master station and multiple slave stations during initialization was done by sequentially polling each slave station from the master station after setting the above identification number. Therefore, there was a problem in that it took a long time to adjust the signal propagation delay time with all the slave stations.

The present invention has been made in view of the above-mentioned problems, and in a state where the signal propagation delay time between the master station and each slave station has not yet been adjusted, each slave station whose identification number has not been set is The first objective is to provide a communication system that efficiently assigns identification numbers so that response signals from slave stations do not overlap, and that allows the identification numbers to achieve high communication efficiency. It is something to do.

In addition to the above-mentioned first object, the present invention provides a communication system that can efficiently adjust the signal propagation delay time between the main station and each slave station at the same time as assigning the above-mentioned identification number at the time of initialization. The second purpose is to provide the following.

[Means to solve the problem]

FIG. 1 is a basic configuration diagram of a first embodiment of the present invention.

In Figure 1, a master station and a plurality of slave stations are connected by a transmission path, and by giving a timing signal from the master station to each slave station, the slave stations given the timing signal can communicate with the master station. This shows the basic configuration of a master station and a slave station in a communication system that responds to communications.

In the main station shown in FIG. 1, 3 is a transmitting means, 4 is a receiving means,
10 is an initialization broadcasting means, 11 is a slave station number assigning means, and 12 is a slave station identification signal storage means. In the slave station, 5 is a reception means, 6 is a response data generation means, 8 is a response delay means, 9 is a transmission means, IO is an initialization signal detection means, 13 is a slave station number storage means, and 15 is a random data means. It is.

The transmitting means 3 of the master station transmits data to the slave stations.

The receiving means 4 of the master station receives signals from the slave stations.

The initialization broadcast means 10 controls the initialization signal to be sent in a broadcast format to the connected slave stations at the time of initialization.

The slave station identification number detection means 12 detects the slave station identification number transmitted from the slave station in response to the initialization signal.

The slave station number assigning stage 11 assigns to the received slave station identification number one of the slave station numbers having a bit number that can distinguish between a plurality of slave stations connectable to the communication system, and stores the number.

At the time of initialization, upon receiving a response from each slave station to the initialization signal, the transmitting means 3 of the master station transmits the slave station identification number and the slave station number to the slave station.

The transmission means 9 of the slave station transmits data to the slave station.

The receiving stage 5 of the slave station receives a signal from the master station.

The initialization signal detection stage 14 detects reception of an initialization signal from the main station.

When the response data generating means 6 receives the timing signal attached with the slave station identification number from the master station, it generates response data to be responded to the master station.

The response delay means 8 delays the transmission of the response data for a set time.

When receiving the initialization signal, the random data means 15 generates random data as a response time from receiving the initialization signal to responding to the main station, and sets it in the response delay means 8; In addition, control is performed to generate and transmit random data as the slave station identification number of the own station.

The slave station number storage means 13 receives and stores the slave station number from the master station at the time of initialization.

FIG. 2 is a basic configuration diagram of a second embodiment of the present invention.

In Figure 2, a master station and a plurality of slave stations are connected by a transmission path, and by giving a timing signal from the master station to each slave station, the slave stations given the timing signal can communicate with the master station. This shows the basic configuration of a master station and a slave station in a communication system that responds to communications.

In the main station shown in FIG. 2, B is a response delay time measuring means;
' is slave station setting delay time adjustment control means, 3 is transmission means, 4
10 is a receiving means, 10 is an initializing broadcasting means, 11 is a slave station number assigning means, and 12 is a slave station identification signal storage means.

In the slave station, 5 is a receiving means, 6 is a response data generating means, 7' is a response delay time adjustment means, 8 is a response delay means, 9 is a transmitting means, 10 is an initialization signal detection means, and 13 is a slave station number storage. 14 is an initialization signal detection means, and 15 is a random data means.

The transmitting means 3 of the master station transmits data to the slave stations.

The receiving means 4 of the master station receives signals from the slave stations.

The initialization broadcast means 10 controls the initialization signal to be sent in a broadcast format to the connected slave stations at the time of initialization.

The response delay time measuring device measures the response delay time from the time when the initialization signal is sent to the time when a response signal to the initialization signal is received at the time of initialization.

The slave station setting delay time adjustment control means 2' detects an error between the response delay time and a predetermined reference delay time, and transmits error adjustment information to the slave station so as to adjust the error in the delay time. let

The slave station identification number detection means 12 detects the slave station identification number transmitted from the slave station in response to the initialization signal.

The slave station number assigning means 11 assigns to the received slave station identification number one of the slave station numbers having the number of bits that can distinguish between a plurality of slave stations connectable to the communication system, and stores the number.

At the time of initialization, upon receiving a response from each slave station to the initialization signal, the transmitting means 3 of the master station transmits the slave station identification number, the slave station number, and the error adjustment information to the slave station.

The transmission stage 9 of the slave station transmits data to the slave station.

The receiving stage 5 of the slave station receives a signal from the master station.

The initialization signal detection means 14 detects reception of an initialization signal from the main station.

When the response data generating means 6 receives the timing signal attached with the slave station identification number from the master station, it generates response data to be responded to to the master station.

The response delay means 8 delays the transmission of the response data by a preset time.

When the response delay time adjustment means 7' receives the error adjustment information from the main station, it adjusts the set time in the response delay means 8 according to the error adjustment information.

The random data means 15, when receiving the initialization signal, generates random data as a response time from reception of the initialization signal to responding to the main station, and sets the response delay to 8 stages. , and controls to generate and transmit random data as the slave station identification number of its own station.

The slave station number storage means I3 receives and stores the slave station number from the master station at the time of initialization.

[Effect]

In the first form of the present invention, at the time of initialization, the initialization broadcasting means 10 of the main station is controlled to transmit the initialization signal in a broadcast format to the connected slave stations at the time of initialization, and thereby,
An initialization signal is simultaneously transmitted from the transmission stage 3 of the master station to all slave stations connected to the system.

Each slave station detects the above-mentioned initialization signal received via the reception means 5 in the initialization signal detection stage 14, and in response, after receiving the initialization signal, the random data means 15 detects the initialization signal from the master station. It generates random data as the response time until it responds to the request and sets the response delay to 8, and also generates and transmits random data as the slave station identification number of its own station.

In this way, the random data as the slave station identification number of the own station is delayed by the response delay means 8 for the time set by the random data, and then sent to the transmission stage 9.
is sent to the main station via.

The response signals from each slave station to the initialization signal to the master station are each subject to the random response time delay described above, so that the probability that response signals from different slave stations will overlap in time when received by the master station is reduced. It becomes small. (if,
If the response signals from different slave stations overlap in time when received by the master station, they will wait until the next initialization. ) The slave station identification number detection stage 12 of the master station detects the slave station identification number transmitted from the slave station in response to the initialization signal, and the slave station number assigning stage 11 detects the slave station identification number transmitted from the slave station in response to the initialization signal. One of the slave station numbers with the number of bits that can distinguish the plurality of slave stations connectable to the communication system is assigned and stored.

The transmitting means 3 of the master station transmits the slave station identification number and the slave station number to the slave station, and after initialization, the error adjustment information is transmitted with only the slave station number attached when transmitting the timing signal. .

The slave station number storage means 13 of the slave station stores the slave station number received from the master station together with the slave station identification number based on the random data sent from the own station at the time of initialization. In subsequent communication between the master station and the slave station, this slave station number is used as a code for identifying the slave station.

Assuming that the slave station number consists of the minimum number of bits that can distinguish the number of slave stations that can be connected to the communication system, a code for identifying the slave station is set by the minimum number of bits, and the number of slave stations in this communication system is Communication efficiency is maximized.

In addition, the main station sends out a one-time initialization signal in broadcast format,
All connected slave stations respond with response signals to which slave station identification numbers based on random data are added, with random delay times, so when the response signals from each slave station are received at the master station, the time is different from each other. The probability of overlapping can be made low.

In the second embodiment of the present invention, at the time of initialization, the main station performs the same processing as in the first embodiment, as well as
When the timing signal is transmitted to each slave station, the response delay time measuring means 1' measures the response delay time from the time of transmitting the timing signal to the time of receiving the response signal to the timing signal, and measures the response delay time at the time of initialization. , the slave station setting delay time adjustment control means 2' measures the response delay time from the sending of the initialization signal to the reception of the response signal to the initialization signal, and adjusts the response delay time and a predetermined reference delay. The slave station is caused to transmit error adjustment information so as to detect the error with the time and adjust the error in the delay time. In accordance with this control, the transmitting means 3 transmits the slave station identification number, the slave station number, and the error adjustment information to the slave station.

When each slave station receives the above signal, it determines whether the signal is addressed to itself based on the slave station identification number, and if the signal is addressed to itself, it performs the same processing as in the first form above. Then, the response delay time adjustment means 7' adjusts the set time in the response delay means 8 according to the error adjustment information received at the same time.

In this way, at the time of initialization, the above-mentioned slave station number is assigned, and at the same time, the response at each slave station is delayed in response to the difference in propagation delay due to the difference in transmission path length depending on the placement position of the slave station, and the variation in transmission path delay due to temperature changes, etc. It becomes possible to adjust the time.

(Embodiment) FIG. 3 is a diagram showing an example of the operation of the main station in the first embodiment of the present invention that implements the first embodiment of the present invention.

In step 100 of FIG. 3, the master station transmits an initialization signal to the slave station, and in step 101, the count L of the delay time measurement counter is set to 1=0.

Then, in step 102, the slave station index is set to i=0.
In steps 103 and 104, the time until a response is received from the first slave station (which has the shortest response delay time due to the delay randomly generated by each slave station as described later) is measured, and when the time measurement is completed, , step 10
5, the slave station index is updated.

Then, in step 106, it is determined whether or not a predetermined time set in advance as the delay time measurement period at the time of initialization has elapsed. If it has not elapsed, the process proceeds to step 108 and the next slave station For the response, step 10 above
Steps 3 to 105 are performed, and the steps are repeated until it is determined in step 106 that the delay time measurement period has elapsed.
When it is determined in step 106 that the delay time measurement period has elapsed, the process proceeds to step 10B.

In step 10B, the number i of slave stations that have stored slave station identification numbers and error correction information τi as described above is set to ■, and the index of the destination slave station is set to j10.

In step 109, j is incremented, and in step 110, one of the slave station numbers prepared in advance by the master station is selected.
The one that has not been assigned to any slave station yet is assigned, and in step 111, the assigned slave station number is transmitted together with the corresponding slave station identification number, and the error corresponding to the slave station identification number previously stored in step 107 is transmitted. One of the sets of modification information τi that has not yet been transmitted is transmitted. Thereafter, in step 112, the operations of steps 109 to 111 are repeated until it is determined that j=I.

FIG. 4 is a diagram showing an example of the operation of the slave station in the first embodiment of the present invention that implements the first form of the present invention.

In step 81 of FIG. 4, the slave station determines whether it has received an initialization signal or a polling signal from the master station, and if it has received an initialization signal, step 8
3, the response delay time Tr obtained as random data generated in the random data generation circuit provided in the slave station.
Let be the set time in the response time counter. and,
In step 84, the count L of the response time counter is set to 110, and in steps 85 and 86, the time is counted until it becomes equal to the set time Tr set in the response time counter as described above. Responds to initialization signals. The response also includes the slave station identification number obtained as random data generated by the random data generating circuit described above.

If the polling signal is received in step 8l, the counter I-t of the response time counter is set to 1 in step 88.
= 0, in steps 89 and 90, time is counted until the time becomes equal to the set time T set in the response time counter, and in step 91, a response to the polling signal is performed.

FIG. 5 shows the timing of signals at the time of initialization between the master station and the slave station in the embodiment of the present invention shown in FIGS. 3 and 4 above.

FIG. 6 is a diagram showing an example of the operation of the main station in the second embodiment of the present invention that implements the second embodiment of the present invention.

The only difference between the procedure in Figure 6 and the procedure in Figure 3 above is:
In FIG. 6, after step l05 in FIG. 3, as step 105', the difference τi=T0-L between the predetermined time T0 and the count L of the response time counter described above is calculated, and the third In step 111' instead of step 111 in the figure, the above-described difference τi is transmitted as a response time correction signal together with the assigned slave station number and the corresponding slave station identification number.

FIG. 7 is a diagram showing an example of the operation of the slave station in the second embodiment of the present invention that implements the second embodiment of the present invention.

The only difference between the procedure in Figure 7 and the procedure in Figure 4 above is:
In FIG. 7, in step 81', the slave station determines whether it has received an initialization signal, a polling signal, or a response time correction signal from the master station, and if error correction information τi If the response time correction signal including the response time correction signal is received, in step 92, the set time T of the response time counter within the own station is corrected as T=T+τ].

Although not shown, as described above, the
In the second embodiment of the present invention, each slave station has a response time counter consisting of a precenterable counter, and in the second embodiment of the invention, the master station has a delay time measurement counter.

The other operations shown in FIGS. 3 to 7 in the master station and the slave station are each realized by software.

In the first and second embodiments described above, each slave station responds to the initialization signal transmitted (simultaneously) in broadcast format from the master station to each slave station based on randomly generated data. However, if the response times of multiple slave stations are close to each other, responses that arrive at the master station later will be ignored. However, even during normal system operation, the above initialization procedure, for example,
This is repeated every second, and the response to the initialization signal is
A slave station that is not accepted by the master station due to competition with other slave stations or signal errors as described above will send a response to the master station again at the next initialization opportunity. The same applies to slave stations newly connected during the system operation period and slave stations newly turned on. At this time, it is assumed that each slave station remembers whether or not it has already been initialized, using a flag or the like, for example.

Furthermore, as described above, the master station will subsequently poll the initialized slave stations that have stored the slave station identification numbers, but the response to the polling signal to the initialized slave stations will be no response. When this happens, the slave station is assumed to have been disconnected from the system by turning off the power, etc., and the memory of the slave station identification number, etc. for the slave station is deleted. However, since a response may not be obtained due to an error during transmission, for example, it is also possible to provide a protective measure such as erasing the memory if there is no response to a predetermined number of pollings.

Note that the communication system of the present invention described below is not limited to the case where the master station and the slave station are connected by a bus-like transmission path as shown in FIG. 8, but can also be connected by other forms of transmission path. For example, the above-mentioned configuration of the communication system of the present invention also holds true when the master station and the slave stations are connected in a star shape, tree shape, or other transmission path. It is clear from the fact that it does not depend on

[Effects of the Invention] According to the communication system of the present invention, when the signal propagation delay time between the master station and each slave station has not yet been adjusted, each slave station can send a message to a slave station whose identification number has not been set. It becomes possible to efficiently assign an identification number so that no duplication of response signals occurs, and to use the identification number to achieve high communication efficiency. Further, at the time of initialization, the signal propagation delay time between the main station and each slave station can be efficiently adjusted at the same time as the identification number is assigned.

[Brief explanation of drawings]

FIG. 1 is a basic configuration diagram of the first embodiment of the present invention, FIG. 2 is a basic configuration diagram of the second embodiment of the invention, and FIG. 3 is a basic configuration diagram of the first embodiment of the invention.
4 is a diagram showing the operation of the slave station in the first embodiment of the present invention. FIG. 5 is a diagram showing the initialization in the first and second embodiments of the present invention. 6 is a diagram showing the operation of the master station in the second embodiment of the present invention, FIG. 7 is a diagram showing the operation of the slave station in the second embodiment of the present invention, and FIG. 8 is a diagram showing the overall configuration of a communication system to which the present invention is applied. [Explanation of symbols] BI1 response delay time measuring means, 2' slave station setting delay time adjustment control means, 31 master station transmitting means, 4 master station receiving means,
10--1 initialization broadcasting means, 11-- slave station number assigning means, 12--1 slave station identification signal storage means, 5-1 slave station receiving means, 6- response data generation means, 7'- response delay time adjustment means. , 81-response delay means, 101-initialization signal detection means, 13-slave station number storage means, 15-random data means. Main station Figure 3 shows the basic configuration of the first embodiment of the present invention Main station 2 Figure 6 shows the operation of the main station in the first embodiment of the invention

Claims (1)

[Claims] 1. A master station and a plurality of slave stations are connected by a transmission path, and a timing signal is given from the master station to each slave station, so that the slave stations to which the timing signal is given can In a communication system that responds to a master station, the master station includes a transmitting means (4) for transmitting a signal to a slave station, a receiving means (5) for receiving a signal from the slave station, and a transmitting means (5) that is initialized at the time of initialization. Initialization broadcasting means (10) for controlling the signal to be transmitted in a broadcast format to connected slave stations; and slave station identification number detection means (12) for detecting the slave station identification number transmitted from the slave station in response to the initialization signal. ), and slave station number assigning means (1) for assigning and storing one slave station number having a number of bits capable of distinguishing a plurality of slave stations connectable to the communication system to the received slave station identification number.
1), when the transmitting means (4) receives a response from each slave station to the initialization signal at the time of initialization, transmits the slave station identification number and the slave station number to the slave station; The slave station includes a transmitting means (9) for transmitting a signal to the master station, a receiving means (5) for receiving a signal from the master station, and an initialization signal detection unit for detecting reception of an initialization signal from the master station. means (14); slave station number storage means (13) for receiving and storing the slave station number at the time of initialization; response data generation means (6) for generating response data to be responded to the station; response delay means (8) for delaying transmission of the response data for a set time; After receiving the initialization signal, generate random data as a response time until responding to the master station and set it in the response delay means (8), and also generate random data as the slave station identification number of the own station. A communication system comprising: random data means (15) for controlling the random data to be transmitted. 2. The initialization broadcasting means (10) performs the following at each predetermined time:
The communication system according to claim 1, wherein the initialization signal is transmitted. 3. The transmitting means (3) of the master station sends the timing signal to the slave station to which the slave station number has been assigned and stored by the slave station number assigning means (11), and the slave station number assigning means ( 11. The communication system according to claim 1, wherein in 11), the memory of assigning a slave station number to a slave station from which a response to the timing signal is not received is deleted. 4. The communication system according to claim 1, wherein each of said slave stations has initialization state storage means for storing whether or not its own station has been initialized. 5. When the transmitting means (3) of the master station stores in the slave station identification number storage means (12) that it has received the same slave station identification number from a plurality of slave stations as a response to the initialization signal, The communication system according to claim 1, wherein the communication system does not respond to said reception. 6. The communication system according to claim 1, wherein in each of the slave stations, a response signal to the initialization signal is a shorter signal than a response signal to a normal timing signal. 7. A master station and multiple slave stations are connected by a transmission path, and the master station gives a timing signal to each slave station, so that the slave stations given the timing signal respond to the master station. In the communication system, the master station includes a transmitting means (4) for transmitting a signal to the slave station, a receiving means (5) for receiving the signal from the slave station, and a means for connecting the initialization signal to the slave station at the time of initialization. Initialization broadcasting means (10) for controlling transmission in a broadcast format; and a response for measuring a response delay time from the time of transmitting the initialization signal to the time of receiving a response signal to the initialization signal at the time of initialization. delay time measuring means (1'); detecting an error between the response delay time and a predetermined reference delay time; and causing the slave station to transmit error adjustment information so as to adjust the error in the delay time. slave station setting delay time adjustment control means (2'); slave station identification number detection means (12) for detecting a slave station identification number transmitted from the slave station in response to the initialization signal; , slave station number assigning means (1
1); during initialization, upon receiving a response from each slave station to the initialization signal, the transmitting means (4) transmits the slave station identification number, the slave station number, and the error adjustment information to the slave station. After the initialization, when transmitting the timing signal, the slave station number is attached and transmitted, and each slave station has a transmitting means (9) for transmitting a signal to the master station, and a transmitting means (9) for transmitting a signal from the master station. receiving means (5) for receiving a signal; initialization signal detection means (14) for detecting reception of an initialization signal from the master station; and slave station number storage means (14) for receiving and storing the slave station number at the time of initialization. 13); and response data generating means (6) for generating response data to be responded to to the master station when a timing signal with a slave station number assigned to the own station is received from the master station; a response delay means (8) for delaying data transmission by a set time; and a response delay time for adjusting the set time in the response delay means (8) according to the error adjustment information upon receiving the error adjustment information from the main station. adjusting means (7), when receiving the initialization signal, generates random data as a response time from receiving the initialization signal until responding to the main station, and transmitting the random data to the response delay means (8); 1. A communication system comprising random data means (15) for controlling the setting and generating and transmitting random data as a slave station identification number of the own station. 8. The initialization broadcasting means (10), at predetermined time intervals,
The communication system according to claim 7, wherein the initialization signal is transmitted. 9. The transmitting means (3) of the master station sends the timing signal to the slave station to which the slave station number assigning means (11) assigns and stores the slave station number, and the slave station number assigning means ( 8. The communication system according to claim 7, wherein in the step 11), the memory of assigning a slave station number to a slave station from which a response to the timing signal is not received is deleted. 10. The communication system according to claim 7, wherein each of the slave stations has initialization state storage means for storing whether or not the slave station has been initialized. 11. When the transmitting means (3) of the master station stores that it has received the same slave station identification number from a plurality of slave stations in the slave station identification number storage means (12) as a response to the initialization signal, The communication system according to claim 7, which does not respond to said reception. 12. The communication system according to claim 7, wherein in each of the slave stations, a response signal to an initialization signal is a shorter signal than a response signal to a normal timing signal.