JP3584561B2 - Intermittent communication system - Google Patents

Description

[0001]
[Industrial applications]
The present invention relates to intermittent transmission and reception between a master station and a plurality of slave stations constituted by wireless lines.
[0002]
[Prior art]
In recent years, intermittent communication systems for a plurality of slave stations have been developed for one master station in order to perform automatic measurement and remote control in factories and warehouses. Intermittent communication measures the time by using timers built in the master station and slave station, and performs intermittent communication at predetermined intermittent time intervals to reduce the power consumption of the master station and slave station. That is. However, the built-in timers of the master station and the slave station have an error, and as time elapses, the timers may intermittently deviate from each other, making intermittent communication impossible. Therefore, the transmission and reception of the synchronization signal are performed at a constant period to correct the timer and maintain the intermittent timing. Hereinafter, the conventional intermittent communication system will be described with reference to the drawings. FIG. 4 is a block diagram of a conventional intermittent communication system, and FIG. 5 is a timing chart. In the figure, a master station 1 has a transmitter and a receiver, a master communication means 2 for performing intermittent communication with slave stations 1A and 1B, a master timer means 4 for determining time intervals t and t 'for performing intermittent communication, And a parent control means 3 for controlling the parent communication means 2 based on a signal from the parent timer means 4. The slave station 1A has a transmitter and a receiver, performs first intermittent communication with the master station 1, and performs first intermittent communication. First slave communication means 2A determines a time interval t between which intermittent communication is performed. And the first child control means 3A for controlling the first child communication means 2A based on the signal from the child timer means 4A. The same configuration is also applied to the slave station 1B (the solid line indicates the transmission direction of the synchronization signal α, and the dashed line indicates the transmission direction of the response signal β returned thereto). In the figure, T and T 'are transmission / reception time intervals of a synchronization signal of a fixed period. t and t ′ are time intervals for transmitting and receiving data (where T = nt, T ′ = nt ′ n: is a positive integer). α is a synchronization signal including time information for performing time correction, and β is a response signal returned to the synchronization signal.
[0003]
The operation will be described below. In the slave station 1A, the first slave timer means 4A outputs to the first slave control means 3A a signal for performing intermittent transmission / reception and transmission of a synchronization signal at time intervals t and T, and outputs the first slave control means 3A. Controls the first slave communication means 2A based on the signal from the first slave timer means 4A to perform intermittent transmission / reception with the master station 1 at a time interval t and transmission of the synchronization signal α at a time interval T of a fixed period. Perform control. After receiving the synchronization signal α, the master station 1 returns a response signal β to the slave station 1A to establish synchronization with the slave station 1A, and the master control unit 3 uses the time information included in the synchronization signal α to The time in the timer means is corrected, and the corrected time is used thereafter. The slave station 1B performs the same operation as the slave station 1A. In FIG. 4, T _AB is the time difference between the synchronization signals transmitted from the slave stations 1A and 1B.
[0004]
[Problems to be solved by the invention]
However, in the above configuration, the time difference T _AB may change due to an error in the timer means of the slave station 1A and the slave station 1B, and a collision may occur. There is a problem that a synchronization signal or a response signal transmitted / received by the slave station collides, synchronization cannot be performed, and communication becomes impossible.
[0005]
An object of the present invention is to solve the above-mentioned problem, and to prevent communication from being disabled due to collision of synchronization signals by adjusting the transmission timing of synchronization signals transmitted from a plurality of slave stations between slave stations. It is.
[0006]
[Means for Solving the Problems]
In order to solve the above problems, an intermittent communication system according to the present invention comprises: a master station having a transmitter and a receiver; a master timer means for determining a time interval for performing intermittent communication; and a signal from the master timer means. A plurality of slave stations, the first slave communication means and the second slave communication means having a transmitter and a receiver, and a time interval for performing intermittent communication. First and second child timer means for determining, first and second child communication means and second child communication means based on signals from the first and second child timer means , A first child control means and a second child control means, and a first child synchronization judgment means and a second child synchronization judgment means for judging that synchronization has been established.
[0007]
[Action]
According to the present invention, with the configuration described above, the slave station 1A returns a response signal to the reception of the synchronization signal transmitted from the slave station 1B, and the first slave control means operates based on the signal from the first slave timer means. The synchronization signal is transmitted to the master station via the first slave communication means, the synchronization is established by receiving the response signal, and the synchronization signal is transmitted to the master station 1 again at the next transmission timing. Upon receiving the response signal, the first slave synchronization determining means determines the establishment of synchronization, transmits a synchronization signal to the slave station 1B, and the slave station 1B returns a response signal after receiving the synchronization signal. By transmitting the synchronization signal, the synchronization with the master station can be established without causing the collision of the synchronization signal.
[0008]
【Example】
Hereinafter, an intermittent communication system according to a first embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram of an intermittent communication system for performing intermittent transmission and reception according to an embodiment of the present invention, and FIG. 2 is a timing chart. In FIG. 2, α is a synchronization signal transmitted at a constant period including time information for performing time correction, β is a response signal returned to the synchronization signal α, T ₁ , T ₂ , T ₃ transmission time interval of the synchronization signal transmitted by the constant _period, t _1, t 2, _{t 3} parent station 1 and the slave station 1A, respectively, the slave station 1A and the slave station 1B, between the master station 1 and the slave station 1B A time interval of intermittent transmission / reception for transmitting / receiving a synchronization signal or data (however, T ₁ = nt ₁ , T ₂ = nt ₂ , T ₃ = nt ₃ n: is a positive integer). In FIG. 1, reference numeral 1 denotes a parent station, 2 denotes a parent communication unit having a transmitter and a receiver and performing intermittent transmission and reception with the child stations 1A and 1B, and 4 represents a parent control unit at time intervals t ₁ and t ₃ for performing intermittent transmission and reception. The parent timer means 3 for outputting a signal to the communication means 3 performs intermittent transmission / reception using the parent communication means 2 in accordance with a signal from the parent timer means 4, and receives a synchronization signal α to obtain a timer based on time information contained in the synchronization signal α. This is a main control means for correcting the time of the means 4. First child timer means 1A is a slave station, 4A is for outputting a signal to the first child control means 3A in the intermittent transmission and reception and the time interval of the synchronization signal transmission _t 1, _{t 2} and _T 1, _{T 2,} 5A Is a first slave synchronization determining means for determining the establishment of synchronization by receiving a synchronization signal α, 2A is a first slave communication means for the master station 1 and the slave station 1B having a transmitter and a receiver, and 3A is a timer means 4A. This is a first child control unit that performs intermittent transmission and reception using the communication unit 2A based on a signal from the communication unit 2A and controls transmission of the synchronization signal α and correction of the time of the timer unit 4A. The same configuration applies to the slave station 1B. The operation of the intermittent communication system configured to perform intermittent transmission and reception configured as described above will be described below with reference to FIGS.
[0009]
First child timer means 4A of the slave station 1A outputs a signal to the first child control means 3A in the parent station 1 and the time interval t _1, the first child control means 3A is first child timer means Intermittent transmission and reception with the master station 1 are performed using the first slave communication means 2A based on the signal from 4A. After the time interval T ₁ has elapsed the synchronization signal transmission to Mataoya station 1, and controls the transmission of the synchronization signal alpha, with the first slave communication unit 2A Ki not a group on a signal from the first child timer means 4A transmits a synchronization signal α to the master station 1, hereafter transmits the synchronization signal following the synchronization signal timing which sent after T ₁ elapses starting from the. After receiving the synchronization signal α, the master station 1 returns a response signal β to the slave station 1A, establishes synchronization with the slave station 1A, corrects the time using the time information included in the synchronization signal α, and thereafter, Use the corrected time. After receiving the response signal β Matako station 1A is for synchronizing signal α transmitted after similar time intervals T ₁ elapses, determines synchronization establishment by the first child synchronization determining unit 5A, the first child control means 3A first child for the first child timer means 4A Ki not a group of a signal from the synchronizing signal α transmitted in the slave station 1B synchronization signal α with the time interval t ₂ of the intermittent transmission and reception after a time interval T ₂ has elapsed and transmitted via the communication means 2A, hereafter transmits the synchronizing signal α transmitted starting point and after a T ₂ has elapsed the next synchronization signal α timing. After receiving the synchronization signal α, the slave station 1B returns a response signal β to the slave station 1A to establish synchronization with the slave station 1A, corrects the time based on time information included in the synchronization signal α, and thereafter, Use the corrected time. Second slave control unit 3B is the second child timer means 4B master station sync signal α with the time interval t ₃ of the intermittent transmission and reception after a time interval T ₃ the course of transmission of the provided credentials synchronizing signal α to the control of the transmits through the second sub communication unit 2B for one, hereafter transmits the synchronizing signal α transmitted after T ₃ has elapsed starting from the timing the next synchronization signal α of. After receiving the synchronization signal α, the master station 1 returns a response signal β to the slave station 1B, establishes synchronization with the slave station 1B, corrects the time with the time information included in the synchronization signal α, and thereafter, Use the corrected time. After the slave station. 1B time interval T ₃ of transmission of the synchronization signal alpha, similarly transmits a synchronization signal alpha to the master station 1, after receiving a response signal β to a synchronous signal alpha, the second child synchronization determination means determining synchronization establishment by 5B, it transmits the synchronization signal α with respect to the slave station 1A with reference to the time interval t ₂ of the intermittent transmission and reception after T ₂ has elapsed as with the slave station 1A above.
[0010]
Hereinafter, an intermittent communication system according to a second embodiment of the present invention will be described with reference to FIG. 4 differs from FIG. 1 in that a slave station 1C is provided, and the configuration of the slave station 1C is the same as that of the slave stations 1A and 1B. The slave station 1A intermittently transmits and receives data or a synchronization signal α with the master station 1 and the slave station 1C at time intervals of t ₁ and t ₂ , and transmits the synchronization signal α at time intervals of T ₁ and T ₂ . The slave station 1C intermittently transmits and receives data or a synchronization signal α to and from the slave station 1A, the master station 1, and the slave station 1B at time intervals of t ₂ , t ₄ , and t ₅ , and at time intervals of T ₂ , T ₄ , and T _5. The synchronization signal α is transmitted. The slave station 1B intermittently transmits and receives data or a synchronization signal α at time intervals of t ₃ and t _{5 to} and from the master station 1 and the slave station 1C, and transmits the synchronization signal α at time intervals of T ₃ and T ₅ .
[0011]
The operation will be described below with reference to FIG. When the slave station 1C receives the synchronization signal α from the slave station 1A or the slave station 1B, the third slave control means 3C transmits the synchronization signal α based on the signal from the third slave timer means 4C. ₄ transmits a synchronization signal α with respect to the main station 1 via a third child communication means 2C using the time interval t ₄ the intermittent transmission and reception after the lapse. Hereinafter transmits the synchronizing signal α transmitted after T ₄ has elapsed starting from the timing the next synchronization signal α of. After receiving the response signal β to the synchronization signal α, the third slave synchronization determination means 5C determines the establishment of synchronization, and transmits the synchronization signal α to the slave station 1A or the slave station 1B. The slave stations 1A and 1B perform the same operation as described above. When the number of slave stations increases to four or more, the slave stations perform the same operation as the above-described slave station 1C. By the above operation, the transmission timing of the synchronization signal transmitted to the master station 1 is adjusted between the slave stations, and the synchronization can be reliably performed without causing the collision of the synchronization signals transmitted by the slave stations. .
[0012]
【The invention's effect】
As is apparent from the above description, according to the intermittent communication system of the present invention, the synchronization is determined between a plurality of slave stations and the synchronization signal is transmitted to the master station. Thus, a highly reliable intermittent communication system can be provided.
[Brief description of the drawings]
FIG. 1 is a block diagram of an intermittent communication system according to a first embodiment of the present invention; FIG. 2 is a timing diagram of the system; FIG. 3 is a block diagram of an intermittent communication system according to a second embodiment of the present invention; FIG. 5 is a block diagram of a conventional intermittent communication system. FIG. 5 is a timing diagram of the system.
1 master station 1A, 1B, 1C slave station 4 master timer means 4A first slave timer means 4B second slave timer means 4C third slave timer means 2 master communication means 2A first slave communication means 2B second Child communication means 2C Third child communication means 3 Parent control means 3A First child control means 3B Second child control means 3C Third child control means 5A First child synchronization determination means 5B Second child synchronization determination Means 5C Third child synchronization determination means

Claims (1)

A master station and a plurality of slave stations transmitting a synchronization signal to the master station to establish synchronization and perform intermittent transmission / reception, wherein the master station has a master communication means having a transmitter and a receiver, and a time for performing intermittent communication. A master timer means for determining an interval and a master control means for controlling the master communication means based on a signal from the master timer means, wherein the first slave station and the second slave station include a transmitter and a receiver. A first child communication unit and a second child communication unit, a first child timer unit and a second child timer unit for determining a time interval for performing intermittent communication, the first child timer unit and the second child unit First and second child control means for controlling the first and second child communication means based on a signal from the timer means and a second child control means for judging that synchronization has been established. A first child synchronization determination unit and a second child synchronization determination unit; After establishing synchronization with the master station, the first slave station establishes synchronization with the second slave station using the synchronization determination means, and the second slave station establishes synchronization with the first slave station. Thereafter, an intermittent communication system for establishing synchronization with the master station using the synchronization determination means.

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