JP2013232800A - Communication system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a communication system that can avoid interference of a superimposed signal due to a fact that a plurality of superimposing terminals perform data transmission to the same superimposition available band at the same time.SOLUTION: A superimposing terminal 22 comprises a reservation unit 28 which transmits reservation data to acquire a transmission right of transmission data at a reserved band as the reserved band which is a superimposition available band at the next time or after, in a reply band which is a superimposition available band determined by a determination unit 27. The reservation unit 28 generates reservation data, and broadcasts the reservation data by a superimposed signal from a superimposing communication unit 23. The superimposing communication unit 23 transmits transmission data by the superimposed signal at a reserved band (superimposition available band) the transmission right of which has been acquired by the reservation data. A superimposing terminal 22 that can transmit transmission data by a superimposed signal at the superimposition available band is only the superimposing terminal 22 that has acquired the transmission right of transmission data at this superimposition available band, and other superimposing terminals 22 are prohibited from transmitting transmission data.

Description

  The present invention relates to a communication system in which a communication terminal that communicates using a transmission signal and a superimposition terminal that communicates using a superimposition signal superimposed on the transmission signal are connected to the same communication line.

  Conventionally, a communication system in which a transmission unit (base unit) and a plurality of terminal devices (slave units) are connected to a transmission line and performs communication between each terminal device and the transmission unit has been widely used. As an example of this type of communication system, the transmission unit periodically monitors the state of the terminal device, and when there is a change in the state of the terminal device, the transmission unit performs other processing to perform processing corresponding to the state change. There is a system for sending a signal to a terminal device (see, for example, Patent Documents 1 to 3).

  However, the communication system configured as described above is originally a system used for on / off control of lighting fixtures and the like, and has a low communication speed, and is not suitable for transmission of information having a relatively large amount of data such as an analog amount. .

  Therefore, a communication system in which an existing communication system in which terminal devices communicate with each other via a transmission unit and a communication system in which terminal devices communicate directly with each other via peer-to-peer (P2P) has been proposed. (For example, refer to Patent Document 4). In this communication system, a communication terminal (first communication terminal) that communicates via a transmission unit (master unit) and a superimposition terminal (second communication terminal) that communicates directly with each other share a communication line (transmission path). Therefore, it is possible to easily add superposition terminals to the existing communication system. The communication terminal performs communication using a transmission signal (first protocol signal) repeatedly sent from the transmission unit to the communication line, and the superposition terminal uses a superposition signal (second protocol signal) superimposed on the transmission signal. Communicate faster.

  Here, the transmission signal is divided into a plurality of areas (periods) in the time axis direction for each frame, and a part of the area is assigned as a superimposable band (communication adaptation period) in which a superposed signal can be superimposed. Signal. That is, the superimposing terminal communicates with the superimposable signal assigned to a part of the transmission signal by using the superimposing signal transmitted through the communication line common to the transmission signal.

Japanese Patent No. 1180690 Japanese Patent No. 1195362 Japanese Patent No. 1144477 JP 2009-225328 A

  However, in the communication system described in Patent Document 4, the period in which communication can be performed using the superimposition signal is limited to the superimposable band. Therefore, when there are a plurality of superposition terminals, the data transmission timings of the plurality of superposition terminals are the same. There is a possibility to concentrate on the superimposable zone. Therefore, a plurality of superposition terminals may cause interference of superposition signals by performing data transmission all at once in the same superposition possible band.

  The present invention has been made in view of the above-described reasons, and an object thereof is to provide a communication system capable of avoiding interference of superimposed signals caused by a plurality of superimposed terminals transmitting data simultaneously to the same superimposable band. .

  The communication system of the present invention includes a transmission unit that repeatedly transmits a transmission signal to a communication line, a communication terminal that communicates using the transmission signal, and a plurality of superpositions that communicate using a superimposed signal superimposed on the transmission signal. A communication system in which a terminal is connected to the communication line, and the transmission signal includes a transmission band for transmitting data to the communication terminal in a time axis direction for each frame, and a return from the communication terminal. A signal of a time division method divided into a plurality of areas including a response band which is a time slot for receiving data, and the superposition terminal transmits data transmitted by the transmission unit using the transmission signal to the transmission band When the transmission reception unit receives secure data prohibiting transmission of the return data in the next reply band in the transmission band, the transmission reception unit receives the return data. A determination unit for determining a band as a superimposable band used for superimposing the superimposition signal, and acquiring a transmission right of transmission data in the reserved band with the superimposable band from the next time as a reserved band in the superimposable band A reservation unit that transmits the reservation data by the superimposition signal, and a data transmission unit that transmits the transmission data by the superimposition signal in the reserved band that has acquired the transmission right.

  In this communication system, when the reservation data is transmitted from a plurality of the superimposition terminals in the same superimposable band, the superposition terminal that has transmitted the reservation data first to the plurality of superimposition terminals. It is preferable that the transmission right in the reserved band is preferentially given by the reservation unit, and the reservation unit transmits the reservation data at a transmission timing predetermined for each of the overlapping terminals in the superimposable band.

  In this communication system, when the reservation data is transmitted from a plurality of the superimposition terminals in the same superimposable band, the superposition terminal that has transmitted the reservation data first to the plurality of superimposition terminals. More preferably, the transmission right in the reserved band is given preferentially, and the reservation unit transmits the reservation data at a transmission timing that is randomly determined for each of the overlapping terminals in the superimposable band.

  In this communication system, it is more preferable that the transmission right is given to the superimposition terminal that first transmitted the reservation data among the plurality of superimposition terminals that transmitted the reservation data to the same superimposable band. .

  In this communication system, it is more preferable that the transmission right is given to the plurality of superimposing terminals that have transmitted the reservation data in the same superimposable band in the order in which the reservation data is transmitted first.

  In this communication system, the reservation data includes length information indicating a data length of the transmission data, and the plurality of superimposing terminals that transmitted the reservation data to the same superimposable band are included in the reservation data. The total length of the data indicated by the length information is grouped so as to be equal to or less than a predetermined allowable length, and the superimposing terminals belonging to the same group are given the transmission right in the same reserved band. desirable.

  In this communication system, the reservation data includes frame information indicating the number of superimposable bands required for transmission of the transmission data, and the superposition terminal has a number of the reservation bands corresponding to the frame information. More preferably, the transmission right is given.

  The communication system of the present invention includes a transmission unit that repeatedly transmits a transmission signal to a communication line, a communication terminal that communicates using the transmission signal, and a plurality of superpositions that communicate using a superimposed signal superimposed on the transmission signal. A communication system in which a terminal is connected to the communication line, and the transmission signal includes a transmission band for transmitting data to the communication terminal in a time axis direction for each frame, and a return from the communication terminal. It consists of a signal of a time division method divided into a plurality of areas including a reply band which is a time slot for receiving data, and the superposition terminal receives the transmission signal transmitted by the transmission unit in the transmission band When the transmission receiving unit receives secure data prohibiting transmission of the return data in the next reply band, the superimposition signal is transmitted using the reply band. A data transmission unit for transmitting transmission data, wherein the data transmission unit transmits the transmission data at a transmission timing predetermined for each of the superimposed terminals in the superimposable band. If the transmission data is being transmitted, the transmission data is not transmitted.

  In the present invention, since the reservation unit transmits the transmission data by the superimposition signal in the superimposable band for which the transmission right is acquired by the reservation data, a plurality of superimposing terminals perform data transmission to the same superimposable band all at once. There is an advantage that interference of the superimposed signal can be avoided.

  Alternatively, in the present invention, since the data transmission unit transmits transmission data at a transmission timing predetermined for each overlapping terminal in the superimposable band, a plurality of superimposing terminals transmit data simultaneously to the same superimposable band. It is possible to avoid the interference of the superimposed signal.

1 is a block diagram illustrating a schematic configuration of a communication system according to a first embodiment. It is a block diagram of the illumination system using the communication system which concerns on Embodiment 1. FIG. FIG. 4 is an explanatory diagram of an operation of a basic system of the communication system according to the first embodiment. FIG. 4 is an explanatory diagram of an operation of a basic system of the communication system according to the first embodiment. FIG. 6 is an explanatory diagram of an operation of the communication system according to the first embodiment. 6 is an explanatory diagram of an operation of a communication system according to Embodiment 2. FIG. 10 is a flowchart of an operation of a reservation unit of the communication system according to the second embodiment. 6 is an explanatory diagram of an operation of a communication system according to Embodiment 2. FIG. FIG. 10 is an explanatory diagram of another operation of the communication system according to the second embodiment. 10 is an explanatory diagram of an operation of a communication system according to Embodiment 3. FIG.

(Embodiment 1)
As shown in FIG. 1, for example, the communication system of the present embodiment includes a transmission unit 1 as a master unit connected to a two-wire communication line 10, and a communication terminal 21 and a superposition terminal 22 as slave units. ing. In FIG. 1 (the same applies to FIGS. 2 and 4), the communication terminal 21 is expressed as the first monitoring terminal 211 or the first control terminal 212, and the superposition terminal 22 is expressed as the second monitoring terminal 221 or the second control terminal 222. This point will be described later. In this communication system, basically, the communication terminal 21 performs communication using a transmission signal (first protocol signal) transmitted through the communication line 10, and the superimposing terminal 22 superimposes the superposed signal (first signal superposed on the transmission signal). (2 protocol signals).

  FIG. 2 shows an example in which the communication system is applied to a lighting system for controlling the lighting fixture 3 in an office building or the like. In the example of FIG. 2, one transmission unit 1 is provided for each area (for example, floor), and one or more communication terminals 21 and one or more superposition terminals 22 are connected to the communication line 10 connected to each transmission unit 1. ing. Further, an office controller 4 for centralized monitoring control of the lighting control system is connected to the communication line 10.

  Further, the transmission unit 1 is connected to an energy saving controller 5 that is a higher-level device. The energy-saving controller 5 is provided for each area (for example, floor), and performs overall monitoring control on the air conditioner 6 in addition to the lighting system to which the communication system is applied. The energy saving controllers 5 in a plurality of areas are connected to a personal computer (personal computer) 7 having a browser function via a network 8 such as the Internet or a LAN, and can be monitored from the personal computer 7. In the example of FIG. 2, the power measurement unit 91 is connected to one second monitoring terminal 221, and this power measurement unit 91 monitors the power consumption of the device connected to the PLC tap 93 via the monitor 92. Measure with

  The plurality of communication terminals 21 are connected in parallel to the transmission unit 1 via the communication line 10. The transmission unit 1 and the communication terminal 21 are time-division multiplex transmission systems (hereinafter referred to as “basic systems”) in which data transmission from the transmission unit 1 to the communication terminal 21 and data transmission from the communication terminal 21 to the transmission unit 1 are performed in a time division manner. ”). In the following, first, a schematic configuration of the basic system will be described.

  In the basic system, the communication terminal 21 includes a first monitoring terminal 211 that monitors a monitoring input of a switch (not shown) such as a wall switch, a relay (not shown), and a load (here, the lighting fixture 3). It is classified into two types, the first control terminal 212 that performs on / off control and the like. Here, the communication terminal 21 stores its own address assigned in advance in each memory (not shown). The first monitoring terminal 211 is not limited to a switch, and may be configured to monitor a monitoring input automatically generated by a sensor such as a human sensor.

  As shown in FIG. 1, the transmission unit 1 includes a transmission communication unit 11 that transmits a transmission signal to the communication line 10, a return request unit 12 that transmits return request data to the communication terminal 21, and return data from the communication terminal 21. A return transmission / reception unit 13, a storage unit 14, and a control unit 15 are provided. The control unit 15 controls the operations of the return request unit 12 and the return transmission / reception unit 13. In the present embodiment, the transmission unit 1 has a microcomputer (microcomputer) as a main component, and implements the functions of each unit by executing a program stored in the storage unit 14.

  The transmission unit 1 stores a control table in which the first monitoring terminal 211 and the first control terminal 212 are associated by an address in the storage unit 14. Here, for example, when the first monitoring terminal 211 has a plurality of circuit switches, all the switches of the first monitoring terminal 211 correspond to only the terminal address unique to the first monitoring terminal 211, and the operation is actually performed. It is not possible to identify the only switch that was made.

  Therefore, in the first monitoring terminal 211, a load number is assigned to each switch so that the only switch actually operated can be specified, and the load number is added after the terminal address of the first monitoring terminal 211. Is used as an address (identifier) unique to the switch. Similarly, a load number is assigned to each relay in the first control terminal 212, and an address in which the load number is added after the terminal address of the first control terminal 212 is set as an address (identifier) unique to the relay. In the control table, the switch-specific address and the relay-specific address are associated one-to-one or one-to-many.

  Next, the operation of the basic system will be described.

  As shown in FIG. 3, the transmission unit 1 repeatedly transmits time-division transmission signals composed of voltage waveforms in a format divided into a plurality of regions in the time axis direction as shown in FIG. That is, the transmission signal is composed of seven areas of a spare interrupt band 101, a spare band 102, a transmission band 103, a reply band 104, an interrupt band 105, a short-circuit detection band 106, and a pause band 107. This is a time-division multiplexed signal with multiple poles (± 24V). In the illustrated example, each section starting from the interrupt band 105 and ending with the reply band 104 in the transmission signal is defined as one frame (F1, F2,...).

  The spare interrupt band 101 is a period for detecting the presence or absence of a secondary interrupt, the spare band 102 is a period set according to the interrupt band 105 and the short-circuit detection band 106, and the transmission band 103 is connected to the communication terminal 21. This is a period for transmitting data. The reply band 104 is a time slot for receiving return data from the communication terminal 21, the interrupt band 105 is a period for detecting the presence or absence of an interrupt signal described later, and the short-circuit detection band 106 is for detecting a short circuit. Is the period. The idle zone 107 is a period for when processing is not in time.

  The transmission unit 1 always transmits a transmission signal whose mode data is the normal mode, and constantly polls the communication terminal 21 sequentially by changing the address data included in the transmission band 103 of this transmission signal cyclically. Do. In the case of constant polling, the communication terminal 21 whose address data included in the transmission band 103 matches its own address receives the data included in the transmission band 103 and transmits the return data in the next reply band 104. Send to unit 1. Here, the communication terminal 21 transmits the return data by a current mode signal (a signal transmitted by short-circuiting the communication line 10 via an appropriate low impedance) synchronized with the transmission signal return band 104. Note that power for the internal circuit of the communication terminal 21 is supplied by rectifying and stabilizing a transmission signal transmitted via the communication line 10.

  On the other hand, when the communication terminal 21 as the first monitoring terminal 211 detects a monitoring input, the communication terminal 21 generates an interrupt signal in synchronization with the interrupt band 105 of the transmission signal. Hereinafter, the operation of the basic system when an interrupt signal is generated in the first monitoring terminal 211 in the communication system of FIG. 1 will be described with reference to FIGS. 3 and 4.

  When the transmission unit 1 detects the interrupt signal generated in the first monitoring terminal 211 in the interrupt band 105 of the first frame F1 of the transmission signal (S11 in FIGS. 3 and 4), the transmission unit 1 enters the transmission signal transmission band 103. Switch the included mode data from normal mode to interrupt polling mode. In the interrupt polling mode, the transmission unit 1 uses the return request unit 12 to transmit return request data consisting of the upper bits of the address in the transmission band 103 of the transmission signal (S12), and cyclically selects the address (upper bits). The address search is performed while changing to. If the address (upper bit) in the return request data matches the upper bit of its own address, the first monitoring terminal 211 that has generated the interrupt signal has its own address in the reply band 104 of the first frame F1. Are transmitted to the transmission unit 1 as return data (S13). As a result, the transmission unit 1 receives the address of the first monitoring terminal 211 that generated the interrupt signal in the first frame F1 at the return transmission / reception unit 13 as return data.

  When the transmission unit 1 acquires the address of the first monitoring terminal 211 that has generated the interrupt signal, the transmission unit 1 designates the address in the transmission band 103 of the next second frame F2 and returns it to the first monitoring terminal 211. Return request data is transmitted from the request unit 12 (S14). When the first monitoring terminal 211 receives the return request data including its own address, in response to this, the first monitoring terminal 211 includes the load number and on / off status of the switch corresponding to the monitoring input in the reply band 104 of the second frame F2. The monitoring data is transmitted as return data to the transmission unit 1 (S15).

  When the transmission unit 1 receives the return data including the monitoring data in the return transmission / reception unit 13, the transmission unit 1 transmits the transmission band 103 of the next third frame F3 to the first control terminal 212 corresponding to the monitoring data on the control table. The control data is transmitted at (S16). Thereby, the 1st control terminal 212 which received control data carries out on-off control of the lighting fixture 3 according to control data.

  As described above, in the basic system, the communication terminals (the first monitoring terminal 211 and the first control terminal 212) 21 communicate with each other via the transmission unit 1 in accordance with the polling / selecting protocol (first protocol). It will be.

  By the way, in the communication system according to the present embodiment, the superimposition terminal 22 performs communication using the superimposition signal superimposed on the transmission signal while sharing the communication line 10 with the basic system.

  Similar to the communication terminal 21, the superposition terminal 22 is classified into two types: a second monitoring terminal 221 that monitors a monitoring input from a sensor or the like, and a second control terminal 222 that controls a load (in this case, the lighting fixture 3). Is done. Here, the superimposing terminal 22 stores its own address individually assigned in advance in each memory (not shown). However, the address area that can be set is distinguished between the communication terminal 21 and the superimposing terminal 22. In the following, addresses “1” to “128” can be used for the entire communication system, of which “1” to “64” are the address area of the communication terminal 21, and “65” to “128” are superposition terminals. Description will be made assuming that the address area is assigned as 22 address areas.

  As for the superposition terminal 22, when a plurality of sensors and loads are connected to one superposition terminal 22, a unique address is not assigned to the superposition terminal 22, but a unique address for each sensor or load. Is assigned. That is, for example, a total of four addresses such as “65”, “66”, “67”, and “68” are assigned to the second control terminal 222 to which four loads are connected.

  As shown in FIG. 1, the superimposing terminal 22 includes a superimposing communication unit 23 that performs communication using a superimposing signal, a transmission receiving unit 24 that receives data transmitted by the transmission unit 1 using a transmission signal in a transmission band 103, and an interface. Unit 25 and (terminal side) control unit 26. Furthermore, the superposition terminal 22 includes a determination unit 27, a reservation unit 28, and a processing unit 29, which will be described later. The interface unit 25 is connected to a sensor device and a lighting fixture 3 which will be described later. The control unit 26 controls operations of the superimposition communication unit 23, the transmission reception unit 24, the interface unit 25, the determination unit 27, the reservation unit 28, and the processing unit 29. In the present embodiment, the superimposing terminal 22 has a microcomputer (microcomputer) as a main component, and implements the functions of each unit by executing a program stored in a memory (not shown).

  Here, the superimposed signal is a signal having a sufficiently high frequency compared to the transmission signal, and the amount of data that can be transmitted per frame (of the transmission signal) is sufficiently large. Therefore, communication using the second protocol can increase the communication speed compared to communication using the first protocol, and is suitable for transmitting information having a relatively large amount of data such as an analog amount.

  Therefore, as shown in FIG. 1, the second monitoring terminal 221 is connected to a sensor device 9 such as an image sensor (not shown) or a power measurement unit 91 (see FIG. 2), and has a relatively large amount of monitoring data. Used for communication. The second control terminal 222 is not used for simple on / off control of the lighting fixture 3, but is used for communication of control data having a relatively large amount of data, such as dimming control and toning control. That is, the 2nd control terminal 222 is connected to the lighting fixture 3 which can perform light control and color control, and controls the lighting fixture 3 according to the control data transmitted using a superimposition signal.

  The superposition terminal 22 of the present embodiment is configured such that the transmission receiver 24 can acquire data transmitted from the transmission unit 1 by a transmission signal. However, it is not necessary for the transmission receiving unit 24 to understand all the transmission signals from the transmission unit 1, and it is only necessary to understand whether or not reserved data to be described later is included in at least the transmission signal transmission band 103.

  Here, the monitoring data is generated by the sensor device 9, and the second monitoring terminal 221 functions as an adapter that converts the monitoring data input from the sensor device 9 and transmits it on the communication line 10. Similarly, the second control terminal 222 functions as an adapter that converts control data received from the communication line 10 according to the standard of the lighting fixture 3 and outputs the converted data to the lighting fixture 3. An example of the standard of the lighting fixture 3 connected to the second control terminal 222 is DALI (Digital Addressable Lighting Interface).

  The superimposing terminal 22 has a function of monitoring a transmission signal used in the basic system and analyzing a data transmission state (hereinafter referred to as “state”) of the transmission signal. Here, the superimposing terminal 22 monitors the transmission signal by the transmission receiving unit 24. The superimposing terminal 22 determines whether or not the superimposing terminal 22 is in a superimposable band suitable for superimposition of the superimposing signal from the analysis result of the state in the determining unit 27, and at the timing determined as the superimposable band in the superimposing communication unit 23. A superimposed signal is superimposed on the transmission signal.

  In the present embodiment, the superimposing terminal 22 uses the return band 104 (see FIG. 3) of the transmission signal as a superimposable band for superimposing the superimposed signal. That is, the reply band 104 does not affect the communication of the first protocol even if the superimposed signal is superimposed, and the superimposed signal is not easily affected by the transmission signal. Furthermore, the reply band 104 has a longer time during which the transmission signal is stable at a high level or a low level than the spare interrupt band 101, the spare band 102, and the pause band 107, and the ratio of the transmission signal to one frame is long. Since it is large, it is suitable for superimposition of a superimposed signal.

  In other areas (the transmission band 103, the interrupt band 105, and the short-circuit detection band 106), the time during which the transmission signal is stable at the high level or the low level is relatively short. It is easy to affect communication. Further, when a superimposed signal is superimposed on the other area, the superimposed signal is also easily affected by a signal (interrupt signal or transmission data) exchanged between the transmission unit 1 and the communication terminal 21. Therefore, in the present embodiment, the area other than the reply band 104 is an area that is not used for superimposing the superimposed signal (hereinafter referred to as “non-superimposable band”).

  As a specific example, the time width of the reply band 104 is about 6.5 ms, and the superposition terminal 22 can superimpose 5 bytes of data on 700 μs by the superposition signal. 46 bytes of data can be transmitted during 104. In this case, if the frame period of the transmission signal is about 15 ms, the transmission rate is about 24 kbps.

  Here, the determination unit 27 of the superimposing terminal 22 determines that the reply band 104 used for transmission of return data from the communication terminal 21 to the transmission unit 1 is a non-superimposable band even if the reply band 104 is used. It is not used for signal superimposition. That is, the superimposing terminal 22 uses the return band 104 in which the return data is not transmitted from the communication terminal 21 to the transmission unit 1 as a superimposable band suitable for superimposing the superimposed signal for superimposing the superimposed signal. Therefore, the determination unit 27 determines whether or not the return data is transmitted for the area recognized as the return band 104 by the transmission reception unit 24, and the return band 104 where the return data is not transmitted can be superimposed. Judge.

  In the communication system according to the present embodiment, the transmission unit 1 includes a band securing unit 18 that transmits securing data for securing the next reply band 104 for superimposing the superimposed signal in the transmission band 103 of the transmission signal by the transmission signal. Have. The band securing unit 18 transmits the secured data from the transmission communication unit 11 in synchronization with the transmission band 103 of the transmission signal. The secured data here is data that secures the next reply band 104 for superimposition of the superimposed signal by prohibiting transmission of return data from all the communication terminals 21 in the next reply band 104, for example, This is dummy data consisting of empty packets having no specific meaning.

  When superimposing terminal 22 receives secure data from transmission unit 1 in transmission band 103 by transmission receiving unit 24, superimposing terminal 22 determines that next reply band 104 is a superimposable band. That is, since the reply band 104 (same frame as the transmission band 103) immediately after the transmission band 103 from which the secure data is transmitted from the transmission unit 1 is not used for transmission of the return data, the determination unit 27 determines whether the reply band 104 104 is determined as a superimposable band.

  In the present embodiment, the transmission unit 1 sends a timing synchronization pulse for time synchronization with the communication terminal 21 every predetermined time (for example, 1 second) to a plurality of communication terminals 21 using the transmission band 103 of the transmission signal. Broadcasting simultaneously. This timing synchronization pulse does not cause the communication terminal 21 to transmit return data, unlike the data that the transmission unit 1 always transmits during polling and the return request data that is transmitted in the interrupt polling mode. That is, the communication terminal 21 does not transmit the return data in the reply band 104 next to the transmission band 103 that has received this timing synchronization pulse.

  Therefore, in the present embodiment, the bandwidth securing unit 18 uses a timing synchronization pulse as secured data. Therefore, when the timing synchronization pulse periodically transmitted from the transmission unit 1 by the transmission signal is received in the transmission band 103, the superimposing terminal 22 determines that the next reply band 104 is a superimposable band.

  The superimposition communication unit 23 functions as a data transmission unit that transmits data using a superimposition signal and a data reception unit that receives data transmitted from another superimposition terminal 22 using a superimposition signal. The superimposition communication unit 23 is configured to transmit a superimposition signal only when the determination unit 27 determines that the band can be superimposed (that is, the next reply band 104 that has received the secured data). In this way, the superimposing terminal 22 superimposes the superimposition signal only on the superimposable band in synchronization with the transmission signal, thereby preventing interference between the first protocol communication using the common communication line 10 and the second protocol communication. To avoid.

  Note that the rising and falling periods of the transmission signal are also not suitable for superimposing the superimposed signal due to the influence of harmonic noise or the influence of a transient response accompanying the signal voltage inversion. Therefore, the determination unit 27 determines that a predetermined avoidance time (for example, 300 μs) after the switching (rise) of the region is a non-overlapping zone even in the reply zone 104 in which the return data is not transmitted.

  The power supply to the superposition terminal 22 is performed by a method (centralized power supply method) that is supplied by rectifying and stabilizing a transmission signal transmitted from the transmission unit 1 via the communication line 10 in the same manner as the communication terminal 21. The However, the power supply to the superposition terminal 22 is not limited to this configuration, and may be performed by a method (local power supply method) that is supplied by rectifying and stabilizing the commercial power supply.

  By the way, in this embodiment, the superimposition terminals 22 can directly communicate with each other by the superimposition signal, and when the superimposition communication unit 23 receives the transmission data transmitted from the other superimposition terminal 22 by the superimposition signal, this transmission is performed. A processing unit 29 that performs predetermined processing using data is provided. The superimposing terminal 22 can transmit the transmission data by unicast by designating the address of the specific superimposing terminal 22 when transmitting the transmission data by the superimposing signal from the superimposing communication unit 23 as the data transmitting unit. Then, basically, transmission data is transmitted by broadcast. That is, the plurality of superimposing terminals 22 are configured to execute some processing in the processing unit 29 by receiving transmission data transmitted by broadcast by any one superimposing terminal 22.

  As an example of the process performed by the processing unit 29, there is a process of performing time adjustment (time synchronization) between the superimposed terminals 22 using time information of a clock unit built in any of the superimposed terminals 22. In this case, each superimposing terminal 22 has a clock unit (not shown) that measures the current time. Here, one superimposing terminal 22 periodically transmits time information indicating the current time measured by its own clock unit as transmission data by broadcasting. Each other superposition terminal 22 that has received the transmission data including the time information performs time adjustment of the clock unit based on the time information in the processing unit 29.

  Thereby, the superimposition terminals 22 can perform time adjustment using a superimposition signal, and can synchronize time about all the superimposition terminals 22 in the communication system. In addition, when the superimposition terminal 22 has a GPS (Global Positioning System) receiver, the clock function of the GPS receiver can be used as a clock unit.

  As another example of the process executed by the processing unit 29, there is a process of performing time adjustment between the superimposed terminals 22 using time information from an external device (not shown). In this case, each superimposing terminal 22 has a clock unit for measuring the current time, and at least one superimposing terminal 22 has an interface (not shown) for connecting an external device such as a GPS receiver. . When the superimposition terminal 22 connected to the external device acquires time information representing the current time from the external device, the superposition terminal 22 adjusts the time of the clock unit based on this time information, and periodically broadcasts the time information as transmission data. Send. Each other superposition terminal 22 that has received the transmission data including the time information performs time adjustment of the clock unit based on the time information in the processing unit 29.

  Thereby, time can be synchronized about all the several superimposition terminals 22 in a communication system. In addition, in this case, since the superimposing terminal 22 to which time information is input from the external device operates differently as a master and the superimposing terminal 22 to which time information is not input from the external device operates as a slave, The master-slave relationship can be identified with respect to the alignment.

  Still another example of the process executed by the processing unit 29 is a survival confirmation process of the superimposed terminal 22. In this case, each superimposing terminal 22 periodically transmits survival information including at least its own address as transmission data. The superposition terminal 22 receives the survival information from the other superposition terminals 22 and confirms the survival state of the superposition terminal 22 of the address included in the survival information by the processing unit 29. That is, each superimposing terminal 22 determines that the superimposing terminal 22 that is the transmission source of the received survival information is operating normally, and some abnormality has occurred in the superimposing terminal 22 to which the surviving information is not transmitted at all. Judge.

  Specifically, each superimposing terminal 22 voluntarily transmits the survival information by broadcast once every predetermined time (for example, one day, one hour). Each superposition terminal 22 stores the reception time of the latest survival information from the other superposition terminals 22 for each superposition terminal 22, and the survival information is stored within a predetermined set time (predetermined time + α) from this time. If it is received, it is determined that it is operating normally and the reception time of the survival information is updated. On the other hand, each superimposing terminal 22 determines that an abnormality has occurred in the superimposing terminal 22 when the next surviving information cannot be received even after a set time has elapsed from the reception time of the latest surviving information.

  Thereby, the multiple superposition terminals 22 can perform survival confirmation by detecting the presence or absence of abnormality by communicating with each other using superposition communication. Therefore, the communication system can detect the presence / absence of abnormality of the superposition terminal 22 without introducing a dedicated management device.

  In addition, since each superimposition terminal 22 transmits survival information only once at a predetermined time, transmission timings of transmission data (survival information) from a plurality of superposition terminals 22 hardly overlap each other. However, even if the transmission timings of the survival information from the plurality of superposition terminals 22 may overlap, the superposition signals from the plurality of superposition terminals 22 interfere with each other by adopting the configuration described later in the communication system. You can avoid that.

  According to the configuration described above, the plurality of superimposing terminals 22 receive the transmission data transmitted by broadcast using one of the superimposing terminals 22 by using the superimposing signal, thereby allowing the processing unit 29 to adjust the time and confirm the survival. Etc. can be executed. Therefore, the communication system can perform time adjustment and survival confirmation of the superimposed terminal 22 without stopping the operation of the basic system using the transmission signal.

  Next, a configuration for avoiding interference between superimposed signals by a plurality of overlapping terminals 22 transmitting data simultaneously in the same superimposable band will be described.

  That is, since a plurality of superimposing devices 22 perform communication using a superimposition signal in a transmission signal superimposable band, the timing at which the superimposition signal is transmitted when the plurality of superimposition terminals 22 perform data transmission all at once. May overlap and interference between superimposed signals may occur on the communication line 10. Therefore, in the present embodiment, the superimposing terminal 22 does not transmit the transmission data as soon as the superimposable band is reached, but first transmits the reservation data and grants the transmission right of the transmission data in the next superimposable band. Upon acquisition, the transmission data is transmitted. The superimposing terminal 22 that can transmit transmission data by a superimposition signal in the superimposable band is only the superimposing terminal 22 that is given the transmission right of transmission data in the superimposable band, and the other superimposing terminals 22 transmit the transmission data. Transmission is prohibited.

  More specifically, the superimposing terminal 22 acquires the transmission right of transmission data in the reserved band in the reply band 104 determined to be a superimposable band by the determination unit 27, with the next superimposable band as a reserved band. Reservation data for this is transmitted by the reservation unit 28. The reservation unit 28 generates reservation data, and transmits the reservation data by broadcast from the superimposition communication unit 23 using a superimposition signal.

  Here, the reservation data includes at least the address of the superimposing terminal 22 that is the transmission source. Therefore, another superimposing terminal 22 that has received the reservation data transmitted by broadcasting from a certain superimposing terminal 22 can identify the superimposing terminal 22 that is the transmission source of the reservation data from the address included in the reservation data.

  The superimposition communication unit 23 functioning as a data transmission unit transmits the transmission data by a superimposition signal in the reserved band (superimposable band) for which the transmission right is acquired by the reservation data. In short, the superimposition communication unit 23 transmits transmission data in a superimposable band reserved in advance with reservation data. For this reason, the superimposing terminal 22 does not transmit a superimposing signal in a reserved band in which it has failed to acquire the transmission right, such as a reserved band in which the transmission right is given to another overlapping terminal 22.

  Specifically, when any one of the plurality of superimposing terminals 22 transmits the reservation data in the reservation unit 28, all the remaining superimposing terminals 22 receive the reservation data, and the reservation data Is given the transmission right of the transmission data in the next superimposable band. Therefore, in the superimposable band in which the transmission right is given to the superimposition terminal 22 that is the transmission source of the reservation data, the superimposition terminal 22 that has received the reservation data does not transmit any superimposition signal. For example, when the superimposition terminal 22 of the address “65” transmits the reservation data among the superposition terminals 22 of the addresses “65” to “67”, the superimposition terminal 22 of the address “65” transmits the next superimposable band (reservation band). Get the right to send data in In other words, when the superimposition terminal 22 having the addresses “66” and “67” receives the reservation data from the superposition terminal 22 having the address “65” by the superimposition communication unit 23, the next superimposable band is transmitted to the superimposition signal. By not using it, it is reserved for the overlapping terminal 22 with the address “65”.

  Here, in this embodiment, it is assumed that the transmission data transmitted by the superimposing terminal 22 has a data length that can be transmitted in one superimposable band. Therefore, the superimposition terminal 22 acquires the transmission right of the transmission data in one superimposable band (reply band 104) per reservation data, and ends transmission of the transmission data in the superimposable band from which the transmission right is acquired. To do.

  Hereinafter, an operation when the superimposition terminal 22 transmits transmission data in the communication system of the present embodiment will be described with reference to FIG.

  The transmission unit 1 performs communication using the transmission signal with the communication terminal 21 in the first frame F1 of the transmission signal, and the timing as the reserved data in the transmission band 103 of the second frame F2 of the transmission signal. A synchronization pulse is transmitted (S21 in FIG. 5). When receiving the timing synchronization pulse in the transmission band 103 of the second frame F2, the superimposition terminal 22 transmits the reservation data by broadcast using the superimposition signal in the reply band 104 of the second frame F2 (S22).

  Thereafter, the transmission unit 1 performs communication using the transmission signal with the communication terminal 21 up to the (n-1) th frame Fn-1 of the transmission signal, and in the transmission band 103 of the nth frame Fn of the transmission signal. A timing synchronization pulse as secured data is transmitted (S23). Upon receiving the timing synchronization pulse in the nth frame Fn, the superimposition terminal 22 that has acquired the transmission right by the reservation data in the second frame F2 transmits the transmission data by the superimposition signal in the reply band 104 of the nth frame Fn. (S24).

  According to the communication system described above, the superposition terminal 22 superimposes the superimposition signal only on the superimposable band of the transmission signal in synchronization with the transmission signal, so that communication with the first protocol using the common communication line 10 is performed. Interference with communication of the second protocol can be avoided. Here, the superimposing terminal 22 uses the reserved data for the determination of the superimposable band, and therefore uses the reply band 104 having a relatively long time width in the transmission signal as a superimposable band for transmission of the superimposing signal. Even relatively long data can be transmitted in one superimposable band. Therefore, since the superimposing terminal 22 does not need to transmit data in small pieces even when transmitting data having a relatively long data length, data having a relatively long data length can be obtained from the superimposing signal without reducing the data transmission speed. Can be transmitted.

  In addition, in the present embodiment, the superimposing terminal 22 does not transmit transmission data as soon as the superimposable band is reached, but first transmits reservation data and grants the transmission right of transmission data in the next superimposable band. Send the transmission data after acquiring. Therefore, in the communication system according to the present embodiment, it is possible to avoid interference (collision) between superimposed signals caused by a plurality of overlapping terminals 22 transmitting data simultaneously in the same overlapping possible band.

  In the communication system of the present embodiment, the timing synchronization pulse for time synchronization with the communication terminal 21 transmitted by the transmission unit 1 at regular time intervals is used as secured data for securing the reply band 104 as a superimposable band. doing. As a result, the transmission unit 1 does not need to newly generate dedicated data as reserved data for securing the reply band 104 for superimposition of the superimposition signal, so that the reply band does not affect the operation of the basic system. 104 can be secured for superimposing the superimposition signal. Therefore, according to this communication system, the transmission signal return band 104 can be used as a superimposable band for transmission of the superimposed signal without changing the specification of the transmission unit 1.

  Note that the band securing unit 18 of the transmission unit 1 is not limited to the configuration using the timing synchronization pulse as the securing data, but may be configured to generate and transmit dedicated securing data separately from the timing synchronization pulse. In this case, the bandwidth securing unit 18 is not limited to the configuration in which the secured data is periodically transmitted, and may be transmitted at a timing determined according to the schedule stored in the storage unit 14, for example, or determined randomly. You may transmit at a timing. Further, the transmission unit 1 may be configured to determine the timing for transmitting the secured data in response to an instruction from a host device such as the energy saving controller 5 (see FIG. 2) or to change the schedule.

  By the way, although this embodiment demonstrated the case where the some superimposition terminal 22 communicates directly with each other with a superimposition signal, not only this example but a communication system is between the superimposition terminal 22 and the transmission unit 1. FIG. A configuration in which communication is performed using a superimposed signal may be used.

  In this case, the transmission unit 1 includes the superimposition communication unit 16 (see FIG. 1) that communicates with the superimposition terminal 22 using a superimposition signal, and is configured to be able to communicate with the superimposition terminal 22 as well as the communication terminal 21. Is done. Thereby, the transmission unit 1 can control the load (the lighting fixture 3) connected to the first control terminal 212, for example, according to the monitoring input generated at the second monitoring terminal 221.

  Specifically, in the control table in the storage unit 12 of the transmission unit 1, the address of the second monitoring terminal 221 (sensor-specific address) and the address of the first control terminal 212 (relay-specific address) are associated with each other. ing. In the control table, the address of the first monitoring terminal 211 and the address of the second control terminal 222 are associated with each other, or the address of the second monitoring terminal 221 and the address of the second control terminal 222 are associated with each other. Or you may.

In this embodiment, the 2nd monitoring terminal 221 transmits the output data of the sensor apparatus (image sensor, power measurement unit 91, etc.) 9 connected to self to the transmission unit 1 as transmission data. The transmission data here refers to the output data (image, power information, temperature, humidity, CO ₂ amount, presence / absence of a person, etc.) of the sensor device 9 serving as a monitoring input, and the address of the second monitoring terminal 221 that is the transmission source. Information, length information indicating the data length, time information, position information, and the like. That is, the superimposition communication unit 16 of the transmission unit 1 receives transmission data based on the superimposition signal transmitted from the second monitoring terminal 221 in a transmission signal superimposable band. As a result, the transmission unit 1 can acquire output data (monitoring input) of the sensor device 9 connected to the second monitoring terminal 221 as transmission data.

  In addition, the transmission unit 1 transmits control data using a superimposed signal to the second control terminal 222 based on the transmission data acquired from the second monitoring terminal 221, and loads (lighting) connected to the second control terminal 222. Control the instrument 3). The correspondence relationship between the second monitoring terminal 221 and the second control terminal 222 is basically set on the control table, but is not limited to this, and the load to be controlled (lighting fixture 3) is not limited to this. An address may be included. Further, the transmission data may include specific control contents relating to, for example, light control or color control.

  Further, when transmitting the control data to the second control terminal 222, the transmission unit 1 uses a superimposed signal superimposed on the transmission signal return band 104, so that the return data from the communication terminal 21 and the control in the reply band 104 are controlled. It is necessary to avoid interference with data (superimposed signal). Therefore, the transmission unit 1 uses the reply band 104 that is the reply band 104 next to the transmission band 103 that has transmitted the secure data and that does not give any superimposition terminal 22 a transmission right for transmission of control data. It is desirable to do.

  Here, the operation of the communication system when controlling the load (lighting fixture 3) connected to the second control terminal 222 according to the monitoring input generated at the second monitoring terminal 221 is illustrated, but the control up to the load control is also performed. Is not an essential configuration for a communication system. That is, for example, when applied to a system that only collects monitoring inputs of the sensor device 9, the transmission unit 1 may be configured to be able to acquire transmission data from the second monitoring terminal 221, and can transmit control data. Not required. In FIG. 1, the configuration in which the superimposition communication unit 16 is built in the transmission unit 1 is illustrated. However, the configuration is not limited thereto, and the superimposition communication unit is provided separately from the transmission unit 1. May be connected to each other.

(Embodiment 2)
In the communication system according to the present embodiment, when reservation data is transmitted from a plurality of superposition terminals 22 in the same superimposable band, the superposition terminal that has transmitted reservation data to the plurality of superposition terminals 22 first. The second embodiment is different from the first embodiment in that the transmission right in the reserved band is preferentially given from FIG. In other words, in this embodiment, when two or more superimposing terminals 22 transmit reservation data in the same superimposable band, superimposition from the next time can be preferentially performed from the superimposing terminal 22 whose reservation data transmission timing is early. The transmission right in the band (reserved band) is given. Hereinafter, the same configurations as those of the first embodiment are denoted by common reference numerals, and description thereof is omitted as appropriate.

  That is, each superimposing terminal 22 transmits the reservation data while receiving the reservation data transmitted by the other superimposing terminal 22, so that the timing at which the superimposing terminal 22 transmits the reservation data and the other superimposing terminal 22 transmit the reservation data. It is possible to grasp both the timing of transmission. Therefore, each superimposing terminal 22 can grasp the prior relationship (order) of the transmission timing of the reservation data for a plurality of superimposing terminals 22 that transmit the reservation data in the same superimposable band.

  Here, there are two methods for giving the transmission right preferentially from the superimposing terminal 22 that has transmitted the reservation data first.

  The first method is a method of giving a transmission right only to one superimposition terminal 22 that has transmitted reservation data first among a plurality of superposition terminals 22. In this method, each superimposing terminal 22 that has transmitted the reservation data compares the timing at which it transmits the reservation data with the timing at which the other superimposing terminal 22 transmits the reservation data, so that its transmission timing is the earliest. The transmission right in the reserved zone can be acquired only when In other words, in the superimposition terminal 22 that transmits the reservation data at the second or later timing, the next superimposable band is not used for transmission data transmission, so that the superimposition terminal 22 that transmitted the reservation data first is used. The next superimposable zone is secured.

  The second method is a method of assigning the transmission right in the superimposable band to all the plurality of superposition terminals 22 that have transmitted the reservation data. In this method, each superimposition terminal 22 that has transmitted the reservation data compares the timing at which the superimposition terminal 22 transmits the reservation data with the timing at which the other superimposition terminal 22 transmits the reservation data. The order in which the reservation data is transmitted for 22 is grasped. In this case, the transmission right is given to the plurality of overlapping terminals 22 in the order in which the reservation data is transmitted first. For example, the superimposition terminal 22 with the earliest transmission timing of the reservation data is given the transmission right of transmission data in the next superimposable band, and the transmission timing of the reservation data is with respect to the second superposition terminal 22. Is given the right to transmit transmission data in the next superimposable band. That is, each superimposition terminal 22 acquires the transmission right of the transmission data in the nth superimposable band after transmitting the reservation data if the transmission timing of its own reservation data is nth.

  By the way, in any of the above two methods, since the superimposition terminal 22 transmits the reservation data using the superimposition signal, if the transmission timing of the reservation data overlaps, the superimposition signals interfere with each other so that the reservation data becomes normal. It may not be received.

  Therefore, in the present embodiment, the reservation unit 28 is configured to transmit reservation data at a transmission timing determined in advance for each superimposing terminal 22 in the superimposable band. Specifically, each superimposing terminal 22 has a predetermined waiting time from the start of the superimposable band to the start of transmission of reservation data based on its own address. Here, assuming that the time required for transmitting the reservation data is a unit time Ta, each superimposing terminal 22 is assigned a waiting time shifted by the unit time Ta.

  Therefore, for example, when the addresses of the plurality of superimposing terminals 22 are “65” to “67”, the transmission timing of the reservation data is the superimposing terminal 22 with the address “65”, the superimposing terminal 22 with “66”, They are set so as to be shifted by unit time Ta in the order of the superposition terminal 22 of “67”. Since the superimposable band starts after a predetermined avoidance time (for example, 300 μs) from the time when the reply band 104 rises as described above, the superposition terminal 22 determines that “(address−64) × Ta + avoidance from the time when the reply band 104 rises. The reservation data is transmitted with a delay of “time”.

  That is, as shown in FIG. 6, when the transmission unit 1 transmits the timing synchronization pulse as the secured data in the transmission band 103 of the second frame F2 of the transmission signal (S31), the superimposing terminal 22 transmits the second frame F2. The reservation data is transmitted in the reply band 104 (S32). At this time, when reservation data is transmitted from a plurality of superposition terminals 22 having addresses “65” to “67”, the transmission timing of the reservation data is the superposition terminals 22 and 66 of the address “65”. The terminal 22 is in the order of the superposition terminal 22 of “67”.

  Thereafter, the transmission unit 1 performs communication using the transmission signal with the communication terminal 21 up to the (n-1) th frame Fn-1 of the transmission signal, and in the transmission band 103 of the nth frame Fn of the transmission signal. A timing synchronization pulse as secured data is transmitted (S33). When receiving the timing synchronization pulse in the nth frame Fn, the superimposing terminal 22 having the address “65” that first transmitted the reservation data in the second frame F2 transmits the superimposition signal in the reply band 104 of the nth frame Fn. Data is transmitted (S34).

  As a result, the plurality of superimposing terminals 22 do not overlap the transmission timing of the reservation data, and can avoid a situation in which the reservation data is not normally received due to interference between the superimposed signals. In addition, since the plurality of superimposing terminals 22 sequentially transmit the reservation data in the same superimposable band, the reservation data from the plurality of superimposing terminals 22 can be transmitted relatively efficiently.

  As another example, the reservation unit 28 may be configured to transmit reservation data at a transmission timing that is randomly determined for each overlapping terminal 22 in the superimposable band. Specifically, each superimposing terminal 22 determines the waiting time from the start of the superimposable band to the start of transmission of the reservation data using a random number when transmitting the reservation data. That is, the waiting time is calculated by multiplying a random number by a coefficient (for example, 10 μs). Here, since the superimposable band starts after a predetermined avoidance time (for example, 300 μs) from the time when the reply band 104 rises as described above, the superposition terminal 22 determines that “random number × coefficient + avoidance” from the time when the reply band 104 rises. The reservation data is transmitted with a delay of “time”.

  In this case, the reservation unit 28 first determines whether another superimposing terminal 22 is transmitting reservation data before starting transmission of reservation data after a waiting time has elapsed from the start of the superimposable band. If transmission is in progress, the transmission of reservation data is forgotten. At this time, the reservation unit 28 confirms the remaining time of the superimposable band, and if there is sufficient remaining time to transmit another reservation data after the transmission of the reservation data being transmitted is completed, the reservation data being transmitted After completing the transmission, the reservation data is transmitted by itself. Here, the reservation unit 28 may re-calculate the waiting time using a random number after confirming the end of transmission of the reservation data from the other superposition terminal 22, and may transmit the reservation data after the obtained waiting time has elapsed.

  The operation of the reservation unit 28 in this case will be briefly described with reference to the flowchart of FIG.

  When the superimposable band starts, the reservation unit 28 first calculates a waiting time using a random number (S41), and determines whether or not reservation data is transmitted from another superimposing terminal 22 after the waiting time has elapsed (S42). ). If there is no transmission of reservation data from the other superposition terminal 22 (S42: Yes), the reservation unit 28 transmits reservation data (S43). On the other hand, if there is transmission of reservation data from another superposition terminal 22 (S42: No), the reservation unit 28 has a sufficient margin for confirming the remaining time of the superimposable band and further transmitting reservation data. It is determined whether or not (S44). Here, if there is no time remaining (S44: Yes), the reservation unit 28 defers transmission of reservation data in this superimposable band (S45). On the other hand, if there is room in the remaining time (S44: No), the reservation unit 28 waits for the completion of transmission of the reservation data from the other superposition terminal 22 (S46), and returns to the waiting time calculation process (S41).

  Thereby, the plurality of superimposing terminals 22 can prevent the transmission timings of the reservation data from overlapping, and can avoid a situation in which the reservation data is not normally received due to interference between the superimposed signals. In addition, since the waiting time is randomly determined, the order in which the plurality of superimposing terminals 22 transmit the reservation data varies, so that an opportunity to transmit the reservation data to the plurality of superimposing terminals 22 is given fairly. become. Therefore, the communication system can avoid giving the transmission right of the transmission data to only the specific superimposing terminal 22 by the specific superimposing terminal 22 transmitting the reservation data first.

  Furthermore, after the reservation unit 28 completes the transmission of the reservation data from the other superimposing terminal 22, if the remaining time of the superimposable band has a sufficient margin, the reservation unit 28 transmits the reservation data to the same superimposable band. One superimposable band can be used for transmission of reservation data from a plurality of superposition terminals 22. Therefore, the communication system can relatively efficiently send reservation data from a plurality of superposition terminals 22.

  Further, when the second method is adopted, if the data length of the transmission data is relatively short, the superimposable band secured as the reserved band is used for transmission of transmission data from a plurality of superposition terminals 22. It is also possible to do. Therefore, the reservation data includes length information indicating the data length of the transmission data to be transmitted in the reservation band, in addition to the address of the superimposing terminal 22 that is the transmission source. The plurality of superimposing terminals 22 that have transmitted the reservation data in the same superimposable band are grouped so that the total data length indicated by the length information included in the reservation data is equal to or less than a predetermined allowable length. The The superimposing terminals 22 belonging to the same group are given transmission rights in the same reserved band.

  Specifically, each superimposing terminal 22 sequentially adds the data length indicated by the length information included in the transmitted reservation data, and until the total data length falls within the allowable length or less, the same group. recognize. That is, since the transmission right is given to the plurality of superposition terminals 22 in the order in which the reservation data is transmitted, the plurality of superpositions are performed within the range in which the total data length of the transmission data falls within the allowable length in the order of transmission of the reservation data. Terminals 22 are classified into the same group. The superimposing terminals 22 classified in the same group acquire the transmission right in the same reserved band, and therefore transmit transmission data in the same superimposable band (reserved band) in the order of transmission of the reserved data.

  For example, as shown in FIG. 8, when the transmission unit 1 transmits a timing synchronization pulse as secured data in the transmission band 103 of the second frame F2 of the transmission signal (S51), the superimposing terminal 22 transmits the second frame F2. The reservation data is transmitted in the reply band 104 (S52). At this time, it is assumed that the reservation data is sequentially transmitted from the two superposition terminals 22 whose addresses are “65” and “66”, respectively, and the total data length of the transmission data from these two superposition terminals 22 is an allowable length. Is assumed to be less than or equal to

  Thereafter, the transmission unit 1 performs communication using the transmission signal with the communication terminal 21 up to the (n-1) th frame Fn-1 of the transmission signal, and in the transmission band 103 of the nth frame Fn of the transmission signal. A timing synchronization pulse as secured data is transmitted (S53). When receiving the timing synchronization pulse in the nth frame Fn, the superimposing terminal 22 having the address “65” that first transmitted the reservation data in the second frame F2 transmits the superimposition signal in the reply band 104 of the nth frame Fn. Data is transmitted (S54). Further, when receiving the timing synchronization pulse in the nth frame Fn, the superimposing terminal 22 having the address “66” transmits the transmission data from the superimposing terminal 22 having the reply band 104 of the nth frame Fn and having the address “65”. After completion, the transmission data is transmitted by the superimposed signal (S55).

  According to this configuration, since a plurality of superimposing terminals 22 can transmit transmission data in one superimposable band, compared to a case where only one transmission data is transmitted per superimposable band. Thus, the superimposable band can be efficiently used for transmission of transmission data.

  In addition, when the data length of the transmission data is long and cannot be transmitted within one superimposable band, the superimposing terminal 22 interrupts communication at the end of the superimposable band and remains in the next superimposable band. Send the data. That is, the superimposing terminal 22 divides the transmission data into a length that can be superimposed on the superimposable band when transmitting the transmission data. In this case, the reservation data includes frame information indicating the number of superimposable bands required for transmission of transmission data, and the superimposing terminal 22 has the right to transmit in the number of superimposable bands (reserved bands) according to the frame information. May be provided.

  Thereby, since the superimposition terminal 22 can acquire the transmission right of the transmission data in the number of superimposable bands necessary for transmitting the transmission data, it is possible to transmit the transmission data using the plurality of superimposable bands. is there. Here, the frame information may be at least one of information directly indicating the number of necessary superimposable bands and the length information described above. In other words, since the length information is information indicating the data length of the transmission data, if the data length that can be transmitted in one superimposable band is known, transmission of transmission data can be performed from the relationship with the known data length. The number of necessary superimposable bands can be specified.

  For example, as shown in FIG. 9, when the transmission unit 1 transmits a timing synchronization pulse as secured data in the transmission band 103 of the first frame F1 of the transmission signal (S61), the superposition terminal 22 transmits the first frame F1. The reservation data is transmitted in the reply band 104 (S62). Thereafter, the transmission unit 1 performs communication using the transmission signal with the communication terminal 21 up to the (n-1) th frame Fn-1 of the transmission signal, and in the transmission band 103 of the nth frame Fn of the transmission signal. A timing synchronization pulse as secured data is transmitted (S63). Upon receiving the timing synchronization pulse in the nth frame Fn, the superimposition terminal 22 that has transmitted the reservation data in the first frame F1 transmits a part of the transmission data by the superimposition signal in the reply band 104 of the nth frame Fn. (S64).

  Thereafter, the transmission unit 1 performs communication using the transmission signal with the communication terminal 21 until the second n-1 frame F2n-1 of the transmission signal, and in the transmission band 103 of the second n frame F2n of the transmission signal. A timing synchronization pulse as secured data is transmitted (S65). Upon receiving the timing synchronization pulse in the second n frame F2n, the superposition terminal 22 that has transmitted the reservation data in the first frame F1 transmits the remainder of the transmission data by the superposition signal in the reply band 104 of the second n frame F2n ( S66).

  According to this configuration, the superimposing terminal 22 uses a plurality of superimposable bands (reserved bands) for which transmission rights have been acquired with reserved data, even for transmission data that does not fit in one superimposable band such as a long packet. Can be sent.

  Other configurations and functions are the same as those of the first embodiment.

(Embodiment 3)
In the communication system of the present embodiment, as a configuration for avoiding interference between superimposed signals from a plurality of overlapping terminals 22, the overlapping communication unit 23 of the overlapping terminal 22 transmits transmission data without using reservation data. This is different from the communication system of the first embodiment. Hereinafter, the same configurations as those of the first embodiment are denoted by common reference numerals, and description thereof is omitted as appropriate.

  In the present embodiment, the superimposition communication unit 23 transmits transmission data at a transmission timing predetermined for each superimposition terminal 22 in the superimposable band, and if other superimposition terminals 22 are transmitting transmission data, the transmission data Is configured not to send. That is, the superimposing terminal 22 is configured to transmit transmission data at a transmission timing determined in advance for each superimposing terminal 22 in the superimposable band, rather than transmitting transmission data as soon as the superimposable band is reached. Yes.

  Specifically, each superimposing terminal 22 determines in advance the waiting time from the start of the superimposable band (that is, the next reply band 104 that has received the secured data) to the start of transmission of transmission data based on its own address. It has been. Here, a waiting time shifted by the delay time Tb is assigned to each superimposing terminal 22. Therefore, for example, when the addresses of the plurality of superimposing terminals 22 are “65” to “67”, the transmission timing of the transmission data is the superimposing terminal 22 with the address “65”, the superimposing terminal 22 with “66”, They are set so as to be shifted by the delay time Tb in the order of the superposition terminal 22 of “67”. Since the superimposable band starts after a predetermined avoidance time (for example, 300 μs) Tc from the time when the reply band 104 rises, the superposition terminal 22 is delayed by “(address−65) × Tb + Tc” from the time when the reply band 104 rises. Transmission data will be transmitted.

  That is, when receiving the timing synchronization pulse in the transmission band 103 of the transmission signal, the superimposing terminal 22 transmits the transmission data using the superimposition signal in the reply band 104 of the same frame. At this time, when a plurality of superposition terminals 22 with addresses “65” to “68” transmit transmission data, the transmission timing of the transmission data is shifted by a delay time Tb as shown in FIG. That is, the superimposition terminal 22 at address “65” starts transmission of transmission data after “Tc” from the rise of the reply band 104 (FIG. 10A), and the superposition terminal 22 at address “66” rises at the rise of the reply band 104. Starts transmission of transmission data after “Tc + Tb” (FIG. 10B). Similarly, the superimposition terminal 22 at address “67” is “Tc + 2Tb” after the rise of the reply band 104 (FIG. 10C), and the superposition terminal 22 at address “68” is “Tc + 3Tb” after the rise of the reply band 104 ( In FIG. 10D, transmission of transmission data is started.

  Here, since the superimposition terminal 22 cannot transmit the transmission data if another superimposition terminal 22 is transmitting the transmission data, the superimposition terminal 22 will not transmit the transmission data. Therefore, when the transmission timing of the transmission data is determined in the order of the addresses “65”, “66”, “67”, “68” as described above, the transmission data from the superimposition terminal 22 at the address “65”. Will be given top priority. That is, the superimposition terminal 22 with addresses “66”, “67”, and “68” can transmit transmission data only when the superposition terminal 22 with address “65” is not transmitting transmission data.

  According to the communication system of the present embodiment described above, since the superimposition terminal 22 transmits the transmission data at a transmission timing predetermined for each superimposition terminal 22, a plurality of superposition terminals 22 are used without using reservation data. It is possible to avoid overlapping of the transmission timings of the superimposed signals between each other. Therefore, interference (collision) between superimposed signals can be avoided. Further, as compared with a configuration in which transmission data is transmitted after reservation data is transmitted, there are advantages that a time required to transmit the transmission data can be shortened and a time lag until the transmission data is transmitted can be shortened.

  Other configurations and functions are the same as those of the first embodiment.

1 Transmission unit 10 Communication line 23 Superimposition communication unit (data transmission unit)
24 Transmission / reception unit 27 Judgment unit 28 Reservation unit 103 Transmission band 104 Reply band 211 (21) First monitoring terminal (communication terminal)
212 (21) First control terminal (communication terminal)
221 (22) Second monitoring terminal (superimposition terminal)
222 (22) Second control terminal (superimposition terminal)

Claims (8)

A transmission unit that repeatedly transmits a transmission signal to a communication line, a communication terminal that communicates using the transmission signal, and a plurality of overlapping terminals that communicate using a superimposed signal superimposed on the transmission signal are connected to the communication line. A connected communication system,
The transmission signal includes a transmission band for transmitting data to the communication terminal in a time axis direction for each frame, and a plurality of return bands that are time slots for receiving return data from the communication terminal. Consisting of time-division signals divided into
The superposition terminal includes a transmission receiving unit that receives data transmitted by the transmission unit using the transmission signal in the transmission band, and reserved data that prohibits transmission of the return data in the next reply band in the transmission band. When received by the transmission receiving unit, a determination unit that determines that the reply band is a superimposable band used for superimposing the superimposition signal, and the reserved band with the next superimposable band as a reserved band in the superimposable band A reservation unit for transmitting reservation data for acquiring the transmission right of transmission data at the superimposition signal, and a data transmission unit for transmitting the transmission data by the superposition signal in the reserved band from which the transmission right has been acquired. A communication system comprising: When the reservation data is transmitted from a plurality of superimposing terminals in the same superimposable band, the superimposing terminals of the plurality of superimposing terminals are given priority from the superimposing terminal that transmitted the reservation data first. The right to send in the reserved zone is given,
The communication system according to claim 1, wherein the reservation unit transmits the reservation data at a transmission timing predetermined for each of the overlapping terminals in the superimposable band. When the reservation data is transmitted from a plurality of superimposing terminals in the same superimposable band, the superimposing terminals of the plurality of superimposing terminals are given priority from the superimposing terminal that transmitted the reservation data first. The right to send in the reserved zone is given,
The communication system according to claim 1, wherein the reservation unit transmits the reservation data at a transmission timing that is randomly determined for each of the overlapping terminals in the superimposable band.   The transmission right is given to the superimposing terminal that first transmitted the reservation data among the plurality of superimposing terminals that transmitted the reservation data to the same superimposable band. 4. The communication system according to 3.   The transmission right is given to the plurality of superimposing terminals that have transmitted the reservation data in the same superimposable band in the order in which the reservation data was transmitted first. The communication system described. The reservation data includes length information indicating a data length of the transmission data,
A plurality of the superimposing terminals that have transmitted the reservation data in the same superimposable band are grouped so that the total data length indicated by the length information included in the reservation data is equal to or less than a predetermined allowable length. 6. The communication system according to claim 5, wherein the superimposing terminals belonging to the same group are given the transmission right in the same reserved band.   The reserved data includes frame information indicating the number of superimposable bands required for transmission of the transmission data, and the superimposing terminal is granted the transmission right in the number of the reserved bands according to the frame information. The communication system according to any one of claims 1 to 6, wherein: A transmission unit that repeatedly transmits a transmission signal to a communication line, a communication terminal that communicates using the transmission signal, and a plurality of overlapping terminals that communicate using a superimposed signal superimposed on the transmission signal are connected to the communication line. A connected communication system,
The transmission signal includes a transmission band for transmitting data to the communication terminal in a time axis direction for each frame, and a plurality of return bands that are time slots for receiving return data from the communication terminal. Consisting of time-division signals divided into
The superposition terminal receives transmission data received by the transmission unit in the transmission band in the transmission reception unit, and secure transmission data prohibiting transmission of the return data in the next reply band in the transmission reception unit. When receiving, a data transmission unit that transmits transmission data by the superimposed signal using the reply band,
The data transmission unit transmits the transmission data at a transmission timing determined in advance for each of the superimposing terminals in the superimposable band, and if the other superimposing terminal is transmitting the transmission data, the transmission data is transmitted. A communication system characterized by not transmitting.

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