JP6089274B2 - Communication system and communication terminal - Google Patents

Description

  The present invention relates to a communication system and a communication terminal.

  Conventionally, as shown in FIG. 20, a transmission parent device 101 constituting a parent device and a plurality of communication terminals 102 constituting a child device are connected to the same communication line L100, and the transmission parent device 101 and each A communication system for performing communication with the communication terminal 102 is provided.

As this type of communication system, a transmission parent device 101 and a plurality of communication terminals 102 are connected by a two-wire communication line L100 , and communication between the transmission parent device 101 and each communication terminal 102 is performed by a time division multiplex transmission method. There is known a system that realizes (see, for example, Patent Document 1).

  In this communication system, when data is transmitted from the transmission master 101 to each communication terminal 102, a voltage signal having a predetermined amplitude for transmitting data by pulse width modulation is used. Further, when data is transmitted from each communication terminal 102 to the transmission base unit 101, a current signal obtained by changing the magnitude of the current is used.

Furthermore, the communication terminal 102 rectifies the transmission signal supplied from the communication line L100 to generate drive power for the terminal itself.

JP 2012-49638 A

  In conventional communication systems, as a power supply method to the slave unit, a drive power source is generated by rectifying and stabilizing the transmission signal transmitted from the transmission master unit through the communication line (stabilized power supply). Method).

  However, when a terminal with a relatively large current consumption such as a monitor terminal having an LCD (Liquid Crystal Display) or an information device having a CPU (Central Processing Unit) operating at high speed is used as a slave unit, a transmission error occurs. There was a risk of occurrence. Specifically, the fluctuation of the current flowing through the communication line L100 (load fluctuation) increases due to the transition of the operating state of the slave unit (for example, LCD backlight on / off, video processing CPU activation / sleep). In this case, the current signal may be distorted and a transmission error may occur.

  Here, for slave units with relatively large current consumption, a configuration in which driving power is supplied via a dedicated power supply wiring may be considered, but a dedicated power supply wiring is installed separately from the communication line. It was necessary and it was disadvantageous in terms of workability.

  The present invention has been made in view of the above reasons, and an object of the present invention is to supply driving power from a parent device to a child device via a communication line, and the child device communicates using a current signal. Is providing the communication system and communication terminal which can suppress a transmission error, without degrading workability.

In the communication system of the present invention, a master unit and a plurality of slave units are connected to a first communication line, the master unit supplies drive power to the plurality of slave units via the first communication line, The plurality of slave units is a communication system that transmits a first signal that is a current signal to the first communication line, and each of the plurality of slave units is allowed to transmit the first signal in synchronization with each other. A communication period and a load fluctuation period for prohibiting transmission of the first signal are set, a transmission process using the first signal is performed only in the communication period, and the first signal is transmitted from the communication period only in the load fluctuation period . The state of the own device is changed by permitting a state transition in which the fluctuation of the current flowing on one communication line becomes large, and the parent device sends a second signal to the first communication line, and the second signal is , One frame in a plurality of time zones including the communication period and the load fluctuation period The time-division voltage signal is divided, and the slave unit operates using the second signal as driving power, and sets the communication period and the load fluctuation period based on the received second signal, respectively. characterized in that it.

  In the present invention, the slave unit changes its own state by executing a control sequence, and when the time length of one control sequence is longer than the time length of the load variation period, It is preferable that the control sequence is divided into a plurality of parts, and each of the divided control sequences is assigned to one of the plurality of load fluctuation periods and sequentially executed.

  In the present invention, at least one of the slave units is configured such that between the first signal transmitted on the first communication line and a third signal transmitted on a second communication line different from the first communication line. When the amount of data of the first signal is larger than a predetermined value, the gateway device divides the first signal into a plurality of signals, and converts each of the divided first signals into a protocol. Each of the third signals is preferably assigned to any one of the plurality of load fluctuation periods and sequentially transmitted to the second communication line.

  In the present invention, the slave unit requests permission of state transition from the master unit before transitioning the state of the slave unit, and transitions the state of the slave unit during the load fluctuation period designated by the master unit. The time length of the load fluctuation period is preferably set by the parent device according to the contents of the state transition of the child device.

  In the present invention, the master unit holds in advance data of current consumption required for each of the slave units during state transition, and sets the load fluctuation period to a plurality of periods based on the current consumption of each of the slave units. Dividing into time domains, assigning the slave units to any of the time domains so that the sum of the current consumption of each of the time domains is equal, the slave unit is assigned to the time domain assigned to itself Therefore, it is preferable to change the state of the own device.

  In the present invention, the master unit includes a measuring unit that measures current consumption supplied at the time of each state transition of the slave unit, and based on the measured value of the current consumption of each slave unit, the load The variable period is divided into a plurality of time domains, and the slave unit is allocated to any one of the time domains so that the sum of the consumption currents of the time domains is equal, and the slave unit is allocated to the own unit. It is preferable that the state of the own device is changed in the given time region.

  In this invention, the master unit communicates with the slave unit using addresses assigned to the slave units, and divides the load variation period into a plurality of time regions corresponding to the addresses. However, it is preferable that the slave unit changes the state of the slave unit in the time domain corresponding to the address of the slave unit.

The communication terminal of the present invention is a communication terminal that is supplied with drive power via a communication line and sends a first signal that is a current signal to the communication line, and a communication period that permits transmission of the current signal; set the load fluctuation period to prohibit the transmission of the current signal, the only communication period performs transmission processing using the current signal, the current flowing through the above communication line from the communication period only to the load variation period This is a time-division voltage signal obtained by changing the state of the own device by permitting a state transition in which the fluctuation becomes large, and dividing one frame into a plurality of time zones including the communication period and the load fluctuation period. 2 signals are received via the communication line to operate using the second signal as driving power, and the communication period and the load fluctuation period are set based on the received second signal, respectively. Features To.

  As described above, in the present invention, since the communication period for permitting signal transmission and the load fluctuation period for prohibiting signal transmission are set, drive power is supplied from the master unit to the slave unit via the communication line. And even if it is the structure which a subunit | mobile_unit communicates using an electric current signal, there exists an effect that a transmission error can be suppressed without degrading workability.

1 is a block diagram illustrating a configuration of a communication system according to a first embodiment. It is a block diagram which shows the structure of the transmission main | base station same as the above. It is a wave form diagram which shows the format of the transmission signal same as the above. It is a block diagram which shows the structure of a communication terminal same as the above. It is a wave form diagram which shows the state transition operation | movement of a communication terminal same as the above. It is a wave form diagram which shows the state transition operation | movement of a monitor terminal same as the above. It is a block diagram which shows the structure of the function part of a monitor terminal same as the above. It is a block diagram which shows another structure of the function part of a monitor terminal same as the above. It is a wave form diagram which shows another state transition operation | movement of a monitor terminal same as the above. (A) (b) It is a wave form diagram which shows the state transition operation | movement of a gateway apparatus same as the above. It is a wave form diagram which shows the state transition operation | movement of the communication terminal of Embodiment 2. It is a sequence diagram which shows the state transition operation | movement of a communication terminal same as the above. FIG. 10 is a block diagram illustrating a configuration of a transmission parent device according to a third embodiment. It is a table figure which shows the data of an electric current data storage part same as the above. It is a sequence diagram which shows the state transition operation | movement of a communication terminal same as the above. FIG. 10 is a block diagram illustrating a configuration of a transmission parent device according to a fourth embodiment. It is a table figure which shows the data of an electric current data storage part same as the above. FIG. 10 is a block diagram illustrating a configuration of a communication system according to a fifth embodiment. It is a wave form diagram which shows the state transition operation | movement of a communication terminal same as the above. It is a block diagram which shows the structure of the conventional communication system.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(Embodiment 1)
FIG. 1 shows a configuration of a communication system according to the present embodiment, in which a transmission parent device 1 constituting a parent device and a communication terminal 2 constituting a child device are connected to the same communication line L1 (first communication line). doing. The communication line L1 is a two-wire type having a pair of signal lines. In addition, when the communication terminal 2 is a monitor terminal, it calls the monitor terminal 2a, and when the communication terminal 2 is a gateway apparatus, it calls the gateway apparatus 2b.

  As shown in FIG. 2, the transmission base unit 1 includes a communication unit 11 and an address storage unit 12. Information of each address of the communication terminal 2 is stored in the address storage unit 12, and the communication unit 11 performs communication control using each address of the communication terminal 2. And the communication part 11 sends out the transmission signal (2nd signal) which consists of a voltage waveform of the format shown in FIG. 3 with respect to the communication line L1. This transmission signal is a voltage signal, and is a bipolar (± 24V) time-division multiplexed signal having a voltage transmission period T1, a current transmission period T2, and a load fluctuation period T3 obtained by dividing one frame into three.

  The voltage transmission period T1 is a time slot in which the transmission master unit 1 generates a voltage signal for transmitting data to the communication terminal 2, and the transmission master unit 1 performs pulse width modulation on a carrier composed of a pulse train of ± 24V. To transmit data. The predetermined pulse train at the start of the voltage transmission period T1 indicates the start of the frame of the transmission signal and constitutes a known synchronization pulse for the communication terminal 2 to synchronize.

  The current transmission period T2 is a period in which a voltage of +24 V is generated, and is a time slot in which the transmission parent device 1 receives a superimposition signal described later from the communication terminal 2. That is, the current transmission period T2 is a period during which the communication terminal 2 is permitted to superimpose the superimposed signal on the transmission signal and transmit data to the transmission master unit 1. This current transmission period T2 corresponds to the communication period of the present invention.

  The load variation period T3 is a period in which a voltage of −24 V is generated, and is a time slot in which the communication terminal 2 is prohibited from transmitting a superimposed signal and the communication terminal 2 is allowed to perform a state transition operation.

  The transmission signal sent from the transmission base unit 1 onto the communication line L1 is a ± 24V bipolar, and is repeatedly sent out on the communication line L1, so that power is always supplied to the communication line L1 by the transmission signal. ing. Therefore, in this system, driving power can be supplied to the communication terminal 2 by using the transmission signal. However, since there is an upper limit to the power supplied by the transmission parent device 1, the power that can be supplied from the transmission parent device 1 to the communication terminal 2 connected to the communication line L1 is limited.

  Next, the communication terminal 2 includes a communication unit 21, an address storage unit 22, a function unit 23, and a power supply unit 24 as shown in FIG. The communication unit 21 receives a voltage signal from the transmission parent device 1 and further superimposes a superimposed signal (first signal) on the transmission signal, and transmits data to the transmission parent device 1. The function unit 23 has functions (such as a monitor function and a gateway function) unique to the communication terminal 2. The address storage unit 22 stores address information of its own terminal. The function unit 23 determines that the destination address included in the voltage signal received by the communication unit 21 matches the address of its own terminal. Perform the corresponding action. The power supply unit 24 rectifies the transmission signal supplied from the communication line L1 to generate driving power for the terminal itself.

  In the present embodiment, the time lengths of the voltage transmission period T1, the current transmission period T2, and the load fluctuation period T3 are determined in advance. Each of the communication terminals 2 receives a transmission signal transmitted from the transmission base unit 1 on the communication line L1, and synchronizes with each other by the above-described synchronization pulse of the voltage transmission period T1, and the voltage transmission period T1 and the current transmission period T2 A load fluctuation period T3 can be set. That is, the plurality of communication terminals 2 can set the voltage transmission period T1, the current transmission period T2, and the load fluctuation period T3 at the same timing.

  The communication unit 21 of the communication terminal 2 receives a transmission signal transmitted from the transmission parent device 1 onto the communication line L1, and receives a voltage signal transmitted from the transmission parent device 1 in the voltage transmission period T1.

  In addition, the communication unit 21 of the communication terminal 2 transmits data to the transmission parent device 1 by superimposing a superimposed signal on the transmission signal in the current transmission period T2. This superimposed signal is a current signal for transmitting data by changing the current flowing on the communication line L1, and is a signal obtained by modulating a carrier wave having a frequency higher than that of the voltage signal.

  In addition, the functional unit 23 of the communication terminal 2 changes the state using the driving power generated by the power supply unit 24 in the load fluctuation period T3. For example, when the communication terminal 2 is the monitor terminal 2a (see FIG. 1), the function unit 23 is configured by an LCD device having a video display function, and the function unit 23 performs state transition such as on / off of the LCD backlight. The operation is performed in the load fluctuation period T3.

  Next, as an example of the state transition operation of the communication terminal 2, the operation of the monitor terminal 2a will be described with reference to FIG. FIG. 5 shows a waveform of a signal transmitted on the communication line L1.

The monitor terminal 2a receives the voltage signal transmitted by the transmission parent device 1 in the voltage transmission period T1. In the current transmission period T2, the monitor terminal 2a superimposes the superimposed signal P on the transmission signal and transmits data to the transmission master unit 1.

  Then, when the LCD backlight of the monitor terminal 2a is off, it is assumed that the transmission master unit 1 transmits a backlight on request using a voltage signal in the voltage transmission period T1 (time t1). The monitor terminal 2a changes the state of the LCD backlight from off to on in the load fluctuation period T3 in the same frame as the voltage transmission period T1 that has received the backlight on request (time t2).

  That is, the communication terminal 2 such as the monitor terminal 2a sets the current transmission period T2 during which the communication terminal 2 transmits the superimposed signal P as a different period from the load fluctuation period T3 during which the state of the functional unit 23 is changed. Therefore, even if the fluctuation (load fluctuation) of the current flowing on the communication line L1 becomes large due to the state transition of the communication terminal 2 (LCD backlight ON / OFF, etc.), the superimposed signal P composed of the current signal is distorted. Transmission errors can be suppressed without occurring.

  Thus, in this embodiment, even if it is the structure which supplies drive power from the transmission main | base station 1 to the communication terminal 2 via the communication line L1, and the communication terminal 2 communicates using an electric current signal, workability | operativity is improved. Transmission errors can be suppressed without deteriorating.

  Moreover, the function part 23 of the communication terminal 2 is changing the state of the own terminal by performing a control sequence. When the time length of one control sequence is longer than the time length of the load fluctuation period T3, the functional unit 23 of the communication terminal 2 divides one control sequence into a plurality of pieces, and each of the divided control sequences is divided into a plurality of pieces. Are assigned to any one of the load fluctuation periods T3 and executed sequentially.

  Hereinafter, the state transition operation of the monitor terminal 2a will be described with reference to FIG. FIG. 6 shows a waveform of a signal transmitted on the communication line L1.

  First, the functional unit 23 of the monitor terminal 2a includes an LCD controller 23a and an LCD backlight 23b as shown in FIG. When the LCD controller 23a is off and the LCD backlight 23b is off, it is assumed that the transmission master 1 transmits a backlight on request using a voltage signal in the voltage transmission period T1 (time t11). The control sequence for performing the backlight on operation of the monitor terminal 2a can be divided into a first sequence for switching the LCD controller 23a from off to on and a second sequence for switching the LCD backlight 23b from off to on. Therefore, the monitor terminal 2a changes the state of the LCD controller 23a from off to on in the load variation period T3 in the same frame as the voltage transmission period T1 that has received the backlight on request (time t12). Next, the monitor terminal 2a changes the state of the LCD backlight 23b from off to on in the load fluctuation period T3 in the next frame (time t13).

  Therefore, the communication terminal 2 can divide and execute one control sequence over a plurality of load fluctuation periods T3, so there is no need to increase the time length of the load fluctuation period T3, and the load fluctuation period T3 is increased. This can suppress a decrease in transmission efficiency.

  Next, when the functional unit 23 of the monitor terminal 2a includes an LCD controller 23a, an LCD backlight 23b, a transmission CPU 23c, a video processing CPU 23d, and an audio processing CPU 23e as shown in FIG. 8, the monitor terminal 2a 9 state transition operation is performed. FIG. 9 shows a waveform of a signal transmitted on the communication line L1.

  In this case, the control sequence for performing the backlight on operation of the monitor terminal 2a can be divided into four sequences. In the first sequence, the transmission CPU 23c is activated from the sleep state, and in the second sequence, the video processing CPU 23d and the audio processing CPU 23e are activated from the sleep state. The third sequence switches the LCD controller 23a from off to on, and the fourth sequence switches the LCD backlight 23b from off to on.

  First, when the LCD controller 23a is off, the LCD backlight 23b is off, the transmission CPU 23c is off, the video processing CPU 23d is off, and the audio processing CPU 23e is off, the transmission master unit 1 uses the voltage signal in the voltage transmission period T1. Assume that a backlight on request has been transmitted (time t21). The monitor terminal 2a activates the transmission CPU 23c from the sleep state during the load fluctuation period T3 within the same frame as the voltage transmission period T1 that has received the backlight on request (time t22). Then, the monitor terminal 2a activates the video processing CPU 23d and the audio processing CPU 23e from the sleep state during the load fluctuation period T3 in the next frame (time t23). Next, the monitor terminal 2a changes the state of the LCD controller 23a from off to on in the load fluctuation period T3 in the next frame (time t24). Next, the monitor terminal 2a changes the state of the LCD backlight 23b from off to on in the load fluctuation period T3 in the next frame (time t25).

  Also in this case, the communication terminal 2 divides and executes one control sequence over a plurality of load fluctuation periods T3, and can suppress a decrease in transmission efficiency due to an increase in the load fluctuation period T3.

  Next, as an example of the state transition operation of the communication terminal 2, the operation of the gateway device 2b (see FIG. 1) will be described with reference to FIGS. 10 (a) and 10 (b). The functional unit 23 of the gateway device 2b performs protocol conversion of signals between the communication line L1 (first communication line) and the communication line L2 (second communication line). Specifically, the functional unit 23 of the gateway device 2b converts the superimposed signal P (first signal) transmitted on the communication line L1 into a signal (third signal) of another communication protocol transmitted on the communication line L2. Converted and sent out on the communication line L2. Further, the functional unit 23 of the gateway device 2b converts a signal of another communication protocol transmitted through the communication line L2 into a superimposed signal P, and sends the signal onto the communication line L1. Then, the functional unit 23 of the gateway device 2b performs a protocol-converted signal transmission operation (state transition operation) in the load fluctuation period T3. The signal transmitted through the communication line L2 is generated using a communication protocol such as RS485, RS422, Ethernet (registered trademark).

  FIG. 10A shows a signal waveform on the communication line L1, and FIG. 10B shows a signal waveform that has been subjected to protocol conversion by the gateway device 2b and transmitted onto the communication line L2. When the data amount of the superimposed signal P to be protocol-converted is larger than a predetermined value that can be transmitted in one load fluctuation period T3, the functional unit 23 of the gateway device 2b divides the superimposed signal P into a plurality of pieces. To do. The functional unit 23 of the gateway device 2b performs protocol conversion on each of the divided superimposed signals P into another communication protocol, assigns each signal after the protocol conversion to any one of the plurality of load fluctuation periods T3, and transmits the communication line L2. Sequentially. In FIG. 10B, the superimposed signal P is divided into two, and each of the two signals after the protocol conversion is assigned to each of the load fluctuation periods T3 of two different frames and transmitted to the communication line L2.

  Therefore, load fluctuation due to the transmission operation (state transition operation) of the gateway device 2b occurs only in the load fluctuation period T3, so that transmission errors can be suppressed without causing distortion in the superimposed signal P made up of current signals. it can. Further, since the gateway device 2b can divide and transmit a signal over a plurality of load fluctuation periods T3, it is not necessary to lengthen the time length of the load fluctuation period T3, and by extending the load fluctuation period T3. A decrease in transmission efficiency can be suppressed.

(Embodiment 2)
The communication system of the present embodiment has the same configuration as that of the first embodiment, and the same components are denoted by the same reference numerals and description thereof is omitted.

  A state transition operation of the communication terminal 2 will be described with reference to FIGS. 11 and 12. FIG. 11 shows a waveform of a signal transmitted on the communication line L1, and FIG. 12 shows a communication sequence.

  First, the communication unit 21 of the communication terminal 2 transmits the load fluctuation request S1 to the transmission parent device 1 using the superimposed signal P in the current transmission period T2 before the function unit 23 performs the state transition operation (time t31). ). That is, the communication terminal 2 requests the transmission master 1 for permission to change the state before changing the state of the own terminal. Further, the communication unit 21 of the communication terminal 2 adds information on the length of time required for the state transition operation of the function unit 23 to the load variation request S1.

  The communication unit 11 of the transmission parent device 1 sends a voltage signal to the communication terminal 2 that is the transmission source of the load variation request S1 in the voltage transmission period T1 of the frame that permits the state transition operation (in this case, the next frame). The used change permission notification S2 is transmitted (time t32). The transmission base unit 1 adds information on the length of the load fluctuation period T3 to the fluctuation permission notification S2. The time length of the load fluctuation period T3 specified by the fluctuation permission notification S2 is set longer than the time length required for the state transition operation based on the load fluctuation request S1 received by the transmission parent device 1. Further, the transmission parent device 1 adjusts the time length of the load fluctuation period T3 of the frame permitting the state transition operation to the specified time length.

  The functional unit 23 of the communication terminal 2 that is the transmission source of the load variation request S1 performs the state transition operation S3 in the load variation period T3 in the same frame as the voltage transmission period T1 that has received the variation permission notification S2 (t33).

  Therefore, the transmission parent device 1 can dynamically assign the communication terminal 2 the load variation period T3 used for the state transition operation and the time length of the load variation period T3 according to the contents of the state transition operation. It becomes possible. That is, it is possible to efficiently use the load fluctuation period T3 and improve control responsiveness in the load fluctuation period T3.

(Embodiment 3)
In the communication system of the present embodiment, the transmission parent device 1 includes a current data storage unit 13 as shown in FIG. The current data storage unit 13 stores in advance data of current consumption required for each communication terminal 2 at the time of state transition.

  Then, the transmission base unit 1 divides the load fluctuation period T3 into a plurality of time regions based on the respective current consumptions of the communication terminals 2, and the sum (maximum value) of the respective current consumptions in the time regions is even. Each communication terminal 2 is assigned to any time region so as to be (grouping).

  Specifically, the current data storage unit 13 of the transmission parent device 1 stores the current consumption data “communication terminal 2A: 100 mA, communication terminal 2B: 500 mA, communication terminal 2C: 400 mA” shown in FIG. I remember it. The data of current consumption of the communication terminal 2 alone is data of current consumed inside the communication terminal 2 without considering a loss due to a voltage drop of the communication line L1.

  Then, as shown in FIG. 15, the transmission base unit 1 divides the load fluctuation period T3 into two time regions D1 and D2, assigns one communication terminal 2B to the time region D1, and sets two in the time region D2. The communication terminals 2A and 2C are grouped. FIG. 15 shows a waveform of a signal transmitted on the communication line L1.

  The communication unit 11 of the transmission parent device 1 transmits the above-described grouping result to each of the communication terminals 2A to 2C using the voltage signal of the voltage transmission period T1 when it starts up, and the communication terminals 2A to 2C Each can recognize the time domain assigned to the terminal itself. And each of communication terminal 2A-2C performs a state transition operation | movement in the time area | region allocated to the self terminal in the load fluctuation period T3. That is, the sum of current consumption in the time domain D1 (maximum value) is 500 mA, the sum of current consumption in the time domain D2 (maximum value) is 500 mA, and the sum of the current consumption in each of the time domains D1 and D2 Value) are equal to each other.

  Therefore, it is possible to evenly allocate the driving power of the communication terminal 2 necessary for the state transition within the load fluctuation period T3, and the power supplied from the transmission parent device 1 can be used efficiently in the load fluctuation period T3. Moreover, since the peak value of the driving power supplied from the transmission parent device 1 to the communication line L1 can be suppressed, the power feeding circuit of the transmission parent device 1 can be configured at low cost.

(Embodiment 4)
In the communication system of the present embodiment, the transmission parent device 1 includes a current measurement unit 14 and a current data storage unit 15 as shown in FIG.

  The current measuring unit 14 actually measures the current consumption of each communication terminal 2 by measuring the current supplied from the transmission parent device 1 to the communication line L1. Specifically, after the transmission master unit 1 is activated, the current measurement unit 14 sequentially transmits an operation request to each of the communication terminals 2 using the voltage signal in the voltage transmission period T1. The functional unit 23 of the communication terminal 2 that has received the operation request executes a state transition operation such as sleep and activation in the load fluctuation period T3. The current measurement unit 14 measures the current consumption of the communication terminal 2 when the function unit 23 of the communication terminal 2 executes the state transition operation. The current measuring unit 14 sequentially transmits an operation request to each of the communication terminals 2 to measure each consumption current supplied at the time of the state transition of the subordinate communication terminal 2 and stores the measurement result in the current data storage unit 15. .

  Specifically, the current data storage unit 15 of the transmission parent device 1 stores current consumption measurement data “communication terminal 2A: 150 mA, communication terminal 2B: 550 mA, communication terminal 2C: 700 mA” shown in FIG. Then, as shown in FIG. 15, the transmission master unit 1 divides the load fluctuation period T3 into two time regions D1 and D2, assigns two communication terminals 2A and 2B to the time region D1, and assigns them to the time region D2. Grouping is performed in which one communication terminal 2C is allocated.

  That is, the transmission base unit 1 divides the load variation period T3 into a plurality of time regions based on the actual current consumption of each of the communication terminals 2, and the sum (maximum value) of the current consumptions in the time regions is calculated. The communication terminals 2 are assigned to any time region so as to be even.

  The communication unit 11 of the transmission parent device 1 transmits the above grouping result to each of the communication terminals 2A to 2C using the voltage signal of the voltage transmission period T1, and each of the communication terminals 2A to 2C The time domain assigned to can be recognized. And each of communication terminal 2A-2C performs a state transition operation | movement in the time area | region allocated to the self terminal in the load fluctuation period T3. That is, the sum of current consumption in the time domain D1 (maximum value) is 700 mA, the sum of current consumption in the time domain D2 (maximum value) is 700 mA, and the sum of the current consumption in the time domains D1 and D2 is equal to each other. Become.

  The actual driving power supplied by the transmission parent device 1 is a combination of the power consumption of the communication terminal 2 alone and the power loss in the communication line L1 from the transmission parent device 1 to the communication terminal 2. Therefore, in the present embodiment, the current supplied from the transmission base unit 1 to the communication line L1 at the time of the state transition of the communication terminal 2 is measured, and either communication terminal 2 is selected based on the actual current consumption of each communication terminal 2. Assigned to the time domain. That is, the grouping can be performed in consideration of the influence of the system configuration such as the loss due to the voltage drop of the communication line L1, and the power (maximum value) supplied from the transmission master unit 1 to the communication line L1 in each time domain. Each communication terminal 2 can be assigned to any time region so as to be even.

  Therefore, it is possible to evenly allocate the driving power of the communication terminal 2 necessary for the state transition within the load fluctuation period T3 based on the actual current consumption. In the load fluctuation period T3, the power supplied to the transmission master unit 1 is reduced. It can be used more efficiently. In addition, since the peak value of the driving power supplied from the transmission parent device 1 to the communication line L1 can be more reliably suppressed, the power supply circuit of the transmission parent device 1 can be configured at low cost.

(Embodiment 5)
FIG. 18 shows a configuration of a communication system according to the present embodiment, and the communication terminal 2 includes a transmission terminal 2c and a superposition terminal 2d. In addition, the same code | symbol is attached | subjected to the structure similar to Embodiment 1, and description is abbreviate | omitted. Hereinafter, when the transmission terminal 2c and the superposition terminal 2d are not distinguished, they are referred to as communication terminals 2.

  The communication protocol is different between the communication signal transmitted through the communication line L1 in the communication between the transmission parent device 1 and the communication terminal 2 and the communication signal transmitted through the transmission line L1 in the communication between the overlapping terminals 2d. Yes. The former communication signal is a pulse-width-modulated bipolar signal, and the latter communication signal uses a current signal obtained by modulating a carrier wave having a frequency higher than that of the former communication signal. Hereinafter, the former communication signal is referred to as a “transmission signal”, and the latter communication signal is referred to as a “superimposition signal”.

  And the communication part 21 of the transmission terminal 2c has a transmission / reception function of a transmission signal, and the communication part 21 of the superimposition terminal 2d has each transmission / reception function of a transmission signal and a superimposition signal.

  A transmission signal used in communication between the transmission parent device 1 and the communication terminal 2 has a predetermined format, and the transmission parent device 1 repeatedly sends it to the communication line L1. Each communication terminal 2 has an address (identification information). By including the address of the communication terminal 2 in the transmission signal transmitted by the transmission master unit 1, the communication terminal 2 is designated and transmitted from the transmission master unit 1. Instructions to each terminal are given. That is, an instruction can be individually given from the transmission base unit 1 to the communication terminal 2 by time division multiplexing. The transmission signal is provided with a period during which information is notified from the communication terminal 2 to the transmission master unit 1.

  The transmission terminal 2 c is connected to a monitoring terminal that receives a monitoring input from a switch or a sensor (not shown) and requests the transmission master 1 to control the load, and a load (not shown) is connected to the transmission terminal 1. There are two types of control terminals that control the load in accordance with instructions from.

  The transmission base unit 1 includes a relation table that associates switches or sensors (hereinafter, the switches and sensors are collectively referred to as monitoring means) and loads. By registering the relation between the monitoring means and the load in the relation table in advance, the transmission master unit 1 controls the load associated with the monitoring means in the relation table according to the switch operation or the change in the sensor output. To do. The relation table may include the contents of load control for the monitoring means.

  As shown in FIG. 19, the transmission signal (second signal) includes a synchronization pulse period T11, a transmission period T12, a return period T13, an interrupt period T14, a short-circuit detection period T15, and a pause period T16. And a bipolar (± 24V) signal. The transmission master unit 1 repeatedly transmits this transmission signal.

  The synchronization pulse period T11 indicates the start of the frame of the transmission signal, and has two periods with different voltage polarities. The voltage polarity changes from + 24V to −24V within the period of the synchronization pulse period T11.

  The transmission period T12 is a period in which an instruction is transmitted from the transmission parent device 1 to the communication terminal 2, and is a time slot in which the transmission parent device 1 generates a voltage signal for transmitting data to the communication terminal 2. The transmission base unit 1 transmits data by performing pulse width modulation on a carrier composed of a pulse train of ± 24V. This voltage signal includes mode information indicating the type of transmission signal, an address for individually specifying the communication terminal 2, and control information indicating the content of the instruction.

  The return period T13 is a period in which a voltage of + 24V is generated and information is notified from the communication terminal 2 to the transmission master unit 1, and the transmission master unit 1 waits without transmitting a signal.

  The interrupt period T14 is a period for generating a voltage of −24V and detecting an interrupt signal output from the communication terminal 2, and the short circuit detection period T15 is generating a voltage of + 24V and generating a communication line. This is a period for detecting a short circuit of L1. The idle period T16 is a period in which a voltage of -24V is generated and data transmission is not performed.

  Each communication terminal 2 performs an operation based on the control information included in the transmission period T12 when its own address is included in the address included in the transmission period T12 of the transmission signal received via the communication line L1. . For example, in the case of a control terminal, since the control content for the load is included in the control information of the transmission signal, the load is controlled according to the control content. The switch operation in the monitoring terminal and the load control result in the control terminal are returned to the transmission master unit 1 by a current mode signal (current signal) in synchronization with the return period T13 (corresponding to the communication period of the present invention). The

  The current mode signal (first signal) is a binary current signal represented by a state where the communication lines L1 are opened and a state where the communication lines L1 are short-circuited via a low impedance element. . For example, the communication terminal 2 has a return circuit in which a return transistor and a resistor are connected in series, and turns on and off the return transistor in a state where a DC voltage obtained by rectifying a transmission signal is applied to the return circuit. Thereby, the magnitude of the current flowing from the communication line L1 to the communication terminal 2 changes, and the communication terminal 2 can generate a current signal on the communication line L1 and transmit the current signal to the transmission master unit 1. .

  The transmission base unit 1 always performs polling for sequentially accessing the communication terminal 2 by cyclically changing the address of the communication terminal 2 included in the transmission signal. In the case of constant polling, the communication terminal 2 whose address included in the transmission signal matches its own address operates if the transmission signal includes control information, and takes control information and returns its operating state. In the period T13, it is returned to the transmission master unit 1.

  By the way, the communication terminal 2 generates an interrupt signal I on the communication line L1 in synchronization with the transmission signal interrupt period T14 when a monitoring input or the like is generated (see FIG. 19). For example, when the monitoring terminal receives a monitoring input from the switch, the monitoring terminal generates an interrupt signal I in the interrupt period T14. When the transmission base unit 1 detects this interrupt signal I, it searches for the communication terminal 2 that generated the interrupt signal I, and accesses the communication terminal 2 to obtain the address of the communication terminal 2.

  When the address of the communication terminal 2 that generated the interrupt signal I is acquired by the transmission parent device 1, the transmission parent device 1 designates the address and causes the communication terminal 2 to return data such as monitoring input. Based on the monitoring input returned from the communication terminal 2, the transmission master unit 1 generates a transmission signal including control information for the communication terminal 2 provided with a load associated with each monitoring input in advance by the relation table. It is sent to the communication line L1. Therefore, the load is controlled in accordance with a request (switch operation or the like) from the communication terminal 2 that has generated the interrupt signal I.

  As described above, the transmission base unit 1 always performs polling at all times to sequentially access all the communication terminals 2. When receiving the interrupt signal from any one of the communication terminals 2, the transmission master unit 1 accesses the communication terminal 2 that generated the interrupt signal I and receives a request from the communication terminal 2. In this way, polling is always performed, and when an interrupt signal I is generated, an operation for preferentially processing a request from the communication terminal 2 that has generated the interrupt signal I is referred to as interrupt polling.

  On the other hand, the superimposing terminal 2d is, for example, a measuring terminal that measures the amount of power consumed by a load, a monitor terminal that displays a measurement result of the measuring device, or the like. The superimposing terminal 2d performs communication using the above-described constant polling and interrupt polling with the transmission master unit 1, and the superimposing terminals 2d communicate with each other using a superimposing signal transmitted on the communication line L1. For example, the monitor terminal collects the measurement results of the measurement terminal.

  For the communication between the superimposing terminals 2d, a superimposing signal P that is transmitted on the communication line L1 while being superimposed on the transmission signal is used. Specifically, the superimposed signal P is transmitted in a superimposable period (corresponding to the communication period of the present invention) appropriately selected from the synchronization pulse period T11 and the pause period T16 of the transmission signal. The superimposed signal P (first signal) is a current signal for data transmission by changing the current flowing on the communication line L1, and is a signal obtained by modulating a carrier wave having a frequency higher than that of the voltage signal.

  Further, since the transmission signal transmitted from the transmission master unit 1 onto the communication line L1 is multipolar and is always polled, power is always supplied to the communication line L1 by the transmission signal. Therefore, in this system, driving power can be supplied to the communication terminal 2 by using the transmission signal. However, since there is an upper limit to the power supplied by the transmission parent device 1, the power that can be supplied from the transmission parent device 1 to the communication terminal 2 connected to the communication line L1 is limited.

  Then, the communication terminal 2 communicates with the transmission master unit 1 using the above-described constant polling and interrupt polling, and communicates between the overlapping terminals 2d using the superimposed signal P, so that state transition such as activation / sleep of its own terminal is performed. Operation is instructed. Each functional unit 23 of the communication terminal 2 instructed to perform the state transition operation causes the state to transition using the driving power generated by the power supply unit 24 in the short circuit detection period T15. That is, the short circuit detection period T15 also serves as the load fluctuation period of the present invention.

  For example, when the superimposing terminal 2d is a monitor terminal, the function unit 23 is configured by an LCD device having a video display function, and the function unit 23 performs a state transition operation such as on / off of the LCD backlight in a short-circuit detection period. Performed at T15.

  Further, as shown in FIG. 19, the transmission master unit 1 has the short-circuit detection period T15 in the same number of time regions D11, D12,. . . , D1n, and one communication terminal 2 is assigned to each time region. The process of assigning the time domain to the communication terminal 2 is automatically performed when the transmission master unit 1 performs the address setting process of the communication terminal 2. Therefore, since the address setting process and the time domain allocation process can be performed simultaneously, for example, a communication sequence for allocating the time domain becomes unnecessary. That is, the cost increase due to the addition of a circuit such as a current measurement unit can be suppressed without increasing the number of steps for assigning the time domain.

  When the address of the communication terminal 2 is set, the communication unit 11 of the transmission parent device 1 transmits the above time domain assignment result to each of the communication terminals 2 using the voltage signal of the voltage transmission period T1, and the communication terminal 2 Each can recognize the time domain assigned corresponding to the address of its own terminal. And each of the communication terminals 2 performs state transition operation | movement in the time area | region allocated to the own terminal of the short circuit detection period T15.

  Therefore, in the short circuit detection period T15, it is possible to prevent the state transitions of the communication terminals 2 from concentrating at the same timing, and to control the load fluctuation in the load fluctuation period T3 to be substantially constant, thereby efficiently using the load fluctuation period T3. Can do. Moreover, since the peak value of the driving power supplied from the transmission parent device 1 to the communication line L1 can be suppressed, the power feeding circuit of the transmission parent device 1 can be configured at low cost.

1 Transmission base unit (base unit)
2 Communication terminal (slave unit)
2a Monitor terminal (slave unit)
2b Gateway device (slave unit)
L1 communication line (first communication line)
L2 communication line (second communication line)

Claims (8)

A master unit and a plurality of slave units are connected to a first communication line, the master unit supplies drive power to the plurality of slave units via the first communication line, A communication system for sending a first signal, which is a signal, to the first communication line,
Each of the plurality of slave units synchronizes with each other to set a communication period in which the transmission of the first signal is permitted and a load fluctuation period in which the transmission of the first signal is prohibited, and only in the communication period The transmission process using one signal is performed, and the state of the own machine is changed by allowing the state transition in which the fluctuation of the current flowing on the first communication line becomes larger than the communication period only during the load fluctuation period.
The base unit sends a second signal to the first communication line, and the second signal is a time-division voltage obtained by dividing one frame into a plurality of time zones including the communication period and the load fluctuation period. Signal,
The slave unit operates using the second signal as driving power, and sets the communication period and the load variation period based on the received second signal.   When the slave unit changes its own state by executing a control sequence, and the time length of one control sequence is longer than the time length of the load fluctuation period, a plurality of the control sequences The communication system according to claim 1, wherein each of the divided control sequences is assigned to one of the plurality of load fluctuation periods and sequentially executed. At least one of the slave units performs protocol conversion between the first signal transmitted on the first communication line and a third signal transmitted on a second communication line different from the first communication line. Gateway device to perform,
When the data amount of the first signal is larger than a predetermined value, the gateway device divides the first signal into a plurality of signals, and converts each of the divided first signals into a plurality of protocol signals. The communication system according to claim 1, wherein the communication system is assigned to any one of the load fluctuation periods and sequentially transmitted to the second communication line.   The child device requests permission of state transition from the parent device before changing the state of the own device, changes the state of the own device during the load fluctuation period specified by the parent device, and changes the load. The communication system according to any one of claims 1 to 3, wherein the time length of the period is set by the parent device in accordance with contents of state transition of the child device. The master unit stores in advance current consumption data required for each of the slave units during state transition, and the load variation period is divided into a plurality of time regions based on the current consumption of the slave units. And assigning the slave unit to any one of the time regions so that the sum of the consumption currents of the time regions becomes equal,
The communication system according to any one of claims 1 to 3, wherein the slave unit changes the state of the slave unit in the time domain assigned to the slave unit. The master unit includes a measurement unit that measures current consumption supplied at each state transition of the slave unit, and sets a plurality of load variation periods based on the measured current consumption values of the slave units. , And the slave unit is allocated to any one of the time regions so that the sum of the consumption currents of the time regions becomes equal,
The communication system according to any one of claims 1 to 3, wherein the slave unit changes the state of the slave unit in the time domain assigned to the slave unit. The master unit communicates with the slave unit using addresses assigned to the slave units, and divides the load fluctuation period into a plurality of time regions corresponding to the addresses,
4. The communication system according to claim 1, wherein the slave unit changes the state of the slave unit in the time domain corresponding to the address of the slave unit. 5. A communication terminal which is supplied with drive power via a communication line and sends a first signal which is a current signal to the communication line,
A communication period for permitting transmission of the current signal and a load fluctuation period for prohibiting transmission of the current signal are set, transmission processing using the current signal is performed only during the communication period, and only during the load fluctuation period. and changing the state of its own allowed state transitions variation of the current is increased through the above said communication line said communication period,
The second signal is driven by receiving the second signal, which is a time-division voltage signal obtained by dividing one frame into a plurality of time zones including the communication period and the load fluctuation period, via the communication line. The communication terminal which operates using electric power and sets the communication period and the load fluctuation period based on the received second signal.

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