JP2016146570A - Master unit for power line communication, information collection system, and selective communication method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform communication with satisfactory quality by the minimum master unit while suppressing the attenuation of a signal in power line communication with the distribution line of a plurality of banks as a target.SOLUTION: A master unit 20 for power line communication capable of communicating with a slave unit comprises: a master unit side communication part 201 for power line communication including a transmission circuit 203, a reception circuit 204, and a switch control part 202 for cooperatively operating with communication; and a connection circuit part 210 arranged between a distribution system group and the master unit side communication part 201 in which a plurality of sets of signal couplers 211 to 218 including switches to be opened/closed by the switch control part 202 are provided one-to-one corresponding to each distribution system for selecting the opening/closing state of the switch on the basis of the command of the switch control part when the master unit side communication part 201 communicates with any slave unit to connect the master unit side communication part 201 only to the distribution line of one distribution system including the slave unit of a communication partner, and to non-connect the master unit communication part 201 to the distribution line of the other distribution system.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a technique for performing communication between a parent device and a plurality of child devices by power line communication (PLC), and more particularly to improvement of communication quality.

  The power line communication is a wired communication technique for transmitting a signal by superimposing a communication signal on the power line, and has an advantage that it is not necessary to separately prepare a signal line if the power line exists. As a suitable usage form of such power line communication, there is a remote meter reading of electric energy. For example, in an apartment house, each unit's watt-hour meter is equipped with a slave unit for power line communication, and by connecting the master unit to the main distribution line in the electrical room, etc., information on the power consumption of all the units is collected by the master unit (For example, refer to FIG. 2 of Patent Document 1). Information collected by the parent device can be transmitted to a power supply source via a communication line such as the Internet.

  If the housing is relatively small, power is distributed from the low-voltage side of one transformer to all units, so only one master unit is sufficient. However, when it comes to a large-scale apartment house, it has a multi-bank configuration with a plurality of transformers under a high-voltage (6.6 kV) receiving line. Power line communication signals rarely reach the adjacent bank via the high voltage line beyond the transformer. Therefore, the communication is limited within each bank, and a master unit is required for each bank.

  For example, FIG. 6 is a diagram showing the distribution systems S1 to S4 in a single line notation when four transformers 11 to 14 that step down from 6.6 kV to 100/200 V are provided. In this case, the power line communication master units 21 to 24 are required for the respective distribution systems S1 to S4. A large number of slave units (not shown) are connected to the ends of the power distribution systems S1 to S4.

  On the other hand, in the case where there are a plurality of distribution systems, it has also been proposed to provide a signal coupler (coupler) between the banks and allow only the power line communication signal to pass (for example, FIG. 3 of Patent Document 2 and Patent Document 3). FIG. 1). FIG. 7 is a diagram simply showing the procedure, and similarly to FIG. 6, four transformers 11 to 14 that step down from 6.6 kV to 100/200 V are provided. Signal couplers 51 to 53 are provided between the banks. The master unit 21 is always connected to the leftmost distribution system S1 in the figure, and the distribution system S1 and the other three distribution systems S2 to S4 are connected via signal couplers 51 to 53, respectively.

JP 2010-28788 A Japanese Patent Laid-Open No. 2003-258689 Japanese Patent No. 4457880

  In the configuration of FIG. 6, the same number of master units as the number of banks is required, and the cost of the entire system increases. On the other hand, in the configuration of FIG. 7, only one master unit is required, and the signal couplers 51 to 53 are relatively low cost. Therefore, the cost of the entire system is lower than that of the configuration of FIG. 7. Since the cost reduction effect of the configuration of FIG. 7 increases as the number of banks increases, the configuration of FIG. 7 is preferable in terms of cost.

  However, in the configuration of FIG. 7, the distribution lines of the plurality of distribution systems S <b> 1 to S <b> 4 are connected to each other as signal transmission paths for power line communication via the signal couplers 51 to 53. Therefore, the signal transmitted from the master unit is transmitted to the plurality of distribution lines, and attenuation is increased. In addition, when a plurality of power distribution systems are connected, the line impedance as a whole decreases, and this further causes signal attenuation. On the other hand, a signal transmitted from the slave unit to the master unit 21 is also transmitted to a plurality of distribution lines, and attenuation is increased. Further, when the line impedance becomes lower than the reception impedance of the master unit, the signal is attenuated.

  In view of such conventional problems, an object of the present invention is to perform good quality communication with a minimum number of base units while suppressing signal attenuation in power line communication for distribution lines of a plurality of banks. .

  The present invention provides the above-mentioned demand when a distribution system group including a plurality of banks as a distribution system from a low voltage side of a transformer to one or a plurality of consumers via a distribution line is provided. A power line communication master unit capable of communicating with a power line communication slave unit provided in each house, including a transmission circuit, a reception circuit, and a switch control unit that operates in conjunction with communication. A plurality of sets of signal couplers, which are located between the base unit side communication unit, the distribution system group, and the base unit side communication unit and include switches that are opened and closed by the switch control unit, correspond to each distribution system on a one-to-one basis. When the master unit side communication unit communicates with any of the slave units, the master unit side communication unit communicates with the slave unit by selecting an open / closed state of the switch based on a command of the switch control unit. Includes the other handset Connected to only distribution line one of the distribution system, the distribution line of the other power distribution system and a connection circuit for a non-connected.

  In addition, the information collection system of the present invention includes a distribution system group in which a distribution system extending from a low voltage side of a transformer to one or a plurality of consumers via a distribution line is defined as a bank, and the demand An information collection system comprising: a power line communication slave unit provided in each house; and a power line communication master unit capable of communicating with the slave unit, wherein the master unit includes a transmission circuit and a reception circuit. And a main unit side communication unit for power line communication including a switch control unit that operates in conjunction with communication, and a switch that is opened and closed by the switch control unit between the power distribution system group and the main unit side communication unit. When a plurality of signal couplers are provided corresponding to each distribution system in a one-to-one correspondence and the base unit side communication unit communicates with any one of the slave units, based on the command of the switch control unit, Select the open / closed state The base unit side communication unit is connected only to the distribution line of one distribution system including the slave unit of the communication partner, and is provided with a connection circuit unit that is not connected to the distribution line of the other distribution system. ing.

  In addition, the present invention provides a distribution system from a low voltage side of a transformer to one or a plurality of consumers via a distribution line as one bank, a distribution system group including a plurality of banks, and each of the consumers. A selection communication method executed by the master unit for a system including the provided slave unit for power line communication and a master unit for power line communication capable of communicating with the slave unit, wherein the master unit is When communicating with one of the slave units, only the distribution line of one distribution system that includes the slave unit of the communication partner is connected for signal transmission, and the distribution line of the other distribution system is disconnected. This is a selective communication method in which communication is performed with a communication partner slave unit in the state, and when communication is completed, communication is performed in the same manner while changing the communication partner, and information is collected from all the slave units.

  ADVANTAGE OF THE INVENTION According to this invention, communication of favorable quality can be performed with the minimum parent machine, suppressing the attenuation | damping of a signal in the power line communication which makes the distribution line of multiple banks object.

It is an example of a connection diagram of an information collection system including a master unit for power line communication according to an embodiment of the present invention. FIG. 2 is a circuit diagram showing details of the master unit in FIG. 1, and is a circuit diagram paying attention to a communication line between the master unit and the slave unit. It is a figure which shows the timing of the request | requirement by polling, and a response. It is a figure which shows the timing of the request | requirement and response by the system which calls from a subunit | mobile_unit. It is a circuit diagram which shows the detail of the main | base station as another example. It is the figure of the prior art which represented the power distribution system in the case of the four transformers which pressure | voltage-fall from 6.6kV to 100 / 200V being represented with the single line description. It is a figure of the prior art which shows simply the point which provides a signal coupler between banks and allows only a signal of power line communication to pass when there are a plurality of power distribution systems.

[Summary of Embodiment]
The gist of the embodiment of the present invention includes at least the following.

  (1) This is a case where a distribution system from a low voltage side of a transformer to one or a plurality of consumers via a distribution line is defined as one bank, and a distribution system group including a plurality of banks is provided. A power line communication master unit capable of communicating with a power line communication slave unit provided in each of the consumers, including a transmission circuit, a reception circuit, and a switch control unit that operates in conjunction with the communication. A signal coupler including a switch that is opened and closed by the switch control unit between the distribution unit group and the distribution unit group and the parent unit communication unit has a one-to-one correspondence with each distribution system. When a plurality of sets are provided and the base unit side communication unit communicates with any one of the slave units, the base unit side communication unit is selected by selecting an open / close state of the switch based on a command of the switch control unit. , Including the remote Connected to only one power distribution system of the distribution lines, the distribution lines of the other power distribution system and a connection circuit for a non-connected.

  According to such a master unit for power line communication, only the power distribution system including the slave unit of the communication partner is connected to the master unit side communication unit. Therefore, even if it is a main | base station common to the distribution system group of several banks, power line communication can be performed only using the distribution line of the connected distribution system. Thereby, attenuation by signal branching can be suppressed and communication quality can be improved.

(2) In the master unit of (1), the switch is configured by a transmission side switch and a reception side switch provided corresponding to each power distribution system, and the connection circuit unit closes the transmission side switch. A transmission route for sending a signal from the transmission circuit only to a distribution line of a corresponding distribution system, and a reception route for delivering a signal returned from the slave device of the communication partner to the reception circuit by closing the reception side switch are separately provided. Is formed.
In this case, when the transmission route and the reception route are common, it is not possible, for example, the transmission / reception communication characteristics can be changed by changing the impedance between the transmission route and the reception route.

(3) In the base unit of (2), the switch control unit controls the transmission side switch and the reception side switch to be closed in synchronization with each other and to be opened in synchronization with each other. The route and the reception route may be formed at the same time, and may be canceled after a predetermined time.
Such an operation is suitable for a polling method in which a slave unit answers questions from the master unit, and is also suitable for collecting information from a plurality of slave units in a bank unit. In this case, the control logic by the switch control unit is simple.

(4) In the base unit of (2), when the switch control unit forms the transmission route, the switch control unit performs control to close the transmission side switch and open the reception side switch to form the reception route. May perform control to close the reception side switch and open the transmission side switch.
In this case, since the transmission route and the reception route are not formed at the same time, establishment of a parallel circuit due to simultaneous formation can be prevented. Therefore, it is not affected by the impedance of the reception route during transmission, and is not affected by the impedance of the transmission route during reception.

(5) In the master unit of any one of (2) to (4), the connection circuit unit is provided with a signal transmission circuit corresponding to each of the transmission route and the reception route for each distribution system. Preferably, the impedance of the connection circuit portion of the transmission route is smaller than the impedance of the connection circuit portion of the reception route and is equal to or close to the impedance of the distribution line of the corresponding distribution system. .
In this case, it is easy to inject transmission power in the transmission route, and sensitivity reduction due to the influence of impedance can be suppressed in the reception route.

(6) In any one of the parent devices (1) to (5), the command of the switch control unit may be output using polling.
In this case, when polling from the parent device to the child device is performed, the distribution system can be selected using this.

(7) In the parent device of any one of (1) to (5), the parent device side communication unit stores a schedule for calling from all the child devices that can be communication partners, and according to the stored schedule, The base unit side communication unit may be connected only to the distribution lines of the corresponding distribution system and disconnected from the distribution lines of other distribution systems.
In this case, the amount of information transmitted from the parent device to the child device can be reduced.

  (8) On the other hand, this information collection system is a distribution system group in which a distribution system that reaches one or a plurality of consumers from the low voltage side of the transformer via a distribution line is defined as one bank, An information collection system comprising: a power line communication slave unit provided in each consumer; and a power line communication master unit capable of communicating with the slave unit, wherein the master unit includes a transmission circuit and a reception unit. A main unit side communication unit for power line communication including a circuit and a switch control unit that operates in conjunction with communication, and a switch that is opened and closed by the switch control unit between the power distribution system group and the main unit side communication unit When the base unit side communication unit communicates with any one of the slave units, the switch based on a command from the switch control unit is provided. Select the open / close state of The base unit side communication unit is connected only to the distribution line of one distribution system including the slave unit of the communication partner, and is provided with a connection circuit unit that is not connected to the distribution line of the other distribution system. ing.

  According to such an information collecting system, only the power distribution system including the slave unit of the communication partner is connected to the master unit side communication unit. Therefore, even if it is a main | base station common to the distribution system group of several banks, power line communication can be performed only using the distribution line of the connected distribution system. Thereby, attenuation by signal branching can be suppressed and communication quality can be improved. Such an information collection system is suitable, for example, as an automatic meter reading system for electric energy.

  (9) Moreover, this is a distribution system group in which a distribution system that reaches one or a plurality of consumers via a distribution line from the low voltage side of the transformer is a bank, and each of the consumers. A power line communication slave unit provided in the system, and a power line communication master unit communicable with the slave unit, a selective communication method executed by the master unit, wherein the master unit is When communicating with one of the slave units, only the distribution line of one distribution system including the slave unit of the communication partner is connected for signal transmission, and the distribution line of the other distribution system is disconnected. This is a selective communication method in which communication is performed with a communication partner slave unit in that state, and when communication is completed, communication is performed in the same manner while changing the communication partner, and information is collected from all the slave units.

  According to such a selective communication method, only the power distribution system including the slave device of the communication partner is connected to the master device. Therefore, even if it is a main | base station common to the distribution system group of several banks, power line communication can be performed only using the distribution line of the connected distribution system. Thereby, attenuation by signal branching can be suppressed and communication quality can be improved. Such a selective communication method is suitable, for example, as an automatic meter reading system for electric energy.

[Details of the embodiment]
Embodiments of the present invention will be described below with reference to the drawings.

<Outline of information collection system>
FIG. 1 is an example of a connection diagram of an information collection system including a master unit for power line communication according to an embodiment of the present invention. A typical use of such an information collection system is remote meter reading of electric energy. For example, the electric energy used by each house in a large-scale apartment house, or the electric energy used by each tenant in a building where a large number of tenants occupy. Is suitable for remote meter reading.

In FIG. 1, for example, four transformers 11, 12, 13, and 14 are connected to a 6.6 kV high-voltage distribution line. Each of the transformers 11 to 14 steps down 6.6 kV to 100 / 200V. The secondary side of the transformers 11 to 14 is connected to a distribution system S1, S2, S3, S4 of a 100 / 200V single-phase three-wire system. Distribution lines L1, L2, L3, and L4 to one or a plurality of consumers are provided under the distribution systems S1 to S4, respectively.
That is, for example, the distribution system from the low voltage side of the transformer 11 to the customer via the distribution line L1 is defined as one bank, and a distribution system group (S1 to S4) is formed in which a plurality (here, 4) banks exist. ing.

  Consumers are provided with watt hour meters 31-34, and the watt hour meters 31-34 are equipped with the functions of the slave units 41, 42, 43, 44 for power line communication, respectively. FIG. 1 illustrates a state in which one slave unit 41 to 44 is connected to each of the distribution lines L1 to L4 of the distribution systems S1 to S4. Actually, in most cases, a large number of slave units are connected to each of the distribution lines L1 to L4.

  In addition, each of the two lines (for example, voltage lines) of the distribution lines L1 to L4 is connected to the concentrator 20C. The concentrator 20C is equipped with the function of the main unit 20 for power line communication. The parent device 20 can communicate with the child devices 41 to 44, and can collect information on the amount of power used from the child devices 41 to 44. The concentrator 20C is connected to a power supply source via, for example, the optical fiber F, and can provide information collected by the parent device 20 to the power supply source.

<Details of main unit>
FIG. 2 is a circuit diagram showing details of the parent device 20 of FIG. 1, and is a circuit diagram paying attention to a communication line between the parent device 20 and the child devices 41 to 44. FIG. In the figure, the main unit 20 is roughly divided into a main unit side communication unit 201, a connection circuit unit 210, and filters (transmission filter 205, reception filters 206, 207, 208, and 209) between them. Has been.

  The base-side communication unit 201 includes a switch control unit 202, a transmission circuit 203, and a reception circuit 204. The connection circuit unit 210 includes signal couplers 211, 212, 213, and 214 on the transmission side (from the base unit side communication unit 201 to the distribution systems S1 to S4) and the reception side (from the distribution system S1 to S4 to the base unit side communication unit). 201) to signal couplers 215, 216, 217, 218 and coupling capacitors 231, 232, 233, 234, 235, 236, 237, 238.

For example, the signal coupler 211 is configured by connecting a coupling transformer Tt1 and a transmission-side switch St1 as illustrated. The same applies to the other signal couplers 212 to 214. The signal coupler 215 is configured by connecting a coupling transformer Tr1 and a reception side switch Sr1 as shown in the figure. The same applies to the other signal combiners 216 to 218.
The signal couplers 211 to 218 are divided into a transmission side and a reception side, and four sets are provided corresponding to the distribution systems S1, S2, S3, and S4 on a one-to-one basis. The correspondence with the power distribution systems S1 to S4 is shown as follows.

(Sender)
S1: Signal coupler 211 (coupling transformer Tt1, transmission side switch St1)
S2: Signal coupler 212 (coupling transformer Tt2, transmission side switch St2)
S3: Signal coupler 213 (coupling transformer Tt3, transmission side switch St3)
S4: Signal coupler 214 (coupling transformer Tt4, transmission side switch St4)
(Receiver)
S1: Signal coupler 215 (coupling transformer Tr1, transmission side switch Sr1)
S2: Signal coupler 216 (coupling transformer Tr2, transmission side switch Sr2)
S3: Signal combiner 217 (coupling transformer Tr3, transmission side switch Sr3)
S4: Signal combiner 218 (coupling transformer Tr4, transmission side switch Sr4)

As for each switch (transmission side switches St1 to St4, reception side switches Sr1 to Sr4), their open / closed state is selected based on a command from the switch control unit 202 of the base unit side communication unit 201. The switch control unit 202 operates in conjunction with communication (transmission / reception).
The coupling capacitors 231 to 238 pass only power line communication signals (for example, 10 to 450 kHz) and cut off the commercial frequency current. Further, by providing the coupling transformers Tt1 to Tt4 and Tr1 to Tr4, the circuit on the secondary side (the right side in FIG. 2) can maintain reliable insulation with respect to the distribution lines L1 to L4.

《Switch control method ・ Selective communication method》
For example, if the communication partner to which the transmission circuit 203 is going to transmit a signal is the slave unit 41, the distribution system including the slave unit 41 is S1, and the distribution line is L1. Therefore, the switch control unit 202 operates in conjunction with the transmission circuit 203 to turn on (close) the transmission side switch St1 and the reception side switch Sr1. The other switches (transmission side switches St2 to St4, reception side switches Sr2 to Sr4) are all turned off (open).

  In this state, when the transmission circuit 203 transmits a signal addressed to the slave unit 41, the signal passes through the transmission filter 205 and is input to the signal coupler 211 in which the transmission side switch St1 is on. The signal that has passed through the signal coupler 211 further passes through the coupling capacitor 231 and is injected into the distribution line L1 of the distribution system S1.

  The subunit | mobile_unit 41 extracts a signal from the distribution line L1. And the subunit | mobile_unit 41 inject | pours the information (electric power amount) which it holds into the distribution line L1 as a response signal. This signal passes through the coupling capacitor 231 and is input to the signal coupler 215 in which the receiving side switch Sr1 is on. The signal that has passed through the signal combiner 215 further passes through the reception filter 206 and reaches the reception circuit 204. When communication with the child device 41 is completed, communication with the other child devices 42 to 44 is sequentially performed.

  Similarly, when communication is performed between the other slave units 42 to 44 and the master unit 20, the switches (transmission side switches St <b> 2 to St <b> 4 of the transmission-side switches St <b> 2 to St <b> 4) are connected in the same manner. When any one / one of the receiving side switches Sr2 to Sr4) is turned on, similar communication is performed.

  As described above, the connection circuit unit 210 includes the signal couplers 211 to 218 including switches that are opened and closed by the switch control unit 202 between the distribution system group (S1 to S4) and the parent device side communication unit 201. A plurality of sets are provided corresponding to each power distribution system on a one-to-one basis. In addition, when the base unit side communication unit 201 communicates with any of the slave units, the connection circuit unit 210 selects the switch open / close state based on a command from the switch control unit 202, thereby causing the base unit side communication unit 201 to Only the distribution line of one distribution system including the slave unit of the communication partner is connected, and the distribution lines of other distribution systems are not connected.

  According to such a parent device 20, only the power distribution system including the communication partner child device is connected to the parent device side communication unit 201. Therefore, even if it is the main | base station 20 common to the distribution system group of several banks, power line communication can be performed only using the distribution line of the connected distribution system. Thereby, attenuation by signal branching can be suppressed and communication quality can be improved.

  Further, the switches of the signal couplers 211 to 218 are configured by transmission side switches St1 to St4 and reception side switches Sr1 to Sr4 provided corresponding to each distribution system. And in this connection circuit part 210, by closing the transmission side switches St1 to St4, the “transmission route” for sending a signal from the transmission circuit 203 only to the distribution lines of the corresponding distribution system, and the reception side switches Sr1 to Sr4 are closed. Accordingly, a “reception route” for sending a signal returned from the slave device of the communication partner to the reception circuit 204 is formed separately. This makes it possible to change the transmission / reception communication characteristics by changing the impedance between the transmission route and the reception route, for example, when the transmission route and the reception route are common.

<When to turn on the switch>
In FIG. 2, the switch control unit 202 closes the transmission side switch (any one of St1 to St4) and the reception side switch (any one of Sr1 to Sr4) in synchronization with each other, and also synchronizes with each other. Can be controlled to open. That is, the transmission route and the reception route described above are formed at the same time, and are canceled simultaneously after a predetermined time.
Such an operation is suitable for a polling method in which a slave unit (any one of 41 to 44) answers an inquiry from the master unit 20, and also when collecting information sequentially from a plurality of slave units in a bank unit. Suitable. In this case, the control logic by the switch control unit 202 is simple.

On the other hand, the switch control unit 202 performs control to close the transmission side switch and open the reception side switch when forming the transmission route, and closes the reception side switch and opens the transmission side switch when forming the reception route. It can also be done.
In this case, since the transmission route and the reception route are not formed at the same time, establishment of a parallel circuit due to simultaneous formation can be prevented. Therefore, it is not affected by the impedance of the reception route during transmission, and is not affected by the impedance of the transmission route during reception.

Thus, for example, the following can be performed.
The impedance of the connection circuit unit 210 of the transmission route is smaller than the impedance of the connection circuit unit 210 of the reception route, and may be equal to or close to the impedance of the distribution line of the corresponding distribution system. In other words, the impedance of the connection circuit unit 210 of the reception route is larger than the impedance of the connection circuit unit 210 of the transmission route.

  In this case, it is easy to inject transmission power in the transmission route, and in the reception route, it is possible to suppress a decrease in sensitivity due to the effect of a decrease in impedance. That is, in the transmission route, the signal can be injected with larger power by impedance matching with the distribution line for injecting the signal. In the reception route, signal attenuation is less likely to occur by making the impedance on the receiving side higher than the impedance of the distribution line.

《Practical selection communication method: Polling》
For example, the parent device 20 performs polling for metering electric energy in the order of the child devices 41 to 44. The polling cycle for the same slave is about once every 30 minutes, for example. As a response to polling, the slave unit returns power meter reading data to the master unit 20. The concentrator 20C receives and aggregates the meter reading data and provides information to the power supply source. In this way, polling can be executed for all the connected slave units within a predetermined time, and responses can be obtained.

  FIG. 3 is a diagram illustrating an example of timing between a request and a response by polling. Here, n is the number of slave units connected to the first distribution line. Base unit 20 outputs a signal “C1-K1” requesting information on the amount of power to the first handset. The slave unit responds to it. This is sequentially performed on the other slave units, and a signal “C1-Kn” requesting information on the amount of electric power is output to the n-th slave unit. When the slave unit responds, Information collection for the first distribution line is completed. The time required for collecting this information is, for example, T1.

  In the case of polling, there is no response from a slave unit not called by the master unit, and a response is returned only from the slave unit called by the master unit. Accordingly, during the time T1 when the information collection from all the slave units connected to the first distribution line is completed, the transmission side switch and the reception side switch corresponding to the first distribution line are turned on, and the other transmission side The switch and the reception side switch may be turned off.

  Similarly, let L be the number of slave units connected to the mth distribution line. Base unit 20 outputs a signal “Cm-K1” requesting information on the amount of power to the first handset. The slave unit responds to it. This is sequentially performed on the other slave units, and a signal “Cm-KL” requesting information on the electric energy is output to the L-th slave unit. When the slave unit responds to the signal, Information collection for the mth distribution line is completed. The time required for collecting this information is, for example, Tm. During time Tm when information collection from all the slave units connected to the mth distribution line is completed, the transmission side switch and the reception side switch corresponding to the mth distribution line are turned on, and the other transmission side switches and The receiving side switch may be turned off.

  In the case of polling, since the parent device itself recognizes which child device it is trying to communicate with, the switch control unit 202 includes a transmission-side switch corresponding to the distribution line of the distribution system including the communication partner child device, and The receiving side switch can be surely selected. That is, since the command of the switch control unit may be output using polling, switch control is easy.

  In the above example, the time until information collection is completed from all the slave units connected to one distribution line, the transmission side switch and the reception side switch corresponding to the distribution line are turned on. The switch and the receiving side switch can be turned on alternately. For example, at time T1 in FIG. 3, when the signal “C1-K1” is output, the transmission side switch is turned on (the reception side switch is off), and the signal “C1-K1” is output from the slave unit. In some cases, turning on the reception side switch (transmission side switch off) may be repeated until the signal "C1-Kn".

  In this case, since the transmission route and the reception route are not formed at the same time, as described above, establishment of a parallel circuit by simultaneous formation can be prevented. Therefore, it is not affected by the impedance of the reception route during transmission, and is not affected by the impedance of the transmission route during reception.

《Practical selection communication method: Call from handset》
On the other hand, instead of polling, a call can be made spontaneously from a slave unit, and the master unit 20 can also collect information. That is, the base unit side communication unit 201 stores a schedule for calling from all the slave units that can be communication partners, and connects the base unit side communication unit 201 only to the distribution lines of the corresponding distribution system according to the stored schedule. However, it is not connected to the distribution lines of other distribution systems. However, voluntary calling is permitted in one distribution system, and the order of the distribution systems needs to be scheduled.
In this case, the amount of information transmitted from the parent device to the child device can be reduced.

  FIG. 4 is a diagram illustrating an example of the timing of a request and a response according to a method of calling from a slave unit. For example, n is the number of slave units connected to the first distribution line. The master unit 20 outputs a common initial timing signal for the n slave units. In response to this, the n slave units output, for example, “C1-K1”,..., “C1-Kn” in accordance with the schedule. When the final “C1-Kn” is output, the information collection for the first distribution line is completed. The time required for collecting this information is, for example, T1.

  At time T1 until information collection is completed from all the slave units connected to the first distribution line, the transmission side switch and reception side switch corresponding to the first distribution line are turned on, and the other transmission side switches And the receiving side switch may be turned off. Further, the transmission side switch is turned on only when the timing signal is output (the reception side switch is off), and the reception side switch is turned on (transmission) while “C1-K1”,..., “C1-Kn” are output. The side switch may be off).

  Similarly, let L be the number of slave units connected to the mth distribution line. Base unit 20 outputs a signal that is a common initial timing for the L slave units. In response to this, the L slave units output, for example, “Cm-K1”,..., “Cm-KL” in accordance with the schedule. When the final “Cm-KL” is output, information collection for the mth distribution line is completed. The time required for collecting this information is, for example, Tm.

In addition, within time T1 and Tm, each slave unit may make a call with a delay time based on a random number starting from a timing signal instead of a predetermined schedule.
Further, instead of the timing signal, the master device and the slave device may use the clocks synchronized with each other to schedule the timing of calling from the slave device.

<Details of the main unit (other examples)>
FIG. 5 is a circuit diagram showing details of the master unit as another example. The difference from FIG. 2 is in the connection method in the signal couplers 211 to 218 in the connection circuit unit 210. That is, in FIG. 5, the transmission side switches St1 to St4 and the reception side switches Sr1 to Sr4 are the primary side (distribution system S1 to S4 side) windings of the coupling transformers Tt1 to Tt4 and Tr1 to Tr4, and the coupling transformer. Between Tt1 to Tt4 and Tr1 to Tr4.

  In the case of the circuit of FIG. 5, as long as the switch (any one of the transmission side switches St1 to St4 and the reception side switches Sr1 to Sr4) is open, no current flows through the primary winding of the corresponding signal coupler. Does not affect the impedance of the distribution line. However, the configuration shown in FIG. 2 on the secondary winding side of the signal coupler is advantageous in reducing the dielectric strength of the switch.

<Others>
In addition, for example, when it is necessary to transmit a signal from the master unit to all the slave units without specifying a communication partner such as broadcast, it is necessary to turn on all the transmission side switches and reception side switches. It is expected that transmission characteristics will deteriorate due to the parallel circuit. Therefore, in such a case, in the transmission circuit 203, broadcast is converted to multicast, signal conversion is performed, and a multicast group in which only slave units connected to one specific distribution line are grouped is formed. If only the transmission side and the reception side switch of the corresponding distribution line are turned on, it takes time compared with the broadcast, but broadcast information can be transmitted for each distribution line.

In FIG. 2, the processing in the receiving circuit 204 is not shown.
(I) One receiving circuit common to the plurality of distribution lines L1 to L4, or
(Ii) It is constituted by a plurality of receiving circuit elements corresponding to each of the distribution systems L1 to L4.
Either of these is possible. (I) is simple, and (ii) has an advantage that reception impedance can be made constant.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

11-14 Transformer 20C Concentrator 20 Master unit 21-24 Master unit 31-34 Energy meter 41-44 Slave unit 51-53 Signal coupler 201 Master unit side communication unit 202 Switch control unit 203 Transmission circuit 204 Reception circuit 205 Transmission Filter 206 to 209 Reception filter 210 Connection circuit 211 to 218 Signal coupler 231 to 238 Coupling capacitor F Optical fiber L1 to L4 Distribution line S1 to S4 Distribution system St1 to St4 Transmission side switch Sr1 to Sr4 Reception side switch

Claims (9)

When a distribution system from a low voltage side of a transformer to one or a plurality of consumers via a distribution line is defined as one bank, and a distribution system group including a plurality of banks is provided, each of the consumers is provided. A main unit for power line communication that can communicate with a slave unit for power line communication provided,
A main unit side communication unit for power line communication including a transmission circuit, a reception circuit, and a switch control unit that operates in conjunction with communication;
A plurality of signal couplers are provided between the power distribution system group and the base unit side communication unit and include switches that are opened and closed by the switch control unit in a one-to-one correspondence with each power distribution system. When the machine side communication unit communicates with any of the slave units, the base unit side communication unit is included in the slave unit of the communication partner by selecting the open / close state of the switch based on the command of the switch control unit A main unit for power line communication that includes a connection circuit unit that is connected only to a distribution line of one distribution system and is not connected to a distribution line of another distribution system. The switch is composed of a transmission side switch and a reception side switch provided corresponding to each distribution system,
The connection circuit unit includes a transmission route for sending a signal from the transmission circuit only to a distribution line of a corresponding distribution system by closing the transmission side switch, and from a communication partner slave unit by closing the reception side switch. 2. The master unit for power line communication according to claim 1, wherein reception routes for delivering a reply signal to the reception circuit are formed separately.   The switch control unit forms the transmission route and the reception route at the same time by controlling the transmission side switch and the reception side switch to be closed in synchronization with each other and to be opened in synchronization with each other. The master unit for power line communication according to claim 2, wherein the master unit is released at the same time after the time.   The switch control unit performs control to close the transmission side switch and open the reception side switch when forming the transmission route, and close the reception side switch and form the transmission side switch when forming the reception route. The master unit for power line communication according to claim 2, wherein control for opening the power line is performed. The connection circuit unit is provided with a circuit for signal transmission corresponding to each of the transmission route and the reception route for each distribution system,
The impedance of the connection circuit unit of the transmission route is smaller than the impedance of the connection circuit unit of the reception route and is equal to or close to the impedance of the distribution line of the corresponding distribution system. The power unit for power line communication according to any one of the above.   The master unit for power line communication according to any one of claims 1 to 5, wherein the command of the switch control unit is output using polling.   The base unit side communication unit stores a schedule for calling from all slave units that can be communication partners, and connects the base unit side communication unit only with a distribution line of the corresponding distribution system according to the stored schedule, The master unit for power line communication according to any one of claims 1 to 5, wherein the master unit is not connected to a distribution line of another distribution system. A distribution system group in which a plurality of banks exist as a distribution system from a low voltage side of a transformer to one or a plurality of consumers via a distribution line,
A slave for power line communication provided to each of the consumers;
A power line communication master unit capable of communicating with the slave unit, and an information collection system comprising:
A main unit side communication unit for power line communication including a transmission circuit, a reception circuit, and a switch control unit that operates in conjunction with communication;
A plurality of signal couplers are provided between the power distribution system group and the base unit side communication unit and include switches that are opened and closed by the switch control unit in a one-to-one correspondence with each power distribution system. When the machine side communication unit communicates with any of the slave units, the base unit side communication unit is included in the slave unit of the communication partner by selecting the open / close state of the switch based on the command of the switch control unit An information collection system comprising a connection circuit unit that is connected only to a distribution line of one distribution system and is not connected to a distribution line of another distribution system. A power distribution system from a low voltage side of a transformer to one or a plurality of consumers via a distribution line is regarded as one bank, a power distribution system group in which a plurality of banks exist, and power line communication provided in each of the consumers A slave unit and a power line communication master unit communicable with the slave unit, a selective communication method executed by the master unit,
When the master unit communicates with one of the slave units, it forms a signal connection only with the distribution line of one distribution system including the slave unit of the communication partner, and the distribution line of the other distribution system Disconnected,
In that state, communicate with the slave device of the communication partner,
A selective communication method in which, after communication is completed, communication is sequentially performed while changing the communication partner, and information is collected from all the slave units.