JP6846999B2 - Communication system, communication equipment, and miswiring detection method - Google Patents

Description

The present invention relates to communication systems, communication devices, and miswiring detection methods.

Currently, there is known a communication system in which a master unit and a plurality of slave units are connected to each other by a plurality of communication line pairs. For example, Patent Document 1 describes a signal transmission system in which a central processing unit and a plurality of terminals are connected by a pair of transmission lines.

In the signal transmission system described in Patent Document 1, the central processing device transmits data to the terminal by voltage transmission, and the terminal transmits data to the central processing device by current transmission. In such a communication system, if there are a plurality of routes connecting the master unit and the slave unit, a failure of the master unit or the slave unit or a communication abnormality may occur.

Japanese Unexamined Patent Publication No. 2-210935

However, for example, when the number of slave units is large, or when the distance between the master unit and the slave units or the distance between the plurality of slave units is long, multiple routes connecting the master unit and the slave units may occur due to incorrect wiring. There is. Therefore, there is a demand for a technique for detecting erroneous wiring that causes a plurality of routes connecting a master unit and a slave unit.

The present invention has been made in view of the above problems, and provides a communication system, a communication device, and an erroneous wiring detection method for detecting erroneous wiring that causes a plurality of routes connecting a master unit and a slave unit. The purpose.

In order to achieve the above object, the communication system according to the present invention
A communication system including a master unit and a plurality of slave units, in which the master unit and the plurality of slave units are interconnected by a plurality of communication line pairs.
The master unit is
A receiving circuit for receiving data from the plurality of slave units by detecting the presence or absence of a current flowing through the communication line pair connected to the master unit among the plurality of communication line pairs is provided.
The plurality of slave units
The first terminal pair to which the first communication line pair of the plurality of communication line pairs is connected and
A second terminal pair to which the second communication line pair of the plurality of communication line pairs is connected and
A first connection point to which one terminal of the first terminal pair and one terminal of the second terminal pair are connected, and the other terminal of the first terminal pair and the second terminal pair. A transmission circuit that transmits data to the master unit by controlling the conduction / non-conduction state between the terminal pair and the second connection point to which the other terminal is connected.
A first current detecting means for detecting the first current flowing through the first communication line pair,
A second current detecting means for detecting the second current flowing through the second communication line pair, and
When the first current and the second current are equal to or higher than a predetermined threshold value when the connection between the first connection point and the second connection point is controlled to be conductive. A signal output means for outputting a predetermined signal is provided.

In the present invention, the first connection point to which one terminal of the first terminal pair and one terminal of the second terminal pair are connected, and the other terminal and the second terminal of the first terminal pair. Flows to the first communication line pair connected to the first terminal pair when the connection between the second connection point to which the other terminal of the terminal pair is connected is controlled to be conductive. When the magnitude of the first current and the magnitude of the second current flowing through the second communication line pair connected to the second terminal pair is equal to or greater than a predetermined threshold value, a predetermined signal is output. To. Therefore, according to the present invention, it is possible to detect erroneous wiring that causes a plurality of routes connecting the master unit and the slave unit.

Configuration diagram of the communication system according to the first embodiment of the present invention Configuration diagram of a master unit and a slave unit according to the first embodiment of the present invention. A flowchart showing a communication control process executed by the slave unit according to the first embodiment of the present invention. A flowchart showing the erroneous wiring detection process shown in FIG. A flowchart showing an erroneous wiring detection process executed by the slave unit according to the second embodiment of the present invention. A flowchart showing a communication control process executed by the master unit according to the second embodiment of the present invention. Configuration diagram of the communication system according to the third embodiment of the present invention Configuration diagram of the slave unit according to the third embodiment of the present invention

(Embodiment 1)
Embodiments of the present invention will be described with reference to the drawings. First, the communication system 1000 according to the first embodiment of the present invention will be described with reference to FIG. The communication system 1000 is a system in which a master unit 100 and a plurality of slave units (slave unit 200, slave unit 300, slave unit 400, slave unit 500) are provided, and the master unit 100 and the plurality of slave units communicate with each other. is there. The communication system 1000 is, for example, a lighting system including a lighting control device and a plurality of lighting devices. In this case, the master unit 100 corresponds to the lighting control device, and the plurality of slave units each correspond to the plurality of lighting devices.

The master unit 100 includes a DC power supply (not shown) and supplies electric power to a plurality of slave units. The plurality of slave units operate on the power supplied from the master unit 100. The master unit 100 transmits data to a plurality of slave units by a voltage signal, and the plurality of slave units transmit data to the master unit 100 by a current signal. In this embodiment, it is assumed that there is no broadcast and a polling method is adopted. That is, the master unit 100 does not transmit data to the plurality of slave units at the same time, and the plurality of slave units transmit data to the master unit 100 when the data is received from the master unit 100. Therefore, the master unit 100 and the plurality of slave units do not transmit data at the same time.

The master unit 100 and the plurality of slave units are connected to each other by a plurality of communication line pairs (communication line pair 13, communication line pair 23, communication line pair 33, communication line pair 43, communication line pair 53), and a plurality of communication line pairs. Communicate with each other via a pair of communication lines. Specifically, the master unit 100 includes a terminal pair 145 including the terminal 141 and the terminal 142, and a terminal pair 146 including the terminal 143 and the terminal 144. The slave unit 200 includes a terminal pair 245 including the terminal 241 and the terminal 242, and a terminal pair 246 including the terminal 243 and the terminal 244. The slave unit 300 includes a terminal pair 345 including the terminal 341 and the terminal 342, and a terminal pair 346 including the terminal 343 and the terminal 344. The slave unit 400 includes a terminal pair 445 including the terminal 441 and the terminal 442, and a terminal pair 446 including the terminal 443 and the terminal 444. The slave unit 500 includes a terminal pair 545 including a terminal 541 and a terminal 542, and a terminal pair 546 including a terminal 543 and a terminal 544.

The terminal 141 and the terminal 143 are connected inside the master unit 100, and the terminal 142 and the terminal 144 are connected inside the master unit 100. The terminal 241 and the terminal 243 are connected inside the slave unit 200, and the terminal 242 and the terminal 244 are connected inside the slave unit 200. The terminal 341 and the terminal 343 are connected inside the slave unit 300, and the terminal 342 and the terminal 344 are connected inside the slave unit 300. The terminal 441 and the terminal 443 are connected inside the slave unit 400, and the terminal 442 and the terminal 444 are connected inside the slave unit 400. The terminal 541 and the terminal 543 are connected inside the slave unit 500, and the terminal 542 and the terminal 544 are connected inside the slave unit 500.

In FIG. 1, the slave unit 300 and the slave unit 500 are erroneously connected by the communication line pair 53 including the communication line 51 and the communication line 52, and a plurality of routes connecting the master unit 100 and the specific slave unit are generated. An example in which miswiring (hereinafter, simply referred to as "miswiring") has occurred is shown. This erroneous wiring is also called loop wiring because a loop is formed by a plurality of routes connecting the master unit 100 and a specific slave unit. If there is such an erroneous wiring, the master unit 100 or a plurality of slave units may break down or a communication abnormality may occur. Therefore, in the present embodiment, when erroneous wiring is detected, the connection relationship is automatically adjusted so as not to be affected by the erroneous wiring (so that the loop wiring is eliminated). Hereinafter, in order to facilitate understanding, first, a case where there is no erroneous wiring will be described.

The master unit 100 and the slave unit 200 are connected to each other by a communication line pair 13 including a communication line 11 and a communication line 12. That is, the terminal 141 and the terminal 241 are connected by the communication line 11, and the terminal 142 and the terminal 242 are connected by the communication line 12. The slave unit 200 and the slave unit 300 are connected to each other by a communication line pair 23 including a communication line 21 and a communication line 22. That is, the terminal 243 and the terminal 341 are connected by the communication line 21, and the terminal 244 and the terminal 342 are connected by the communication line 22. The master unit 100 and the slave unit 400 are connected to each other by a communication line pair 33 including a communication line 31 and a communication line 32. That is, the terminal 143 and the terminal 441 are connected by the communication line 31, and the terminal 144 and the terminal 442 are connected by the communication line 32. The slave unit 400 and the slave unit 500 are connected to each other by a communication line pair 43 including the communication line 41 and the communication line 42. That is, the terminal 443 and the terminal 541 are connected by the communication line 41, and the terminal 444 and the terminal 542 are connected by the communication line 42.

Here, if the wiring length becomes long, the influence of the voltage drop in the wiring becomes large, and there is a high possibility that communication by the voltage signal cannot be performed normally. Therefore, the master unit 100, the slave unit 200, the slave unit 300, the slave unit 400, and the slave unit 500 are connected so that the wiring length is within a predetermined length (for example, 100 m) or less. In FIG. 1, the length of the communication line pair 13 is 30 m, the length of the communication line pair 23 is 20 m, the length of the communication line pair 33 is 50 m, and the length of the communication line pair 43 is 50 m. An example is shown. In this case, the wiring length from the master unit 100 to the slave unit 200 is 30 m, the wiring length from the master unit 100 to the slave unit 300 is 30 m + 20 m = 50 m, and the wiring length from the master unit 100 to the slave unit 400 is 50 m. The wiring length from the master unit 100 to the slave unit 500 is 50 m + 50 m = 100 m. Therefore, the master unit 100 can normally transmit a voltage signal to any of the slave unit 200, the slave unit 300, the slave unit 400, and the slave unit 500.

When transmitting data to any of the slave units, the master unit 100 applies a predetermined power supply voltage (for example, 12V or 24V) between the terminals 145 while reversing the polarity. The data is basically binary data represented by a combination of 1 and 0. For example, the master unit 100 applies 12V to the terminals 141 and 143 and 0V to the terminals 142 and 144 during the period of transmitting the bit corresponding to 0. On the other hand, the master unit 100 applies 0V to the terminals 141 and 143 and 12V to the terminals 142 and 144 during the period of transmitting the bit corresponding to 1.

Here, when the influence of the voltage drop according to the wiring length is small, basically, the terminal 141, the terminal 143, the terminal 241 and the terminal 243, the terminal 341, the terminal 343, the terminal 441, the terminal 443, the terminal 541, and the terminal 543 are used. A voltage of the same degree is applied to. Therefore, the plurality of slave units can receive data from the master unit 100 by monitoring the polarity of the power supply voltage applied between the terminal pairs.

For example, in the slave unit 200, a bit corresponding to 0 is transmitted during a period in which the polarity of the voltage between the terminals 245 is negative (for example, a period in which 12V is applied to the terminals 241 and 0V is applied to the terminals 242). It can be regarded as a period of time. On the other hand, in the slave unit 200, a bit corresponding to 1 is transmitted during a period in which the polarity of the voltage between the terminals 245 is positive (for example, a period in which 0V is applied to the terminals 241 and 12V is applied to the terminals 242). It can be regarded as a period of time. Then, the slave unit 200 can receive the data transmitted by the master unit 100 by combining the received bits. It is assumed that the bit string constituting the data includes a bit string indicating the device of the data transmission source and transmission destination.

On the other hand, when transmitting data to the master unit 100, the plurality of slave units transmit data to the master unit 100 by switching the conduction / non-conduction state between the terminal pairs. For example, the slave unit 200 controls the terminal pair 245 to be in a conductive state during the period of transmitting the bit corresponding to 1, and controls the terminal pair 245 to be in the non-conducting state during the period of transmitting the bit corresponding to 0. Here, since the power supply voltage is applied between the terminal pairs 245, a current flows through the communication line pair 13 when the terminal pair 245 is controlled to be in a conductive state. The current flowing through the communication line pair 13 means that the current flows through the communication line 11 and the communication line 12. Basically, the magnitude of the current flowing through the communication line 11 and the magnitude of the current flowing through the communication line 12 are about the same, and the direction of the current flowing through the communication line 11 and the direction of the current flowing through the communication line 12 are opposite to each other. It is suitable. Hereinafter, the "magnitude of electric current" is appropriately and simply referred to as "current".

On the other hand, the master unit 100 can receive data from the slave unit 200 by detecting the presence or absence of a current flowing through the communication line pair 13. For example, the master unit 100 can be regarded as a period during which a current equal to or higher than the threshold value is flowing through the communication line pair 13 and a period during which the bit corresponding to 1 is transmitted. On the other hand, the master unit 100 can be regarded as a period during which a current equal to or greater than the threshold value does not flow through the communication line pair 13 and a period during which the bit corresponding to 0 is transmitted. Then, the master unit 100 can receive the data transmitted by the slave unit 200 by combining the received bits.

Here, if there is no erroneous wiring, that is, if the slave unit 300 and the slave unit 500 are not connected by the communication line pair 53, the slave unit 300 is connected only to the slave unit 200. Therefore, while the slave unit 200 transmits data, the only path through which current flows from the slave unit 200 to the master unit 100 is the communication line pair 13.

Next, a case where there is an erroneous wiring, that is, a case where the slave unit 300 and the slave unit 500 are connected by a communication line pair 53 including the communication line 51 and the communication line 52 will be described. In this case, the terminal 343 and the terminal 543 are connected by the communication line 51, and the terminal 344 and the terminal 544 are connected by the communication line 52. The length of the communication line pair 53 is assumed to be 20 m.

Here, for example, it is assumed that the slave unit 200 transmits data to the master unit 100. In this case, the slave unit 200 controls the terminal pair 245 to be in a conductive state during the period of transmitting the bit corresponding to 1. When the terminal pair 245 is controlled to be in a conductive state, a power supply voltage is applied between the terminal pair 245, so that a current flows through the communication line pair 13. However, between the slave unit 200 and the master unit 100, a path 1 composed of a communication line pair 13, a communication line pair 23, a communication line pair 53, a communication line pair 43, and a communication line pair 33 are configured. There are two current paths with the path 2. Therefore, when the terminal pair 245 is controlled to be in a conductive state, a current also flows through the communication line pair 23, the communication line pair 53, the communication line pair 43, and the communication line pair 33.

The length of the route 1 is 30 m, and the length of the route 2 is 20 m + 20 m + 50 m + 50 m = 140 m. Therefore, the magnitude of the current flowing through the path 1 is larger than the magnitude of the current flowing through the path 2. The magnitude of the current monitored by the master unit 100 is the total magnitude of the magnitude of the current flowing in the path 1 and the magnitude of the current flowing in the path 2. Therefore, the magnitude of the current monitored by the master unit 100 is larger when there is erroneous wiring than when there is no erroneous wiring. It is considered that there is no problem in itself that the magnitude of the current monitored by the master unit 100 becomes large. However, the fact that there is an erroneous wiring itself means that an unexpected connection is made, and it may lead to a failure of the master unit 100 or a plurality of slave units, or a communication abnormality. Therefore, when transmitting data, the plurality of slave units check whether or not there is an erroneous wiring, and if an erroneous wiring is detected, automatically adjust the connection relationship so that the influence of the erroneous wiring is eliminated.

For example, the slave unit 200 controls the terminal pair 245 to be in a conductive state during the period of transmitting the bit corresponding to 1, and confirms whether or not a current is flowing in both the path 1 and the path 2. Then, when the slave unit 200 detects that a current is flowing in both the path 1 and the path 2, the slave unit 200 cuts off the path (for example, the path 2) in which the flowing current is smaller. The fact that the current flowing through the path is small means that the length of the path is long. In general, normal pathways are designed to be short. Therefore, the long path is more likely to be a path formed by miswiring than the short path. In addition, if a short route is blocked and a long route is left, normal communication may not be possible. Therefore, when erroneous wiring is detected, it is preferable that the path with the smaller flowing current is cut off.

Next, the configurations of the master unit 100 and the slave unit 200 will be described with reference to FIG. The configuration of the slave unit 300, the slave unit 400, and the slave unit 500 is basically the same as the configuration of the slave unit 200.

The master unit 100 includes a transmission circuit 110, a reception circuit 120, a control unit 130, a terminal pair 145, a terminal pair 146, a notification unit 150, a power supply terminal 161 and a capacitor 162, and a ground terminal 163. Be prepared.

The transmission circuit 110 transmits data by a voltage signal according to the control by the control unit 130. The transmission circuit 110 outputs an H level voltage (for example, 5V) from a first transmission terminal (terminal indicated by Tx1) included in the control unit 130 (not shown), and a second transmission terminal (not shown) included in the control unit 130. When an L level voltage (for example, 0V) is output from (terminal indicated by Tx2), 0V is applied to the terminal 141 and V1 is applied to the terminal 142. On the other hand, when the L level voltage is output from the first transmission terminal and the H level voltage is output from the second transmission terminal, the transmission circuit 110 applies V1 to the terminal 141 and 0V to the terminal 142. Apply. V1 is the power supply voltage of the master unit 100.

The level of the voltage output from the second transmission terminal is the opposite of the level of the voltage output from the first transmission terminal. For example, when transmitting the bit corresponding to 1, the control unit 130 outputs an H level voltage from the first transmission terminal and outputs an L level voltage from the second transmission terminal. Further, when transmitting a bit corresponding to 0, the control unit 130 outputs an L level voltage from the first transmission terminal and outputs an H level voltage from the second transmission terminal. Therefore, the voltage of terminal 141 is lower than the voltage of terminal 142 when the bit corresponding to 1 is transmitted, and the voltage of terminal 141 is higher than the voltage of terminal 142 when the bit corresponding to 0 is transmitted. Become. Basically, the voltage of the terminal 141 and the voltage of the terminal 143 are the same, and the voltage of the terminal 142 and the voltage of the terminal 144 are the same.

The transmission circuit 110 includes an NPN (Negative Positive Negative) transistor 111, a PNP (Positive Negative Positive) transistor 112, an NPN transistor 113, and a PNP transistor 114. The collector of the NPN transistor 111 and the collector of the NPN transistor 113 are connected to the power supply terminal 161. The base of the NPN transistor 111 and the base of the PNP transistor 112 are connected to the first transmission terminal. The emitter of the NPN transistor 111 and the emitter of the PNP transistor 112 are connected to the terminals 142 and 144.

The collector of the PNP transistor 112 and the collector of the PNP transistor 114 are connected to the ground terminal 128 via the resistor 126 and to the non-inverting input terminal of the operational amplifier 122 via the capacitor 123. The base of the NPN transistor 113 and the base of the PNP transistor 114 are connected to the second transmission terminal. The emitter of the NPN transistor 113 and the emitter of the PNP transistor 114 are connected to terminals 141 and 143. When the NPN transistor 111 and the PNP transistor 114 are turned on, the NPN transistor 113 and the PNP transistor 114 are turned off. Further, when the NPN transistor 111 and the PNP transistor 114 are turned off, the NPN transistor 113 and the PNP transistor 114 are turned on.

The receiving circuit 120 supplies the control unit 130 with a voltage signal corresponding to data (bit data) transmitted as a current signal from any of the slave units. When the receiving circuit 120 detects that the current flowing through the communication line pair 13 or the communication line pair 33 exceeds a predetermined threshold value, the receiving circuit 120 is connected to a receiving terminal (terminal indicated by Rx) provided in the control unit 130. It supplies an H-level voltage signal. On the other hand, when the receiving circuit 120 detects that the current flowing through the communication line pair 13 or the communication line pair 33 is less than this threshold value, the receiving circuit 120 supplies an L level voltage signal to the receiving terminal.

The receiving circuit 120 includes a power supply terminal 121, an operational amplifier 122, a capacitor 123, a resistor 124, a resistor 125, a resistor 126, a ground terminal 127, and a ground terminal 128. The power supply terminal 121 is connected to a DC power supply (not shown) included in the master unit 100, and a power supply voltage (V1) is applied. The operational amplifier 122 compares the input voltage applied to the non-inverting input terminal with the reference voltage applied to the inverting input terminal. The operational amplifier 122 outputs an H level voltage from the output terminal when the input voltage is higher than the reference voltage, and outputs an L level voltage from the output terminal when the input voltage is lower than the reference voltage.

The capacitor 123 cuts off the DC component supplied to the inverting input terminal of the operational amplifier 122. The resistor 124 and the resistor 125 are connected in series between the power supply terminal 121 and the ground terminal 127. The resistor 124 and the resistor 125 apply a reference voltage obtained by dividing the power supply voltage to the inverting input terminal of the operational amplifier 122. The resistor 126 limits the current flowing from the power supply terminal 161 to the ground terminal 128. The ground terminal 127 and the ground terminal 128 are connected to a DC power supply (not shown) included in the master unit 100, and 0 V is applied.

The control unit 130 controls the overall operation of the master unit 100. The control unit 130 controls the transmission circuit 110 to transmit data to any of the slave units. For example, the control unit 130 outputs a voltage at a level corresponding to the bit data to be transmitted from the first transmission terminal. The control unit 130 outputs a voltage at a level opposite to the level of the voltage output from the first transmission terminal from the second transmission terminal. Further, the control unit 130 identifies the data transmitted from any of the slave units based on the voltage signal supplied from the reception circuit 120. For example, the control unit 130 samples bit data according to the level of the voltage applied to the receiving terminal, and identifies the transmitted data from the bit data string obtained by the sampling.

Further, when the erroneous wiring is detected, the control unit 130 controls the notification unit 150 to notify that the erroneous wiring has been detected. The control unit 130 is composed of, for example, a microcomputer including a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), and the like.

The terminal pair 145 includes terminals 141 and 142. The terminal pair 145 is connected to the terminal pair 245 via the communication line pair 13. That is, the terminal 141 is connected to the terminal 241 via the communication line 11, and the terminal 142 is connected to the terminal 242 via the communication line 12. The terminal pair 146 includes terminals 143 and terminals 144. The terminal pair 146 is connected to the terminal pair 445 via the communication line pair 33. That is, the terminal 143 is connected to the terminal 441 via the communication line 31, and the terminal 144 is connected to the terminal 442 via the communication line 32.

The notification unit 150 notifies the user by light, image, or voice that the erroneous wiring has been detected according to the control by the control unit 130. The notification unit 150 is, for example, an LED (Light Emitting Diode), a liquid crystal display, a touch screen, and a speaker.

The power supply terminal 161 is connected to a DC power supply included in the master unit 100, and a power supply voltage is applied. The capacitor 162 is provided between the power supply terminal 161 and the ground terminal 163, and an AC component (high frequency component) output from the power supply terminal 161 flows to the ground terminal 163. The ground terminal 163 is connected to a DC power supply included in the master unit 100, and 0 V is applied.

The slave unit 200 includes a transmission circuit 110, a reception circuit 120, a control unit 230, a terminal pair 245, a terminal pair 246, a rectifier circuit 250, a switch 261 and a switch 262, a current detection unit 263, and a current. It includes a detection unit 264, a connection point 265, a connection point 266, a comparison unit 270, a signal output unit 280, and a power supply terminal 291.

The transmission circuit 210 transmits data to the master unit 100 by a current signal according to the control by the control unit 230. The transmission circuit 210 includes an NPN transistor 211 and a resistor 212. The collector of the NPN transistor 211 is connected to the power supply terminal 291. The base of the NPN transistor 211 is connected to a transmission terminal (terminal indicated by Tx) included in the control unit 230 (not shown). The emitter of the NPN transistor 211 is connected to a reference terminal (terminal indicated by S0) included in the control unit 230 via a resistor 212. The NPN transistor 211 is turned on when an H-level voltage is applied to the base, and is turned off when an L-level voltage is applied to the base. When the NPN transistor 211 is turned off, no current flows through the communication line pair 13. On the other hand, when the NPN transistor 211 is turned on, a current flows through the communication line pair 13.

If the NPN transistor 211 is turned on when the voltage of the terminal 241 is higher than the voltage of the terminal 242, the power supply terminal 161 → NPN transistor 113 → terminal 141 → communication line 11 → terminal 241 → switch 261 → diode 253 → power supply terminal 291. → NPN transistor 211 → Resistance 212 → Diode 252 → Switch 261 → Terminal 242 → Communication line 12 → Terminal 142 → PNP transistor 112 → Resistance 126 → Ground terminal 128. On the other hand, if the NPN transistor 211 is turned on when the voltage of the terminal 241 is lower than the voltage of the terminal 242, the power supply terminal 161 → NPN transistor 111 → terminal 142 → communication line 12 → terminal 242 → switch 261 → diode 254 → power supply. A current flows through the route of terminal 291 → NPN transistor 211 → resistor 212 → diode 251 → switch 261 → terminal 241 → communication line 11 → terminal 141 → PNP transistor 114 → resistor 126 → ground terminal 128. The resistor 212 is a load resistor and limits the current flowing in the current path of the NPN transistor 211.

The receiving circuit 220 supplies the control unit 230 with a voltage signal corresponding to data (bit data) transmitted as a voltage signal from the master unit 100. When the voltage of the terminal 242 is higher than the voltage of the terminal 241, the receiving circuit 220 supplies an H level (for example, 5V) voltage signal to a receiving terminal (terminal indicated by Rx) included in the control unit 230 (not shown). .. On the other hand, when the voltage of the terminal 241 is higher than the voltage of the terminal 242, the receiving circuit 220 supplies an L level (for example, 0V) voltage signal to the receiving terminal included in the control unit 230.

The receiving circuit 220 includes a Zener diode 221, a resistor 222, and a resistor 223. The anode of the Zener diode 221 is connected to the reference terminal, and the cathode of the Zener diode 221 is connected to the receiving terminal. The Zener diode 221 prevents the voltage of the receiving terminal from becoming higher than the breakdown voltage (for example, 5V) with respect to the voltage of the reference terminal. The resistor 222 is provided between the connection point 266 and the receiving terminal and limits the voltage applied to the receiving terminal. The resistor 223 is provided between the reference terminal and the receiving terminal in parallel with the Zener diode 221.

The control unit 230 controls the overall operation of the slave unit 200. The control unit 230 controls the transmission circuit 210 to transmit data to the master unit 100. For example, the control unit 230 outputs a voltage at a level corresponding to the bit data to be transmitted from the transmission terminal. Further, the control unit 230 identifies the data transmitted from the master unit 100 based on the voltage signal supplied from the reception circuit 220. For example, the control unit 230 samples bit data according to the level of the voltage applied to the receiving terminal, and identifies the transmitted data from the bit data string obtained by the sampling. Further, the control unit 230 executes lighting control (not shown) according to the control by the master unit 100. The control unit 230 is composed of, for example, a microcomputer including a CPU, a ROM, a RAM, and the like.

The terminal pair 245 includes terminals 241 and terminals 242. The terminal pair 246 includes terminals 243 and terminals 244. The terminal pair 246 is connected to the terminal pair 345 via the communication line pair 23. That is, the terminal 243 is connected to the terminal 341 via the communication line 21, and the terminal 244 is connected to the terminal 342 via the communication line 22.

The rectifier circuit 250 rectifies the positive and negative power supply voltages applied between the terminals 245 and generates V2, which is the operating power supply of the slave unit 200. The operating power supply V2 of the slave unit 200 has a voltage similar to V1 which is the power supply voltage of the master unit 100, and is supplied to each module from the power supply terminal 291. The rectifier circuit 250 includes a diode 251, a diode 252, a diode 253, and a diode 254. The anode of the diode 251 and the anode of the diode 252 are connected to one output terminal (output terminal on the low voltage side). The cathode of the diode 253 and the cathode of the diode 254 are connected to the other output terminal (output terminal on the high voltage side). The cathode of the diode 251 and the anode of the diode 253 are connected to a connection point 265 which is one of the input terminals. The cathode of the diode 252 and the anode of the diode 254 are connected to the connection point 266, which is the other input terminal.

The switch 261 is a switch for disconnecting the communication line pair 13 connected to the terminal pair 245 from the slave unit 200 according to the control by the control unit 230. The switch 261 controls the short-circuit / open state between the terminal 241 and the connection point 265, and also controls the short-circuit / open state between the terminal 242 and the connection point 266. The switch 261 controls the short-circuit / open state between the terminal 241 and the connection point 265 and the short-circuit / open state between the terminal 242 and the connection point 266 to be the same short-circuit / open state. The switch 261 is, for example, a double-sided switch that simultaneously controls between two pairs of contacts.

The switch 262 is a switch for disconnecting the communication line pair 23 connected to the terminal pair 246 from the slave unit 200 according to the control by the control unit 230. The switch 262 controls the short-circuit / open state between the terminal 243 and the connection point 265, and also controls the short-circuit / open state between the terminal 244 and the connection point 266. The switch 262 controls the short-circuit / open state between the terminal 243 and the connection point 265 and the short-circuit / open state between the terminal 244 and the connection point 266 to be the same short-circuit / open state. The switch 262 is, for example, a double-sided switch that simultaneously controls between two pairs of contacts.

The current detection unit 263 detects the current flowing through the communication line pair 13, and supplies a voltage signal indicating the magnitude of the detected current to the comparison unit 270. In the present embodiment, the current detection unit 263 detects the current flowing through the communication line 11 by detecting the current flowing between the terminal 241 and the connection point 265. However, the current detection unit 263 may detect the current flowing through the communication line 12 by detecting the current flowing between the terminal 242 and the connection point 266. The current detection unit 263 includes, for example, a shunt resistor for current detection or a current transformer.

The current detection unit 264 detects the current flowing through the communication line pair 23, and supplies a voltage signal indicating the magnitude of the detected current to the comparison unit 270. In the present embodiment, the current detection unit 264 detects the current flowing through the communication line 21 by detecting the current flowing between the terminal 243 and the connection point 265. However, the current detection unit 264 may detect the current flowing through the communication line 22 by detecting the current flowing between the terminal 244 and the connection point 266. The current detection unit 264 includes, for example, a shunt resistor for current detection or a current transformer.

The connection point 265 is a point on the wiring connecting the switch 261 and the switch 262 when the terminal 241 and the terminal 243 are connected via the switch 261 and the switch 262. The connection point 265 is connected to one of the input terminals included in the rectifier circuit 250. The connection point 266 is a point on the wiring connecting the switch 261 and the switch 262 when the terminal 242 and the terminal 244 are connected via the switch 261 and the switch 262. The connection point 266 is connected to the other input terminal included in the rectifier circuit 250.

The transmission circuit 210 controls the current flowing through the communication line pair 13 by controlling the conduction / non-conduction state between the connection point 265 and the connection point 266. That is, the transmission circuit 210 controls the connection point 265 and the connection point 266 to be in a conductive state when a current is passed through the communication line pair 13, and is connected to the connection point 265 when no current is passed through the communication line pair 13. The connection with the point 266 is controlled to be non-conducting.

The comparison unit 270 compares the magnitude of the current indicated by the voltage signal supplied from the current detection unit 263 with a predetermined threshold value, and whether the current flowed by the transmission circuit 210 is flowing through the communication line pair 13. Determine if not. Further, the comparison unit 270 compares the magnitude of the current indicated by the voltage signal supplied from the current detection unit 264 with a predetermined threshold value, and the current flowed by the transmission circuit 210 flows to the communication line pair 23. Determine if it is. The comparison unit 270 supplies a voltage signal indicating the discrimination result to the signal output unit 280.

Further, the comparison unit 270 compares the magnitude of the current indicated by the voltage signal supplied from the current detection unit 263 with the magnitude of the current indicated by the voltage signal supplied from the current detection unit 264, and compares the communication line pair 13 with the magnitude of the current indicated by the voltage signal supplied from the current detection unit 264. It is determined which of the communication lines vs. 23 the larger current is flowing. The comparison unit 270 supplies a voltage signal indicating the discrimination result to the signal output unit 280. The comparison unit 270 is composed of, for example, a comparator, an A / D (Analog / Digital) converter, a microcomputer, and the like.

The signal output unit 280 determines whether or not there is erroneous wiring based on the voltage signal supplied from the comparison unit 270. When the signal output unit 280 determines that there is an erroneous wiring, the signal output unit 280 supplies a signal indicating that the erroneous wiring has been detected (hereinafter referred to as "miswiring detection signal") to the control unit 230. The miswiring detection signal may include information indicating which of the communication line pair 13 and the communication line pair 23 is flowing a larger current. Further, the signal output unit 280 can determine whether or not the transmission circuit 210 is passing a current based on the voltage signal supplied from the control unit 230. The signal output unit 280 is composed of, for example, a microcomputer including a CPU, a ROM, a RAM, and the like.

The power supply terminal 291 is a power supply terminal for supplying V2, which is an operating power supply of the slave unit 200 generated by the rectifier circuit 250, to each module. The description of the slave unit 300 in FIG. 2 will be omitted.

Next, the communication control process executed by the slave unit 200 will be described with reference to the flowchart shown in FIG. The slave unit 200 is connected to the master unit 100, for example, and when the power is turned on, the communication control process is started. Here, it is assumed that the switch 261 and the switch 262 included in the slave unit 200 are in a conductive state when the power is turned on. Since the communication control processing executed by the slave units 300, 400, and 500 is basically the same as the communication control processing executed by the slave unit 200, the description thereof will be omitted or simplified. Further, in the present embodiment, since the master unit 100 basically does not execute the process related to the detection of erroneous wiring, the description of the process of the master unit 100 will be omitted or simplified.

First, the control unit 230 monitors the level of the receiving terminal (step S101). That is, the control unit 230 samples the level of the voltage applied from the receiving circuit 220 to the receiving terminal. When the process of step S101 is completed, the control unit 230 determines whether or not data has been received from the master unit 100 (step S102). For example, the control unit 230 generates a bit string based on the sampled voltage level, and determines whether or not one frame of data has been received. When the control unit 230 determines that the data has not been received from the master unit 100 (step S102: NO), the control unit 230 returns the process to step S101.

On the other hand, when the control unit 230 determines that the data has been received from the master unit 100 (step S102: YES), the control unit 230 executes the process according to the received data (step S103). For example, when the control unit 230 receives data instructing the lighting to be turned on, the control unit 230 turns on the lighting. When the control unit 230 completes the process of step S103, the control unit 230 generates a bit string of data to be transmitted (step S104). The data to be transmitted is data to be returned to the master unit 100.

When the process of step S104 is completed, the control unit 230 selects a bit to be transmitted from the generated bit string (step S105). The bits are selected in order from the beginning of the generated bit string. When the control unit 230 completes the process of step S105, the control unit 230 sets the transmission terminal to a level corresponding to the selected bit (step S106). For example, if the selected bit is 1, the transmit terminal is set to H level (eg, 5V), and if the selected bit is 0, the transmit terminal is set to L level (eg, 0V). ..

When the process of step S106 is completed, the control unit 230 determines whether or not the level of the transmission terminal is the H level (step S107). The fact that the level of the transmission terminal is H level means that the transmission circuit 210 controls the connection point 265 and the connection point 266 to be in a conductive state, and a current flows. When the control unit 230 determines that the level of the transmission terminal is the H level (step S107: YES), the control unit 230 executes the erroneous wiring detection process (step S108). The miswiring detection process will be described in detail with reference to the flowchart shown in FIG.

First, the current detection unit 263 detects the first current (step S201). The first current is, for example, the current flowing through the communication line 11. Next, the current detection unit 264 detects the second current (step S202). The second current is, for example, the current flowing through the communication line 21. Here, the comparison unit 270 determines whether or not the first current and the second current are equal to or greater than the threshold value (step S203). When the comparison unit 270 determines that the first current or the second current is not equal to or greater than the threshold value (step S203: NO), the control unit 230 ends the erroneous wiring detection process.

When the comparison unit 270 determines that the first current and the second current are equal to or higher than the threshold value (step S203: YES), the signal output unit 280 outputs an erroneous wiring detection signal to the control unit 230 (step S204). .. The miswiring detection signal includes the magnitude of the first current, the magnitude of the second current, whether or not the first current and the second current are equal to or greater than the threshold value, and the first current and the first. Information indicating the magnitude relationship with the current of 2 may be included. When the signal output unit 280 completes the process of step S204, the control unit 230 determines whether or not the first current is equal to or less than the second current (step S205).

When the control unit 230 determines that the first current is equal to or less than the second current (step S205: YES), the control unit 230 controls the first switch to the open state (step S206). The first switch is switch 261. On the other hand, when the control unit 230 determines that the first current is not equal to or less than the second current (step S205: NO), the control unit 230 controls the second switch to the open state (step S207). The second switch is a switch 262.

For example, as shown in FIG. 1, it is assumed that the terminal pair 346 and the terminal pair 546 are connected by the communication line pair 53, causing erroneous wiring. In this case, in step S203, it is determined that the first current and the second current are equal to or greater than the threshold value. Here, the length of the path through which the first current flows is 30 m, which is the length of the communication line pair 13. On the other hand, the length of the path through which the second current flows is 20 m in the length of the communication line pair 23, 20 m in the length of the communication line pair 53, 50 m in the length of the communication line pair 43, and the communication line pair. It is 140 m, which is the total of 33 lengths of 50 m. Therefore, in step S205, it is determined that the first current is not equal to or less than the second current, and in step S207, the switch 262, which is the second switch, is controlled to be in the open state. Therefore, the communication line pair 23 is separated from the slave unit 200, and the loop wiring is eliminated. When the control unit 230 completes the process of step S206 or step S207, the control unit 230 ends the erroneous wiring detection process.

When the control unit 230 completes the process of step S108, it waits for one bit of time (step S109). When the process of step S109 is completed, the control unit 230 determines whether or not all the bits have been selected (step S110). When the control unit 230 determines that all the bits have been selected (step S110: YES), it considers that the data transmission has been completed, and returns the process to step S101. On the other hand, when the control unit 230 determines that any of the bits has not been selected (step S110: NO), the control unit 230 returns the process to step S105 and selects the next bit.

In the present embodiment, when the connection point 265 and the connection point 266 are controlled to be in a conductive state, the magnitude of the first current flowing through the communication line pair 13 and the second current flowing through the communication line pair 23 When the magnitude of is equal to or greater than a predetermined threshold value, an erroneous wiring detection signal is output. Therefore, according to the present invention, it is possible to detect erroneous wiring that causes a plurality of routes connecting the master unit 100 and the slave unit 200.

Further, in the present embodiment, when the erroneous wiring detection signal is output, one of the first switch and the second switch is controlled to be in the open state. Therefore, according to the present embodiment, it is possible to make one route connecting the master unit 100 and the slave unit 200. Further, in the present embodiment, when the erroneous wiring detection signal is output, the shorter route is not separated from the slave unit 200, and the longer route is separated from the slave unit 200. Therefore, according to the present embodiment, it can be expected that the possibility that a communication abnormality will occur due to the disconnection of the route is reduced.

(Embodiment 2)
In the first embodiment, when an erroneous wiring that causes a plurality of routes connecting the master unit 100 and the slave unit 200 is detected, the longer route is cut off by the slave unit 200 to complete the process. However, this method may not be preferable when a plurality of routes connecting the master unit 100 and the slave unit 200 are generated due to erroneous wiring to another slave unit instead of erroneous wiring to the slave unit 200.

For example, in the first embodiment, the communication line pair 23 is separated from the slave unit 200 due to the incorrect wiring of the communication line pair 53, but it is desirable that the communication line pair 53 is separated from the slave unit 300 or the slave unit 500. In fact, when the communication line pair 23 is separated from the slave unit 200, the length of the route from the slave unit 300 to the master unit 100 is 20 m, which is the length of the communication line pair 53, and 50 m, which is the length of the communication line pair 43. The total length of the communication line pair 33 is 50 m, which is 120 m, and there is a possibility that the slave unit 300 and the master unit 100 cannot communicate with each other.

Therefore, in the present embodiment, when erroneous wiring is detected by the slave unit 200, the slave unit 200 notifies the master unit 100 that the erroneous wiring has been detected, and an appropriate communication line pair is controlled according to the control by the master unit 100. The method of separating is described. The configuration of the communication system 1000 according to the present embodiment is basically the same as the configuration of the communication system 1000 according to the first embodiment. Therefore, in the present embodiment, the description of the configuration of the communication system 1000 will be omitted, and the processing of the communication system 1000 will be mainly described.

First, the erroneous wiring detection process executed by the slave unit 200 will be described with reference to the flowchart of FIG. The erroneous wiring detection process shown in FIG. 5 is a process executed in place of the erroneous wiring detection process shown in FIG. The communication control process executed by the slave unit 200 according to the present embodiment is basically the same as the communication control process shown in FIG. 3, and thus the description thereof will be omitted.

First, the control unit 230 determines whether or not the start bit is being transmitted (step S301). When the control unit 230 determines that the start bit is not being transmitted (step S301: NO), the control unit 230 ends the erroneous wiring detection process. As described above, in the present embodiment, the slave unit 200 is not transmitting the start bit even when the level of the transmission terminal is H level (when the bit corresponding to 1 is being transmitted). , Do not execute the miswiring detection process.

When the control unit 230 determines that the start bit is being transmitted (step S301: YES), the control unit 230 determines whether or not the erroneous wiring detection process is being exempted (step S302). When the control unit 230 determines that the miswiring detection process is being exempted (step S302: YES), the control unit 230 ends the miswiring detection process. As described above, in the present embodiment, the slave unit 200 does not execute the erroneous wiring detection process when the erroneous wiring detection process is being exempted even while the start bit is being transmitted. For example, control release indicating that the slave unit 200 returns the one switch that has been controlled to the open state by detecting incorrect wiring to the short-circuited state according to the instruction from the master unit 100, and then returns the one switch to the short-circuited state. The erroneous wiring detection process is exempted until the completion data is transmitted to the master unit.

When the control unit 230 determines that the erroneous wiring detection process is not exempted (step S302: NO), the current detection unit 263 detects the first current (step S303), and the current detection unit 264 determines that the second current is not being exempted. The current is detected (step S304). Then, the comparison unit 270 determines whether or not the first current and the second current are equal to or greater than the threshold value (step S305). When the comparison unit 270 determines that the first current or the second current is not equal to or greater than the threshold value (step S305: NO), the control unit 230 ends the erroneous wiring detection process.

When the comparison unit 270 determines that the first current and the second current are equal to or higher than the threshold value (step S305: YES), the signal output unit 280 outputs an erroneous wiring detection signal to the control unit 230 (step S306). .. When the signal output unit 280 completes the process of step S306, the control unit 230 determines whether or not the first current is equal to or less than the second current (step S307).

When the control unit 230 determines that the first current is equal to or less than the second current (step S307: YES), the control unit 230 controls the first switch to be in the open state (step S308). On the other hand, when the control unit 230 determines that the first current is not equal to or less than the second current (step S307: NO), the control unit 230 controls the second switch to the open state (step S309).

When the control unit 230 completes the process of step S308 or step S309, the control unit 230 transmits data indicating the completion of control to the master unit 100 (step S310). The data indicating the completion of control is data for notifying the master unit 100 that the slave unit 200 has opened one of the switches in response to the detection of erroneous wiring. Since the slave unit 100 executes the erroneous wiring detection process during the transmission of the start bit, the data indicating the control completion is promptly performed by rewriting the bit string after the start bit with the bit string constituting the data indicating the control completion. Can be sent. When the control unit 230 completes the process of step S310, the control unit 230 ends the erroneous wiring detection process.

Next, the communication control process executed by the master unit 100 will be described with reference to the flowchart shown in FIG. This communication control process is a process for disconnecting an appropriate communication line pair by an appropriate slave unit when an erroneous wiring is detected by any of the plurality of slave units. When the power is turned on, the master unit 100 starts executing the communication control process shown in FIG.

First, the control unit 130 monitors the level of the receiving terminal (step S401). That is, the control unit 130 samples the level of the voltage applied from the receiving circuit 120 to the receiving terminal. When the process of step S401 is completed, the control unit 130 determines whether or not data indicating the completion of control has been received from the first slave unit (step S402). For example, the control unit 130 generates a bit string based on the sampled voltage level to generate data for one frame, and whether or not the generated data for one frame is data indicating control completion. To determine. The first slave unit is a slave unit that has transmitted data indicating the completion of control, and is a slave unit that has detected erroneous wiring. In the present embodiment, it is assumed that the first slave unit is the slave unit 200. When the control unit 130 determines that the data indicating the completion of control has not been received from the first slave unit (step S402: NO), the control unit 130 returns the process to step S401.

On the other hand, when the control unit 130 determines that the data indicating the completion of control has been received from the first slave unit (step S402: YES), the control unit 130 transmits the data requesting a response to all the slave units (step S403). The data requesting a response is sent to the slave unit that pays attention to transmit the data indicating the response to the master unit 100 in order to determine whether or not the master unit 100 and the slave unit of interest can communicate with each other. The requested data. The data indicating the response is data that the slave unit that has received the data requesting the response from the master unit 100 returns to the master unit 100.

In the present embodiment, when data is transmitted from the master unit 100 to the slave unit of interest, the slave unit of interest employs a polling method of transmitting some data to the master unit 100. Therefore, the content of the data requesting the response may be anything, and the content of the data indicating the response may be anything. The control unit 130 transmits data requesting a response to each of the slave unit 200, the slave unit 300, the slave unit 400, and the slave unit 500 in order. The control unit 130 does not have to transmit the data requesting a response to the first slave unit. Further, the control unit 130 can transmit data requesting a response by controlling the transmission circuit 110.

On the other hand, the slave unit that has received the data requesting the response from the master unit 100 determines the bit string that constitutes the data indicating the response in step S104, and in the processing of steps S105 to S110, the slave unit that indicates the response is used as the master unit. Send to 100.

When the process of step S403 is completed, the control unit 130 determines whether or not the data indicating the response has been received from all the slave units (step S404). Receiving response data from all slave units means that the master unit 100 and all slave units can communicate normally in the wiring state after switch control by the first slave unit. .. On the other hand, the fact that the data indicating the response is not received from any of the slave units means that the master unit 100 and any of the slave units cannot normally communicate with each other in the wiring state after the switch control by the first slave unit.

When the control unit 130 determines that the data indicating the response has been received from all the slave units (step S404: YES), the control unit 130 returns the process to step S401. On the other hand, when the control unit 130 determines that the data indicating the response is not received from any of the slave units (step S404: NO), the control unit 130 transmits the data requesting the release of control to the first slave unit (step S405).

On the other hand, the first slave unit that has received the data requesting the release of control from the master unit 100 controls one of the switches controlled in the open state to the short-circuited state in step S103. Then, the first slave unit determines the bit string constituting the data indicating the completion of control release in step S104, and transmits the data indicating the response to the master unit 100 in the processing of steps S105 to S110. In this case, the first slave unit determines in step S302 that the miswiring detection is being exempted, and does not execute the miswiring detection process.

When the process of step S405 is completed, the control unit 130 receives data indicating the completion of control release from the first slave unit (step S406). When the control unit 130 completes the process of step S406, the control unit 130 transmits data requesting a response to the second slave unit (step S407). The second slave unit is a slave unit for which data indicating a response was not received in the determination process in step S404. The data requesting the response transmitted in step S407 and the data requesting the response transmitted in step S403 may be similar data or different data. When the control unit 130 completes the process of step S407, the control unit 130 returns the process to step S401.

On the other hand, the second slave unit that has received the data requesting the response from the master unit 100 determines the bit string constituting the data indicating the response in step S104, and the data indicating the response in the processing of steps S105 to S110. Is transmitted to the master unit 100. The second slave unit detects erroneous wiring in the erroneous wiring detection process executed when the data indicating the response is transmitted to the master unit 100. Then, in step S308 or step S309, the second slave unit controls one switch to the open state, and in step S310, transmits data indicating the completion of control to the master unit 100.

Then, when the master unit 100 receives the data indicating the completion of control from the second slave unit, the master unit 100 considers the second slave unit as the first slave unit and executes the communication control process shown in FIG. After that, until it is determined in step S404 that data indicating a response has been received from all the slave units, the communication control process shown in FIG. 3, the erroneous wiring detection process shown in FIG. 5, and the communication control process shown in FIG. 6 are performed. It is executed repeatedly.

For example, in the communication system 1000 shown in FIG. 1, it is assumed that erroneous wiring is first detected by the slave unit 200. In this case, the route from terminal pair 246 to terminal pair 345 is longer than the route from terminal pair 245 to terminal pair 145. Therefore, the switch 262 connected to the terminal pair 246 is controlled in the open state. Then, the route from the slave unit 300 to the master unit 100 is only the route from the terminal pair 346 to the terminal pair 146, but the length of this route is 20 m + 50 m + 50 m = 120 m, which exceeds 100 m. Therefore, the slave unit 300 cannot communicate with the master unit 100. Then, the master unit 100 transmits the data requesting the release of control to the slave unit 200, causes the slave unit 200 to control the switch 262 in the short-circuited state, and transmits the data requesting the response to the slave unit 300.

On the other hand, the slave unit 300 executes an erroneous wiring detection process in the process of transmitting the data indicating the response to the master unit 100 in response to receiving the data requesting the response. In this case, the route from terminal pair 346 to terminal pair 146 is longer than the route from terminal pair 345 to terminal pair 145. Therefore, the switch connected to the terminal pair 346 is controlled in the open state. In this case, the length of the route from the master unit 100 to any slave unit is 100 m or less. Therefore, the state in which the slave unit 300 is disconnected from the communication line pair 53 is maintained, and the master unit 100 and all the slave units can communicate with each other.

In the present embodiment, when erroneous wiring is detected by any of the slave units, the communication line pair that is likely to be the cause of erroneous wiring is disconnected. Therefore, according to the present embodiment, it can be expected that the influence of incorrect wiring is automatically and appropriately eliminated.

(Embodiment 3)
In the first embodiment and the second embodiment, an example in which the master unit 100 and the plurality of slave units have two terminal pairs has been described. In the present invention, the number of terminal pairs included in the master unit 100 and the plurality of slave units is not limited to this example as long as there is a possibility that a plurality of routes connecting the master unit 100 and any of the slave units 200 may occur. .. For example, the number of terminal pairs included in the master unit 100 and the plurality of slave units may be one or three or more. Hereinafter, an example will be described in which the master unit 100 has one terminal pair, the slave unit 200 has three terminal pairs, and the slave unit 300, the slave unit 400, and the slave unit 500 have two terminal pairs.

The configuration of the communication system 1100 according to the present embodiment will be described with reference to FIG. 7. The communication system 1100 includes a master unit 101, a slave unit 201, a slave unit 300, a slave unit 400, and a slave unit 500. The terminal pair 145 included in the master unit 101 is connected to the terminal pair 245 included in the slave unit 201 by the communication line pair 13. The terminal pair 246 included in the slave unit 201 is connected to the terminal pair 345 included in the slave unit 300 by the communication line pair 23. The terminal pair 249 included in the slave unit 201 is connected to the terminal pair 445 included in the slave unit 400 by the communication line pair 33. The terminal pair 446 included in the slave unit 400 is connected to the terminal pair 545 included in the slave unit 500 by the communication line pair 43. Here, it is assumed that the terminal pair 346 included in the slave unit 300 is erroneously connected to the terminal pair 546 included in the slave unit 500 by the communication line pair 53.

FIG. 8 shows the configuration of the slave unit 201 according to the present embodiment. The slave unit 201 has a configuration in which a terminal pair 249, a switch 267, and a current detection unit 268 are added to the slave unit 200. The terminal pair 249 includes terminals 247 and terminals 248. The terminal 247 is connected to the communication line 31. Further, the terminal 247 is connected to the connection point 265 via the switch 267. Terminal 248 is connected to the communication line 32. Further, the terminal 248 is connected to the connection point 266 via the switch 267.

The switch 267 is provided between the terminal 247 and the connection point 265 and between the terminal 248 and the connection point 266, and is in a conductive / non-conducting state between the terminal 247 and the connection point 265, and the terminal 248. It controls the conduction / non-conduction state between the connection point 266 and the connection point 266. The switch 267 is controlled in a conductive / non-conducting state according to the control by the control unit 230. The current detection unit 268 detects the current flowing between the terminal 247 and the connection point 265, that is, the current flowing through the communication line pair 33. The current detection unit 268 supplies a voltage signal indicating the magnitude of the detected current to the comparison unit 270.

Next, the operation of the communication system 1100 will be described. In the miswiring detection process shown in FIG. 5, the slave unit 201 detects a third current after the process of step S304. The third current is the current detected by the current detection unit 268. Further, in step S305, the slave unit 201 determines whether or not two of the first current, the second current, and the third current are equal to or greater than the threshold value. Then, the slave unit 201 controls the switch corresponding to the current that is not the maximum among the currents equal to or greater than the threshold value in the open state.

For example, when all of the first current, the second current, and the third current are equal to or more than the threshold value, and the first current is larger than either of the second current and the third current, the second current. The switch 262 corresponding to the current of the above and the switch 267 corresponding to the third current are controlled in the open state. According to such control, it can be expected that all the routes connecting the slave unit 201 and the master unit 100, which are not the shortest, are separated from the slave unit 201, and the loop wiring due to erroneous wiring is eliminated.

In the configuration shown in FIG. 7, there is only one route connecting the slave unit 201 and the master unit 100, and there is no loop wiring between the slave unit 201 and the master unit 100. Therefore, the erroneous wiring detection process executed by the slave unit 201 does not detect the erroneous wiring. However, there are a plurality of routes in the route connecting the slave unit 300 and the master unit 100, the route connecting the slave unit 400 and the master unit 100, and the route connecting the slave unit 500 and the master unit 100. Therefore, in the erroneous wiring detection process executed by the slave unit 300, the slave unit 400, and the slave unit 500, erroneous wiring is detected.

For example, it is assumed that the slave unit 300 of the slave unit 300, the slave unit 400, and the slave unit 500 executes the erroneous wiring detection process earliest. In this case, in the erroneous wiring detection process executed by the slave unit 300, the route 1 from the terminal pair 345 to the master unit 100 is 50 m + 20 m = 70 m, and the route 2 from the terminal pair 346 to the master unit 100 is 40 m + 30 m + 30 m + 20 m = 120 m. .. Therefore, the communication line pair 53 is separated from the slave unit 300, and the route 2 is separated. In this case, the length of the route from the master unit 100 to all the slave units is 100 m or less, and the process is completed.

On the other hand, for example, it is assumed that the slave unit 400 of the slave unit 300, the slave unit 400, and the slave unit 500 executes the erroneous wiring detection process earliest. In this case, in the erroneous wiring detection process executed by the slave unit 400, the route 1 from the terminal pair 445 to the master unit 100 is 30 m + 20 m = 50 m, and the route 2 from the terminal pair 446 to the master unit 100 is 30 m + 40 m + 50 m + 20 m = 140 m. .. Therefore, the communication line pair 43 is separated from the slave unit 400, and the route 2 is separated. In this case, the length of the route from the slave unit 500 to the master unit 100 is 40 m + 50 m + 20 m = 110 m, which exceeds 100 m. Therefore, communication between the master unit 100 and the slave unit 500 becomes impossible.

Therefore, under the control of the master unit 100, the disconnection of the path 2 by the slave unit 400 is released, and then the erroneous wiring detection process by the slave unit 500 is executed. In this case, in the erroneous wiring detection process executed by the slave unit 500, the route 1 from the terminal pair 545 to the master unit 100 is 30 m + 30 m + 20 m = 80 m, and the route 2 from the terminal pair 546 to the master unit 100 is 40 m + 50 m + 20 m = 110 m. .. Therefore, the communication line pair 53 is separated from the slave unit 500, and the route 2 is separated. In this case, the length of the route from the master unit 100 to all the slave units is 100 m or less, and the process is completed.

In the present embodiment, when erroneous wiring is detected by any of the slave units, the communication line pair that is likely to be the cause of erroneous wiring is disconnected. Therefore, according to the present embodiment, it can be expected that the influence of incorrect wiring is automatically and appropriately eliminated.

(Modification example)
Although the embodiments of the present invention have been described above, various modifications and applications are possible in carrying out the present invention.

In the present invention, which part of the configuration, function, and operation described in the above embodiment is adopted is arbitrary. Further, in the present invention, in addition to the above-described configurations, functions, and operations, further configurations, functions, and operations may be adopted.

In the first embodiment, an example in which the communication line pair is automatically disconnected when an erroneous wiring is detected has been described. In the present invention, when erroneous wiring is detected, other processing may be executed. For example, when erroneous wiring is detected, data indicating that erroneous wiring has been detected may be transmitted from the slave unit that detected the erroneous wiring to the master unit 100. In this case, the master unit 100 can, for example, notify the user of information indicating that erroneous wiring has been detected by light, image, or voice via the notification unit 150. In addition to the process of automatically disconnecting the communication line pair, a process of notifying the user that an erroneous wiring has been detected may be executed.

In the first embodiment, an example in which the switch 261 is one double-sided switch has been described. In the present invention, the switch 261 may be composed of two switch groups, a switch arranged between the terminal 241 and the connection point 265 and a switch arranged between the terminal 242 and the connection point 266. Good. In this case, the conduction / non-conduction state of the two switch groups is controlled at the same time. The switch 262 may also be composed of two switch groups instead of a double-sided switch.

In the first embodiment, an example has been described in which the communication system 1000 is a lighting system, the master unit 100 is a lighting control device, and the slave unit 200, the slave unit 300, the slave unit 400, and the slave unit 500 are lighting devices. Of course, in the present invention, the communication system may be another system. For example, the communication system 1000 may be an air conditioning system, the master unit 100 may be an outdoor unit, and the slave unit 200, the slave unit 300, the slave unit 400, and the slave unit 500 may be indoor units. Further, it goes without saying that the number of the plurality of slave units is not limited to four.

In the first embodiment, an example in which the control unit 230, the comparison unit 270, and the signal output unit 280 are separated has been described. In the present invention, the control unit 230, the comparison unit 270, and the signal output unit 280 do not have to be separated. For example, the comparison unit 270 and the signal output unit 280 may be incorporated in the control unit 230, and the control unit 230 may have the function of the comparison unit 270 and the function of the signal output unit 280. In this case, the miswiring detection signal may not be a signal output to the outside of the control unit 230, but a signal output to an internal component of the control unit 230. For example, the miswiring detection signal may be an interrupt signal that generates an interrupt to be executed when miswiring is detected, or a flag writing signal for writing a flag indicating that miswiring has been detected. .. Further, the miswiring detection signal may be a control signal for the switch 261 or the switch 262.

The present invention allows for various embodiments and modifications without departing from the broad spirit and scope of the present invention. Moreover, the above-described embodiment is for explaining the present invention, and does not limit the scope of the present invention. That is, the scope of the present invention is indicated not by the embodiment but by the claims. Then, various modifications made within the scope of the claims and the equivalent meaning of the invention are considered to be within the scope of the present invention.

The present invention is applicable to a communication system in which a master unit and a plurality of slave units communicate with each other.

11,12,21,22,31,32,31,41,42,51,52 communication line, 13,23,33,43,53 communication line pair, 100,101 master unit, 110,210 transmission circuit, 111 , 113,211 NPN transistor, 112,114 PNP transistor, 120,220 reception circuit, 121,161,291 power supply terminal, 122 operational amplifier, 123,162 capacitor, 124,125,126,212,222,223 resistors, 127, 128,163 Ground terminal, 130,230 Control unit, 141,142,143,144,241,242,243,244,247,248,341,342,343,344,441,442,443,444,541 542,543,544 terminals, 145,146,245,246,249,345,346,445,445,545,546 terminal pairs, 150 notification unit, 200,201,300,400,500 slave unit, 221 Zener diode , 250 rectifier circuit, 251,252,253,254 capacitor, 261,262,267 switch, 263,264,268 current detector, 265,266 connection point, 270 comparison unit, 280 signal output unit, 1000,1100 communication system

Claims (6)

A communication system including a master unit and a plurality of slave units, in which the master unit and the plurality of slave units are interconnected by a plurality of communication line pairs.
The master unit is
A receiving circuit for receiving data from the plurality of slave units by detecting the presence or absence of a current flowing through the communication line pair connected to the master unit among the plurality of communication line pairs is provided.
The plurality of slave units
The first terminal pair to which the first communication line pair of the plurality of communication line pairs is connected and
A second terminal pair to which the second communication line pair of the plurality of communication line pairs is connected and
A first connection point to which one terminal of the first terminal pair and one terminal of the second terminal pair are connected, and the other terminal of the first terminal pair and the second terminal pair. A transmission circuit that transmits data to the master unit by controlling the conduction / non-conduction state between the terminal pair and the second connection point to which the other terminal is connected.
A first current detecting means for detecting the first current flowing through the first communication line pair,
A second current detecting means for detecting the second current flowing through the second communication line pair, and
When the first current and the second current are equal to or higher than a predetermined threshold value when the connection between the first connection point and the second connection point is controlled to be conductive. A signal output means for outputting a predetermined signal is provided.
Communications system. The plurality of slave units
While controlling the short-circuit / open state between the one terminal of the first terminal pair and the first connection point, the other terminal of the first terminal pair and the second connection are connected. The first switch that controls the short-circuit / open state between the points and
While controlling the short-circuit / open state between the one terminal of the second terminal pair and the first connection point, the other terminal of the second terminal pair and the second connection are connected. A second switch that controls the short-circuit / open state between points and
When the signal is output from the signal output means, the control means for controlling one of the first switch and the second switch in an open state is provided.
The communication system according to claim 1. When the signal is output from the signal output means, the control means controls the first switch to be in an open state when the first current is smaller than the second current, and outputs the signal. When the signal is output from the means and the second current is smaller than the first current, the second switch is controlled to be in the open state.
The communication system according to claim 2. The master unit includes a transmission circuit that transmits data to the plurality of slave units by switching the polarity of a voltage applied between a pair of communication lines connected to the master unit.
The plurality of slave units include a receiving circuit that receives data from the master unit by detecting the polarity of the voltage applied between the first connection point and the second connection point.
When the plurality of slave units control one of the switches in the open state, the plurality of slave units transmit data indicating the completion of control to the master unit.
When the master unit receives data indicating the completion of control from the first slave unit among the plurality of slave units, the master unit transmits data requesting a response to the plurality of slave units.
When the plurality of slave units receive the data requesting the response from the master unit, the plurality of slave units transmit the data indicating the response to the master unit.
When there is a second slave unit among the plurality of slave units for which the data indicating the response is not received, the master unit transmits data requesting control release to the first slave unit.
When the first slave unit receives data requesting the release of control from the master unit, the first slave unit controls one of the switches to a short-circuited state, and transmits data indicating the completion of control release to the master unit.
When the master unit receives the data indicating the completion of the control release from the first slave unit, the master unit transmits the data requesting the response to the second slave unit.
The communication system according to claim 3. A communication device that is one of a plurality of slave units that communicate with the master unit.
The master unit and the plurality of slave units are connected to each other by a plurality of communication line pairs.
Two or more communication line pairs connected to the same slave unit among the plurality of communication line pairs are connected to each other.
A voltage is applied by the master unit between the communication line pairs connected to the master unit among the plurality of communication line pairs.
The communication device is
The first terminal pair to which the first communication line pair of the plurality of communication line pairs is connected and
A second terminal pair to which the second communication line pair of the plurality of communication line pairs is connected and
A first connection point to which one terminal of the first terminal pair and one terminal of the second terminal pair are connected, and the other terminal of the first terminal pair and the second terminal pair. A transmission circuit that transmits data to the master unit by controlling the conduction / non-conduction state between the terminal pair and the second connection point to which the other terminal is connected.
A first current detecting means for detecting the first current flowing through the first communication line pair,
A second current detecting means for detecting the second current flowing through the second communication line pair, and
When the first current and the second current are equal to or higher than a predetermined threshold value when the connection between the first connection point and the second connection point is controlled to be conductive. A signal output means for outputting a predetermined signal is provided.
Communication equipment. An erroneous wiring detection method in a communication system in which a master unit and a plurality of slave units are provided and the master unit and the plurality of slave units are interconnected by a plurality of communication line pairs.
Two or more communication line pairs connected to the same slave unit among the plurality of communication line pairs are connected to each other.
A voltage is applied between the communication line pairs connected to the master unit among the plurality of communication line pairs.
A first terminal in which one terminal of a first terminal pair included in the first slave unit of the plurality of slave units is connected to one terminal of a second terminal pair included in the first slave unit. And the second connection point to which the other terminal of the first terminal pair and the other terminal of the second terminal pair are connected are controlled to be in a conductive state.
The first current flowing through the first communication line pair connected to the first terminal pair among the plurality of communication line pairs and the second terminal pair connected to the second terminal pair among the plurality of communication line pairs. When the second current flowing through the second communication line pair is equal to or greater than a predetermined threshold value, a predetermined signal is output.
Miswiring detection method.

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