Slave Station and Signal Transmission System

Abstract

A child station 2 comprises: four input terminals; a first sensor device that has four first conduction circuit units respectively associated with the four input terminals and that has such a circuit configuration that a current flows through an i-th one of the first conduction circuit units and no current flows through the first conduction circuit units other than the i-th one; a second sensor device that has four second conduction circuit units respectively associated with the four input terminals and that has such a circuit configuration that a current flows through a j-th one of the second conduction circuit units and no current flows through the second conduction circuit units other than the j-th one; and a control device that detects a state in which currents flowed through the i-th one of the first conduction circuit units and through the j-th one of the second conduction circuit units, thereby determining that a power supply line P+, a power supply line P0, a signal line D+, and a signal line D− are connected to the input terminals.

Description

[Technical field]

[0001] The present disclosure relates to a slave station and a signal transmission system. [Background technology]

[0002] In the technical field of automatic control, it is common for a control unit to transmit a control signal to drive and control a large number of controlled units located at a distance from the control unit, while a monitoring signal is transmitted from a sensor unit to the control unit to monitor and control the area around the sensor unit.

[0003] Examples of the control unit include a sequence controller, a programmable controller, a computer, etc. Examples of the controlled unit include a motor, a solenoid, a solenoid valve, a relay, a thyristor, a lamp, etc. Examples of the sensor unit include a reed switch, a microswitch, a push button switch, etc.

[0004] Conventionally, a system has been constructed in which a parent station that communicates with a control unit and at least one child station that communicates with a controlled unit or a sensor unit are connected via common wiring such as a control signal line, a power supply line, etc. This realizes interconnection between the control unit and the controlled unit, and between the control unit and the sensor unit.

[0005] Therefore, in recent years, as the controlled devices have become smaller, the wiring space has become smaller and the wiring work has become more time-consuming as devices are arranged at a higher density.

[0006] Therefore, instead of wiring individually, there is a system that transmits data signals and clock signals from a control unit to a controlled unit while superimposing driving power sources via a common wiring, and enables the controlled unit to extract the data signal and the clock signal, respectively. This reduces the number of common wirings in the entire system, and improves the efficiency of wiring work (for example, see Patent Document 1).

[0007] There is also a system that transmits a clock signal from the control unit to the sensor unit while superimposing the driving power supply via a common wiring, and enables the sensor unit to extract the driving power supply and the clock signal, respectively. This reduces the number of common wirings in the entire system, and improves the efficiency of wiring work (for example, see Patent Document 2).

[0008] Also, there is a system in which a distribution unit is provided on a common wiring that connects a first unit as a parent station and a second group of units as child stations. In this system, a data signal and a clock signal are transmitted to a controlled unit through a common wiring between the distribution unit and the child stations while superimposing a driving power supply. In this system, a clock signal is transmitted to a sensor unit through a common wiring between the distribution unit and the child stations while superimposing a driving power supply (for example, see Patent Document 3).

[0009] There is also a technique in which a data signal is transmitted between each slave station and the master station via a common wiring while a driving power supply is superimposed (for example, see Patent Document 4). [Prior art documents] [Patent documents]

[0010] [Patent Document 1] Japanese Patent Application Publication No. 64-072623 [Patent Document 2] Japanese Patent Publication No. 64-089839 [Patent Document 3] Japanese Patent Application Publication No. 03-006997 [Patent Document 4] JP 2002-271878 A Summary of the Invention [Problem to be solved by the invention]

[0011] However, in the conventional techniques described in Patent Documents 1 to 4, a worker must wire a plurality of common wirings such as control signal lines, power lines, etc., specifically, the type of wiring for each connection destination of each type of wiring such as signal line D+, signal line D-, power line P+, ​​power line P0, etc., while checking the type of wiring. Therefore, it takes a lot of time to connect the common wirings to the correct terminal positions.

[0012] The present disclosure has been made to solve the above-mentioned problems, and has an object to provide a slave station and a signal transmission system that can reduce the time required to connect a common wiring. [Means for solving the problem]

[0013] The slave station according to the present disclosure has four input terminals to which four lines, namely, a power supply line P+ and a power supply line P0 for supplying power, and signal lines D+ and D- for supplying various signals, can be connected in any order as multiple wirings used in common with the master station, and first to fourth first conduction circuit units corresponding to the four input terminals, respectively, and when the power supply line P+ is connected to the i-th input terminal of the four input terminals, a current flows in the i-th first conduction circuit unit and no current flows in the first conduction circuit units other than the i-th one. A first sensor device has first to fourth second conduction circuit units corresponding to the four input terminals, respectively, and when the power supply line P0 is connected to the j-th input terminal of the four input terminals, a current flows in the j-th first conduction circuit unit and no current flows in the j-th first conduction circuit unit. The present invention is provided with a second sensor device having a circuit configuration in which a current flows through the first and second conductive circuit sections and no current flows through the second conductive circuit sections other than the jth one, and a control device in which power is supplied by a current flowing through the first and second conductive circuit sections and the conduction results of the first and second conductive circuit sections are readable, and which determines that a power supply line P+ is connected to the i-th input terminal, a power supply line P0 is connected to the j-th input terminal, and a signal line D+ and a signal line D- are connected to two input terminals other than the i-th and j-th input terminals by detecting a state in which a current flows through the i-th first conductive circuit section and the j-th second conductive circuit section, where i is an integer between 1 and 4, and j is an integer between 1 and 4 and different from i.

[0014] A signal transmission system according to the present disclosure includes the above-mentioned slave station and a master station that controls the above-mentioned external device via the slave station. Effect of the Invention

[0015] According to the present disclosure, it is possible to reduce the time required to connect common wiring. [Brief description of the drawings]

[0016] [Figure 1] 1 is a diagram showing a signal transmission system in a first embodiment. [Diagram 2] 2 is a diagram showing an internal configuration of a slave station shown in FIG. 1; [Diagram 3] 3 is a diagram showing an internal configuration of the signal switching device of FIG. 2. [Figure 4] FIG. 11 is a diagram showing a signal transmission system in a second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] Embodiment 1 Fig. 1 is a diagram showing a signal transmission system in the embodiment 1. As shown in Fig. 1, the signal transmission system includes a master station 1, a plurality of slave stations 2, and a plurality of transmission processing devices 9. The number of slave stations 2 may be one or more.

[0018] The parent station 1 and the multiple child stations 2 are connected via multiple wirings 3 that are used in common. In the example of FIG. 1, four lines, a power line P+, ​​a power line P0, a signal line D+, and a signal line D-, can function as the multiple wirings 3. A power source 4 is connected to the power line P+ and the power line P0. Therefore, the parent station 1 can supply power to the multiple child stations 2 via the power line P+ and the power line P0. That is, the power line P+ and the power line P0 are used to supply power.

[0019] Specifically, the power line P+ is set to a higher potential than the power line P0. The power line P+ and the power line P0 are electrically connected within the parent station 1. Therefore, if the power line P+ and the power line P0 are also electrically connected via the child station 2, a current flows in the order of the parent station 1, the power line P+, ​​the child station 2, and the power line P0. This current flow enables the power line P+ and the power line P0 to supply power to the child station 2 and the transmission processing device 9. The internal configuration of the child station 2, which will be described in detail below, is configured using a current flow based on the potential difference between the power line P+ and the power line P0.

[0020] Furthermore, the master station 1 can supply various signals to the multiple slave stations 2 via the signal line D+ and the signal line D-. That is, the signal line D+ and the signal line D- are used to supply signals.

[0021] A transmission processing device 9 is provided for each of the multiple slave stations 2. Power is supplied to each transmission processing device 9 from the corresponding slave station 2. Each transmission processing device 9 can perform various operations in response to various signals. Each transmission processing device 9 is controlled by the master station 1 and is an external device.

[0022] Fig. 2 is a diagram showing an internal configuration of the slave station 2 in Fig. 1. As shown in Fig. 2, the slave station 2 includes a first sensor device 21, a second sensor device 22, a control device 23, a transformer device 24, a signal switching device 25, four input terminals 27a to 27d, and four output terminals 28a to 28d.

[0023] In addition, the slave station 2 is provided with, as wiring-related components, an outgoing signal line 291a, a return signal line 291b, a first detection signal line 292, a second detection signal line 293, input signal lines 294a to 294d, a control signal line 296, and output signal lines 297a and 297b.

[0024] 1 can be connected to each of the four input terminals 27a-27d in any order. Therefore, the four lines, the power line P+, ​​the power line P0, the signal line D+, and the signal line D-, can be connected to each of the input terminals 27a-27d in any order. In the slave station 2 according to the present disclosure, the line connected to each of the input terminals 27a-27d can be any of the four lines, and the slave station 2 is characterized in that the line type is automatically identified within the slave station 2.

[0025] In the following description, the four input terminals 27a to 27d will be referred to as No. 1 to No. 4 when named in alphabetical order of the suffixes. That is, the input terminals 27a to 27d will be referred to as input terminals 27(1) to 27(4). Similarly, in the following description, the four output terminals 28a to 28d will be referred to as No. 1 to No. 4 when named in alphabetical order of the suffixes. That is, the output terminals 28a to 28d will be referred to as output terminals 28(1) to 28(4).

[0026] Furthermore, the four output terminals 28(1)-28(4) can be connected to external devices as first to fourth output destinations corresponding to the four input terminals 27(1)-27(4), respectively. In the example of Figs. 1 and 2, the external device corresponds to the transmission processing device 9. The four output terminals 28(1)-28(4) output power supplied through the power supply line P+ and the power supply line P0 to the transmission processing device 9. The four output terminals 28(1)-28(4) output various signals supplied through the signal line D+ and the signal line D- to the transmission processing device 9.

[0027] Therefore, the features of the slave station 2 will be described in detail using a specific wiring example.

[0028] First, the first sensor device 21 will be described. The first sensor device 21 has first conductive circuit parts 21A to 21D. The first conductive circuit parts 21A to 21D correspond to the four input terminals 27a to 27d, respectively. Thus, the first first conductive circuit part 21A corresponds to the input terminal 27a. The second first conductive circuit part 21B corresponds to the input terminal 27b. The third first conductive circuit part 21C corresponds to the input terminal 27c. The fourth first conductive circuit part 21D corresponds to the input terminal 27d.

[0029] That is, the first conductive circuit portions 21A to 21D are provided in parallel with the input terminals 27a to 27d in a one-to-one correspondence.

[0030] In the following description, the four first conduction circuit parts 21A-21D will be referred to as numbers 1-4 when they are named in alphabetical order of the suffixes. That is, the first conduction circuit parts 21A-21D will be referred to as first conduction circuit parts 21(1)-21(4). When referring to a part other than that order, they will be named as follows. For example, when referring to a part other than the first first conduction circuit part 21(1), it will be referred to as first conduction circuit part 21(1^).

[0031] The first conductive circuit section 21A has a function of passing a current in one direction. The first conductive circuit section 21A is composed of, for example, a photocoupler. The first conductive circuit section 21A includes a first input section 21Ai and a first detection section 21Ao.

[0032] The first input section 21Ai is a circuit element that functions as a light-emitting element. The first input section 21Ai is composed of, for example, a light-emitting diode. The anode side of the light-emitting diode in the first input section 21Ai is connected to the input terminal 27a. The cathode side of the light-emitting diode in the first input section 21Ai is connected to the outgoing signal line 291a. The outgoing signal line 291a is provided with a branch point b1. The outgoing signal line 291a is connected to the control device 23 from the branch point b1 via the transformer 24. Also, the outgoing signal line 291a is connected to the transmission processing device 9 from the branch point b1 via the output terminal 28a. Also, the outgoing signal line 291a is connected to the terminal P+ on the output side of the signal switching device 25 from the branch point b1. Therefore, the current flowing through the outgoing signal line 291a can supply power as a V+ voltage to the control device 23 via the transformer 24. Also, the current flowing through the outgoing signal line 291a can supply power to the transmission processing device 9. Moreover, the current flowing through the outgoing signal line 291a can supply power to the signal switching device 25. That is, the first input portion 21Ai and the outgoing signal line 291a form a path through which a current flows in one direction.

[0033] The first detection unit 21Ao is a circuit element that functions as a light receiving element. The first detection unit 21Ao is composed of, for example, a phototransistor. The collector side of the phototransistor in the first detection unit 21Ao is connected to the outgoing signal line 291a. The emitter side of the phototransistor in the first detection unit 21Ao is connected to the control device 23 via the first detection signal line 292.

[0034] Therefore, the first sensor device 21 has a circuit configuration that realizes the following functions when the power supply line P+ is connected to the first input terminal 27(1) of the four input terminals 27(1) to 27(4). That is, the first sensor device 21 has a circuit configuration in which a current flows through the first first conduction circuit portion 21(1) and no current flows through the first conduction circuit portions 21(2) to 21(4) other than the first.

[0035] The first conductive circuit section 21B has a function of passing a current in one direction. The first conductive circuit section 21B is composed of, for example, a photocoupler. The first conductive circuit section 21B includes a first input section 21Bi and a first detection section 21Bo.

[0036] The first input section 21Bi is a circuit element that functions as a light-emitting element. The first input section 21Bi is composed of, for example, a light-emitting diode. The anode side of the light-emitting diode in the first input section 21Bi is connected to the input terminal 27b. The cathode side of the light-emitting diode in the first input section 21Bi is connected to the outgoing signal line 291a. Therefore, similar to the case of the first input section 21Ai, in the first input section 21Bi, power can be supplied to the control device 23, the transmission processing device 9, and the signal switching device 25 by the current flowing through the outgoing signal line 291a. That is, a path that flows a current in one direction is formed by the first input section 21Bi and the outgoing signal line 291a.

[0037] The first detection unit 21Bo is a circuit element that functions as a light receiving element. The first detection unit 21Bo is composed of, for example, a phototransistor. The collector side of the phototransistor in the first detection unit 21Bo is connected to the outgoing signal line 291a. The emitter side of the phototransistor in the first detection unit 21Bo is connected to the control device 23 via the first detection signal line 292.

[0038] Therefore, the first sensor device 21 has a circuit configuration that realizes the following function when the power supply line P+ is connected to the second input terminal 27(2) of the four input terminals 27(1) to 27(4). That is, the first sensor device 21 has a circuit configuration in which a current flows through the second first conduction circuit portion 21(2) and no current flows through the first conduction circuit portions 21(1), 21(3), and 21(4) other than the second.

[0039] The first conductive circuit section 21C has a function of passing a current in one direction. The first conductive circuit section 21C is composed of, for example, a photocoupler. The first conductive circuit section 21C includes a first input section 21Ci and a first detection section 21Co.

[0040] The first input section 21Ci is a circuit element that functions as a light-emitting element. The first input section 21Ci is composed of, for example, a light-emitting diode. The anode side of the light-emitting diode in the first input section 21Ci is connected to the input terminal 27c. The cathode side of the light-emitting diode in the first input section 21Ci is connected to the outgoing signal line 291a. Therefore, similar to the case of the first input section 21Ai, in the first input section 21Ci, power can be supplied to the control device 23, the transmission processing device 9, and the signal switching device 25 by the current flowing through the outgoing signal line 291a. That is, a path that flows a current in one direction is formed by the first input section 21Ci and the outgoing signal line 291a.

[0041] The first detection unit 21Co is a circuit element that functions as a light receiving element. The first input unit 21Ci is composed of, for example, a phototransistor. The collector side of the phototransistor in the first detection unit 21Co is connected to the outgoing signal line 291a. The emitter side of the phototransistor in the first detection unit 21Co is connected to the control device 23 via the first detection signal line 292.

[0042] Therefore, the first sensor device 21 has a circuit configuration that realizes the following function when the power supply line P+ is connected to the third input terminal 27(3) among the four input terminals 27(1) to 27(4). That is, the first sensor device 21 has a circuit configuration in which a current flows through the third first conduction circuit portion 21(3) and no current flows through the first conduction circuit portions 21(1), 21(2), and 21(4) other than the third.

[0043] The first conductive circuit section 21D has a function of passing a current in one direction. The first conductive circuit section 21D is composed of, for example, a photocoupler. The first conductive circuit section 21D includes a first input section 21Di and a first detection section 21Do.

[0044] The first input section 21Di is a circuit element that functions as a light-emitting element. The first input section 21Di is composed of, for example, a light-emitting diode. The anode side of the light-emitting diode in the first input section 21Di is connected to the input terminal 27d. The cathode side of the light-emitting diode in the first input section 21Di is connected to the outgoing signal line 291a. Therefore, similar to the case of the first input section 21Ai, the first input section 21Di can also supply power to the control device 23, the transmission processing device 9, and the signal switching device 25 by the current flowing through the outgoing signal line 291a. That is, the first input section 21Di and the outgoing signal line 291a form a path that allows a current to flow in one direction.

[0045] The first detection unit 21Do is a circuit element that functions as a light receiving element. The first detection unit 21Do is composed of, for example, a phototransistor. The collector side of the phototransistor in the first detection unit 21Do is connected to the outgoing signal line 291a. The emitter side of the phototransistor in the first detection unit 21Do is connected to the control device 23 via the first detection signal line 292.

[0046] Therefore, the first sensor device 21 has a circuit configuration that realizes the following function when the power supply line P+ is connected to the fourth input terminal 27(4) among the four input terminals 27(1) to 27(4): A current flows through the fourth first conduction circuit portion 21(4), and no current flows through the first conduction circuit portions 21(1) to 21(3) other than the fourth.

[0047] In other words, the first sensor device 21 has first to fourth first conductive circuit portions 21(1) to 21(4) corresponding to the four input terminals 27(1) to 27(4), respectively.

[0048] In the following description, i is an integer between 1 and 4. The first sensor device 21 has a circuit configuration that realizes the following functions when a power supply line P+ is connected to the i-th input terminal 27(i) of the four input terminals 27(1) to 27(4). That is, the first sensor device 21 has a circuit configuration in which a current flows through the i-th first conduction circuit section 21(i) and a current flows through the i-th first detection signal line 292(i). The first sensor device 21 also has a circuit configuration in which no current flows through the first conduction circuit sections 21(i^) other than the i-th, and no current flows through the first detection signal lines 292(i^) other than the i-th.

[0049] Next, the second sensor device 22 will be described. The second sensor device 22 is provided in parallel with the first sensor device 21. The second sensor device 22 has second conductive circuit parts 22A to 22D. The second conductive circuit parts 22A to 22D correspond to the four input terminals 27a to 27d, respectively. Thus, the first second conductive circuit part 22A corresponds to the input terminal 27a. The second second conductive circuit part 22B corresponds to the input terminal 27b. The third second conductive circuit part 22C corresponds to the input terminal 27c. The fourth second conductive circuit part 22D corresponds to the input terminal 27d.

[0050] That is, the second conductive circuit portions 22A to 22D are provided in parallel with the input terminals 27a to 27d in a one-to-one relationship, respectively. Therefore, the second conductive circuit portions 22A to 22D are provided in parallel with the first conductive circuit portions 21A to 21D in a one-to-one relationship, respectively.

[0051] In the following description, the four second conduction circuit units 22A-22D will be referred to as numbers 1 to 4 when they are named in alphabetical order of the suffixes. That is, the second conduction circuit units 22A-22D will be referred to as second conduction circuit units 22(1)-22(4). When referring to a unit other than that order, they will be named as follows. For example, when referring to a unit other than the first second conduction circuit unit 22(1), it will be referred to as second conduction circuit unit 22(1^).

[0052] The second conductive circuit section 22A has a function of passing a current in one direction. The second conductive circuit section 22A is composed of, for example, a photocoupler. The second conductive circuit section 22A includes a second input section 22Ai and a second detection section 22Ao.

[0053] The second input section 22Ai is a circuit element that functions as a light-emitting element. The second input section 22Ai is composed of, for example, a light-emitting diode. The cathode side of the light-emitting diode in the second input section 22Ai is connected to the input terminal 27a. The anode side of the light-emitting diode in the second input section 22Ai is connected to the return signal line 291b. The return signal line 291b is provided with branch points b2 to b4. The return signal line 291b is connected to the control device 23 via the branch points b2 to b4. The return signal line 291b is also connected to the transmission processing device 9 from the branch point b2 via the output terminal 28b. The return signal line 291b is also connected to the transformer device 24 via the branch points b2 and b3. The return signal line 291b is also connected to the terminal P0 on the output side of the signal switching device 25 via the branch points b2 to b4. Therefore, the current returning from each of the control device 23, the transmission processing device 9, and the signal switching device 25 via the return signal line 291b flows into the anode side of the light emitting diode in the second input section 22Ai. That is, a path for returning the current in one direction is formed by the return signal line 291b and the second input section 22Ai.

[0054] The second detection unit 22Ao is a circuit element that functions as a light receiving element. The second detection unit 22Ao is composed of, for example, a phototransistor. The collector side of the phototransistor in the second detection unit 22Ao is connected to the outgoing signal line 291a. The emitter side of the phototransistor in the first detection unit 21Ao is connected to the control device 23 via the second detection signal line 293.

[0055] Therefore, the second sensor device 22 has a circuit configuration that realizes the following functions when the power line P0 is connected to the first input terminal 27(1) of the four input terminals 27(1) to 27(4). That is, the second sensor device 22 has a circuit configuration in which a current flows through the first second conduction circuit portion 22(1) and no current flows through the second conduction circuit portions 22(2) to 22(4) other than the first.

[0056] The second conductive circuit section 22B has a function of passing a current in one direction. The second conductive circuit section 22B is composed of, for example, a photocoupler. The second conductive circuit section 22B includes a second input section 22Bi and a second detection section 22Bo.

[0057] The second input section 22Bi is a circuit element that functions as a light-emitting element. The second input section 22Bi is composed of, for example, a light-emitting diode. The cathode side of the light-emitting diode in the second input section 22Bi is connected to the input terminal 27b. The anode side of the light-emitting diode in the second input section 22Bi is connected to the return signal line 291b. Therefore, similar to the case of the second input section 22Ai, the current returning from each of the control device 23, the transmission processing device 9, and the signal switching device 25 through the return signal line 291b flows into the anode side of the light-emitting diode in the second input section 22Bi. That is, a path that returns the current in one direction is formed by the return signal line 291b and the second input section 22Bi.

[0058] The second detection unit 22Bo is a circuit element that functions as a light receiving element. The second detection unit 22Bo is composed of, for example, a phototransistor. The collector side of the phototransistor in the second detection unit 22Bo is connected to the outgoing signal line 291a. The emitter side of the phototransistor in the second detection unit 22Bo is connected to the control device 23 via the second detection signal line 293.

[0059] Therefore, the second sensor device 22 has a circuit configuration that realizes the following function when the power line P0 is connected to the second input terminal 27(2) of the four input terminals 27(1) to 27(4). That is, the second sensor device 22 has a circuit configuration in which a current flows through the second second conduction circuit portion 22(2) and no current flows through the second conduction circuit portions 22(1), 22(3), and 22(4) other than the second.

[0060] The second conductive circuit section 22C has a function of passing a current in one direction. The second conductive circuit section 22C is, for example, configured with a photocoupler. The second conductive circuit section 22C includes a second input section 22Ci and a second detection section 22Co.

[0061] The second input section 22Ci is a circuit element that functions as a light-emitting element. The second input section 22Ci is composed of, for example, a light-emitting diode. The cathode side of the light-emitting diode in the second input section 22Ci is connected to the input terminal 27c. The anode side of the light-emitting diode in the second input section 22Ci is connected to the return signal line 291b. Therefore, similar to the case of the second input section 22Ai, the current returning from each of the control device 23, the transmission processing device 9, and the signal switching device 25 through the return signal line 291b flows into the anode side of the light-emitting diode in the second input section 22Ci. That is, a path that returns the current in one direction is formed by the return signal line 291b and the second input section 22Ci.

[0062] The second detection unit 22Co is a circuit element that functions as a light receiving element. The second detection unit 22Co is composed of, for example, a phototransistor. The collector side of the phototransistor in the second detection unit 22Co is connected to the outgoing signal line 291a. The emitter side of the phototransistor in the second detection unit 22Co is connected to the control device 23 via the second detection signal line 293.

[0063] Therefore, the second sensor device 22 has a circuit configuration that realizes the following function when the power line P0 is connected to the third input terminal 27(3) among the four input terminals 27(1) to 27(4). That is, the second sensor device 22 has a circuit configuration in which a current flows through the third second conduction circuit portion 22(3) and no current flows through the second conduction circuit portions 22(1), 22(2), and 22(4) other than the third.

[0064] The second conductive circuit section 22D has a function of passing a current in one direction. The second conductive circuit section 22D is composed of, for example, a photocoupler. The second conductive circuit section 22D includes a second input section 22Di and a second detection section 22Do.

[0065] The second input section 22Di is a circuit element that functions as a light-emitting element. The second input section 22Di is composed of, for example, a light-emitting diode. The cathode side of the light-emitting diode in the second input section 22Di is connected to the input terminal 27d. The anode side of the light-emitting diode in the second input section 22Di is connected to the return signal line 291b. Therefore, similar to the case of the second input section 22Ai, the current returning from each of the control device 23, the transmission processing device 9, and the signal switching device 25 through the return signal line 291b flows into the anode side of the light-emitting diode in the second input section 22Di. That is, the return signal line 291b and the second input section 22Di form a path that returns the current in one direction.

[0066] The second detection unit 22Do is a circuit element that functions as a light receiving element. The second detection unit 22Do is composed of, for example, a phototransistor. The collector side of the phototransistor in the second detection unit 22Do is connected to the outgoing signal line 291a. The emitter side of the phototransistor in the second detection unit 22Do is connected to the control device 23 via the second detection signal line 293.

[0067] Therefore, the second sensor device 22 has a circuit configuration that realizes the following function when the power supply line P0 is connected to the fourth input terminal 27(4) among the four input terminals 27(1) to 27(4). That is, the second sensor device 22 has a circuit configuration in which a current flows through the fourth second conduction circuit portion 22(4) and no current flows through the second conduction circuit portions 22(1) to 22(3) other than the fourth.

[0068] In other words, the second sensor device 22 has first to fourth second conductive circuit portions 22(1) to 22(4) corresponding to the four input terminals 27(1) to 27(4), respectively.

[0069] In the following description, j is an integer between 1 and 4, different from i. The second sensor device 22 has a circuit configuration that realizes the following functions when a power line P0 is connected to the j-th input terminal 27(j) among the four input terminals 27(1) to 27(4). That is, the second sensor device 22 has a circuit configuration in which a current flows through the j-th second conduction circuit section 22(j) and a current flows through the j-th second detection signal line 293(j). The second sensor device 22 also has a circuit configuration in which no current flows through second conduction circuit sections 22(j^) other than the j-th, and no current flows through second detection signal lines 293(j) other than the j-th.

[0070] As described above, when a current flows through the first conductive circuit section 21(i) and the second conductive circuit section 22(j), power is supplied to the control device 23, the transmission processing device 9, and the signal switching device 25.

[0071] Next, the control device 23 will be described. The control device 23 can read the continuity results by the first conduction circuit section 21(i) and the second conduction circuit section 22(j) via the first detection signal line 292 and the second detection signal line 293 shown in Fig. 2. Here, the continuity results refer to the detection results of the first detection sections 21Ao-21Do and the second detection sections 22Ao-22Do.

[0072] The control device 23 detects a state in which a current flows through the first conduction circuit portion 21(i) via the first detection signal line 292, and detects a state in which a current flows through the second conduction circuit portion 22(j) via the second detection signal line 293. As a result, the control device 23 determines that the power supply line P+ is connected to the i-th input terminal 27(i) and the power supply line P0 is connected to the j-th input terminal 27(j). The control device 23 also determines that the signal line D+ and the signal line D- are connected to the two input terminals 27(m), 27(n) other than the i-th and j-th input terminals.

[0073] That is, the control device 23 makes the following determination based on the detection results of the first detection units 21Ao to 21Do and the second detection units 22Ao to 22Do. Here, the detection results are the output results from the first detection units 21Ao to 21Do and the second detection units 22Ao to 22Do.

[0074] That is, among the input terminals 27(1)-27(4), the control device 23 determines which input terminal 27(i) is connected to the power line P+ and which input terminal 27(j) is connected to the power line P0. The control device 23 also makes the following determination based on the detection results of the first detection units 21Ao-21Do and the second detection units 22Ao-22Do. That is, the control device 23 determines that the signal line D+ and the signal line D- are connected to the two input terminals 27(m),(n) other than the i-th and j-th input terminals among the input terminals 27(1)-27(4).

[0075] For example, when a current flows from the input terminal 27a to the first input section 21Ai, the first detection section 21Ao detects that a current has flowed to the first input section 21Ai. In this case, the power line P+ of the multiple wirings 3 is connected to the input terminal 27a. Therefore, when the first detection section 21Ao detects that a current has flowed to the first input section 21Ai via the first detection signal line 292, the control device 23 makes the following judgment. That is, the control device 23 judges that the power line P+ is connected to the input terminal 27a of the input terminals 27a to 27d.

[0076] Furthermore, when a current flows from the input terminal 27b to the first input section 21Bi, the first detection section 21Bo detects that a current has flowed to the first input section 21Bi. In this case, the power supply line P+ of the multiple wirings 3 is connected to the input terminal 27b. Therefore, when the first detection section 21Bo detects that a current has flowed to the first input section 21Bi via the first detection signal line 292, the control device 23 makes the following judgment. That is, the control device 23 judges that the power supply line P+ is connected to the input terminal 27b of the input terminals 27a to 27d.

[0077] Furthermore, when a current flows from the input terminal 27c to the first input section 21Ci, the first detection section 21Co detects that a current has flowed to the first input section 21Ci. In this case, the power line P+ of the multiple wirings 3 is connected to the input terminal 27c. Therefore, when the first detection section 21Co detects that a current has flowed to the first input section 21Ci via the first detection signal line 292, the control device 23 makes the following judgment. That is, the control device 23 judges that the power line P+ is connected to the input terminal 27c of the input terminals 27a to 27d.

[0078] Furthermore, when a current flows from the input terminal 27d to the first input section 21Di, the first detection section 21Do detects that a current has flowed to the first input section 21Di. In this case, the power line P+ of the multiple wirings 3 is connected to the input terminal 27d. Therefore, when the first detection section 21Do detects that a current has flowed to the first input section 21Di via the first detection signal line 292, the control device 23 makes the following judgment. That is, the control device 23 judges that the power line P+ is connected to the input terminal 27d of the input terminals 27a to 27d.

[0079] Also, for example, when a current flows from the return signal line 291b to the second input section 22Ai, the second detection section 22Ao detects that a current has flowed to the second input section 22Ai. In this case, the power line P0 of the multiple wirings 3 is connected to the input terminal 27a. Therefore, when the second detection section 22Ao detects that a current has flowed to the second input section 22Ai via the second detection signal line 293, the control device 23 makes the following judgment. That is, the control device 23 judges that the power line P0 is connected to the input terminal 27a of the input terminals 27a to 27d.

[0080] Furthermore, when a current flows from the return signal line 291b to the second input section 22Bi, the second detection section 22Bo detects that a current has flowed to the second input section 22Bi. In this case, the power supply line P0 of the multiple wirings 3 is connected to the input terminal 27b. Therefore, when the second detection section 22Bo detects that a current has flowed to the second input section 22Bi via the second detection signal line 293, the control device 23 makes the following judgment. That is, the control device 23 judges that the power supply line P0 is connected to the input terminal 27b of the input terminals 27a to 27d.

[0081] Also, when a current flows from the return signal line 291b to the second input unit 22Ci, the second detection unit 22Co detects that a current has flowed to the second input unit 22Ci. In this case, the power line P0 of the multiple wirings 3 is connected to the input terminal 27c. Therefore, when the second detection unit 22Co detects that a current has flowed to the second input unit 22Ci via the second detection signal line 293, the control device 23 makes the following judgment. That is, the control device 23 judges that the power line P0 is connected to the input terminal 27c of the input terminals 27a to 27d.

[0082] Furthermore, when a current flows from the return signal line 291b to the second input unit 22Di, the second detection unit 22Do detects that a current has flowed to the second input unit 22Di. In this case, the power line P0 of the multiple wirings 3 is connected to the input terminal 27d. Therefore, when the second detection unit 22Do detects that a current has flowed to the second input unit 22Di via the second detection signal line 293, the control device 23 makes the following judgment. That is, the control device 23 judges that the power line P0 is connected to the input terminal 27d of the input terminals 27a to 27d.

[0083] In other words, the control device 23 identifies the first detection signal line 292(i) that is in the ON state in the first detection signal line 292. As a result, the control device 23 determines the input terminal 27(i) to which the power line P+ is connected among the input terminals 27(1) to 27(4) based on the detection results of the first detection units 21Ao to 21Do. Also, the control device 23 identifies the second detection signal line 293(j) that is in the ON state in the second detection signal line 293. As a result, the control device 23 determines the input terminal 27(j) to which the power line P0 is connected among the input terminals 27(1) to 27(4) based on the detection results of the second detection units 22Ao to 22Do. In this way, the control device 23 determines the input terminal 27(i) to which the power line P+ is connected and the input terminal 27(j) to which the power line P0 is connected among the input terminals 27(1) to 27(4).

[0084] Moreover, the control device 23 determines that the signal line D+ and the signal line D- are connected to the remaining two input terminals 27(m) and 27(n) other than the input terminal 27(i) and the input terminal 27(j). In this manner, the control device 23 and the signal switching device 25 execute a cooperative process.

[0085] Specifically, the following process is executed. That is, the signal switching device 25 is connected to the input terminals 27a to 27d via the input signal lines 294a to 294d. Also, the signal switching device 25 is connected to the output terminals 28a to 28d via the outgoing signal line 291a, the return signal line 291b, the output signal line 297a, and the output signal line 297b. Also, the signal switching device 25 receives a control signal from the control device 23 via a control signal line 296.

[0086] That is, the signal switching device 25 connects the two input terminals 27(m), 27(n) to the signal lines D+ and D- based on the control signal supplied from the control device 23. This connects the input terminals 27(m), 27(n) to the output terminals 28c, 28d. Therefore, various signals supplied from the signal lines D+ and D- are supplied to the transmission processing device 9.

[0087] Furthermore, when the driving result of the transmission processing device 9 differs from the pre-expected result, the control device 23 performs the following process. That is, the control device 23 supplies a control signal to the signal switching device 25 for switching the combination of connections between the two input terminals 27(m), 27(n) and the two output terminals 28c, 28d. The driving result of the transmission processing device 9 will be described later.

[0088] Next, the signal switching device 25 will be specifically described. Fig. 3 is a diagram showing the internal configuration of the signal switching device 25 of Fig. 2. As shown in Fig. 3, terminals A to D on the input side of the signal switching device 25 are connected to corresponding input signal lines 294a to 294d of Fig. 2. Furthermore, a terminal D+ on the output side of the signal switching device 25 is connected to an output signal line 297a of Fig. 2. Furthermore, a terminal D- on the output side of the signal switching device 25 is connected to an output signal line 297b of Fig. 2.

[0089] The signal switching device 25 includes a first changeover switch 251 and a second changeover switch 252. The first changeover switch 251 and the second changeover switch 252 are provided in parallel.

[0090] The first changeover switch 251 includes a first changeover input section 251i, a first changeover output section 251o, and a first changeover selection section 251sw. The first changeover input section 251i has four terminals a1 to d1 corresponding to the terminals A to D on the input side of the signal switching device 25. The first changeover selection section 251sw selects one of the four terminals a1 to d1 of the first changeover input section 251i and connects it to the first changeover output section 251o. The first changeover output section 251o is connected to the terminal D+ on the output side.

[0091] The second changeover switch 252 includes a second changeover input section 252i, a second changeover output section 252o, and a second changeover selection section 252sw. The second changeover input section 252i has four terminals a2 to d2 corresponding to the input side terminals A to D of the signal switching device 25. The second changeover selection section 252sw selects one of the four terminals a2 to d2 of the second changeover input section 252i and connects it to the second changeover output section 252o. The second changeover output section 252o is connected to the output side terminal D-.

[0092] For example, when the control device 23 judges that the terminals A and B are connected to the input terminals 27(i) and (j), respectively, it judges that the terminals C and D are connected to the input terminals 27(m) and (n), respectively. Then, the control device 23 transmits a control signal to the signal switching device 25 via the terminals T1 and T2, and connects the terminals C and D+ and the terminals D and D- at the same time. As a result, the terminal C is connected to the transmission processing device 9 via the output terminal 28c. Also, the terminal D is connected to the transmission processing device 9 via the output terminal 28d. As a result, the input signal line 294c is connected to the transmission processing device 9 via the output terminal 28c. Also, the input signal line 294d is connected to the transmission processing device 9 via the output terminal 28d. As a result, when the transmission processing device 9 can recognize the signals input from the output terminals 28c and 28d, the driving result of the transmission processing device 9 is a result that is expected in advance. Here, the driving result of the transmission processing device 9 is the recognition result of the signal by the transmission processing device 9. The signal recognition result by the transmission processing device 9 is the recognition result of transmission data predetermined in the transmission processing device 9. When the transmission processing device 9 recognizes the predetermined transmission data, the control device 23 performs the following operation.

[0093] That is, the control device 23 maintains the connection state of the terminals C and D+ by the first switching selection unit 251sw and the connection state of the terminals D and D- by the second switching selection unit 252sw. Furthermore, when the signals input from the output terminals 28c and 28d cannot be recognized as predetermined transmission data, the control device 23 performs the following operation.

[0094] That is, the control device 23 releases the connection state of terminal C and terminal D+ by the first switching selection unit 251sw, and establishes the connection state of terminal C and terminal D- by the first switching selection unit 251sw. Also, the control device 23 releases the connection state of terminal D and terminal D- by the second switching selection unit 252sw, and establishes the connection state of terminal D and terminal D+ by the second switching selection unit 252sw. The signal recognition result by the transmission processing device 9 may be transmitted to the control device 23 by a feedback circuit (not shown).

[0095] Next, the operation of the slave station 2 will be described using specific connection examples. Hereinafter, 12 connection examples, from the first case to the twelfth case, will be described individually.

[0096] <First case: input terminal 27a is connected to power line P+; input terminal 27b is connected to power line P0> A case will be described where the power supply line P+ is connected to the input terminal 27a and the power supply line P0 is connected to the input terminal 27b.

[0097] The anode side of the light emitting diode in the first input section 21Ai is connected to the power line P+ via the input terminal 27a, and the cathode side of the light emitting diode in the first input section 21Ai is connected to the output terminal 28a via the forward signal line 291a. Thus, the P+ voltage from the power line P+ is connected to the output terminal 28a via the first input section 21Ai.

[0098] On the other hand, the power supply line P0 is connected to the cathode side of the light-emitting diode in the second input section 22Bi via the input terminal 27b, and the output terminal 28b is connected to the anode side of the light-emitting diode in the second input section 22Bi via the return signal line 291b.

[0099] Therefore, the current flowing from the input terminal 27a flows through the first path and the second path. That is, the first path is a path passing through the first input unit 21Ai, the outgoing signal line 291a, the transformer device 24, the control device 23, and the branch points b4 to b2. The second path is a path passing through the first input unit 21Ai, the outgoing signal line 291a, the output terminal 28a, the transmission processing device 9, the output terminal 28b, and the branch point b2. The current that has flowed through the first path and the current that has flowed through the second path join together at the return signal line 291b, and flows to the input terminal 27b via the second input unit 22Bi.

[0100] Also, when a current flows through the light-emitting diode in the first input section 21Ai, the first conductive circuit section 21A is turned ON. As a result, the P+ voltage on the collector side of the phototransistor in the first detection section 21Ao is output to the emitter side of the phototransistor in the first detection section 21Ao. As a result, it is determined that the wiring 3 connected to the input terminal 27a is the power line P+, ​​and information on the wiring 3 connected to the input terminal 27a is transmitted to the control device 23 as P+ terminal information ON. As a result, the control device 23 determines that the power line P+ is connected to the input terminal 27a.

[0101] Also, when a current flows through the light emitting diode in the second input section 22Bi, the second conductive circuit section 22B is turned ON. As a result, the P+ voltage on the collector side of the phototransistor in the second detection section 22Bo is output to the emitter side of the phototransistor in the second detection section 22Bo. As a result, it is determined that the wiring 3 connected to the input terminal 27b is the power line P0, and information on the wiring 3 connected to the input terminal 27b is transmitted to the control device 23 as P0 terminal information ON. As a result, the control device 23 determines that the power line P0 is connected to the input terminal 27b.

[0102] The control device 23 also determines that either the signal line D+ or the signal line D- is connected to the remaining input terminal 27c other than the input terminal 27a and the input terminal 27b. The control device 23 also determines that the other of the signal line D+ or the signal line D- is connected to the remaining input terminal 27d other than the input terminal 27a and the input terminal 27b. Based on these recognition results, the control device 23 connects the input terminal 27c and the input terminal 27d to the transmission processing device 9 via the signal switching device 25.

[0103] For example, the control device 23 sends a D+ control signal among the control signals to the first changeover switch 251 via the terminal T1 to connect the terminal C and the terminal D+. The control device 23 also sends a D- control signal among the control signals to the second changeover switch 252 via the terminal T2 to connect the terminal D and the terminal D-.

[0104] The control device 23 maintains the current connection state if the transmission processing device 9 recognizes the predetermined transmission data. If the transmission processing device 9 does not recognize the predetermined transmission data, the control device 23 connects the terminal D and the terminal D+ with the D+ control signal, and connects the terminal C and the terminal D- with the D- control signal. As a result, the control device 23 maintains the current connection state if the transmission processing device 9 recognizes the predetermined transmission data. Also, as a result, the control device 23 displays error information indicating that a malfunction has occurred in one of the signal line D+, the signal line D-, and the transmission processing device 9 if the transmission processing device 9 does not recognize the predetermined transmission data.

[0105] <Second case: input terminal 27a is connected to power line P+; input terminal 27c is connected to power line P0> A case will be described where the power supply line P+ is connected to the input terminal 27a and the power supply line P0 is connected to the input terminal 27c.

[0106] The anode side of the light emitting diode in the first input section 21Ai is connected to the power line P+ via the input terminal 27a, and the cathode side of the light emitting diode in the first input section 21Ai is connected to the output terminal 28a via the forward signal line 291a. Thus, the P+ voltage from the power line P+ is connected to the output terminal 28a via the first input section 21Ai.

[0107] On the other hand, the power supply line P0 is connected to the cathode side of the light-emitting diode in the second input section 22Ci via the input terminal 27c, and the output terminal 28b is connected to the anode side of the light-emitting diode in the second input section 22Ci via the return signal line 291b.

[0108] Therefore, the current flowing from the input terminal 27a flows through the first path and the second path. That is, the first path is a path passing through the first input unit 21Ai, the outgoing signal line 291a, the transformer device 24, the control device 23, and the branch points b4 to b2. The second path is a path passing through the first input unit 21Ai, the outgoing signal line 291a, the output terminal 28a, the transmission processing device 9, the output terminal 28b, and the branch point b2. The current that has flowed through the first path and the current that has flowed through the second path join together at the return signal line 291b, and flows to the input terminal 27c via the second input unit 22Ci.

[0109] Also, when a current flows through the light-emitting diode in the first input section 21Ai, the first conductive circuit section 21A is turned ON. As a result, the P+ voltage on the collector side of the phototransistor in the first detection section 21Ao is output to the emitter side of the phototransistor in the first detection section 21Ao. As a result, it is determined that the wiring 3 connected to the input terminal 27a is the power line P+, ​​and information on the wiring 3 connected to the input terminal 27a is transmitted to the control device 23 as P+ terminal information ON. As a result, the control device 23 determines that the power line P+ is connected to the input terminal 27a.

[0110] Also, when a current flows through the light-emitting diode in the second input section 22Ci, the second conductive circuit section 22C is turned ON. As a result, the P+ voltage on the collector side of the phototransistor in the second detection section 22Co is output to the emitter side of the phototransistor in the second detection section 22Co. As a result, it is determined that the wiring 3 connected to the input terminal 27c is the power line P0, and information on the wiring 3 connected to the input terminal 27c is transmitted to the control device 23 as P0 terminal information ON. As a result, the control device 23 determines that the power line P0 is connected to the input terminal 27c.

[0111] The control device 23 also recognizes that either the signal line D+ or the signal line D- is connected to the remaining input terminal 27b other than the input terminal 27a and the input terminal 27c. The control device 23 also recognizes that either the signal line D+ or the signal line D- is connected to the remaining input terminal 27d other than the input terminal 27a and the input terminal 27c. Based on these recognition results, the control device 23 connects the input terminal 27b and the input terminal 27d to the transmission processing device 9 via the signal switching device 25.

[0112] For example, the control device 23 sends a D+ control signal among the control signals to the first changeover switch 251 via the terminal T1 to connect the terminal B and the terminal D+. The control device 23 also sends a D- control signal among the control signals to the second changeover switch 252 via the terminal T2 to connect the terminal D and the terminal D-.

[0113] The control device 23 maintains the current connection state if the predetermined transmission data is recognized by the transmission processing device 9. If the predetermined transmission data is not recognized by the transmission processing device 9, the control device 23 connects terminal D and terminal D+ with a D+ control signal, and connects terminal B and terminal D- with a D- control signal. As a result, the control device 23 maintains the current connection state if the predetermined transmission data is recognized by the transmission processing device 9. Also, as a result, the control device 23 displays error information indicating that a malfunction has occurred in either the signal line D+, the signal line D-, or the transmission processing device 9 if the predetermined transmission data is not recognized by the transmission processing device 9.

[0114] <Third case: input terminal 27a is connected to power line P+; input terminal 27d is connected to power line P0> A case will be described where the power supply line P+ is connected to the input terminal 27a and the power supply line P0 is connected to the input terminal 27d.

[0115] The anode side of the light emitting diode in the first input section 21Ai is connected to the power line P+ via the input terminal 27a, and the cathode side of the light emitting diode in the first input section 21Ai is connected to the output terminal 28a via the forward signal line 291a. Thus, the P+ voltage from the power line P+ is connected to the output terminal 28a via the first input section 21Ai.

[0116] On the other hand, the power supply line P0 is connected to the cathode side of the light-emitting diode in the second input section 22Di via the input terminal 27d, and the output terminal 28b is connected to the anode side of the light-emitting diode in the second input section 22Di via the return signal line 291b.

[0117] Therefore, the current flowing from the input terminal 27a flows through the first path and the second path. That is, the first path is a path passing through the first input unit 21Ai, the outgoing signal line 291a, the transformer device 24, the control device 23, and the branch points b4 to b2. The second path is a path passing through the first input unit 21Ai, the outgoing signal line 291a, the output terminal 28a, the transmission processing device 9, the output terminal 28b, and the branch point b2. The current that has flowed through the first path and the current that has flowed through the second path join together at the return signal line 291b, and flows to the input terminal 27d via the second input unit 22Di.

[0118] Also, when a current flows through the light-emitting diode in the first input section 21Ai, the first conductive circuit section 21A is turned ON. As a result, the P+ voltage on the collector side of the phototransistor in the first detection section 21Ao is output to the emitter side of the phototransistor in the first detection section 21Ao. As a result, it is determined that the wiring 3 connected to the input terminal 27a is the power line P+, ​​and information on the wiring 3 connected to the input terminal 27a is transmitted to the control device 23 as P+ terminal information ON. As a result, the control device 23 determines that the power line P+ is connected to the input terminal 27a.

[0119] Also, when a current flows through the light-emitting diode in the second input section 22Di, the second conductive circuit section 22D is turned ON. As a result, the P+ voltage on the collector side of the phototransistor in the second detection section 22Do is output to the emitter side of the phototransistor in the second detection section 22Do. As a result, it is determined that the wiring 3 connected to the input terminal 27d is the power line P0, and information on the wiring 3 connected to the input terminal 27d is transmitted to the control device 23 as P0 terminal information ON. As a result, the control device 23 determines that the power line P0 is connected to the input terminal 27d.

[0120] The control device 23 also recognizes that either the signal line D+ or the signal line D- is connected to the remaining input terminal 27b other than the input terminal 27a and the input terminal 27d. The control device 23 also recognizes that either the signal line D+ or the signal line D- is connected to the remaining input terminal 27c other than the input terminal 27a and the input terminal 27d. Based on these recognition results, the control device 23 connects the input terminal 27b and the input terminal 27c to the transmission processing device 9 via the signal switching device 25.

[0121] For example, the control device 23 sends a D+ control signal among the control signals to the first changeover switch 251 via the terminal T1 to connect the terminal B and the terminal D+. The control device 23 also sends a D- control signal among the control signals to the second changeover switch 252 via the terminal T2 to connect the terminal C and the terminal D-.

[0122] The control device 23 maintains the current connection state if the transmission processing device 9 recognizes the predetermined transmission data. If the transmission processing device 9 does not recognize the predetermined transmission data, the control device 23 connects terminal C and terminal D+ with a D+ control signal, and connects terminal B and terminal D- with a D- control signal. As a result, the control device 23 maintains the current connection state if the transmission processing device 9 recognizes the predetermined transmission data. Also, as a result, the control device 23 displays error information indicating that a malfunction has occurred in one of the signal line D+, the signal line D-, and the transmission processing device 9 if the transmission processing device 9 does not recognize the predetermined transmission data.

[0123] <Fourth Case: Input terminal 27b is connected to power line P+; Input terminal 27a is connected to power line P0> A case will be described where the power supply line P+ is connected to the input terminal 27b and the power supply line P0 is connected to the input terminal 27a.

[0124] The anode side of the light emitting diode in the first input section 21Bi is connected to the power line P+ via the input terminal 27b, and the cathode side of the light emitting diode in the first input section 21Bi is connected to the output terminal 28a via the outgoing signal line 291a. Thus, the P+ voltage from the power line P+ is connected to the output terminal 28a via the first input section 21Bi.

[0125] On the other hand, the power supply line P0 is connected to the cathode side of the light-emitting diode in the second input section 22Ai via the input terminal 27a, and the output terminal 28b is connected to the anode side of the light-emitting diode in the second input section 22Ai via the return signal line 291b.

[0126] Therefore, the current flowing from the input terminal 27b flows through the first path and the second path. That is, the first path is a path passing through the first input unit 21Bi, the outgoing signal line 291a, the transformer device 24, the control device 23, and the branch points b4 to b2. The second path is a path passing through the first input unit 21Bi, the outgoing signal line 291a, the output terminal 28a, the transmission processing device 9, the output terminal 28b, and the branch point b2. The current that has flowed through the first path and the current that has flowed through the second path join together at the return signal line 291b, and flows to the input terminal 27a via the second input unit 22Ai.

[0127] Also, when a current flows through the light emitting diode in the first input section 21Bi, the first conductive circuit section 21B is turned ON. As a result, the P+ voltage on the collector side of the phototransistor in the first detection section 21Bo is output to the emitter side of the phototransistor in the first detection section 21Bo. As a result, it is determined that the wiring 3 connected to the input terminal 27b is the power line P+, ​​and information on the wiring 3 connected to the input terminal 27b is transmitted to the control device 23 as P+ terminal information ON. As a result, the control device 23 determines that the power line P+ is connected to the input terminal 27b.

[0128] Also, when a current flows through the light-emitting diode in the second input section 22Ai, the second conductive circuit section 22A is turned ON. As a result, the P+ voltage on the collector side of the phototransistor in the second detection section 22Ao is output to the emitter side of the phototransistor in the first detection section 21Ao. As a result, it is determined that the wiring 3 connected to the input terminal 27a is the power line P0, and information on the wiring 3 connected to the input terminal 27a is transmitted to the control device 23 as P0 terminal information ON. As a result, the control device 23 determines that the power line P0 is connected to the input terminal 27a.

[0129] The control device 23 also recognizes that either the signal line D+ or the signal line D- is connected to the remaining input terminal 27c other than the input terminal 27b and the input terminal 27a. The control device 23 also recognizes that either the signal line D+ or the signal line D- is connected to the remaining input terminal 27d other than the input terminal 27b and the input terminal 27a. Based on these recognition results, the control device 23 connects the input terminal 27c and the input terminal 27d to the transmission processing device 9 via the signal switching device 25.

[0130] For example, the control device 23 sends a D+ control signal among the control signals to the first changeover switch 251 via the terminal T1 to connect the terminal C and the terminal D+. The control device 23 also sends a D- control signal among the control signals to the second changeover switch 252 via the terminal T2 to connect the terminal D and the terminal D-.

[0131] The control device 23 maintains the current connection state if the transmission processing device 9 recognizes the predetermined transmission data. If the transmission processing device 9 does not recognize the predetermined transmission data, the control device 23 connects the terminal D and the terminal D+ with the D+ control signal, and connects the terminal C and the terminal D- with the D- control signal. As a result, the control device 23 maintains the current connection state if the transmission processing device 9 recognizes the predetermined transmission data. Also, as a result, the control device 23 displays error information indicating that a malfunction has occurred in one of the signal line D+, the signal line D-, and the transmission processing device 9 if the transmission processing device 9 does not recognize the predetermined transmission data.

[0132] <Fifth Case: Input terminal 27b is connected to power line P+; Input terminal 27c is connected to power line P0> A case will be described where the power supply line P+ is connected to the input terminal 27b, and the power supply line P0 is connected to the input terminal 27c.

[0133] The anode side of the light emitting diode in the first input section 21Bi is connected to the power line P+ via the input terminal 27b, and the cathode side of the light emitting diode in the first input section 21Bi is connected to the output terminal 28a via the outgoing signal line 291a. Thus, the P+ voltage from the power line P+ is connected to the output terminal 28a via the first input section 21Bi.

[0134] On the other hand, the power supply line P0 is connected to the cathode side of the light-emitting diode in the second input section 22Ci via the input terminal 27c, and the output terminal 28b is connected to the anode side of the light-emitting diode in the second input section 22Ci via the return signal line 291b.

[0135] Therefore, the current flowing from the input terminal 27b flows through the first path and the second path. That is, the first path is a path passing through the first input unit 21Bi, the outgoing signal line 291a, the transformer device 24, the control device 23, and the branch points b4 to b2. The second path is a path passing through the first input unit 21Bi, the outgoing signal line 291a, the output terminal 28a, the transmission processing device 9, the output terminal 28b, and the branch point b2. The current that has flowed through the first path and the current that has flowed through the second path join together at the return signal line 291b, and flows to the input terminal 27c via the second input unit 22Ci.

[0136] Also, when a current flows through the light emitting diode in the first input section 21Bi, the first conductive circuit section 21B is turned ON. As a result, the P+ voltage on the collector side of the phototransistor in the first detection section 21Bo is output to the emitter side of the phototransistor in the first detection section 21Bo. As a result, it is determined that the wiring 3 connected to the input terminal 27b is the power line P+, ​​and information on the wiring 3 connected to the input terminal 27b is transmitted to the control device 23 as P+ terminal information ON. As a result, the control device 23 determines that the power line P+ is connected to the input terminal 27b.

[0137] Also, when a current flows through the light-emitting diode in the second input section 22Ci, the second conductive circuit section 22C is turned ON. As a result, the P+ voltage on the collector side of the phototransistor in the second detection section 22Co is output to the emitter side of the phototransistor in the second detection section 22Co. As a result, it is determined that the wiring 3 connected to the input terminal 27c is the power line P0, and information on the wiring 3 connected to the input terminal 27c is transmitted to the control device 23 as P0 terminal information ON. As a result, the control device 23 determines that the power line P0 is connected to the input terminal 27c.

[0138] The control device 23 also determines that either the signal line D+ or the signal line D- is connected to the remaining input terminal 27a other than the input terminal 27b and the input terminal 27c. The control device 23 also determines that either the signal line D+ or the signal line D- is connected to the remaining input terminal 27d other than the input terminal 27b and the input terminal 27c. Based on these determination results, the control device 23 connects the input terminal 27a and the input terminal 27d to the transmission processing device 9 via the signal switching device 25.

[0139] For example, the control device 23 sends a D+ control signal among the control signals to the first changeover switch 251 via the terminal T1 to connect the terminal A and the terminal D+. The control device 23 also sends a D- control signal among the control signals to the second changeover switch 252 via the terminal T2 to connect the terminal D and the terminal D-.

[0140] The control device 23 maintains the current connection state if the transmission processing device 9 recognizes the predetermined transmission data. If the transmission processing device 9 does not recognize the predetermined transmission data, the control device 23 connects the terminal D and the terminal D+ with the D+ control signal, and connects the terminal A and the terminal D- with the D- control signal. As a result, the control device 23 maintains the current connection state if the transmission processing device 9 recognizes the predetermined transmission data. Also, as a result, the control device 23 displays error information indicating that a malfunction has occurred in one of the signal line D+, the signal line D-, and the transmission processing device 9 if the transmission processing device 9 does not recognize the predetermined transmission data.

[0141] <Sixth Case: Input terminal 27b is connected to power line P+; Input terminal 27d is connected to power line P0> A case will be described where the power supply line P+ is connected to the input terminal 27b, and the power supply line P0 is connected to the input terminal 27d.

[0142] The anode side of the light emitting diode in the first input section 21Bi is connected to the power line P+ via the input terminal 27b, and the cathode side of the light emitting diode in the first input section 21Bi is connected to the output terminal 28a via the outgoing signal line 291a. Thus, the P+ voltage from the power line P+ is connected to the output terminal 28a via the first input section 21Bi.

[0143] On the other hand, the power supply line P0 is connected to the cathode side of the light-emitting diode in the second input section 22Di via the input terminal 27d, and the output terminal 28b is connected to the anode side of the light-emitting diode in the second input section 22Di via the return signal line 291b.

[0144] Therefore, the current flowing from the input terminal 27b flows through the first path and the second path. That is, the first path is a path passing through the first input unit 21Bi, the outgoing signal line 291a, the transformer device 24, the control device 23, and the branch points b4 to b2. The second path is a path passing through the first input unit 21Bi, the outgoing signal line 291a, the output terminal 28a, the transmission processing device 9, the output terminal 28b, and the branch point b2. The current that has flowed through the first path and the current that has flowed through the second path join together at the return signal line 291b, and flows to the input terminal 27d via the second input unit 22Di.

[0145] Also, when a current flows through the light-emitting diode in the first input section 21Bi, the first conductive circuit section 21B is turned ON. As a result, the P+ voltage on the collector side of the phototransistor in the first detection section 21Bo is output to the emitter side of the phototransistor in the first detection section 21Bo. As a result, it is determined that the wiring 3 connected to the input terminal 27b is the power line P+, ​​and information on the wiring 3 connected to the input terminal 27b is transmitted to the control device 23 as P+ terminal information ON. As a result, the control device 23 recognizes that the power line P+ is connected to the input terminal 27b.

[0146] Also, when a current flows through the light-emitting diode in the second input section 22Di, the second conductive circuit section 22D is turned ON. As a result, the P+ voltage on the collector side of the phototransistor in the second detection section 22Do is output to the emitter side of the phototransistor in the second detection section 22Do. As a result, it is determined that the wiring 3 connected to the input terminal 27d is the power line P0, and information on the wiring 3 connected to the input terminal 27d is transmitted to the control device 23 as P0 terminal information ON. As a result, the control device 23 recognizes that the power line P0 is connected to the input terminal 27d.

[0147] The control device 23 also determines that either the signal line D+ or the signal line D- is connected to the remaining input terminal 27a other than the input terminal 27b and the input terminal 27d. The control device 23 also determines that either the signal line D+ or the signal line D- is connected to the remaining input terminal 27c other than the input terminal 27b and the input terminal 27d. Based on these determination results, the control device 23 connects the input terminal 27a and the input terminal 27c to the transmission processing device 9 via the signal switching device 25.

[0148] For example, the control device 23 sends a D+ control signal among the control signals to the first changeover switch 251 via the terminal T1 to connect the terminal A and the terminal D+. The control device 23 also sends a D- control signal among the control signals to the second changeover switch 252 via the terminal T2 to connect the terminal C and the terminal D-.

[0149] The control device 23 maintains the current connection state if the transmission processing device 9 recognizes the predetermined transmission data. If the transmission processing device 9 does not recognize the predetermined transmission data, the control device 23 connects terminal C and terminal D+ with a D+ control signal, and connects terminal A and terminal D- with a D- control signal. As a result, the control device 23 maintains the current connection state if the transmission processing device 9 recognizes the predetermined transmission data. Also, as a result, the control device 23 displays error information indicating that a malfunction has occurred in one of the signal line D+, the signal line D-, and the transmission processing device 9 if the transmission processing device 9 does not recognize the predetermined transmission data.

[0150] <Seventh case: input terminal 27c is connected to power line P+; input terminal 27a is connected to power line P0> A case will be described where the power supply line P+ is connected to the input terminal 27c and the power supply line P0 is connected to the input terminal 27a.

[0151] The power line P+ is connected to the anode side of the light emitting diode in the first input section 21Ci via the input terminal 27c, and the output terminal 28a is connected to the cathode side of the light emitting diode in the first input section 21Ci via the forward signal line 291a. Thus, the P+ voltage from the power line P+ is connected to the output terminal 28a via the first input section 21Ci.

[0152] On the other hand, the power supply line P0 is connected to the cathode side of the light-emitting diode in the second input section 22Ai via the input terminal 27a, and the output terminal 28b is connected to the anode side of the light-emitting diode in the second input section 22Ai via the return signal line 291b.

[0153] Therefore, the current flowing from the input terminal 27c flows through the first path and the second path. That is, the first path is a path passing through the first input unit 21Ci, the outgoing signal line 291a, the transformer device 24, the control device 23, and the branch points b4 to b2. The second path is a path passing through the first input unit 21Ci, the outgoing signal line 291a, the output terminal 28a, the transmission processing device 9, the output terminal 28b, and the branch point b2. The current that has flowed through the first path and the current that has flowed through the second path join together at the return signal line 291b, and flows to the input terminal 27a via the second input unit 22Ai.

[0154] Also, when a current flows through the light-emitting diode in the first input section 21Ci, the first conductive circuit section 21C is turned ON. As a result, the P+ voltage on the collector side of the phototransistor in the first detection section 21Co is output to the emitter side of the phototransistor in the first detection section 21Co. As a result, it is determined that the wiring 3 connected to the input terminal 27c is the power line P+, ​​and information on the wiring 3 connected to the input terminal 27c is transmitted to the control device 23 as P+ terminal information ON. As a result, the control device 23 recognizes that the power line P+ is connected to the input terminal 27c.

[0155] Also, when a current flows through the light-emitting diode in the second input section 22Ai, the second conductive circuit section 22A is turned ON. As a result, the P+ voltage on the collector side of the phototransistor in the second detection section 22Ao is output to the emitter side of the phototransistor in the first detection section 21Ao. As a result, it is determined that the wiring 3 connected to the input terminal 27a is the power line P0, and information on the wiring 3 connected to the input terminal 27a is transmitted to the control device 23 as P0 terminal information ON. As a result, the control device 23 recognizes that the power line P0 is connected to the input terminal 27a.

[0156] The control device 23 also determines that either the signal line D+ or the signal line D- is connected to the remaining input terminal 27b other than the input terminal 27c and the input terminal 27a. The control device 23 also determines that either the signal line D+ or the signal line D- is connected to the remaining input terminal 27d other than the input terminal 27c and the input terminal 27a. Based on these determination results, the control device 23 connects the input terminal 27b and the input terminal 27d to the transmission processing device 9 via the signal switching device 25.

[0157] For example, the control device 23 sends a D+ control signal among the control signals to the first changeover switch 251 via the terminal T1 to connect the terminal B and the terminal D+. The control device 23 also sends a D- control signal among the control signals to the second changeover switch 252 via the terminal T2 to connect the terminal D and the terminal D-.

[0158] The control device 23 maintains the current connection state if the predetermined transmission data is recognized by the transmission processing device 9. If the predetermined transmission data is not recognized by the transmission processing device 9, the control device 23 connects terminal D and terminal D+ with a D+ control signal, and connects terminal B and terminal D- with a D- control signal. As a result, the control device 23 maintains the current connection state if the predetermined transmission data is recognized by the transmission processing device 9. Also, as a result, the control device 23 displays error information indicating that a malfunction has occurred in either the signal line D+, the signal line D-, or the transmission processing device 9 if the predetermined transmission data is not recognized by the transmission processing device 9.

[0159] <Eighth Case: Input terminal 27c is connected to power line P+; Input terminal 27b is connected to power line P0> A case will be described where the power supply line P+ is connected to the input terminal 27c, and the power supply line P0 is connected to the input terminal 27b.

[0160] The power line P+ is connected to the anode side of the light emitting diode in the first input section 21Ci via the input terminal 27c, and the output terminal 28a is connected to the cathode side of the light emitting diode in the first input section 21Ci via the forward signal line 291a. Thus, the P+ voltage from the power line P+ is connected to the output terminal 28a via the first input section 21Ci.

[0161] On the other hand, the power supply line P0 is connected to the cathode side of the light-emitting diode in the second input section 22Bi via the input terminal 27b, and the output terminal 28b is connected to the anode side of the light-emitting diode in the second input section 22Bi via the return signal line 291b.

[0162] Therefore, the current flowing from the input terminal 27c flows through the first path and the second path. That is, the first path is a path passing through the first input unit 21Ci, the outgoing signal line 291a, the transformer device 24, the control device 23, and the branch points b4 to b2. The second path is a path passing through the first input unit 21Ci, the outgoing signal line 291a, the output terminal 28a, the transmission processing device 9, the output terminal 28b, and the branch point b2. The current flowing through the first path and the current flowing through the second path join together at the return signal line 291b, and flows to the input terminal 27b via the second input unit 22Bi.

[0163] Also, when a current flows through the light-emitting diode in the first input section 21Ci, the first conductive circuit section 21C is turned ON. As a result, the P+ voltage on the collector side of the phototransistor in the first detection section 21Co is output to the emitter side of the phototransistor in the first detection section 21Co. As a result, it is determined that the wiring 3 connected to the input terminal 27c is the power line P+, ​​and information on the wiring 3 connected to the input terminal 27c is transmitted to the control device 23 as P+ terminal information ON. As a result, the control device 23 determines that the power line P+ is connected to the input terminal 27c.

[0164] Also, when a current flows through the light emitting diode in the second input section 22Bi, the second conductive circuit section 22B is turned ON. As a result, the P+ voltage on the collector side of the phototransistor in the second detection section 22Bo is output to the emitter side of the phototransistor in the second detection section 22Bo. As a result, it is determined that the wiring 3 connected to the input terminal 27b is the power line P0, and information on the wiring 3 connected to the input terminal 27b is transmitted to the control device 23 as P0 terminal information ON. As a result, the control device 23 determines that the power line P0 is connected to the input terminal 27b.

[0165] The control device 23 also determines that either the signal line D+ or the signal line D- is connected to the remaining input terminal 27a other than the input terminal 27c and the input terminal 27b. The control device 23 also determines that the other of the signal line D+ or the signal line D- is connected to the remaining input terminal 27d other than the input terminal 27c and the input terminal 27b. Based on these determination results, the control device 23 connects the input terminal 27a and the input terminal 27d to the transmission processing device 9 via the signal switching device 25.

[0166] For example, the control device 23 sends a D+ control signal among the control signals to the first changeover switch 251 via the terminal T1 to connect the terminal A and the terminal D+. The control device 23 also sends a D- control signal among the control signals to the second changeover switch 252 via the terminal T2 to connect the terminal D and the terminal D-.

[0167] The control device 23 maintains the current connection state if the transmission processing device 9 recognizes the predetermined transmission data. If the transmission processing device 9 does not recognize the predetermined transmission data, the control device 23 connects the terminal D and the terminal D+ with the D+ control signal, and connects the terminal A and the terminal D- with the D- control signal. As a result, the control device 23 maintains the current connection state if the transmission processing device 9 recognizes the predetermined transmission data. Also, as a result, the control device 23 displays error information indicating that a malfunction has occurred in one of the signal line D+, the signal line D-, and the transmission processing device 9 if the transmission processing device 9 does not recognize the predetermined transmission data.

[0168] <Ninth Case: Input terminal 27c is connected to power line P+; Input terminal 27d is connected to power line P0> A case will be described where the power supply line P+ is connected to the input terminal 27c, and the power supply line P0 is connected to the input terminal 27d.

[0169] The power line P+ is connected to the anode side of the light emitting diode in the first input section 21Ci via the input terminal 27c, and the output terminal 28a is connected to the cathode side of the light emitting diode in the first input section 21Ci via the forward signal line 291a. Thus, the P+ voltage from the power line P+ is connected to the output terminal 28a via the first input section 21Ci.

[0170] On the other hand, the power supply line P0 is connected to the cathode side of the light-emitting diode in the second input section 22Di via the input terminal 27d, and the output terminal 28b is connected to the anode side of the light-emitting diode in the second input section 22Di via the return signal line 291b.

[0171] Therefore, the current flowing from the input terminal 27c flows through the first path and the second path. That is, the first path is a path passing through the first input unit 21Ci, the outgoing signal line 291a, the transformer device 24, the control device 23, and the branch points b4 to b2. The second path is a path passing through the first input unit 21Ci, the outgoing signal line 291a, the output terminal 28a, the transmission processing device 9, the output terminal 28b, and the branch point b2. The current that has flowed through the first path and the current that has flowed through the second path join together at the return signal line 291b, and flows to the input terminal 27d via the second input unit 22Di.

[0172] Also, when a current flows through the light-emitting diode in the first input section 21Ci, the first conductive circuit section 21C is turned ON. As a result, the P+ voltage on the collector side of the phototransistor in the first detection section 21Co is output to the emitter side of the phototransistor in the first detection section 21Co. As a result, it is determined that the wiring 3 connected to the input terminal 27c is the power line P+, ​​and information on the wiring 3 connected to the input terminal 27c is transmitted to the control device 23 as P+ terminal information ON. As a result, the control device 23 determines that the power line P+ is connected to the input terminal 27c.

[0173] Also, when a current flows through the light-emitting diode in the second input section 22Di, the second conductive circuit section 22D is turned ON. As a result, the P+ voltage on the collector side of the phototransistor in the second detection section 22Do is output to the emitter side of the phototransistor in the second detection section 22Do. As a result, it is determined that the wiring 3 connected to the input terminal 27d is the power line P0, and information on the wiring 3 connected to the input terminal 27d is transmitted to the control device 23 as P0 terminal information ON. As a result, the control device 23 determines that the power line P0 is connected to the input terminal 27d.

[0174] The control device 23 also determines that either the signal line D+ or the signal line D- is connected to the remaining input terminals 27a other than the input terminals 27c and 27d. The control device 23 also determines that either the signal line D+ or the signal line D- is connected to the remaining input terminals 27b other than the input terminals 27c and 27d. Based on these determination results, the control device 23 connects the input terminals 27a and 27b to the transmission processing device 9 via the signal switching device 25.

[0175] For example, the control device 23 sends a D+ control signal among the control signals to the first changeover switch 251 via the terminal T1 to connect the terminal A and the terminal D+. The control device 23 also sends a D- control signal among the control signals to the second changeover switch 252 via the terminal T2 to connect the terminal B and the terminal D-.

[0176] The control device 23 maintains the current connection state if the predetermined transmission data is recognized by the transmission processing device 9. If the predetermined transmission data is not recognized by the transmission processing device 9, the control device 23 connects terminal B and terminal D+ with a D+ control signal, and connects terminal A and terminal D- with a D- control signal. As a result, the control device 23 maintains the current connection state if the predetermined transmission data is recognized by the transmission processing device 9. Also, as a result, the control device 23 displays error information indicating that a malfunction has occurred in one of the signal line D+, the signal line D-, or the transmission processing device 9 if the predetermined transmission data is not recognized by the transmission processing device 9.

[0177] <10th Case: Input terminal 27d is connected to power line P+; Input terminal 27a is connected to power line P0> A case will be described where the power supply line P+ is connected to the input terminal 27d and the power supply line P0 is connected to the input terminal 27a.

[0178] The anode side of the light emitting diode in the first input section 21Di is connected to the power line P+ via the input terminal 27d, and the cathode side of the light emitting diode in the first input section 21Di is connected to the output terminal 28a via the outgoing signal line 291a. Thus, the P+ voltage from the power line P+ is connected to the output terminal 28a via the first input section 21Di.

[0179] On the other hand, the power supply line P0 is connected to the cathode side of the light-emitting diode in the second input section 22Ai via the input terminal 27a, and the output terminal 28b is connected to the anode side of the light-emitting diode in the second input section 22Ai via the return signal line 291b.

[0180] Therefore, the current flowing from the input terminal 27d flows through the first path and the second path. That is, the first path is a path passing through the first input unit 21Di, the outgoing signal line 291a, the transformer device 24, the control device 23, and the branch points b4 to b2. The second path is a path passing through the first input unit 21Di, the outgoing signal line 291a, the output terminal 28a, the transmission processing device 9, the output terminal 28b, and the branch point b2. The current that has flowed through the first path and the current that has flowed through the second path join together at the return signal line 291b, and flows to the input terminal 27a via the second input unit 22Ai.

[0181] Also, when a current flows through the light-emitting diode in the first input section 21Di, the first conductive circuit section 21D is turned ON. As a result, the P+ voltage on the collector side of the phototransistor in the first detection section 21Do is output to the emitter side of the phototransistor in the first detection section 21Do. As a result, it is determined that the wiring 3 connected to the input terminal 27d is the power line P+, ​​and information on the wiring 3 connected to the input terminal 27d is transmitted to the control device 23 as P+ terminal information ON. As a result, the control device 23 recognizes that the power line P+ is connected to the input terminal 27d.

[0182] Also, when a current flows through the light-emitting diode in the second input section 22Ai, the second conductive circuit section 22A is turned ON. As a result, the P+ voltage on the collector side of the phototransistor in the second detection section 22Ao is output to the emitter side of the phototransistor in the first detection section 21Ao. As a result, it is determined that the wiring 3 connected to the input terminal 27a is the power line P0, and information on the wiring 3 connected to the input terminal 27a is transmitted to the control device 23 as P0 terminal information ON. As a result, the control device 23 recognizes that the power line P0 is connected to the input terminal 27a.

[0183] The control device 23 also recognizes that either the signal line D+ or the signal line D- is connected to the remaining input terminal 27b other than the input terminal 27d and the input terminal 27a. The control device 23 also recognizes that either the signal line D+ or the signal line D- is connected to the remaining input terminal 27c other than the input terminal 27d and the input terminal 27a. Based on these recognition results, the control device 23 connects the input terminal 27b and the input terminal 27c to the transmission processing device 9 via the signal switching device 25.

[0184] For example, the control device 23 sends a D+ control signal among the control signals to the first changeover switch 251 via the terminal T1 to connect the terminal B and the terminal D+. The control device 23 also sends a D- control signal among the control signals to the second changeover switch 252 via the terminal T2 to connect the terminal C and the terminal D-.

[0185] The control device 23 maintains the current connection state if the transmission processing device 9 recognizes the predetermined transmission data. If the transmission processing device 9 does not recognize the predetermined transmission data, the control device 23 connects terminal C and terminal D+ with a D+ control signal, and connects terminal B and terminal D- with a D- control signal. As a result, the control device 23 maintains the current connection state if the transmission processing device 9 recognizes the predetermined transmission data. Also, as a result, the control device 23 displays error information indicating that a malfunction has occurred in one of the signal line D+, the signal line D-, and the transmission processing device 9 if the transmission processing device 9 does not recognize the predetermined transmission data.

[0186] <11th case: input terminal 27d is connected to power line P+; input terminal 27b is connected to power line P0> A case will be described where the power supply line P+ is connected to the input terminal 27d and the power supply line P0 is connected to the input terminal 27b.

[0187] The anode side of the light emitting diode in the first input section 21Di is connected to the power line P+ via the input terminal 27d, and the cathode side of the light emitting diode in the first input section 21Di is connected to the output terminal 28a via the outgoing signal line 291a. Thus, the P+ voltage from the power line P+ is connected to the output terminal 28a via the first input section 21Di.

[0188] On the other hand, the power supply line P0 is connected to the cathode side of the light-emitting diode in the second input section 22Bi via the input terminal 27b, and the output terminal 28b is connected to the anode side of the light-emitting diode in the second input section 22Bi via the return signal line 291b.

[0189] Therefore, the current flowing from the input terminal 27d flows through the first path and the second path. That is, the first path is a path passing through the first input unit 21Di, the outgoing signal line 291a, the transformer device 24, the control device 23, and the branch points b4 to b2. The second path is a path passing through the first input unit 21Di, the outgoing signal line 291a, the output terminal 28a, the transmission processing device 9, the output terminal 28b, and the branch point b2. The current that has flowed through the first path and the current that has flowed through the second path join together at the return signal line 291b, and flows to the input terminal 27b via the second input unit 22Bi.

[0190] Also, when a current flows through the light-emitting diode in the first input section 21Di, the first conductive circuit section 21D is turned ON. As a result, the P+ voltage on the collector side of the phototransistor in the first detection section 21Do is output to the emitter side of the phototransistor in the first detection section 21Do. As a result, it is determined that the wiring 3 connected to the input terminal 27d is the power line P+, ​​and information on the wiring 3 connected to the input terminal 27d is transmitted to the control device 23 as P+ terminal information ON. As a result, the control device 23 determines that the power line P+ is connected to the input terminal 27d.

[0191] Also, when a current flows through the light emitting diode in the second input section 22Bi, the second conductive circuit section 22B is turned ON. As a result, the P+ voltage on the collector side of the phototransistor in the second detection section 22Bo is output to the emitter side of the phototransistor in the second detection section 22Bo. As a result, it is determined that the wiring 3 connected to the input terminal 27b is the power line P0, and information on the wiring 3 connected to the input terminal 27b is transmitted to the control device 23 as P0 terminal information ON. As a result, the control device 23 determines that the power line P0 is connected to the input terminal 27b.

[0192] The control device 23 also determines that either the signal line D+ or the signal line D- is connected to the remaining input terminal 27a other than the input terminal 27d and the input terminal 27b. The control device 23 also determines that either the signal line D+ or the signal line D- is connected to the remaining input terminal 27c other than the input terminal 27d and the input terminal 27b. Based on these determination results, the control device 23 connects the input terminal 27a and the input terminal 27c to the transmission processing device 9 via the signal switching device 25.

[0193] For example, the control device 23 sends a D+ control signal among the control signals to the first changeover switch 251 via the terminal T1 to connect the terminal A and the terminal D+. The control device 23 also sends a D- control signal among the control signals to the second changeover switch 252 via the terminal T2 to connect the terminal C and the terminal D-.

[0194] The control device 23 maintains the current connection state if the transmission processing device 9 recognizes the predetermined transmission data. If the transmission processing device 9 does not recognize the predetermined transmission data, the control device 23 connects terminal C and terminal D+ with a D+ control signal, and connects terminal A and terminal D- with a D- control signal. As a result, the control device 23 maintains the current connection state if the transmission processing device 9 recognizes the predetermined transmission data. Also, as a result, the control device 23 displays error information indicating that a malfunction has occurred in one of the signal line D+, the signal line D-, and the transmission processing device 9 if the transmission processing device 9 does not recognize the predetermined transmission data.

[0195] <12th case: input terminal 27d is connected to power line P+; input terminal 27c is connected to power line P0> A case will be described where the power supply line P+ is connected to the input terminal 27d and the power supply line P0 is connected to the input terminal 27c.

[0196] The anode side of the light emitting diode in the first input section 21Di is connected to the power line P+ via the input terminal 27d, and the cathode side of the light emitting diode in the first input section 21Di is connected to the output terminal 28a via the outgoing signal line 291a. Thus, the P+ voltage from the power line P+ is connected to the output terminal 28a via the first input section 21Di.

[0197] On the other hand, the power supply line P0 is connected to the cathode side of the light-emitting diode in the second input section 22Ci via the input terminal 27c, and the output terminal 28b is connected to the anode side of the light-emitting diode in the second input section 22Ci via the return signal line 291b.

[0198] Therefore, the current flowing from the input terminal 27d flows through the first path and the second path. That is, the first path is a path passing through the first input unit 21Di, the outgoing signal line 291a, the transformer device 24, the control device 23, and the branch points b4 to b2. The second path is a path passing through the first input unit 21Di, the outgoing signal line 291a, the output terminal 28a, the transmission processing device 9, the output terminal 28b, and the branch point b2. The current that has flowed through the first path and the current that has flowed through the second path join together at the return signal line 291b, and flows to the input terminal 27c via the second input unit 22Ci.

[0199] Also, when a current flows through the light-emitting diode in the first input section 21Di, the first conductive circuit section 21D is turned ON. As a result, the P+ voltage on the collector side of the phototransistor in the first detection section 21Do is output to the emitter side of the phototransistor in the first detection section 21Do. As a result, it is determined that the wiring 3 connected to the input terminal 27d is the power line P+, ​​and information on the wiring 3 connected to the input terminal 27d is transmitted to the control device 23 as P+ terminal information ON. As a result, the control device 23 recognizes that the power line P+ is connected to the input terminal 27d.

[0200] Also, when a current flows through the light-emitting diode in the second input section 22Ci, the second conductive circuit section 22C is turned ON. As a result, the P+ voltage on the collector side of the phototransistor in the second detection section 22Co is output to the emitter side of the phototransistor in the second detection section 22Co. As a result, it is determined that the wiring 3 connected to the input terminal 27c is the power line P0, and information on the wiring 3 connected to the input terminal 27c is transmitted to the control device 23 as P0 terminal information ON. As a result, the control device 23 recognizes that the power line P0 is connected to the input terminal 27c.

[0201] The control device 23 also determines that either the signal line D+ or the signal line D- is connected to the remaining input terminals 27a other than the input terminals 27d and 27c. The control device 23 also determines that either the signal line D+ or the signal line D- is connected to the remaining input terminals 27b other than the input terminals 27d and 27c. Based on these determination results, the control device 23 connects the input terminals 27a and 27b to the transmission processing device 9 via the signal switching device 25.

[0202] For example, the control device 23 sends a D+ control signal among the control signals to the first changeover switch 251 via the terminal T1 to connect the terminal A and the terminal D+. The control device 23 also sends a D- control signal among the control signals to the second changeover switch 252 via the terminal T2 to connect the terminal B and the terminal D-.

[0203] The control device 23 maintains the current connection state if the predetermined transmission data is recognized by the transmission processing device 9. If the predetermined transmission data is not recognized by the transmission processing device 9, the control device 23 connects terminal B and terminal D+ with a D+ control signal, and connects terminal A and terminal D- with a D- control signal. As a result, the control device 23 maintains the current connection state if the predetermined transmission data is recognized by the transmission processing device 9. Also, as a result, the control device 23 displays error information indicating that a malfunction has occurred in one of the signal line D+, the signal line D-, or the transmission processing device 9 if the predetermined transmission data is not recognized by the transmission processing device 9.

[0204] As described above, the slave station 2 according to the first embodiment includes the outgoing signal line 291a connected to the output side of the first input unit 21Ai-21Di, and the return signal line 291b connecting the outgoing signal line 291a and the input side of the second input unit 22Ai-22Di. This allows the control device 23 to determine whether the power line P+ is connected to the input terminal 27(i) among the four input terminals 27(1)-27(4). The control device 23 can also determine whether the power line P0 is connected to the input terminal 27(j) among the four input terminals 27(1)-27(4). As a result, in each slave station 2, the input terminals 27(i),(j) can be connected to the output terminals 28a,28b, respectively, and the input terminals 27(m),(n) can be connected to the output terminals 28c,28d, respectively.

[0205] Furthermore, the control device 23 determines which of the four input terminals 27(1) to 27(4) the power lines P+ and P0 are connected to, and then performs the following control. That is, the control device 23 can determine which of the remaining two input terminals 27(m) and 27(n) the signal line D+ is connected to. The control device 23 can also determine which of the input terminals 27(m) and 27(n) the signal line D- is connected to. As a result, the worker can connect the four wirings 3, the power lines P+ and P0, and the signal lines D+ and D-, to any position of the four input terminals 27(1) to 27(4). This can reduce the time required to connect the common wirings 3. Furthermore, even if the wirings are connected to any position, the connection relationship is automatically identified within each slave station 2 to establish the correct connection relationship, so that it is possible to prevent an error from occurring in the connection of the common wirings 3.

[0206] In the first embodiment, the power source 4 is an external power source provided outside the master station 1 and the slave station 2, but it may be built into the master station 1.

[0207] Embodiment 2 The second embodiment differs from the first embodiment in the following three points. An identification device 5 and a separation device 7 are further provided on the upstream side of the slave station 2. The multiple wirings 3 used in common are not configured with four types of wires, but with two types of wires: a type in which a first signal is superimposed on a power line P+, ​​and a type in which a second signal is superimposed on a power line P0. The parent station 1 has a built-in power supply 4.

[0208] 4 is a diagram showing a signal transmission system in the embodiment 2. As shown in FIG. 4, the signal transmission system further includes a discrimination device 5 and a separation device 7.

[0209] The identification device 5 is provided on the upstream side of the input terminals 27a to 27d of the slave station 2 shown in Fig. 2. The identification device 5 has two superimposed input terminals to which two lines, a first superimposed line 31 of a first line type and a second superimposed line 32 of a second line type, can be connected in any order, and identifies the first superimposed line 31 and the second superimposed line 32. In the first superimposed line 31, a first signal corresponding to a signal to be passed through the signal line D+ is superimposed on the power supplied as a P+ voltage via the power line P+. In the second superimposed line 32, a second signal corresponding to a signal to be passed through the signal line D- is superimposed on the power supplied as a P0 voltage via the power line P0.

[0210] The separation device 7 is provided between the identification device 5 and the slave station 2. The separation device 7 performs the following operation based on the identification result by the identification device 5. That is, the separation device 7 separates the first superimposed line 31 into two lines, a power line P+ and a signal line D+, and separates the second superimposed line 32 into two lines, a power line P0 and a signal line D-. The separation device 7 connects each of the four separated lines to four input terminals 27(1) to 27(4). As a result, the connection destinations of the first superimposed line 31 and the second superimposed line 32 can be separated into four input terminals 27(1) to 27(4).

[0211] As described above, the signal transmission system according to the second embodiment distinguishes between the first superimposed line 31 and the second superimposed line 32 by the identification device 5. Furthermore, the signal transmission system separates the connection destinations of the first superimposed line 31 and the second superimposed line 32 into the four input terminals 27(1) to 27(4) based on the identification result. As a result, even if a signal is superimposed on power, the slave station 2 can be used.

[0212] In addition, in the first and second embodiments, the voltage between the power supply line P+ and the power supply line P0 may be different, such as 0V and -24V, +12V and -12V, etc., depending on the internal circuits of the parent station 1, the child station 2, and the transmission processing device 9.

[0213] In the first and second embodiments, an example in which the first conductive circuit sections 21A to 21D are composed of, for example, photocouplers has been described, but the present invention is not particularly limited to this. For example, the first conductive circuit sections 21A to 21D may be composed of a current transformer. Also, for example, the first conductive circuit sections 21A to 21D may be composed of a photointerrupter. The same applies to the second conductive circuit sections 22A to 22D.

[0214] In the first and second embodiments, an example has been described in which the signal recognition result by the transmission processing device 9 is transmitted to the control device 23 by a feedback circuit (not shown), but the present invention is not particularly limited to this. For example, the signal recognition result by the transmission processing device 9 may be transmitted to the control device 23 by a wireless circuit (not shown).

[0215] In the first and second embodiments, the signal transmission system includes the transmission processing device 9. However, the transmission processing device 9 is an external device of the slave station 2 and may be separated from the slave station 2. In this case, the connection between the outgoing signal line 291a and the return signal line 291b may be realized via the control device 23.

[0216] In the first and second embodiments, the signal switching device 25 is implemented by the first switching selection unit 251sw and the second switching selection unit 252sw, but the present invention is not limited to this. For example, the switching may be implemented by other elements such as FETs. [Explanation of symbols]

[0217] 1 parent station, 2 child station, 21 first sensor device, 21A to 21D first conductive circuit section, 21Ai to 21Di first input section, 21Ao to 21Do first detection section, 22 second sensor device, 22A to 22D second conductive circuit section, 22Ai to 22Di second input section, 22Ao to 22Do second detection section, 23 control device, 24 transformer device, 25 signal switching device, 251 first changeover switch, 251i first changeover input section, 251o first changeover output section, 251sw first changeover selection section, 252 second changeover switch, 252i second changeover input section, 252o second changeover output section, 252sw second changeover selection section, 27a to 27d input terminals, 28a to 28d output terminals, 291a forward signal line, 291b return signal line, 292 first detection signal line, 293 second detection signal line, 294a to 294d input signal line, 296 control signal line, 297a, 297b output signal lines, 3 wiring, 31 first overlapping line, 32 second overlapping line, 9 transmission processing device, 4 power supply, 5 identification device, 7 separation device, b1 to b4 branch points.

Claims

1. Four input terminals to which four lines, namely, power supply line P+ and power supply line P0 for supplying power, and signal line D+ and signal line D- for supplying various signals, can be connected in any order as multiple wiring lines used in common with the parent station; a first sensor device having a circuit configuration including first to fourth first conduction circuit units corresponding to the four input terminals, respectively, such that when the power supply line P+ is connected to an i-th input terminal among the four input terminals, a current flows through the i-th first conduction circuit unit, and no current flows through first conduction circuit units other than the i-th one; a second sensor device having a circuit configuration including first to fourth second conduction circuit units corresponding to the four input terminals, respectively, such that when the power supply line P0 is connected to a j-th input terminal among the four input terminals, a current flows through the j-th second conduction circuit unit, and no current flows through second conduction circuit units other than the j-th second conduction circuit unit; a control device that supplies power by causing a current to flow through the first conduction circuit unit and the second conduction circuit unit, and is capable of reading the conduction results of the first conduction circuit unit and the second conduction circuit unit, and that determines, by detecting a state in which a current flows through the i-th first conduction circuit unit and the j-th second conduction circuit unit, that the power supply line P+ is connected to the i-th input terminal, the power supply line P0 is connected to the j-th input terminal, and the signal line D+ and the signal line D- are connected to two input terminals other than the i-th and j-th input terminals, wherein the i is an integer between 1 and 4, and the j is an integer between 1 and 4 and different from the i.

2. four output terminals that can be connected to an external device as first to fourth output destinations corresponding to the four input terminals, respectively, and that output the power supplied by the power supply line P+ and the power supply line P0 and the various signals supplied by the signal line D+ and the signal line D- to the external device; a signal switching device that connects the four input terminals and the four output terminals based on a control signal supplied from the control device, 2. The slave station according to claim 1, wherein the control device supplies the control signal to the signal switching device to switch a connection combination between two input terminals among the four input terminals corresponding to terminals other than the i-th and j-th input terminals and two output terminals among the four output terminals corresponding to terminals other than the i-th and j-th output terminals when the driving result of the external device differs from a previously expected result.

3. A slave station according to claim 2; a master station that controls the external device via the slave station.

4. an identification device that is provided upstream of each of the input terminals, and has two superimposed input terminals that can connect two lines in any order: a first superimposed line in which a first signal corresponding to the signal to be passed through the signal line D+ is superimposed on power corresponding to the power supplied through the power line P+, ​​and a second superimposed line in which a second signal corresponding to the signal to be passed through the signal line D- is superimposed on power corresponding to the power supplied through the power line P0; and The signal transmission system according to claim 3, further comprising a separation device that separates the first superimposed line into two lines, the power supply line P+ and the signal line D+, and separates the second superimposed line into two lines, the power supply line P0 and the signal line D-, and each of the four separated lines is connected to the four input terminals.

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