Control Systems and Terminals

Abstract

To obtain a control system and a terminal unit capable of improving reliability.SOLUTION: A control system comprises: a first relay connected between a load and a power supply, switching whether or not to feed power from the power supply to the load by being opened and closed; a second relay connected between the load and the power supply, switching whether or not to feed power from the power supply to the load by being opened and closed; a controller; and a control circuit that controls the first relay or the second relay depending on a transmission signal from the controller. The control circuit, when the number of opening / closing times of the first relay is equal to or less than a predetermined first limit value, opens and closes the first relay depending on the transmission signal, and when the number of opening / closing times of the first relay becomes larger than the first limit value, switches a relay to be opened and closed depending on the transmission signal from the first relay to the second relay.SELECTED DRAWING: Figure 7

Description

Technical Field

[0001] The present disclosure relates to a control system and a terminal device.

Background Art

[0002] Patent Document 1 discloses an illumination system in which an illumination fixture is turned off or on by an opening / closing unit that is a relay.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] A relay switch such as that in Patent Document 1 switches between a power supply state and a cut-off state by mechanically disconnecting a switch. For this reason, there was a risk of arcing occurring between the relay contacts during switching. Due to this arc, the relay contacts could wear out, causing the relay switch to overheat and potentially shortening the life of the relay switch. There was also a possibility that the relay switch could burn out. In particular, when the relay switch was operated continuously, it was more likely to overheat.

[0005] On the one hand, there is a relay switch using relay contacts that are less likely to be worn by an arc. However, such relay switches are generally expensive. For this reason, an expensive relay switch with arc countermeasures may be used for only one of the two relay switches. However, both a general relay switch and a relay switch with arc countermeasures generally have substantially the same opening and closing speed of the relay contacts. Also, the operation of the relay contacts is a mechanical operation. For this reason, there is generally a large variation in the opening and closing speed of the relay switch. Therefore, even when trying to turn off two relay switches simultaneously, it is assumed that it is difficult to specify which relay contacts of which relay switch will become open first. At this time, if a general relay switch becomes open before the expensive relay switch, the above-described problem is not solved, and there is a risk that the relay switch will enter a heat generation state.

[0006] The present disclosure has been made to solve the above-described problems, and an object thereof is to obtain a control system and a terminal device capable of improving reliability.

Means for Solving the Problems

[0007] The control system according to the present disclosure is connected between a load Lighting fixtures that are and a power supply, and a first relay that switches the presence or absence of power supply from the power supply to the lighting fixtures by opening and closing, and a second relay that is connected between the lighting fixtures and the power supply and switches the presence or absence of power supply from the power supply to the lighting fixtures by opening and closing, a controller, and a control circuit that controls the first relay and and the second relay according to a transmission signal from the controller, An illuminance sensor; and is provided. The control circuit opens and closes the first relay according to the transmission signal when the number of opening and closing operations of the first relay is equal to or less than a predetermined first limit value, and when the number of opening and closing operations of the first relay exceeds the first limit value, switches the relay to be opened and closed according to the transmission signal from the first relay to the second relay. Furthermore, when the illuminance sensor detects that the lighting fixture is turned on in a state in which the first relay is controlled to cut off power supply to the lighting fixture, the relay to be opened or closed in response to the transmission signal is switched from the first relay to the second relay. and so on.

[0008] The terminal device according to the present disclosure is a load Lighting fixtures that areand a power source, and opening and closing the lighting fixtures a first relay for switching on / off the supply of power to the lighting fixtures and the power supply, and opening and closing the lighting fixtures a second relay that switches whether or not power is supplied to the first relay; and when the number of times that the first relay is opened and closed is equal to or less than a predetermined first limit value, the first relay is opened and closed in response to a transmission signal from a controller, and when the number of times that the first relay is opened and closed exceeds the first limit value, the relay that is opened and closed in response to the transmission signal is switched from the first relay to the second relay; Furthermore, when an illuminance sensor detects that the lighting fixture is turned on in a state in which the first relay is controlled to cut off power supply to the lighting fixture, the relay to be opened or closed in response to the transmission signal from the controller is switched from the first relay to the second relay. and a control circuit. [Effects of the Invention]

[0009] In the control system and terminal according to the present disclosure, when the number of times the first relay is opened and closed exceeds a first limit value, the relay that opens and closes is switched from the first relay to the second relay, thereby improving reliability. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a block diagram of a lighting control system equipped with a single-ended terminal device according to a first embodiment. [Figure 2] 1 is a block diagram of a lighting control system equipped with a double-ended terminal device according to a first embodiment. [Figure 3] FIG. 2 is a perspective view of a terminal according to the first embodiment. [Figure 4] FIG. 2 is a plan view of the terminal according to the first embodiment. [Figure 5] FIG. 10 is a diagram illustrating the connection state of a single-ended terminal device. [Figure 6] FIG. 10 is a diagram illustrating the connection state of a double-ended terminal device. [Figure 7] 2 is a block diagram showing the internal configuration of a single-ended terminal device according to the first embodiment; FIG. [Figure 8] 2 is a block diagram showing the internal configuration of a double-ended terminal device according to the first embodiment; FIG. DETAILED DESCRIPTION OF THE INVENTION

[0011] A control system and a terminal device according to the present embodiment will be described with reference to the drawings. The same or corresponding components may be denoted by the same reference numerals, and repeated description may be omitted.

[0012] Embodiment 1. FIG. 1 is a block diagram of an illumination control system 100 including a single-pole terminal device 83 according to Embodiment 1. FIG. 2 is a block diagram of an illumination control system 200 including a double-pole terminal device 84 according to Embodiment 1. The illumination control systems 100 and 200 include a management PC 90, a management device 81, an illumination controller 82, a single-pole terminal device 83 or a double-pole terminal device 84, an illuminance sensor 86, and a plurality of lighting fixtures 85.

[0013] The illuminance sensor 86 is also called a dimming controller. The management device 81 is composed of, for example, a microcomputer. The management device 81 monitors and sets the state of the entire illumination control system based on information from the illumination controller 82. A management PC 90 is provided as a user interface for the illumination control systems 100 and 200.

[0014] The illumination controller 82 communicates with the terminal device 83 or 84, the illuminance sensor 86, a wall switch (not shown), various sensors, etc. via a communication line 8. The transmission signals transmitted and received by the illumination controller 82 include address data and control data. The management PC 90, the management device 81, and the illumination controller 82 are connected by a LAN (Local Area Network) 1 which is a wired or wireless communication network.

[0015] The terminal devices 83 and 84 are terminal devices for a control system and are also called relay terminal devices or terminal devices with built-in relays. One terminal device 83 and two terminal devices 84 are connected in parallel to the illumination controller 82. The number of terminal devices provided in each illumination control system may be one or more.

[0016] Terminal devices 83 and 84 are connected to lighting fixtures 85. The lighting fixtures 85, which are loads, are connected to the first terminal of the power supply 10 by the first wiring 10a and to the second terminal of the power supply 10 by the second wiring 10b. The power supply 10 is, for example, a power supply for loads with an AC voltage of 100 to 250V.

[0017] In the lighting control system 100, one-side terminal device 83 is connected to the first wiring 10a side. The second wiring 10b is connected to the lighting fixture 85. The terminal device 83 switches the conduction and interruption of the first wiring 10a by a built-in relay to turn the lighting fixture 85 on and off.

[0018] In the lighting control system 200, the two-side terminal device 84 is connected to the first wiring 10a and the second wiring 10b. The terminal device 84 switches the conduction and interruption of the first wiring 10a and the second wiring 10b by a built-in relay to turn the lighting fixture 85 on and off.

[0019] The illuminance sensor 86 is installed adjacent to the lighting fixture 85. The illuminance sensor 86 detects the floor-reflected light 4b of the light 4a from the lighting fixture 85. Thereby, the illuminance sensor 86 detects the brightness level around the lighting fixture 85. The information detected by the illuminance sensor 86 is transmitted to the lighting controller 82. Thereby, the lighting controller 82 can determine whether the lighting fixture 85 is on or off.

[0020] Each of the terminal devices 83 and 84 is assigned and set with a unique address. The terminal devices 83 and 84 are identified by the set addresses. The terminal devices 83 and 84 receive the transmission signals sent by the lighting controller 82 via the communication line 8. The terminal devices 83 and 84 have a microcomputer 63 as described later. The microcomputer 63 compares the address data included in the transmission signal with the unique address set in the terminal device. When the microcomputer 63 determines that the address data of the transmission signal matches the unique address set in itself, the terminal device controls the relay according to the control data included in the transmission signal.

[0021] FIG. 3 is a perspective view of terminal units 83 and 84 according to the first embodiment. FIG. 4 is a plan view of terminal units 83 and 84 according to the first embodiment. Terminal units 83 and 84 have an upper case 71 and a lower case 72. The upper case 71 and the lower case 72 are cases for storing circuit boards. The circuit boards include, for example, a control board and a main board. The control board is a low-voltage board to which transmission signals are input. The control board has circuits formed thereon for communication with other devices and for controlling the relays. The main board has multiple relays.

[0022] The upper case 71 holds terminal fittings 75a and 75b for connecting the communication line 8 and the load. Each of the terminal units 83 and 84 has four terminal fittings 75a. Each of the terminal units 83 and 84 also has eight terminal fittings 75b. The terminal fittings 75a are lined up at one end of the upper case 71 in the longitudinal direction. The terminal fittings 75b are lined up at the other end of the upper case 71 in the longitudinal direction.

[0023] The terminal fitting 75a corresponds to the input terminal of the terminal devices 83, 84. The terminal devices 83, 84 receive a transmission signal from the lighting controller 82 via the terminal fitting 75a. The terminal fitting 75b corresponds to the output terminal of the relay that the terminal devices 83, 84 have. The power supply 10 and the load are connected in series to the terminal fitting 75b. A high voltage is applied to the terminal fitting 75b. To ensure safety, the terminal fitting 75b is covered with a protective cover 76.

[0024] The upper case 71 has an upper surface 73 in the center in the longitudinal direction. A nameplate (not shown) is affixed to the upper surface 73. A recess is formed in the upper case 71 at a location sandwiched between the upper surface 73 and the terminal fitting 75a. An operation surface 74 is provided in the recess. A switch operation portion of the address setting portion 77 protrudes from the operation surface 74. The switch operation portion is a DIP switch. By setting the address setting portion 77 provided on the control board, a unique address can be set in the terminals 83 and 84.

[0025] FIG. 5 is a diagram illustrating the connection state of a single-pole terminal device 83. Note that a spare relay, which will be described later, is omitted from FIG. 5. The terminal device 83 has two terminals connected to the communication line 8. The terminal device 83 also has load-side terminals 51 to 58. The terminal device 83 has four single-pole circuits. Loads 11, 13, 15, and 17 are connected to the terminal device 83. The loads 11, 13, 15, and 17 are, for example, lighting fixtures 85. The terminal device 83 can independently control the output to the loads 11, 13, 15, and 17.

[0026] The communication line 8 is connected to a terminal for the communication line 8 of the terminal device 83 via a jumper wiring. Furthermore, the load-side terminal 51 is connected to one terminal of the load 11, and the terminal 52 is connected to the first wiring 10a. The other terminal of the load 11 is connected to the second wiring 10b. The terminal 51 is a terminal that supplies power to one terminal of the load 11. Furthermore, the terminal 52 is a terminal that receives power from the first wiring 10a of the power source 10.

[0027] Similarly, terminal 53 is connected to one terminal of load 13, and terminal 54 is connected to the first wiring 10a. The other terminal of load 13 is connected to the second wiring 10b. Terminal 55 is connected to one terminal of load 15, and terminal 56 is connected to the first wiring 10a. The other terminal of load 15 is connected to the second wiring 10b. Terminal 57 is connected to one terminal of load 17, and terminal 58 is connected to the first wiring 10a. The other terminal of load 17 is connected to the second wiring 10b.

[0028] A relay 41 is provided between terminals 51 and 52. A relay 42 is provided between terminals 53 and 54. A relay 43 is provided between terminals 55 and 56. A relay 44 is provided between terminals 57 and 58. The relays 41 to 44 open and close independently. The relays 41 to 44 are mechanical relays. Each of the relays 41 to 44 has contacts provided on the load 11, 13, 15, 17 side, and a coil for opening and closing the contacts. When the coil is energized, the contacts close. When the coil is de-energized, the contacts open.

[0029] FIG. 6 is a diagram illustrating the connection state of a double-pole terminal device 84. Note that a spare relay, which will be described later, is omitted from FIG. 6. The terminal device 84 has two terminals connected to the communication line 8. The terminal device 84 also has load-side terminals 31 to 38. The terminal device 84 has two double-pole circuits. Loads 12 and 14 are connected to the terminal device 84. The loads 12 and 14 are, for example, lighting fixtures 85. The terminal device 84 can independently control the output to the loads 12 and 14.

[0030] The communication line 8 is connected to a terminal for the communication line 8 of the terminal device 84 via a jumper wiring. Furthermore, the load-side terminal 31 is connected to one terminal of the load 12, and the terminal 33 is connected to the other terminal of the load 12. The terminal 31 is a terminal that supplies power to one terminal of the load 12. The terminal 33 is a terminal that supplies power to the other terminal of the load 12. Similarly, the terminal 35 is connected to one terminal of the load 14, and the terminal 37 is connected to the other terminal of the load 14.

[0031] The terminals 32 and 36 are connected to the first wiring 10a, and the terminals 34 and 38 are connected to the second wiring 10b. The terminals 32 and 36 are terminals that receive power from the first wiring 10a of the power supply 10. The terminals 34 and 38 are terminals that receive power from the second wiring 10b of the power supply 10.

[0032] A relay 21 is provided between terminals 31 and 32. A relay 22 is provided between terminals 33 and 34. A relay 23 is provided between terminals 35 and 36. A relay 24 is provided between terminals 37 and 38. Relays 21 and 22 open and close in conjunction with each other. Relays 23 and 24 open and close in conjunction with each other. Relays 21 to 24 are mechanical relays. Relays 21 to 24 have contacts provided on the loads 12 and 14 sides, and coils for opening and closing the contacts. When the coil is energized, the contacts close. When the coil is de-energized, the contacts open.

[0033] FIG. 7 is a block diagram showing the internal configuration of the single-cut terminal device 83 according to the first embodiment. In FIG. 7, an example in which two terminal devices 83 are connected to the lighting controller 82 is shown. Further, in FIG. 7, for the sake of convenience, only loads 11 and 13 out of loads 11, 13, 15, 17 are shown, and only relays 41 and 42 out of relays 41 to 44 are shown.

[0034] The terminal device 83 is connected between the load 11 and the power supply 10, and includes a relay 41 that switches the presence or absence of power supply from the power supply 10 to the load 11 by opening and closing. The terminal device 83 is connected between the load 13 and the power supply 10, and includes a relay 42 that switches the presence or absence of power supply from the power supply 10 to the load 13 by opening and closing. Further, the terminal device 83 is connected between the load 11 and the power supply 10, and includes a spare relay 141 that switches the presence or absence of power supply from the power supply 10 to the load 11 by opening and closing. Further, the terminal device 83 is connected between the load 13 and the power supply 10, and includes a spare relay 142 that switches the presence or absence of power supply from the power supply 10 to the load 13 by opening and closing.

[0035] The relay 41 and the spare relay 141 are both provided on the first wiring 10a. The relay 42 and the spare relay 142 are both provided on the first wiring 10a.

[0036] Although not shown, corresponding spare relays are also provided for the relays 43 and 44. Hereinafter, the control of the relays 41, 42 and the spare relays 141, 142 will be described, but the control of the relays 43, 44 and their spare relays is the same.

[0037] The terminal device 83 includes a communication power supply circuit 60, a DC / DC circuit 61, a microcomputer 63, and drive circuits 64 to 67 as control circuits. The communication power supply circuit 60 receives power supply from the lighting controller 82 via the communication line 8, and generates power for driving the relays 41, 42 and the spare relays 141, 142. Further, the communication power supply circuit 60 transmits the control data of the transmission signal to the microcomputer 63.

[0038] The DC / DC circuit 61 steps down the voltage supplied from the communication power supply circuit 60 to generate the operating voltage of the microcomputer 63. The microcomputer 63 receives the transmission signal transmitted by the lighting controller 82 via the communication power supply circuit 60, and transmits a control signal for controlling the relays 41, 42 and the spare relays 141, 142 to the drive circuits 64 to 67. In this way, the control circuit of the present embodiment controls the relays 41, 42 or the spare relays 141, 142 according to the transmission signal from the lighting controller 82.

[0039] The microcomputer 63 has a processor and a memory. The memory is, for example, a non-volatile memory. The microcomputer 63 stores in the memory the number of times the transmission signal transmitted by the lighting controller 82 is received at regular intervals. The number of times the transmission signal is received corresponds to the number of times the relay is opened and closed. Further, a predetermined first limit value of the number of times the relays 41, 42 are opened and closed is set in the memory of the microcomputer 63. The setting of the first limit value is performed, for example, from the management PC 90. The first limit value may be a different value for the relays 41, 42.

[0040] The terminal device 83 includes a display unit. The display unit is, for example, the LED 62. The LED 62 displays the state of the terminal device 83 according to a signal from the microcomputer 63. The LED 62 lights up, for example, when the contacts of the relays 41, 42 or the spare relays 141, 142 are in the closed state.

[0041] The drive circuits 64 to 67 open and close the relays 41, 42 or the spare relays 141, 142 according to the control signal from the microcomputer 63. By operating the relays 41, 42 or the spare relays 141, 142, the loads 11, 13 can be turned on or off.

[0042] When the number of times the relay 41 is opened and closed is equal to or less than the first limit value, the microcomputer 63 opens and closes the relay 41 according to the transmission signal. When the number of times the relay 41 is opened and closed exceeds the first limit value, the microcomputer 63 switches the relay to be opened and closed according to the transmission signal from the relay 41 to the spare relay 141. That is, when the number of times the relay 41 is opened and closed is equal to or less than the first limit value, the relay 41 opens and closes according to the transmission signal, and the spare relay 141 does not open and close. When the number of times the relay 41 is opened and closed exceeds the first limit value, the spare relay 141 opens and closes according to the transmission signal, and the relay 41 does not open and close. The same applies to the relay 42 and the spare relay 142.

[0043] In addition, the microcomputer 63 causes the LED 62 to display that the controlled relay has been switched. That is, the microcomputer 63 notifies the outside through the LED 62 that the number of times the relay 41 or the relay 42 is opened and closed has exceeded the first limit value.

[0044] FIG. 8 is a block diagram showing the internal configuration of the two-way terminal device 84 according to the first embodiment. FIG. 8 is different from FIG. 7 in that the terminal device 83 is replaced by the terminal device 84. In FIG. 8, for convenience, only the load 12 among the loads 12 and 14 is shown, and only the relays 21 and 22 among the relays 21 to 24 are shown.

[0045] The terminal device 84 includes relays 21 and 22 that are connected between the load 12 and the power supply 10 and switch the presence or absence of power supply from the power supply 10 to the load 12 by opening and closing. The terminal device 84 also includes spare relays 121 and 122 that are connected between the load 12 and the power supply 10 and switch the presence or absence of power supply from the power supply 10 to the load 12 by opening and closing. The relay 21 and the spare relay 121 are both provided on the first wiring 10a. The relay 22 and the spare relay 122 are both provided on the second wiring 10b.

[0046] Although not shown in the figure, corresponding spare relays are also provided for the relays 23 and 24. Hereinafter, the control of the relays 21 and 22 and the spare relays 121 and 122 will be described, but the control of the relays 23 and 24 and their spare relays is the same.

[0047] The operations of the communication power supply circuit 60, DC / DC circuit 61, LED 62, microcomputer 63, and drive circuits 64 to 67 are the same as those of the terminal device 83. A predetermined first limit value for the number of times that relays 21 and 22 are opened and closed is set in the memory of the microcomputer 63. The first limit value may be different for relays 21 and 22 and for relays 23 and 24.

[0048] When the number of times that relays 21 and 22 are opened and closed is equal to or less than a first limit value, microcomputer 63 opens and closes relays 21 and 22 in response to the transmission signal. When the number of times that relays 21 and 22 are opened and closed exceeds the first limit value, microcomputer 63 switches the relays that are opened and closed in response to the transmission signal from relays 21 and 22 to spare relays 121 and 122.

[0049] Generally, relay failure in terminal units is caused by contact welding. When the contacts are welded, they remain conductive. In a double-pole terminal unit, even if the relay on one end fails, as long as the relay on the other end is operating normally, the lighting fixture connected to the terminal unit will turn on and off normally. This means that users may not notice the relay failure and continue to use the faulty relay. Also, in the case of a single-pole terminal unit, if the relay fails, the lighting fixture will remain on rather than turn off. This means that it is expected that the relay will continue to be used. Continued use of a faulty relay may further deteriorate the relay contacts, causing the relay contacts to continue to overheat.

[0050] In contrast, in this embodiment, when the number of relay opening and closing times exceeds the first limit value, the relay that opens and closes is switched to the spare relay. This makes it possible to prevent relays 21, 22, 41, and 42 from failing due to deterioration caused by contact damage, etc. In other words, the relay can be switched to the spare relay before a failure occurs, thereby improving reliability. Furthermore, this embodiment makes it possible to avoid malfunctions in the on / off operation of the lighting fixtures due to relay failure, and also avoids the need to replace terminals 83 and 84 when they fail.

[0051] Also, in the present embodiment, even when using an inexpensive relay without using an expensive relay with arc countermeasures, problems due to relay failure can be avoided. Therefore, an inexpensive and highly reliable lighting control system can be obtained.

[0052] A predetermined second limit value may be set in the memory of the microcomputer 63. When the number of opening and closing operations of the standby relay 141 exceeds the predetermined second limit value, the microcomputer 63 may not open and close the relay 41 and the standby relay 141 even when receiving a transmission signal. Further, the microcomputer 63 may notify the outside through the LED 62 that the number of opening and closing operations of the standby relay 141 has exceeded the second limit value.

[0053] Thereby, it is possible to stop the relay control before the failure of the standby relay 141 and suppress the terminal devices 83 and 84 from operating in a defective state. Also, it is possible to prompt the user to replace the product. Here, the standby relay 141 has been described, but a second limit value may be set for the standby relays 142, 121, and 122. The first limit value and the second limit value are set in accordance with the ratings of the relay and the standby relays, for example.

[0054] Also, when the illuminance sensor 86 detects that the lighting fixture 85 is in the lit state while the microcomputer 63 controls the relay 41 to cut off the power supply to the lighting fixture 85, the relay that is opened and closed according to the transmission signal may be switched from the relay 41 to the standby relay 141. Here, the relay 41 has been described, but the same control may be performed for the relays 42, 21, and 22. According to such control, it is possible to detect a failure of the relay and switch the relay.

[0055] Similarly, when illuminance sensor 86 detects that lighting fixture 85 is on while microcomputer 63 controls standby relay 141 to cut off power supply to lighting fixture 85, microcomputer 63 may stop opening and closing standby relay 141. In other words, even when microcomputer 63 receives a transmission signal, it may not open or close relay 41 and standby relay 141. While the description has been given here of standby relay 141, similar control may be performed on standby relays 142, 121, and 122.

[0056] In this embodiment, the terminals 83 and 84 have relays. In other words, the terminals and relays are integrated. However, this is not limiting, and the terminals and relays may be provided separately. Furthermore, the power source 10 is not limited to an AC power source, and may be a DC power source.

[0057] The relay and standby relay of this embodiment may be latching relays. A latching relay closes its contacts when a voltage is applied to the set coil. A latching relay maintains the closed state of its contacts even when the voltage application to the set coil is removed. Furthermore, the contacts open when a voltage is applied to the set coil in the reverse direction, i.e., when a voltage is applied to the reset coil.

[0058] The technical features described in this embodiment may be used in appropriate combination. [Explanation of symbols]

[0059] 4a Light, 4b Floor reflected light, 8 Communication line, 10 Power supply, 10a First wiring, 10b Second wiring, 11, 12, 13, 14, 15, 17 Load, 21-24 Relay, 31-38 Terminal, 41-44 Relay, 51-58 Terminal, 60 Communication power supply circuit, 61 DC / DC circuit, 63 Microcomputer, 64-67 Drive circuit, 71 Upper case, 72 Lower case, 73 Upper surface, 74 Operation panel, 75a, 75b Terminal fitting, 76 Protective cover, 77 Address setting unit, 81 Management device, 82 Lighting controller, 83, 84 Terminal device, 85 Lighting fixture, 86 Illuminance sensor, 100 Lighting control system, 121, 122 Spare relay, 141, 142 Spare relay, 200 Lighting control system, 90 Management PC

Claims

1. A first relay connected between a lighting fixture as a load and a power supply, and switching the presence or absence of power supply from the power supply to the lighting fixture by opening and closing; A second relay connected between the lighting fixture and the power supply, and switching the presence or absence of power supply from the power supply to the lighting fixture by opening and closing; A controller; A control circuit for controlling the first relay and the second relay according to a transmission signal from the controller; An illuminance sensor; Comprising; When the number of opening and closing operations of the first relay is equal to or less than a predetermined first limit value, the control circuit opens and closes the first relay according to the transmission signal. When the number of opening and closing operations of the first relay exceeds the first limit value, the relay that is opened and closed according to the transmission signal is switched from the first relay to the second relay. Further, when the illuminance sensor detects that the lighting fixture is in a lit state while the first relay is controlled to cut off the power supply to the lighting fixture, the relay that is opened and closed according to the transmission signal is switched from the first relay to the second relay. A control system characterized by this.

2. The lighting fixture is connected to a first terminal of the power supply by a first wiring and to a second terminal of the power supply by a second wiring, The control system according to claim 1, wherein both the first relay and the second relay are provided on the first wiring.

3. The control system according to claim 1 or 2, wherein when the number of opening and closing operations of the second relay exceeds a predetermined second limit value, the control circuit does not open and close the second relay even when receiving the transmission signal.

4. Comprising a display unit, The control system according to any one of claims 1 to 3, wherein the control circuit externally notifies the display unit that the number of opening and closing operations of the first relay has exceeded the first limit value.

5. Comprising a display unit, The control system according to any one of claims 1 to 3, wherein the control circuit externally notifies the display unit that the number of opening and closing operations of the second relay has exceeded a predetermined second limit value.

6. A first relay connected between a lighting fixture as a load and a power supply, and switching the presence or absence of power supply from the power supply to the lighting fixture by opening and closing; A second relay connected between the lighting fixture and the power supply, and switching the presence or absence of power supply from the power supply to the lighting fixture by opening and closing; When the number of opening and closing operations of the first relay is equal to or less than a predetermined first limit value, the first relay is opened and closed according to a transmission signal from a controller. When the number of opening and closing operations of the first relay exceeds the first limit value, the relay that is opened and closed according to the transmission signal is switched from the first relay to the second relay. Further, when an illuminance sensor detects that the lighting fixture is in a lit state while the first relay is controlled to cut off power supply to the lighting fixture, a control circuit that switches the relay that is opened and closed according to the transmission signal from the first relay to the second relay. A terminal device characterized by comprising the above.

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