Terminal box, connection control method and fire alarm system

Abstract

The application provides a terminal box, a connection control method and a fire alarm system. The terminal box comprises a first interface, a second interface, a detection interface, a first circuit adapted to match a temperature sensing cable connected in a first direction, a second circuit adapted to match a temperature sensing cable connected in a second direction, and a control unit; the first interface is connected with an information transceiving port and a power port of the control unit, the second interface is grounded, and the first circuit and the second circuit are connected with the detection interface and the control unit respectively; the first interface is used for connecting a first bus of the temperature sensing cable, the second interface is used for connecting a second bus of the temperature sensing cable, and the detection interface is used for connecting a temperature sensing wire of the temperature sensing cable; and the control unit is used for detecting the connection direction of the temperature sensing cable through the first circuit and the second circuit, and adjusting the on-off of the first circuit and the second circuit based on the connection direction of the temperature sensing cable. The application does not need manual identification of the connection direction of the temperature sensing cable during construction.

Description

Technical Field

[0001] This invention relates to the field of temperature-sensing cable technology, and in particular to a terminal box, a connection control method, and a fire alarm system. Background Technology

[0002] Temperature sensing cable equipment typically consists of a temperature sensing cable, a signal processing unit, and a terminal box. Because the temperature sensing cable contains embedded point-type temperature sensing units, adjacent units are electrically interconnected. Therefore, during on-site installation, a terminal box needs to be installed at the very end to ensure the complete functionality of the temperature sensing unit at the end. The terminal box enables electrical interconnection with the end-of-line temperature sensing unit, helping it achieve complete detection and fault detection functions. Furthermore, its structure must possess a certain level of protection to safeguard the cable end and its own circuitry.

[0003] The temperature sensing cable based on the embedded distributed temperature sensing unit is directional. Traditional terminal boxes can only be connected to one of the two ends of the temperature sensing cable, which requires careful identification of the direction of the temperature sensing cable during on-site construction, causing some inconvenience and difficulty to the construction. Summary of the Invention

[0004] This invention provides a terminal box, a connection control method, and a fire alarm system to solve the problem of identifying the cable direction when connecting a temperature sensing cable to the terminal box.

[0005] In a first aspect, embodiments of the present invention provide a terminal box, comprising:

[0006] The system comprises a first interface, a second interface, a detection interface, a first circuit adapted to match a temperature sensing cable connected in a first direction, a second circuit adapted to match a temperature sensing cable connected in a second direction, and a control unit; the first interface is connected to the information transceiver port and the power supply port of the control unit, the second interface is grounded, and the first circuit and the second circuit are respectively connected to the detection interface and the control unit.

[0007] The first interface is used to connect the first bus of the temperature sensing cable, the second interface is used to connect the second bus of the temperature sensing cable, and the detection interface is used to connect the temperature sensing wire of the temperature sensing cable.

[0008] The control unit is used to detect the connection direction of the temperature sensing cable through the first circuit and the second circuit, and adjust the on / off state of the first circuit and the second circuit based on the connection direction of the temperature sensing cable.

[0009] Secondly, embodiments of the present invention provide a connection control method, including:

[0010] The control unit acquires a first electrical signal through a first circuit and a second electrical signal through a second circuit; wherein the first electrical signal is acquired when the first circuit is turned on and the second circuit is turned off, and the second electrical signal is acquired when the first circuit is turned off and the second circuit is turned on.

[0011] The control unit determines the connection direction of the temperature sensing cable based on the amplitude of the first and second electrical signals;

[0012] The control unit connects the first circuit or the second circuit based on the connection direction of the temperature sensing cable.

[0013] Thirdly, embodiments of the present invention provide a fire alarm system, including a signal processing unit, a temperature sensing cable, and a terminal box as described in the first aspect or any implementation thereof; the temperature sensing cable is connected between the signal processing unit and the terminal box along a first direction or the opposite second direction, the first bus of the temperature sensing cable is connected to the first interface of the terminal box, the second bus is connected to the second interface of the terminal box, and the temperature sensing cable is connected to the detection interface of the terminal box.

[0014] The signal processing unit is used to issue a fault indication indicating a short circuit in the first bus or the second bus when the terminal box cannot be found, and to issue a fault indication indicating a short circuit in the first bus and the second bus when an overcurrent signal is detected.

[0015] This invention provides a terminal box, a connection control method, and a fire alarm system. The terminal box is equipped with a first circuit for matching a temperature-sensing cable connected in a first direction and a second circuit for matching a temperature-sensing cable connected in a second direction. During construction, the terminal box can be directly connected to the temperature-sensing cable through the first interface, the second interface, and the detection interface, without the need for manual identification of the connection direction of the temperature-sensing cable. After connection, the control terminal detects the connection direction of the temperature-sensing cable based on the first and second circuits and automatically selects to activate either the first or second circuit. Regardless of whether the connection direction of the temperature-sensing cable is the first or second direction, electrical interconnection with the temperature-sensing unit can be achieved. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a schematic diagram of the structure of a temperature-sensing cable provided in an embodiment of the present invention;

[0018] Figure 2 This is a schematic diagram showing the connection relationship between two temperature sensing units provided in an embodiment of the present invention;

[0019] Figure 3 This is a schematic diagram of the structure of a terminal box provided in an embodiment of the present invention;

[0020] Figure 4 This is a schematic diagram of the circuit structure of a terminal box provided in an embodiment of the present invention;

[0021] Figure 5 This is a schematic diagram of the connection relationship between the temperature sensing cable connected along the first direction and the terminal box according to an embodiment of the present invention;

[0022] Figure 6 This is a schematic diagram of the connection relationship between the temperature sensing cable connected along the second direction and the terminal box according to an embodiment of the present invention;

[0023] Figure 7 This is a schematic diagram of the connection relationship between the temperature sensing cable and the terminal box when the temperature sensing line is broken, according to an embodiment of the present invention.

[0024] Figure 8 This is a schematic diagram of the connection relationship between a temperature sensing cable with its sensing wire short-circuited to the first bus and a terminal box, provided in an embodiment of the present invention.

[0025] Figure 9 This is a schematic diagram of the connection relationship between a temperature sensing cable with its sensing wire short-circuited to the second bus and a terminal box, provided in an embodiment of the present invention.

[0026] Figure 10 This is a flowchart illustrating the implementation of a connection control method according to an embodiment of the present invention;

[0027] Figure 11 This is a schematic diagram of the structure of a fire alarm system provided in an embodiment of the present invention. Detailed Implementation

[0028] To enable those skilled in the art to better understand this solution, the technical solutions in the embodiments of this solution will be clearly described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this solution, not all of them. Based on the embodiments of this solution, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of this solution.

[0029] The term "comprising" and any other variations thereof in the specification, claims, and accompanying drawings of this invention mean "including but not limited to," and are intended to cover a non-exclusive inclusion, not limited to the examples listed herein. Furthermore, the terms "first" and "second," etc., are used to distinguish different objects, not to describe a specific order.

[0030] The implementation of the present invention will be described in detail below with reference to the accompanying drawings:

[0031] Figure 1 This is a schematic diagram of a temperature-sensing cable provided in an embodiment of the present invention. (Refer to...) Figure 1 The temperature-sensing cable 100 may include a first bus 110, a second bus 120, temperature-sensing units 130, and temperature-sensing lines 140. The first bus 110 and the second bus 120 extend approximately parallel to each other. Multiple temperature-sensing units 130 may be configured, and these units are evenly spaced along the length of the temperature-sensing cable 100. Adjacent temperature-sensing units 130 are connected via temperature-sensing lines 140. Each temperature-sensing unit 130 is addressable, with each unit corresponding to a unique address. Each temperature-sensing unit 130 is connected to the first bus 110 and the second bus 120, which provide power and serve as signal transmission carriers. When a fire occurs at a location, the electrical parameters of the temperature-sensing line 140 at that location change, such as a change in resistance. The temperature-sensing units 130 connected to that section of the temperature-sensing line 140 can identify the fire event based on the resistance change and report the fire event via the first bus 110 and / or the second bus 120.

[0032] Figure 2 It shows Figure 1 A schematic diagram showing the electrical connection between two adjacent temperature sensing units 130A and 130B. (See diagram below.) Figure 2 As shown, the temperature sensing wire 140 is connected between two temperature sensing units 130A and 130B. Temperature sensing unit 130A provides a power supply circuit 150 for the temperature sensing wire 140, and the other temperature sensing unit 130B provides a grounding circuit 160. The power supply circuit 150 and the grounding circuit 160 are connected through the temperature sensing wire 140. Specifically, the power supply circuit 150 may include a second power supply 151, a fifth resistor R5, and a sixth resistor R6 connected in series. The grounding circuit 160 may include a grounded seventh resistor R7. The temperature sensing wire 140 is connected between the sixth resistor R6 and the seventh resistor R7. The temperature sensing unit 130 performs AD sampling on the voltage division on the power supply circuit 150 (between the fifth resistor R5 and the sixth resistor R6) to determine the fire situation on the temperature sensing wire 140. For example, when a fire occurs, the resistance of the temperature sensing wire 140 changes, so the voltage division obtained by AD sampling will also change.

[0033] During construction, the temperature sensing unit 130 at the end of the temperature sensing cable 100 may provide a power circuit 150 or a grounding circuit 160. The temperature sensing cable 100 can be connected in a first direction or the opposite second direction. When the temperature sensing cable 100 is connected in the first direction, the temperature sensing unit 130 at the end of the temperature sensing cable 100 provides a grounding circuit 160; when the temperature sensing cable 100 is connected in the second direction, the temperature sensing unit 130 at the end of the temperature sensing cable 100 provides a power circuit 150. Traditional terminal boxes 200 can only be connected to one designated end of the temperature sensing cable 100, which requires careful identification of the connection direction of the temperature sensing cable 100 during on-site construction, causing inconvenience and difficulty for workers, making it challenging to ensure this requirement is met.

[0034] It is important to note that, in Figure 2 The diagram shows that temperature sensing unit 130A provides a power supply circuit 150 and temperature sensing unit 130B provides a grounding circuit 160. However, in practice, each temperature sensing unit provides both a power supply circuit and a grounding circuit. For example, temperature sensing unit 130A also has a seventh resistor R7 to provide a grounding circuit to the temperature sensing unit (not shown) to its left; temperature sensing unit 130B also has a second power supply 151, a fifth resistor R5, and a sixth resistor R6 to provide a power supply circuit to the temperature sensing wire (not shown) to its right. However, in practice, the connection direction of the temperature sensing cable 100 is often unidentifiable, i.e., the temperature sensing unit at the end of the temperature sensing cable cannot be identified. Figure 2 The temperature sensing unit 130A or temperature sensing unit 130B in the traditional terminal box 200 can only be matched with one of them.

[0035] Figure 3 A schematic diagram of a terminal box 200 according to an embodiment of the present invention is shown below, in conjunction with... Figure 3 Provide a detailed description.

[0036] like Figure 3 As shown, the terminal box 200 includes a first interface 210, a second interface 220, a detection interface 230, a first circuit 260 adapted to match a temperature sensing cable connected in a first direction, a second circuit 270 adapted to match a temperature sensing cable connected in a second direction, and a control unit 250. The first circuit 260 and the second circuit 270 constitute a connection switching circuit 240. The first interface 210 is connected to the information transceiver port and the power port of the control unit 250, the second interface 220 is grounded, and the first circuit 260 and the second circuit 270 are respectively connected to the detection interface 230 and the control unit 250.

[0037] The first interface 210 is used to connect the first bus of the temperature sensing cable, the second interface 220 is used to connect the second bus of the temperature sensing cable, and the detection interface 230 is used to connect the temperature sensing wire of the temperature sensing cable.

[0038] The control unit 250 is used to detect the connection direction of the temperature sensing cable through the first circuit 260 and the second circuit 270, and adjust the on / off state of the first circuit 260 and the second circuit 270 based on the connection direction of the temperature sensing cable.

[0039] In this embodiment, the first circuit 260 is adapted to match the temperature sensing cable 100 connected along the first direction (i.e., the temperature sensing unit at the end of the temperature sensing cable is...). Figure 2 The temperature sensing unit 130A in the middle), and the second circuit 270 are adapted to match the temperature sensing cable 100 connected along the second direction (i.e., the temperature sensing unit at the end of the temperature sensing cable is...). Figure 2 The temperature sensing unit 130B, the first circuit 260, and the second circuit 270 are both configured to be switched on and off. For example... Figure 3 As shown, the second interface 220 is grounded, and the first interface 210 is connected to the information transceiver port (TX / RX) and the power supply port (HV) of the control unit 250, respectively. + When the terminal box 200 is connected to the temperature sensing cable, the first and second buses of the temperature sensing cable supply power to the control unit 250 and serve as carriers for information transmission.

[0040] The control unit 250 can be a microcontroller unit (MCU). The control unit 250 is coupled to the first circuit 260 and the second circuit 270 respectively. The control unit 250 is configured to control the connection and disconnection of the first circuit 260 and the second circuit 270. The control unit 250 is configured to determine the connection direction of the temperature-sensing cable based on the output of the first circuit 260 and / or the second circuit 270, and select to connect either the first circuit 260 or the second circuit 270 according to the determined connection direction, so that the first circuit 260 or the second circuit 270 completes electrical cross-linking (electrical connection) with the temperature-sensing unit at the end of the temperature-sensing cable, thereby enabling the temperature-sensing unit at the end of the temperature-sensing cable to perform the corresponding function. The terminal box 200 of this invention can be used at both ends of the temperature-sensing cable. During construction, workers do not need to identify the arrangement direction of the temperature-sensing cable; the terminal box 200 can be directly connected to the end of the temperature-sensing cable.

[0041] As can be seen from the above, the terminal box provided in this embodiment of the invention can be used at both ends of the temperature-sensing cable. During construction, workers do not need to identify the arrangement direction of the temperature-sensing cable; they can simply connect the terminal box to the end of the temperature-sensing cable. Specifically, after the terminal box is connected to the temperature-sensing cable, the terminal box can choose to connect to either the first circuit 260 or the second circuit 270 to achieve electrical interconnection with the temperature-sensing unit at the end of the temperature-sensing cable, thereby helping the temperature-sensing unit to perform fire detection and fault detection functions.

[0042] In one possible implementation, such as Figure 4As shown, the first circuit 260 includes a first power supply 261, a first resistor R1, a first switch 263, and a second resistor R2 connected in series. The control unit 250 obtains the output of the first circuit 260 through the detection point 265 on the second resistor R2. The second resistor R2 is connected to the detection interface 230, and the control terminal of the first switch 263 is connected to the control unit 250.

[0043] The control unit 250 is used to control the on / off state of the first circuit 260 via the first switch 263.

[0044] In this embodiment, the opening and closing of the first switch 263 is controlled by the control unit 250. When the first switch 263 is turned on, the first circuit 260 is turned on, and when the first switch 263 is turned off, the first circuit 260 is turned off.

[0045] In one possible implementation, Figure 4 The specific structure of the second circuit 270 is also shown. The second circuit 270 includes a third resistor R3 connected in series between the detection interface 230 and ground, and a second switch 272;

[0046] The control unit 250 is used to control the on / off state of the second circuit 270 via the second switch 272.

[0047] In this embodiment, the connection and disconnection of the second switch 272 are controlled by the control unit 250. When the second switch 272 is connected, the second circuit 270 is connected; when the second switch 272 is disconnected, the second circuit 270 is disconnected.

[0048] The first power supply 261 is generated by the low dropout linear regulator (LDO) inside the control unit 250 (MCU). The voltage of the first power supply 261 is the same as that of the second power supply 151 (both are VCC). The resistance value of the first resistor R1 is the same as that of the fifth resistor R5, the resistance value of the second resistor R2 is the same as that of the sixth resistor R6, and the resistance value of the third resistor R3 is the same as that of the seventh resistor R7.

[0049] In one possible implementation, the control unit 250 is specifically used to acquire a first electrical signal through the first circuit 260, acquire a second electrical signal through the second circuit 270, and determine the connection direction of the temperature sensing cable based on the amplitude of the first and second electrical signals.

[0050] The first electrical signal corresponds to the state where the first circuit 260 is on and the second circuit 270 is off, and the second electrical signal corresponds to the state where the first circuit 260 is off and the second circuit 270 is on.

[0051] In this embodiment, a detection point 265 is provided on the first circuit 260, and the detection point 265 is located between the first switch 263 and the second resistor R2. The control unit 250 is connected to the detection point 265 and can collect the electrical signal of the detection point 265, for example... Figure 3 In this circuit, the AD pin of the control unit 250 is connected to the detection point 265 to acquire the voltage at the detection point 265 and convert it into an AD value (digital quantity). Specifically, when the first switch 263 is turned on, the control unit 250 acquires the first electrical signal U1 (i.e., the output of the first circuit 260) of the detection point 265, and when the second switch 272 is turned on, it acquires the second electrical signal U2 (i.e., the output of the second circuit 270) of the detection point 265. The control unit 250 can determine the connection direction of the temperature sensing cable 100 based on the first electrical signal U1 and the second electrical signal U2, and select to turn on the first circuit 260 or the second circuit 270 based on the determined direction of the temperature sensing cable 100. The control unit 250 can also determine whether there is a fault on the temperature sensing cable 100 and the type of fault based on the first electrical signal U1 and the second electrical signal U2, and output a corresponding fault signal when a fault is determined to exist on the temperature sensing cable 100.

[0052] The connection and disconnection of the first circuit 260 and the second circuit 270 can be set to be mutually exclusive. When the first circuit 260 is on, the second circuit 270 is off; when the second circuit 270 is on, the first circuit 260 is off. The control unit 250 can be configured to connect the first circuit 260 and / or the second circuit 270 respectively, and accordingly acquire the output of the first circuit 260 and the output of the second circuit 270. When it is necessary to connect the first circuit 260 and the second circuit 270 respectively, the first circuit 260 can be connected first, the second circuit 270 can be disconnected, and then the second circuit 270 can be connected and the first circuit 260 can be disconnected; alternatively, the second circuit 270 can be connected first, the first circuit 260 can be disconnected, and then the first circuit 260 can be connected and the second circuit 270 can be disconnected. The specific connection sequence can be set as needed, and the present invention is not limited thereto. When the first circuit 260 is turned on, the first circuit 260 and the temperature sensing unit (temperature sensing wire) at the end of the temperature sensing cable are electrically interconnected, and the control unit 250 can obtain the output of the first circuit 260; when the second circuit 270 is turned on, the second circuit 270 and the temperature sensing unit at the end of the temperature sensing cable are electrically interconnected, and the control unit 250 can obtain the output of the second circuit 270.

[0053] Figure 5 A schematic diagram showing the connection between the temperature sensing cable 100 connected along the first direction and the terminal box 200 is shown, as follows. Figure 5As shown, when the terminal box 200 is connected to the end of the temperature sensing cable 100 connected in the first direction, the control unit 250 sequentially turns on the first circuit 260 (first switch 263) and the second circuit 270 (second switch 272), and accordingly acquires the first electrical signal U1 and the second electrical signal U2, where U1=VCC*(R7+R2+RT) / (R7+R1+R2+RT), U2=0, and RT is the resistance value of the temperature sensing cable 140.

[0054] Figure 6 A schematic diagram showing the connection between the temperature sensing cable 100 connected along the second direction and the terminal box 200 is shown, as follows. Figure 6 As shown, when the terminal box 200 is connected to the end of the temperature sensing cable 100 connected in the second direction, the control unit 250 sequentially turns on the first circuit 260 (first switch 263) and the second circuit 270 (second switch 272), and accordingly acquires the first electrical signal U1 and the second electrical signal U2, where U1=VCC, U2=VCC*R3 / (R5+R6+R3+RT).

[0055] Therefore, when the temperature sensing cable 100 is connected along the first direction and along the second direction, the first electrical signal U1 and the second electrical signal U2 will have different theoretical sampling values ​​in the two cases. The connection direction of the temperature sensing cable can be determined based on the theoretical sampling value and the actual sampling value. Specifically, the control unit 250 can be configured to: determine that the temperature sensing cable 100 is connected along the first direction and select to turn on the first circuit 260 when the first electrical signal U1 is close to the first threshold and the second electrical signal U2 is close to zero; and determine that the temperature sensing cable 100 is connected along the second direction and select to turn on the second circuit 270 when the first electrical signal U1 is close to the parameter (voltage) of the first power supply 261 and the second electrical signal U2 is close to the second threshold. The first threshold can be: VCC*(R7+R2+RT) / (R7+R1+R2+RT), and the second threshold can be: VCC*R3 / (R5+R6+R3+RT). When the difference between the first electrical signal U1 (or the second electrical signal U2) and the AD value of a certain value is no more than 10 bits (in other embodiments, it can also be no more than 20 bits, 15 bits, 5 bits, 3 bits, etc.), then the first electrical signal U1 (or the second electrical signal U2) is considered to be close to that value. For example, if the difference between the first electrical signal U1 and the AD value of the first threshold is no more than 10 bits, then the first electrical signal U1 is considered to be close to the first threshold. If the difference between the second electrical signal U2 and the AD value of the second threshold is no more than 10 bits, then the second electrical signal U2 is considered to be close to the second threshold. This will not be elaborated further.

[0056] Therefore, by using the terminal box 200 of the present invention, when the temperature sensing cable 100 is laid out on site, there is no need to consider its connection direction. The terminal box 200 can be directly connected to the end of the temperature sensing cable 100. The terminal box 200 can automatically detect the connection direction of the temperature sensing cable 100 and select an appropriate circuit for matching.

[0057] In one possible implementation, such as Figure 3 As shown, it also includes an alarm unit 280, which is connected to the control unit 250;

[0058] The control unit 250 is also used to issue an alarm via the alarm unit 280 when there is an open circuit or short circuit in the temperature sensing cable.

[0059] In this embodiment, the control unit 250 is configured to receive a fire alarm signal and control the alarm unit 280 to issue an alarm based on the fire alarm signal. The alarm unit 280 can issue an alarm in the form of sound, light, vibration, or a combination thereof. When a fire occurs in the detection area of ​​the heat-sensing cable 100, the signal processing unit issues a fire alarm signal, and the control unit 250 issues an alarm based on the fire alarm signal, assisting firefighters in identifying the alarm cable and quickly locating the fire.

[0060] like Figure 4 As shown, the alarm unit 280 may include a light-emitting element 281 and a fourth resistor 282. The light-emitting element 281 may be, for example, a light-emitting diode (LED). One end of the light-emitting element 281 is connected to the control unit 250, and the other end is grounded through the fourth resistor 282. When the control unit 250 receives a fire alarm signal, the control unit 250 supplies power to the light-emitting unit, thereby illuminating the light-emitting unit (it may flash or remain constantly lit) to assist firefighters in identifying the alarm cable.

[0061] According to one embodiment of the present invention, such as Figure 4 As shown, the alarm unit 280 may specifically include a buzzer 283 and a transistor 284. The transistor 284 may be, for example, an NPN transistor. The buzzer 283 is connected between the collector of the transistor and the first interface 210. The base of the transistor 284 is connected to the control unit 250, and the emitter of the transistor 284 is grounded. When the control unit 250 receives a fire alarm signal, it controls the collector and emitter of the transistor 284 to connect, powering the first bus of the temperature sensing cable to the buzzer 283, causing the buzzer 283 to sound to assist firefighters in identifying the alarm cable.

[0062] The control unit 250 can also be configured to output a fault signal based on the output of the first circuit 260 and / or the second circuit 270. Specifically, the control unit 250 can determine whether a fault exists on the temperature sensing cable and the type of fault based on the output of the first circuit 260 and / or the second circuit 270. The fault type can be a short circuit between the first bus and the temperature sensing cable, a short circuit between the second bus and the temperature sensing cable, an open circuit in the temperature sensing cable, etc., and outputs a corresponding fault signal when a fault is determined to exist on the temperature sensing cable. The fault signal can include, for example, one or more of the following: a short circuit signal between the first bus and the temperature sensing cable, a short circuit signal between the second bus and the temperature sensing cable, and an open circuit signal in the temperature sensing cable. With the above settings, the terminal box 200 can perform fault diagnosis on the temperature sensing cable, which helps to avoid connecting a faulty temperature sensing cable to the fire alarm system.

[0063] Figure 7 This diagram illustrates the connection between the temperature sensing cable 100 (with a broken temperature sensing wire 140) and the terminal box 200. Figure 7 As shown, when the terminal box 200 is connected to the end of the temperature sensing cable 100, the control unit 250 sequentially connects the first circuit 260 (first switch 263) and the second circuit 270 (second switch 272), and accordingly acquires the first electrical signal U1 and the second electrical signal U2. When the temperature sensing wire 140 at the end of the temperature sensing cable 100 is open-circuited, U1=VCC and U2=0. The control unit 250 can be configured to determine that the temperature sensing wire 140 is open-circuited and output a temperature sensing wire open-circuit signal when the first electrical signal U1 is close to the parameter (voltage) of the first power supply 261 and the second electrical signal is close to zero.

[0064] Figure 8 A schematic diagram showing the connection between the temperature sensing cable 100 (with the temperature sensing wire 140 short-circuited to the first bus 110) and the terminal box 200 is shown. Figure 8 As shown, when the terminal box 200 is connected to the end of the temperature sensing cable 100, the control unit 250 sequentially connects the first circuit 260 (first switch 263) and the second circuit 270 (second switch 272), and accordingly acquires the first electrical signal U1 and the second electrical signal U2. When the temperature sensing cable 140 is short-circuited with the first bus 110, since the voltage on the first bus 110 is much greater than the voltage of the first power supply 261, and the resistance value of the second resistor R2 is large, and the ESD circuit inside the AD pin of the control unit 250 clamps the voltage at the detection point 265 to VCC, U1=VCC and U2=VCC. Based on this, the control unit 250 can be configured to: when both the first electrical signal U1 and the second electrical signal U2 are close to the parameters (voltage) of the first power supply 261, determine that the first bus 110 is short-circuited with the temperature sensing cable 140, and output a short-circuit signal between the first bus and the temperature sensing cable.

[0065] Figure 9A schematic diagram showing the connection between the temperature sensing cable 100 (with the temperature sensing wire 140 short-circuited to the second bus 120) and the terminal box 200 is shown, as follows. Figure 9 As shown, when the terminal box 200 is connected to the end of the temperature sensing cable 100, the control unit 250 sequentially connects the first circuit 260 (first switch 263) and the second circuit 270 (second switch 272), and accordingly acquires the first electrical signal U1 and the second electrical signal U2, where U1 = VCC * (R2 + RT) / (R1 + R2 + R3), and U2 = 0. Based on this, the control unit 250 can be configured to: when the first electrical signal U1 is close to the third threshold and the second electrical signal is close to zero, determine that the second bus 120 is short-circuited with the temperature sensing line 140, and output a short-circuit signal between the second bus and the temperature sensing line.

[0066] like Figure 5 As shown, the control unit 250 can be configured to output a fault signal or a fire alarm signal based on changes in the output of the first circuit 260 after selecting to activate the first circuit 260. Specifically, when the control unit 250 detects that the first electrical signal U1 suddenly increases to near the output voltage (e.g., VCC) of the first power supply 261, the control unit 250 outputs a short-circuit signal between the temperature sensing wire 140 and the first bus 110 and the temperature sensing wire 140; when the control unit 250 detects that the first electrical signal U1 suddenly decreases and approaches the fourth threshold (the fourth threshold is, for example, VCC*R2 / (R1+R2)), the control unit 250 outputs a short-circuit signal between the second bus 120 and the temperature sensing wire 140. When a fire occurs near the temperature sensing wire 140, the resistance value of the temperature sensing wire 140 changes due to temperature, which in turn causes a voltage change at the detection point 265. The control unit 250 detects the change in the first electrical signal U1 and outputs a fire alarm signal. With the above settings, the terminal box 200 can help the temperature sensing unit 130 at the end of the temperature sensing cable 100 to realize fire detection and fault detection functions.

[0067] The above embodiment describes the detection at detection point 265 as an example. However, the present invention is not limited to this. For example, a first detection point can be set in the first circuit 260 and a second detection point can be set in the second circuit 270. When the first circuit 260 and the second circuit 270 are connected, the electrical signals (first electrical signal U1 and second electrical signal U2) at the location can be detected to determine the connection direction of the temperature sensing cable and the fault condition.

[0068] like Figure 6 As shown, the control unit 250 can be configured to stop detecting the output of the second circuit 270 after selecting to turn on the second circuit 270, that is, to turn off the AD sampling function to prevent leakage.

[0069] See Figure 10The flowchart illustrating the implementation of the connection control method provided in this embodiment of the invention is described in detail below:

[0070] Step 301: The control unit acquires a first electrical signal through a first circuit and a second electrical signal through a second circuit; wherein the first electrical signal is acquired when the first circuit is turned on and the second circuit is turned off, and the second electrical signal is acquired when the first circuit is turned off and the second circuit is turned on.

[0071] Step 302: The control unit determines the connection direction of the temperature sensing cable based on the amplitude of the first electrical signal and the second electrical signal.

[0072] Step 303: The control unit connects the first circuit or the second circuit based on the connection direction of the temperature sensing cable.

[0073] In one possible implementation, the control unit determines the connection direction of the temperature sensing cable based on the amplitudes of the first and second electrical signals, including:

[0074] When the difference between the first electrical signal and the first threshold is within a preset range, and the second electrical signal is within a preset range, the control unit determines that the temperature sensing cable is connected along the first direction.

[0075] In one possible implementation, the control unit determines the connection direction of the temperature sensing cable based on the amplitudes of the first and second electrical signals, including:

[0076] When the difference between the voltage of the first electrical signal and the voltage of the first power supply is within a preset range, and the difference between the second electrical signal and the second threshold is within a preset range, the control unit determines that the temperature sensing cable is connected along the second direction.

[0077] One possible implementation also includes:

[0078] When the difference between the voltage of the first electrical signal and the voltage of the first power supply is within a preset range, and the difference between the second electrical signal and zero is within a preset range, the control unit determines that the temperature sensing wire of the temperature sensing cable is open-circuited.

[0079] When the difference between the voltage of the first electrical signal and the second electrical signal and the voltage of the first power supply are both within a preset range, the control unit determines that the first bus of the temperature sensing cable is short-circuited with the temperature sensing wire.

[0080] When the difference between the first electrical signal and the third threshold is within a preset range, and the difference between the second electrical signal and zero is within a preset range, the control unit determines that the second bus of the temperature sensing cable is short-circuited with the temperature sensing cable.

[0081] Figure 11 A fire alarm system 300 according to an embodiment of the present invention is shown below, in conjunction with... Figure 11 Please provide a detailed explanation.

[0082] like Figure 11 As shown, the fire alarm system 300 includes a signal processing unit 310, a temperature sensing cable 100, and a terminal box 200. The temperature sensing cable 100 is connected between the signal processing unit 310 and the terminal box 200 in a first direction or a second direction opposite to it. The first bus 110 of the temperature sensing cable 100 is connected to the first interface 210 of the terminal box 200, the second bus 120 is connected to the second interface 220 of the terminal box 200, and the temperature sensing wire 140 at the end of the temperature sensing cable 100 is connected to the detection interface of the terminal box 200.

[0083] The signal processing unit 310 is used to issue a fault prompt indicating a short circuit in the first bus 110 or the second bus 120 when the terminal box 200 cannot be found, and to issue a fault prompt indicating a short circuit in the first bus 110 and the second bus 120 when an overcurrent signal is detected.

[0084] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A terminal box, characterized in that, The device includes a first interface, a second interface, a detection interface, a first circuit adapted to match a temperature sensing cable connected in a first direction, a second circuit adapted to match a temperature sensing cable connected in a second direction, and a control unit; the first interface is connected to the information transceiver port and the power supply port of the control unit, the second interface is grounded, and the first circuit and the second circuit are respectively connected to the detection interface and the control unit. The first interface is used to connect to the first bus of the temperature sensing cable, the second interface is used to connect to the second bus of the temperature sensing cable, and the detection interface is used to connect to the temperature sensing wire of the temperature sensing cable. The control unit is used to detect the connection direction of the temperature sensing cable through the first circuit and the second circuit, and adjust the on / off state of the first circuit and the second circuit based on the connection direction of the temperature sensing cable.

2. The terminal box as described in claim 1, characterized in that, The first circuit includes a first power supply, a first resistor, a first switch, and a second resistor connected in series. The second resistor is connected to the detection interface, and the control terminal of the first switch is connected to the control unit. The control unit is used to control the on / off state of the first circuit via the first switch.

3. The terminal box as described in claim 2, characterized in that, The control unit is specifically used to acquire a first electrical signal through the first circuit, acquire a second electrical signal through the second circuit, and determine the connection direction of the temperature sensing cable based on the amplitude of the first electrical signal and the second electrical signal; Wherein, the first electrical signal corresponds to the state where the first circuit is on and the second circuit is off, and the second electrical signal corresponds to the state where the first circuit is off and the second circuit is on.

4. The terminal box as described in claim 1, characterized in that, It also includes an alarm unit, which is connected to the control unit; The control unit is also used to issue an alarm through the alarm unit when there is an open circuit or short circuit in the temperature sensing cable.

5. The terminal box as described in claim 1, characterized in that, The second circuit includes a third resistor and a second switch connected in series between the detection interface and ground; The control unit is used to control the on / off state of the second circuit via the second switch.

6. A connection control method for a terminal box according to any one of claims 1 to 5, characterized in that, The method includes: The control unit acquires a first electrical signal through a first circuit and a second electrical signal through a second circuit; wherein the first electrical signal is acquired when the first circuit is turned on and the second circuit is turned off, and the second electrical signal is acquired when the first circuit is turned off and the second circuit is turned on. The control unit determines the connection direction of the temperature sensing cable based on the amplitudes of the first electrical signal and the second electrical signal; The control unit connects to either the first circuit or the second circuit based on the connection direction of the temperature sensing cable.

7. The connection control method as described in claim 6, characterized in that, The control unit determines the connection direction of the temperature sensing cable based on the amplitudes of the first electrical signal and the second electrical signal, including: When the difference between the first electrical signal and the first threshold is within a preset range, and the second electrical signal is within a preset range, the control unit determines that the temperature sensing cable is connected along the first direction.

8. The connection control method as described in claim 6, characterized in that, The first circuit includes a first power supply, a first resistor, a first switch, and a second resistor connected in series. The second resistor is connected to the detection interface, and the control terminal of the first switch is connected to the control unit. The control unit determines the connection direction of the temperature sensing cable based on the amplitudes of the first electrical signal and the second electrical signal, including: When the difference between the voltage of the first electrical signal and the voltage of the first power supply is within a preset range, and the difference between the second electrical signal and the second threshold is within a preset range, the control unit determines that the temperature sensing cable is connected along the second direction.

9. The connection control method as described in claim 6, characterized in that, The first circuit includes a first power supply, a first resistor, a first switch, and a second resistor connected in series. The second resistor is connected to the detection interface, and the control terminal of the first switch is connected to the control unit. The method further includes: The control unit determines that the temperature sensing wire of the temperature sensing cable is open-circuited when the difference between the voltage of the first electrical signal and the voltage of the first power supply is within a preset range, and the difference between the second electrical signal and zero is within a preset range. When the difference between the voltage of the first electrical signal and the voltage of the second electrical signal and the voltage of the first power supply are both within a preset range, the control unit determines that the first bus of the temperature sensing cable is short-circuited with the temperature sensing cable. When the difference between the first electrical signal and the third threshold is within a preset range, and the difference between the second electrical signal and zero is within a preset range, the control unit determines that the second bus of the temperature sensing cable is short-circuited with the temperature sensing cable.

10. A fire alarm system, characterized in that, The device includes a signal processing unit, a temperature sensing cable, and a terminal box as described in any one of claims 1 to 5; the temperature sensing cable is connected between the signal processing unit and the terminal box in a first direction or a second direction opposite to it, a first bus of the temperature sensing cable is connected to a first interface of the terminal box, a second bus is connected to a second interface of the terminal box, and the temperature sensing cable is connected to a detection interface of the terminal box. The signal processing unit is used to issue a fault prompt indicating a short circuit in the first bus or the second bus when the terminal box cannot be found, and to issue a fault prompt indicating a short circuit in the first bus and the second bus when an overcurrent signal is detected.

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