Fire detection two bus loop hardware diagnostic circuit and diagnostic method thereof

Abstract

The application provides a fire detection two-bus loop hardware diagnosis circuit and a diagnosis method thereof, which comprises a central processing unit, a two-bus module, a short circuit detection module, a power module, a ground detection module, an open circuit detection module, a relay group and equipment; the first connecting end of the two-bus module is connected with the power module and the short circuit detection module respectively; the short circuit detection module is connected with the central processing unit; the central processing unit is connected with the ground detection module and the open circuit detection module respectively; the open circuit detection module is connected with the relay group; the relay group is connected with the equipment and the second connecting end of the two-bus module respectively. The application can diagnose and process three common problems of the two-bus loop, adopts a single central processing unit to process, aims at diagnosing three common problems of the two-bus loop, i.e. open circuit, short circuit and ground, and ingeniously reduces the diagnosis cost.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of fire detection alarm display controller, and particularly relates to a fire detection two-bus loop hardware diagnosis circuit and a diagnosis method thereof. BACKGROUND

[0002] The two-bus uses only two lines for field communication, saves construction cost and cable cost, and brings great convenience to field construction and later maintenance; and the two-bus has a wide application in the field of fire detection alarm display control.

[0003] Compared with other line systems, the two-bus is a bus technology that combines the power supply line and the signal line into one, achieving signal and power supply sharing. In actual application, the two-bus is usually connected in a “two-in and two-out” manner, and there are four connection points when a two-bus loop device is connected to the two-bus loop. In engineering projects, there are usually many loop devices connected to the two-bus loop, and in the process of project construction and system use, it is easy to cause line disconnection, loose connection, line short circuit or poor insulation causing leakage, etc. If such a fire detection alarm display controller does not have loop diagnosis capability, it will not be easy for engineering and maintenance personnel to detect, and will cause some or even all two-bus loop devices to have abnormal power supply, power loss, and will cause the loop devices to not work normally.

[0004] Patent document CN113655752A discloses a two-bus device, a self-checking method thereof, and a building automatic control system; the two-bus device provided by the scheme comprises: a two-bus, a two-bus module for controlling input and output of the two-bus, a detection module connected to the input and output of the two-bus module in a breakable manner, and a power supply module for power supply. The scheme avoids the difficulty in troubleshooting of the entire system caused by the failure of the two-bus device after the two-bus device is powered on, and can quickly and accurately detect the failure of the two-bus device; however, it does not have loop diagnosis capability, and cannot play the function of fire detection alarm display control if a fire occurs, which may cause significant property loss and personnel casualties, etc.

[0005] This problem needs to be solved urgently. SUMMARY

[0006] In view of the defects in the prior art, the purpose of the present application is to provide a fire detection two-bus loop hardware diagnosis circuit and a diagnosis method thereof.

[0007] The application provides a fire detection two-bus loop hardware diagnosis circuit, which comprises a central processor, a two-bus module, a short circuit detection module, a power supply module, a ground detection module, an open circuit detection module, a relay group and equipment.

[0008] The first connecting end of the two-bus module is connected with the power supply module and the short circuit detection module respectively; the short circuit detection module is connected with the central processor; the central processor is connected with the ground detection module and the open circuit detection module respectively; the open circuit detection module is connected with the relay group; and the relay group is connected with the equipment and the second connecting end of the two-bus module respectively.

[0009] Preferably, the two-bus module comprises a two-bus level output circuit, a second operational amplifier circuit and a transistor.

[0010] The two-bus level output circuit is connected with the second operational amplifier circuit; the second operational amplifier circuit is connected with the base of the transistor; the collector of the transistor is the first connecting end; and the emitter of the transistor is the second connecting end.

[0011] Preferably, the short circuit detection module comprises a first operational amplifier circuit, a voltage limiting protection circuit and a sampling resistor.

[0012] The sampling resistor is connected with the first operational amplifier circuit; the first operational amplifier circuit is connected with the voltage limiting protection circuit; the sampling resistor is connected with the power supply module and the first connecting end of the two-bus module respectively; and the power supply module is used for providing power supply.

[0013] Preferably, the ground detection module comprises a first voltage divider circuit, a first voltage follower and a third relay.

[0014] The central processor is connected with the first voltage divider circuit and the third relay respectively; the first voltage divider circuit is connected with the first voltage follower; the first voltage follower is connected with the third relay; and the third relay is grounded.

[0015] The open circuit detection module comprises a second voltage divider circuit and a second voltage follower.

[0016] The central processor is connected with the second voltage divider circuit; and the second voltage divider circuit is connected with the second voltage follower.

[0017] Preferably, the relay group comprises a second relay and a first relay.

[0018] The second relay is connected with the second voltage follower; and the second relay is connected with the first relay.

[0019] The device is used for fire detection alarm display; the first relay is connected to the device; and the device is connected to the second relay.

[0020] Preferably, the second connection end of the two-bus module is connected to the first relay and the second relay respectively.

[0021] According to the application, a fire detection two-bus loop short circuit detection method is provided, which is realized based on a fire detection two-bus loop hardware diagnosis circuit and includes the following steps:

[0022] The central processor controls the normally open end of the first relay to be closed and the normally open end of the second relay to be opened; the two-bus module closes the normally open end of the first relay and sends a downlink command pulse voltage signal to the device; based on the downlink command pulse voltage signal, the device forms a current signal by changing the pulse width to reply to the two-bus module, so as to realize communication; the current changes in the range of 8mA-20mA.

[0023] The sampling resistor of the short circuit detection module converts the current signal into a voltage signal; the first operational amplifier circuit operates the voltage signal, and the voltage limiting protection circuit transmits the calculation result to the central processor;

[0024] Based on the voltage signal, the short circuit detection module judges whether there is a short circuit, and if the result is yes, an alarm is given; if the result is no, no processing is performed.

[0025] Preferably, the central processor can periodically turn on and off the first relay according to a preset period.

[0026] The short circuit detection module judges whether there is a short circuit, that is, judges whether the voltage is higher than 10V, and if the result is yes, there is no short circuit and no processing is performed; if the result is no, there is a short circuit and an alarm is given.

[0027] According to the application, a fire detection two-bus loop grounding detection method is provided, which is realized based on a fire detection two-bus loop hardware diagnosis circuit and includes the following steps:

[0028] The central processor controls the normally open end of the first relay to be closed and the normally open end of the second relay to be opened.

[0029] The central processor controls the normally open end of the third relay to be closed, the first voltage follower of the grounding detection module is isolated from external voltage, and the voltage is output to the first voltage dividing circuit; the first voltage dividing circuit divides the voltage to obtain a voltage dividing result; the central processor receives the voltage dividing result and judges whether the grounding is normal according to the voltage dividing result, that is, judges whether the value of the voltage dividing result is 1V-3V, and if the result is yes, an alarm is given; if the result is no, no processing is performed.

[0030] The fire detection two-bus loop open circuit detection method provided by the application is realized based on a hardware diagnosis circuit of the fire detection two-bus loop, and comprises the following steps: a central processing unit controls a normally open end of a first relay to be closed and a normally open end of a second relay to be opened; an input end of a device is connected to the normally open end of the first relay; an output end of the device is connected to the normally open end of the second relay; based on the second relay, a second voltage follower of the open circuit detection module transmits a signal to a second voltage dividing circuit to obtain a second voltage dividing signal; and the central processing unit receives the second voltage dividing signal and judges whether the voltage value is 0; if yes, an alarm is given; and if no, no processing is performed.

[0031] Compared with the prior art, the application has the following beneficial effects:

[0032] 1. The application can diagnose and process three common problems of a two-bus loop, adopts a processing mode of a single central processing unit, and is aimed at diagnosing three common problems of a two-bus loop, i.e., open circuit, short circuit and grounding, and ingeniously reduces the diagnosis cost.

[0033] 2. The diagnosis method disclosed by the application has high real-time performance, can quickly find fault problems, and can respond.

[0034] 3. The application solves the three common problems of a two-bus loop, such as easy disconnection of a line, virtual connection of a line, short circuit of a line or leakage caused by poor insulation of a line, and guarantees the normal work of a two-bus loop device. BRIEF DESCRIPTION OF DRAWINGS

[0035] Other characteristics, objects and advantages of the application will become more apparent from the following detailed description of non-limiting embodiments, with reference to the accompanying drawings:

[0036] Figure 1 A schematic diagram of a fire detection alarm display controller provided by the application is shown in the figure;

[0037] Figure 2 A two-bus loop diagnosis circuit provided by the application is shown in the figure. DETAILED DESCRIPTION

[0038] The application will be described in detail below with reference to specific embodiments. The following embodiments will help those skilled in the art to further understand the application, but do not limit the application in any form. It should be pointed out that those skilled in the art can make several changes and improvements without departing from the concept of the application. These all belong to the protection scope of the application.

[0039] Some specific embodiments of the two-bus loop diagnosis method of the fire detection alarm display controller provided by the application are provided below.

[0040] The fire detection alarm display controller according to the present application, as shown in Figure 1 , comprises:

[0041] a CPU module, which is used for centralized processing of information of the fire detection alarm display controller, and is used for information interaction with the loop communication unit and the display unit;

[0042] a loop communication unit, which comprises a loop communication bottom plate and a loop communication processing plate, and is used for communication with the CPU module and communication with the two-bus loop device, and is used for collecting information reported by the loop device and reporting the CPU host module;

[0043] a power module, which is used for power supply of the fire detection alarm display controller and the loop device;

[0044] a display unit, which is used for display of state information of the fire detection alarm display controller;

[0045] a two-bus loop device, which is referred to as a device or a loop device, and is connected with the loop communication processing plate in the loop communication unit. The two-bus signal line is led out from the loop communication unit, connected to the loop input end of the loop device, and then connected to the loop input end of the next loop device through the loop output end of the loop device, and so on, and the whole loop is connected in a ring type. The device comprises a smoke temperature detector, a manual alarm button and an alarm.

[0046] As shown in Figure 2 , the present application provides a two-bus loop hardware diagnosis circuit of a fire detection alarm display controller, which comprises:

[0047] a central processor, which is used for real-time control of a two-bus level output circuit to output a two-bus loop command pulse signal, control of a controller relay driving circuit to open or close a relay, sampling of an input voltage value and analog-digital conversion, and judgment of detection results of each circuit, and reporting of an exception as soon as found.

[0048] a two-bus level output circuit, which is used in combination with a No. 2 operational amplifier circuit, i.e., a second operational amplifier circuit and a transistor. The two-bus level output circuit is connected with the input end of the No. 2 operational amplifier circuit in the same direction, the reverse input end of the No. 2 operational amplifier is connected with the transmitter of the transistor, and the output end is connected with the base of the transistor. The two-bus level output circuit has the ability to output a correct two-bus loop command pulse signal after receiving a control signal of the central processor. According to the two-bus protocol requirement, the voltage amplitude of the two-bus loop command pulse signal is defined.

[0049] a relay group, which is composed of two same relays, and is used for controlling the passage of the loop field device. In normal work, only a No. 1 relay, i.e., a first relay is opened, and a No. 2 relay, i.e., a second relay is opened when an open circuit fault occurs in the loop.

[0050] The open circuit detection circuit, i.e. the open circuit detection module, detects the voltage amplitude of the circuit field device connected to the 2nd relay end, buffers and isolates the input voltage through the 2nd voltage follower, i.e. the second voltage follower, and then transmits the voltage to the central processor through the 2nd voltage dividing circuit, i.e. the second voltage dividing circuit, after voltage dividing processing.

[0051] The short circuit detection circuit, i.e. the short circuit detection module, is composed of the 1st operational amplifier circuit, i.e. the first operational amplifier circuit, and the voltage limiting protection circuit, which mainly collects the voltage value converted by the sampling resistor, amplifies the voltage value according to a certain amplification factor, protects the central processor pin through the voltage limiting protection circuit, and then transmits it to the central processor.

[0052] The ground detection circuit is composed of the 3rd relay, the 1st voltage follower and the 1st voltage dividing circuit. The normally open end of the 3rd relay is connected to the ground, the common end is connected to the positive input end of the 1st voltage follower, and the output end of the 1st voltage follower is connected to the 1st voltage dividing circuit.

[0053] The sampling resistor is used to convert the current signal generated by the two-bus circuit device into a voltage signal for operation and conversion by the short circuit detection circuit.

[0054] Drive the 1st relay to act, the normally open end is closed, and the normally open end of the 2nd relay remains open;

[0055] The two-bus level output circuit is connected to the emitter of the transistor through the 2nd operational amplifier circuit, and then connected to the common end of the 1st relay and the common end of the 2nd relay. When the normally open end of the 1st relay is closed, the downlink command pulse voltage signal is sent to the two-bus circuit device;

[0056] The two-bus circuit device adopts a ring connection, with the input end connected to the normally open end of the 1st relay and the output end connected to the normally open end of the 2nd relay;

[0057] The open circuit detection circuit is applied to the normally open end of the 2nd relay, first through a voltage follower, and then transmitted to the central processor through the 2nd voltage dividing circuit;

[0058] The central processor detects the value after the 2nd voltage dividing circuit processing, and judges whether the value is abnormal. Under normal circumstances, the voltage value of the loop open circuit detection is 0 amplitude. It indicates that there is a breakpoint on the two-bus circuit, at which time the fire detection alarm display controller displays the fault to inform the relevant personnel to check the two-bus circuit line;

[0059] Meanwhile, the central processor sends a high-level control signal to control the relay drive circuit to drive the No.2 relay to act, and the normally open end is closed, and the No.2 relay provides power for the two-bus loop device through one way, so that power supply for both ends of the two-bus loop can be realized.

[0060] The two-bus loop short circuit detection scheme of the fire detection alarm display controller comprises:

[0061] In the normal working state of the fire detection alarm display controller, the central processor sends a high-level control signal to control the relay drive circuit to drive the No.1 relay to act, and the normally open end is closed, and the normally open end of the No.2 relay remains disconnected.

[0062] The No.2 operational amplifier circuit is connected to the common end of the No.1 relay by the two-bus level output circuit, and when the normally open end is closed with the common end, the downlink command pulse voltage signal is sent to the two-bus loop device.

[0063] After receiving the downlink command pulse voltage signal, the two-bus loop device usually pulls up the two-bus loop current in the form of pulse width to achieve the purpose of communication.

[0064] When the two-bus loop device pulls up the current, the sampling resistor converts the pulled-up current signal into a voltage signal, the No.1 operational amplifier circuit operates, and the result is transmitted to the central processor through the voltage limiting protection circuit; the pulled-up current ranges from 8mA to 20mA.

[0065] If the loop current is too high, the central processor will detect the abnormal voltage to determine that the two-bus loop device is short-circuited, and report the fire detection alarm display controller to display fault information to inform the relevant personnel to check the two-bus loop circuit; the abnormal voltage is lower than 10V.

[0066] The central processor controls the No.1 relay to be periodically switched on and off, on one hand, to disconnect the connection with the two-bus loop device, and on the other hand, to periodically detect the loop current, so that the two-bus loop device can be normally communicated when the loop current returns to normal.

[0067] The two-bus loop grounding detection scheme of the fire detection alarm display controller comprises:

[0068] In the normal working state of the fire detection alarm display controller, the central processor sends a high-level control signal to control the relay drive circuit to drive the No.1 relay to act, and the normally open end is closed, and the normally open end of the No.2 relay remains disconnected.

[0069] The No.3 relay in the grounding detection circuit is used to connect the normally open end with the ground, and the common end is connected with the No.1 voltage follower.

[0070] The No. 3 relay is controlled by the central processor to drive the relay driving circuit in a certain cycle time, to drive the No. 3 relay to act, and the normally open end is closed to start detecting the voltage of the ground to the ground detection circuit;

[0071] Firstly, the external voltage is buffered and isolated by the No. 1 voltage follower, and the voltage is output to the No. 1 voltage dividing circuit;

[0072] The No. 1 voltage dividing circuit performs voltage dividing processing, and transmits the voltage dividing result to the central processor;

[0073] The central processor obtains the output result, determines whether it is abnormal according to the voltage value and range specified in the bus communication, specifically, detects and judges whether the voltage dividing value of the voltage to ground is 1V-3V, and if the result is yes, it is determined that the voltage to ground is abnormal, and the fire detection alarm display controller is reported to display the fault information to inform the relevant personnel to check the two bus loop lines; if the result is no, it is not processed.

[0074] In embodiment 2, the two bus loop hardware diagnostic circuit of the fire detection alarm display controller of the application comprises:

[0075] The central processor controls the two bus level output circuit to output the two bus loop command pulse signal; controls the relay driving circuit to open or close the relay; samples and converts the output voltage value of the operational amplifier, judges the detection result of each circuit, and reports immediately if an abnormality occurs. The two bus level output circuit is used in combination with the No. 2 operational amplifier circuit and the transistor. The two bus level output circuit is connected to the input end of the No. 2 operational amplifier circuit, the reverse input end of the No. 2 operational amplifier is connected to the transmitter of the transistor, and the output end is connected to the base of the transistor. After receiving the control signal of the central processor, the two bus level output circuit has the ability to correctly output the two bus loop command pulse signal. According to the requirement of the two bus protocol, the voltage amplitude of the two bus loop command pulse signal is defined, and 20V is set as the high level and 10V is set as the low level.

[0076] The relay group is composed of two same relays, which control the passage with the loop field device, and only the No. 1 relay is opened in normal work, and the No. 2 relay is opened when the loop has an open circuit fault.

[0077] The open circuit detection circuit detects the voltage amplitude of the loop field device connected to the No. 2 relay end, which is not less than 10V voltage in normal case, buffers and isolates the input voltage through the No. 2 voltage follower, and then judges the open circuit condition through the No. 2 voltage dividing circuit and the central processor through the analog-to-digital converter.

[0078] Short circuit detection circuit, by No. 1 operational amplifier circuit and voltage limiting protection circuit, mainly is the voltage value after the sampling resistance conversion, the voltage value is amplified according to certain amplification, through voltage limiting protection circuit, the central processing unit pin is protected, then into the central processing unit.

[0079] Ground detection circuit, by No. 3 relay, No. 1 voltage follower and No. 1 voltage divider circuit, a group of contacts of No. 3 relay is connected to ground, the common end is connected to the positive input end of No. 1 voltage follower, and the output end of No. 1 voltage follower is connected to No. 1 voltage divider circuit.

[0080] Sampling resistance, for converting the current signal generated by the two bus loop device into a voltage signal for the short circuit detection circuit to operate and convert.

[0081] Embodiment 3, the two bus loop open circuit detection method of the fire detection alarm display controller, comprising:

[0082] Step 1: in the normal working state of the fire detection alarm display controller, the central processing unit sends a high level control signal to control the relay drive circuit, drives No. 1 relay, i.e. the first relay, to act, the normally open end is closed, and the normally open end of No. 2 relay, i.e. the second relay, remains disconnected;

[0083] Step 2: connect the emitter of the transistor to No. 2 operational amplifier circuit, i.e. the second operational amplifier circuit, and connect the common end of No. 1 relay and the common end of No. 2 relay, when the normally open end of No. 1 relay is closed with the common end, send down command pulse voltage signal to the two bus loop device;

[0084] Step 3: the two bus loop device adopts ring connection, the input end is connected to the normally open end of No. 1 relay, and the output end is connected to the normally open end of No. 2 relay;

[0085] Apply open circuit detection circuit to the normally open end of No. 2 relay, first through a voltage follower, and then transmit to the central processing unit through No. 2 voltage divider circuit;

[0086] Step 4: the central processing unit detects the value after the processing of No. 2 voltage divider circuit, judges whether the value is abnormal, and in the normal case, the voltage value of loop open circuit detection is 0 amplitude. Then it is proved that there is a breakpoint on the two bus loop, at this time, the fire detection alarm display controller is reported to display the fault, so as to inform the relevant personnel to check the two bus loop line;

[0087] Step 5: the central processing unit sends a high level control signal to control the relay drive circuit, drives No. 2 relay to act, the normally open end is closed, and one way through No. 2 relay to supply power to the two bus loop device, realizes two bus loop two end power supply.

[0088] The fire detection alarm display controller two-wire loop short circuit detection method of the present application comprises:

[0089] Step A1: In the normal working state of the fire detection alarm display controller, the central processor sends a high-level control signal to control the relay drive circuit, drive the No. 1 relay to act, and the normally open end is closed, and the normally open end of the No. 2 relay remains disconnected;

[0090] Step A2: The No. 2 operational amplifier circuit, i.e. the second operational amplifier circuit, is connected to the common end of the No. 1 relay in combination with the two-wire level output circuit, and after the normally open end and the common end are closed, a downlink command pulse voltage signal is sent to the two-wire loop device;

[0091] Step A3: After receiving the downlink command pulse voltage signal, the two-wire loop device pulls up the two-wire loop current to 10mA through the pulse width to achieve the purpose of communication; the pulse width is determined according to the protocol requirements.

[0092] Step A4: When the two-wire loop device pulls up the current, the sampling resistor converts the pulled-up current signal into a voltage signal, the No. 1 operational amplifier circuit, i.e. the first operational amplifier circuit, performs operation, and the result is transmitted to the central processor through the voltage limiting protection circuit;

[0093] Step A5: If the loop current is too high, the central processor will detect this abnormal voltage to determine that the two-wire loop device has a short circuit, and report the fire detection alarm display controller to display fault information to inform the relevant personnel to check the two-wire loop circuit;

[0094] Step A6: At the same time, the central processor controls the No. 1 relay to be periodically switched on and off, on the one hand to disconnect the connection with the two-wire loop device, and on the other hand to periodically detect the loop current, if the loop current returns to normal, the two-wire loop device is normally communicated.

[0095] The fire detection alarm display controller two-wire loop short circuit detection method of the present application comprises:

[0096] Step B1: In the normal working state of the fire detection alarm display controller, the central processor sends a high-level control signal to control the relay drive circuit, drive the No. 1 relay to act, and the normally open end is closed, and the normally open end of the No. 2 relay, i.e. the second relay, remains disconnected;

[0097] Step B2: The No. 3 relay, i.e. the third relay, in the ground detection circuit is used to connect the normally open end to the ground, and the common end is connected to the No. 1 voltage follower;

[0098] Step B3: the No. 3 relay is controlled by the central processor to drive the relay driving circuit in a certain cycle time, to drive the No. 3 relay to act, and the normally open end is closed to start the ground detection circuit to detect the voltage of the ground;

[0099] Step B4: first pass through the No. 1 voltage follower, i.e. the first voltage follower, to buffer and isolate the external voltage, and output the voltage to the No. 1 voltage dividing circuit;

[0100] Step B5: the No. 1 voltage dividing circuit, i.e. the first voltage dividing circuit, performs voltage dividing processing, and transmits the voltage dividing result to the central processor;

[0101] Step B6: the central processor obtains the output result, judges whether the result is abnormal, and reports the fire detection alarm display controller to display the fault information, to inform the relevant personnel to check the two bus loop lines.

[0102] In the description of the present application, it should be understood that the terms "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application.

[0103] The specific embodiments of the present application are described above. It should be understood that the present application is not limited to the above specific embodiments, and those skilled in the art can make various changes or modifications within the scope of the claims, which does not affect the essential content of the present application. In the case of no conflict, the embodiments of the present application and the features in the embodiments can be combined with each other arbitrarily.

Claims

1. A hardware diagnostic circuit for a two-wire bus loop in fire detection, characterized in that, include: Central processing unit, dual-bus module, short-circuit detection module, power supply module, grounding detection module, open-circuit detection module, relay group and equipment; The first connection terminal of the dual-bus module is connected to the power supply module and the short-circuit detection module respectively; the short-circuit detection module is connected to the central processing unit; the central processing unit is connected to the ground detection module and the open-circuit detection module respectively; the open-circuit detection module is connected to the relay group. The relay group is respectively connected to the second connection terminal of the device and the two-bus module; The dual-bus module includes: a dual-bus level output circuit, a second operational amplifier circuit, and a transistor; The dual-bus level output circuit is connected to the second operational amplifier circuit; the second operational amplifier circuit is connected to the base of the transistor; the collector of the transistor is the first connection terminal; and the emitter of the transistor is the second connection terminal. The short-circuit detection module includes: a first operational amplifier circuit, a voltage limiting protection circuit, and a sampling resistor; The sampling resistor is connected to the first operational amplifier circuit; the first operational amplifier circuit is connected to the voltage limiting protection circuit; the sampling resistor is connected to the first connection terminal of the power supply module and the dual-bus module respectively; the power supply module is used to provide power. The grounding detection module includes: a first voltage divider circuit, a first voltage follower, and a third relay; The central processing unit is connected to the first voltage divider circuit and the third relay respectively; the first voltage divider circuit is connected to the first voltage follower; the first voltage follower is connected to the third relay; the third relay is grounded; The open-circuit detection module includes: a second voltage divider circuit and a second voltage follower; The central processing unit is connected to the second voltage divider circuit; the second voltage divider circuit is connected to the second voltage follower. The relay group includes: a second relay and a first relay; The second relay is connected to the second voltage follower; the second relay is connected to the first relay; The device is used for fire detection, alarm, and display; the first relay is connected to the device; the device is connected to the second relay; The second connection terminal of the dual-bus module is connected to the first relay and the second relay respectively.

2. A method for detecting short circuits in a two-wire fire detector loop, implemented based on the hardware diagnostic circuit for a two-wire fire detector loop as described in claim 1, characterized in that... include: The central processing unit controls the normally open terminal of the first relay to close, and the normally open terminal of the second relay to open. The two-bus module closes the normally open terminal of the first relay and sends a downlink command pulse voltage signal to the device. Based on the downlink command pulse voltage signal, the device generates a current signal by varying the pulse width to reply to the two-bus module, thereby achieving communication; the current variation range is 8mA~20mA. The sampling resistor of the short-circuit detection module converts the current signal into a voltage signal; the first operational amplifier circuit calculates the voltage signal, and after passing through the voltage limiting protection circuit, the calculation result is transmitted to the central processing unit. Based on the voltage signal, the short-circuit detection module determines whether there is a short circuit. If the result is yes, an alarm is triggered; if the result is no, no action is taken.

3. The fire detection two-wire loop short-circuit detection method according to claim 2, characterized in that, The central processing unit can periodically switch the first relay on and off according to a preset cycle; The short circuit detection module determines whether there is a short circuit by checking whether the voltage is higher than 10V. If the result is yes, there is no short circuit and no action is taken. If the result is no, there is a short circuit and an alarm is triggered.

4. A method for detecting grounding of a two-wire fire detector loop, implemented based on the hardware diagnostic circuit for a two-wire fire detector loop as described in claim 1, characterized in that... include: The central processing unit controls the normally open terminal of the first relay to close, and the normally open terminal of the second relay to open. The central processing unit controls the normally open terminal of the third relay to close, causing the first voltage follower of the grounding detection module to isolate the external voltage and output the voltage to the first voltage divider circuit; the first voltage divider circuit performs voltage division processing to obtain the voltage division result; the central processing unit receives the voltage division result and determines whether the grounding condition is normal based on the voltage division result, that is, whether the value of the voltage division result is 1V-3V. If the result is yes, an alarm is triggered; if the result is no, no action is taken.

5. A method for detecting open circuits in a two-wire fire detector loop, implemented based on the hardware diagnostic circuit for a two-wire fire detector loop as described in claim 1, characterized in that... include: The central processing unit controls the normally open terminal of the first relay to close, and the normally open terminal of the second relay to open. Connect the input terminal of the device to the normally open terminal of the first relay; Connect the output terminal of the device to the normally open terminal of the second relay; Based on the second relay, the second voltage follower of the open circuit detection module transmits a signal to the second voltage divider circuit to obtain a second voltage divider signal; the central processing unit receives the second voltage divider signal and determines whether the voltage value is 0V. If the result is yes, an alarm is triggered; if the result is no, no action is taken.

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