Portable residual current electrical fire detector on-site detection device and method

Abstract

The present invention provides a portable residual current electrical fire detector on-site detection device and method, and relates to the field of residual leakage current detection technology. The present invention uses a circuit board with an ARM single-chip microcomputer as the core built into the detection device to perform closed-loop control on the output current, has good stability, and can display the current set current value and real-time current value of the device; the detection device is easy to operate on-site, is powered by a rechargeable battery, and has a wide range of applications; it fills the gap in the field of residual current electrical fire detector on-site detection, and is of great significance to the safe operation, performance evaluation and fault analysis of residual current electrical fire detectors at engineering sites.

Description

Technical Field

[0001] The invention relates to the technical field of residual leakage current detection, and in particular to an on-site detection device and method for a portable residual current electrical fire detector. Background Art

[0002] The standard of residual current electrical fire detectors is whether the leakage alarm parameters can meet international standards, national standards, and industry standards. It is one of the important indicators for evaluating the performance of residual current electrical fire detectors. At present, the detection device of residual current electrical fire detectors is mainly for indoor leakage current generators. Usually, the performance parameters of residual current electrical fire detector samples that have not been put into use in the project are detected. There are two ways to conduct on-site testing of residual current electrical fire detectors installed on site. One is to use a method such as connecting an electrical device to the ground wire or PE at any phase for testing. These methods have many shortcomings, single test items, backward detection methods, qualitative detection, and cannot be quantitatively detected. The detection data is inaccurate, and the external device method is a strong current operation with a high risk factor. It also needs to destroy the insulation performance of the line, and many engineering sites are not allowed. Instead, a current generator is used for testing, but the current generators on the market are generally large in size and require 220V AC power supply, so they cannot be used at sites without power supply.

[0003] To sum up, there is currently no portable residual current electrical fire detector on-site detection device that can be used in engineering sites in China. The development of such a residual current electrical fire detector on-site detection device will fill the gap in the field of residual current electrical fire detector on-site detection, and is of great significance to the safe operation, performance evaluation and fault analysis of residual current electrical fire detectors at engineering sites. Summary of the invention

[0004] In view of the deficiencies in the prior art, the present invention provides a portable on-site detection device and method for residual current electrical fire detectors.

[0005] In order to solve the above technical problems, the technical solution adopted by the present invention is:

[0006] In one aspect, a portable residual current electrical fire detector on-site detection device includes a housing, a keypad, and a battery panel;

[0007] The shell is provided with a test port, a charging port, a current transformer, a switch button and a circuit. The test port has two red and black onboard banana sockets, wherein the red one is the positive pole and the black one is the negative pole. The positive and negative poles of the test port are connected through a lantern banana plug connection line; one side of the primary side of the current transformer is connected to the positive pole of the banana socket, one end of the lantern banana plug is connected to the positive pole of the test port, and the other end is connected to the negative pole of the test port; one end of the switch button is connected to the battery panel, and the other end is connected to the circuit;

[0008] The test port, charging port and switch button holes are arranged on the side baffle of the housing;

[0009] The key board comprises a key frame and a key membrane, the key membrane protrusion is arranged at the hollow part of the key frame, and the key frame is fixed on the housing through a bayonet;

[0010] The battery panel is provided with a battery compartment inside, the battery compartment has a battery embedded therein, the battery panel is connected to the bottom of the shell through a buckle, and the battery is connected to a charging status indicator light and a charging completion indicator light.

[0011] The shell is made of plastic.

[0012] The circuit comprises a main control module, a battery charging module, a voltage boosting module, a current generating digital power amplifier module, a reference voltage module, a current acquisition module, a liquid crystal module, a key module, a voltage step-down module, a 2.4G wireless transmission module, a Bluetooth wireless transmission module, and an EEPROM storage module; wherein the main control module is respectively connected with the current digital power amplifier module, the current acquisition module, the liquid crystal module, the key module, the voltage step-down module, the 2.4G wireless transmission module, the Bluetooth wireless transmission module, and the EEPROM storage module; the battery charging module is connected with the battery in the battery panel, the switch button in the shell, and the voltage step-down module; and the voltage boosting module is connected with the switch button in the shell and the reference voltage module.

[0013] The current acquisition module includes a current transformer and an amplifying and filtering unit. The amplifying and filtering unit receives a detection signal from the current transformer, amplifies and filters the detection signal result to obtain an amplifying and filtering result, and transmits the amplifying and filtering result to a current generating digital power amplifier module. One side of the primary side of the current transformer is connected to the current generating digital power amplifier module, and the other side of the primary side of the current transformer is connected to the positive pole of the banana socket.

[0014] On the other hand, a portable residual current electrical fire detector on-site detection method is implemented based on the aforementioned portable residual current electrical fire detector on-site detection device, comprising the following steps:

[0015] Step 1: After the test port is connected via a banana plug, the circuit status on the display changes from "open" to "connected";

[0016] Step 2: After detecting that the "Function" button is pressed, enter the current setting state and set the desired output current value. Use the "+100", "+10", "+1", "-100", "-10", and "-1" buttons to set the current value;

[0017] Step 3: After the "Confirm" button is pressed, the current starts to output and eventually stabilizes at the current setting value;

[0018] Step 4: After the "Cancel" button is pressed, the current stops outputting;

[0019] Step 5: Press the "Select" button to enter the wireless communication state, select the 2.4G wireless communication method, use the portable residual current generator field detection device as the host of the temperature generator to receive the information uploaded by it, or select the Bluetooth wireless communication method to upload data to the mobile phone APP.

[0020] The beneficial effects of adopting the above technical method are:

[0021] The present invention provides a portable on-site detection device and method for residual current electrical fire detectors. The detection device has a built-in circuit board using an ARM single-chip microcomputer as the core, performs closed-loop control on the output current, has good stability, and can display the current set current value and the real-time current value of the device. The detection device is easy to operate on-site, is powered by a rechargeable battery, and has a wide range of applications. The detection device fills the gap in the field of on-site detection of residual current electrical fire detectors, and is of great significance to the safe operation, performance evaluation and fault analysis of residual current electrical fire detectors at engineering sites. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 A circuit system block diagram of a specific embodiment of the present invention;

[0023] Figure 2 A circuit diagram of a battery charging module according to a specific embodiment of the present invention;

[0024] Figure 3 A circuit diagram of a voltage boost module according to a specific embodiment of the present invention;

[0025] Figure 4 A circuit diagram of a current generating digital power amplifier module according to a specific embodiment of the present invention;

[0026] Figure 5 A circuit diagram of a reference voltage module according to a specific embodiment of the present invention;

[0027] Figure 6 A circuit diagram of a current acquisition module according to a specific embodiment of the present invention;

[0028] Figure 7A circuit diagram of a voltage step-down module according to a specific embodiment of the present invention;

[0029] Figure 8 A key module circuit diagram of a specific embodiment of the present invention;

[0030] Fig. 9 A circuit diagram of a liquid crystal module according to a specific embodiment of the present invention;

[0031] Fig.10 A circuit diagram of a main control module in a specific embodiment of the present invention;

[0032] Fig.11 The 2.4G wireless transmission module circuit diagram of the specific implementation mode of the present invention;

[0033] Fig.12 A circuit diagram of a Bluetooth module according to a specific embodiment of the present invention;

[0034] Fig.13 A circuit diagram of an EEPROM storage module according to a specific embodiment of the present invention;

[0035] Fig.14 It is a flow chart of a specific implementation mode of the present invention; DETAILED DESCRIPTION

[0036] The specific implementation of the present invention is further described in detail below in conjunction with the accompanying drawings and examples. The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0037] In one aspect, a portable residual current electrical fire detector on-site detection device includes a housing, a keypad, and a battery panel;

[0038] The shell is provided with a test port, a charging port, a current transformer, a switch button and a circuit. The test port has two red and black onboard banana sockets, of which the red one is the positive pole and the black one is the negative pole. The positive and negative poles of the test port are connected through the lantern banana plug connection line to generate current; the other side of the primary side of the current transformer is connected to the positive pole of the banana socket. One end of the lantern banana plug is connected to the positive pole of the test port, and the other end passes through the current transformer and is connected to the negative pole of the test port. The generated current passes through the current transformer, and the circuit regulates and controls the output current. One end of the switch button is connected to the battery panel, and the other end is connected to the voltage boost module in the circuit to control the on and off of the circuit.

[0039] The test port, charging port and switch button holes are arranged on the side baffle of the housing;

[0040] The shell is made of plastic;

[0041] The key board comprises a key frame and a key membrane, the key membrane protrusion is arranged at the hollow part of the key frame, and the key frame is fixed on the housing through a bayonet;

[0042] The battery panel is provided with a battery compartment inside which a battery is embedded. The battery panel is connected to the bottom of the housing through buckles to provide power to the circuit. The lithium-ion battery linear charging controller chip is connected to the charging status indicator light and the charging completion indicator light.

[0043] The circuit is as Figure 1 As shown, it includes a main control module, a battery charging module, a voltage boosting module, a current generating digital power amplifier module, a reference voltage module, a current acquisition module, a liquid crystal module, a key module, a voltage step-down module, a 2.4G wireless transmission module, a Bluetooth wireless transmission module, and an EEPROM storage module; wherein the main control module is respectively connected to the current digital power amplifier module, the current acquisition module, the liquid crystal module, the key module, the voltage step-down module, the 2.4G wireless transmission module, the Bluetooth wireless transmission module, and the EEPROM storage module; the battery charging module is connected to the battery in the battery panel, the switch button in the shell, and the voltage step-down module; the voltage boosting module is connected to the switch button in the shell and the reference voltage module; the charging port is connected to the lithium-ion battery linear charging controller chip,

[0044] The voltage boost module increases the battery voltage to a required voltage through a boost control chip, and provides power for a digital power amplifier circuit, a liquid crystal display circuit, and a reference voltage circuit.

[0045] The current generating digital power amplifier module is used to gain amplify the analog signal generated by the MCU, and the gain-amplified signal is converted into a current signal through a filter inductor. The filter inductor is connected to one side of the primary side of the current transformer, and the other side of the primary side of the current transformer is connected to the positive pole of the banana socket.

[0046] The reference voltage module generates a stable voltage through a regulated voltage and a voltage follower, and provides a constant reference voltage for the sampling circuit.

[0047] The current acquisition module includes a current transformer and an amplifying and filtering unit. The amplifying and filtering unit receives a detection signal from the current transformer, amplifies and filters the detection signal result to obtain an amplified and filtered result, and transmits the amplified and filtered result to the AD unit of the microprocessor.

[0048] The voltage step-down module provides power to the MCU and the current sampling operational amplifier circuit through a step-down chip.

[0049] The key module is used for setting the working mode of the current generator, setting the working current amplitude, selecting the wireless communication mode, and controlling the upload of the detection data. The working mode is set by pressing the key of the key circuit, and the MCU circuit reads the signal transmitted by the key circuit, displays the mode information on the display screen of the liquid crystal display module, and sets the output current value and data transmission mode according to actual needs.

[0050] The liquid crystal module displays the working state of the residual current generator, displays the set current value, and displays the real-time dynamic current value after the test starts.

[0051] The 2.4G wireless transmission module adopts a wireless serial port LC12S module, which can realize data communication with the temperature generator.

[0052] The Bluetooth wireless transmission module adopts the JDY-23 ultra-low power Bluetooth 5.0 BLE module, which can realize data transmission between the module and the mobile phone.

[0053] The EEPROM storage module can store current setting values ​​and module address information.

[0054] The battery charging module is as follows Figure 2 As shown, the charging port P12 is connected to the lithium-ion battery linear charging controller U6, the 2nd pin of U6 is connected to R15 to program the charging current, the 6th pin of U6 is connected to R11, DS1 to realize the charging completion indication function, the 7th pin of U6 is connected to R14, DS2 to realize the charging status indication. The 5th pin of U6 is connected to the battery;

[0055] The voltage boost module circuit is as follows Figure 3 As shown, the battery P7 is connected to the push button switch 1 and 4 pins through the fuse F1, and the push button switch 3 and 6 pins are connected to the front end of the boost circuit, and then connected to the filter network composed of C10 and C11, and further connected to the energy storage inductor L2, and further connected to the freewheeling diode D1. On the other hand, it is connected to the 4th pin of the boost control chip U4 and the resistor R17. R17 is connected to the G pole of MOSFET Q14, and the 2nd pin of U4 is connected to the gate of Q14 to drive Q14. The freewheeling diode D1 is connected to the filter network composed of C13 and C19, and on the other hand, it is connected to the feedback network composed of R19, R20 and the 6th pin of U4. The 4.2V battery voltage V37 is increased to 5V V50 through U4 to provide power for the digital power amplifier circuit, LCD display circuit, and reference voltage circuit.

[0056] The current generating digital power amplifier module is as follows Figure 4As shown, the DA (digital / analog) output pin of the MCU is connected to the voltage divider circuit composed of R21 and R22, and the input end of the digital power amplifier module M1 receives the voltage signal from the voltage divider circuit. On the other hand, the positive pole of the output end of the digital power amplifier module M1 is connected in series with the filter inductor and the primary side of the current transformer and connected to the positive pole of the banana socket P5, and the output end of the digital power amplifier module is connected to the negative pole of the banana socket.

[0057] The reference voltage module is as follows Figure 5 As shown, the voltage regulator circuit composed of TL431, R2, R4, and R7 outputs the reference voltage of VREF. The VREF reference voltage is divided by the resistors R5, R6, and R8 in series, and the voltage of 1 / 2VREF is output and connected to the 3rd pin of the operational amplifier OP07. The voltage follower composed of OP07, C3, and C4 realizes the stability of the 1 / 2VREF reference voltage, providing a constant reference voltage for the sampling circuit.

[0058] The current acquisition circuit is composed of a current transformer and an operational amplifier circuit. Figure 6 As shown, the output end of the current transformer H1 is connected to C4, and the resistor R59 is the voltage-taking resistor of the current transformer output signal. On the other hand, one side of the current transformer output is connected to the 1 / 2VREF precision voltage, and the other side is connected to the filter network composed of R62, R63, and C36. The filter network is connected to the 3rd pin of the operational amplifier U4, and U4, R66, and R67 form a signal amplification circuit. The specific implementation process is that the positive and negative poles of the test port are connected through the lantern banana plug connection line, and the output current that generates the output current generates a mA-level signal through the current transformer, which is amplified by the sampling resistor to generate an mV signal. The mV signal passes through the signal amplification circuit to generate a 0-3.3V signal, which is transmitted to the AD pin of the MCU.

[0059] The voltage step-down circuit is as follows Figure 7 As shown, the XC6206 step-down control chip is used to provide power V33 for the MCU and the current sampling operational amplifier circuit. V33 generates a digital voltage V33A through isolation of the 0 ohm resistor R55 and filtering of C42 and C43 for use by the MCU.

[0060] The key circuit adopts a matrix scanning method such as Figure 8As shown, the current generator working mode setting, working current amplitude setting, wireless communication mode selection, and detection data upload control are realized. After the detection device is started, the current value to be output is set by the key of the key circuit. Taking 500mA as an example, the current output value is set to 500mA through the key circuit. The MCU circuit reads the signal transmitted by the key circuit, displays the current size through the display screen of the display circuit, and starts to control the current output size according to the current value set by the key circuit. A 50Hz sine wave is generated through the DA module and DMA module of the MCU, and amplified through the digital power amplifier circuit, and the current sampling current collects the current signal, which is transmitted to the MCU as feedback to form a closed-loop control. Through this closed-loop control, the current output value is stabilized at 500mA.

[0061] The liquid crystal display module is as follows Fig. 9 As shown, the LCD screen uses a 2.7-inch 160X128RGB C-STN LCD screen, based on the U1698 driver chip, connected to the MCU via the 8080 bus, and the driver circuit composed of R39, T4 and R29 is used to adjust the backlight brightness of the display. The LCD screen can display the working status of the residual current generator, the set current value, and the real-time dynamic current value after the test starts.

[0062] The main control unit module is as follows Fig.10 As shown in the figure, it consists of STM32F103VET6 chip and peripheral circuits used to support the normal operation of ARM chip. The processor main frequency can reach up to 72MHZ, 12-bit DAC digital-to-analog converter, analog comparator and other functions. The effective value calculation of 128 points of data is completed within a voltage zero-crossing signal cycle, and data display, data communication and other functions are realized at the same time. The CPU circuit is connected to the current generating digital power amplifier output circuit, current acquisition circuit, display and key circuit, voltage step-down circuit, 2.4G wireless communication circuit, and Bluetooth wireless communication circuit.

[0063] The 2.4G wireless transmission module is as follows: Fig.11 As shown, the wireless serial port LC12S module is used to realize data communication with the temperature generator.

[0064] The Bluetooth wireless transmission module is as follows: Fig.12 As shown, the JDY-23 ultra-low power Bluetooth 5.0 BLE module is used, the working frequency band is 2.4GHZ range, the modulation mode is GFSK, the maximum transmission power is 4db, and the maximum transmission distance is 60 meters, which can realize data transmission between the module and the mobile phone.

[0065] The EEPROM storage module is as follows Fig.13 As shown, W25Q80 is used, which can store current setting value and module address information.

[0066] On the other hand, a portable residual current electrical fire detector on-site detection method is implemented based on the aforementioned portable residual current electrical fire detector on-site detection device, such as Fig.14 As shown, the following steps are included:

[0067] Step 1: After the test port is connected via a banana plug, the circuit status on the display changes from "open" to "connected";

[0068] Step 2: After detecting that the "Function" button is pressed, enter the current setting state and set the desired output current value. Use the "+100", "+10", "+1", "-100", "-10", and "-1" buttons to set the current value;

[0069] Step 3: After the "Confirm" button is pressed, the current starts to output and eventually stabilizes at the current setting value;

[0070] Step 4: After the "Cancel" button is pressed, the current stops outputting;

[0071] Step 5: Press the "Select" button to enter the wireless communication state, select the 2.4G wireless communication method, use the portable residual current generator field detection device as the host of the temperature generator to receive the information uploaded by it, or select the Bluetooth wireless communication method to upload data to the mobile phone APP.

[0072] In this embodiment, the current generator is powered on and initialized, specifically including initialization of the LCD display unit, initialization of the 2.4G wireless module, initialization of the Bluetooth module, initialization of the key, initialization of the MCU, and initialization of the storage unit. The main program, interrupt processing function, and DMA transmission are executed respectively. The main loop program is executed to determine whether a key is pressed and to execute the corresponding functional operation.

[0073] Execute interrupt processing function and DMA transfer to realize sinusoidal current output control, as follows:

[0074] Create a data table that can generate a sine wave in the MCU static memory. The data table contains 128 data. Use DMA to establish a channel between the DAC and the static memory. The DAC module obtains the data that can generate a sine wave in the static memory through the DAM channel, and then obtains a sine wave at the output pin after digital-to-analog conversion. Use timer TIM2 to trigger the DAC to obtain a sine wave with a period of 20ms. Further control the amplitude of the sinusoidal current.

[0075] After initialization, the current setting value stored in the EEPROM is read. If a button is pressed to set the current value, the new current setting value is stored in the EEPROM. The current setting value is generated by the sinusoidal current, divided, amplified, and converted into current through the inductive load, flows through the primary side of the current transformer, and the current value is collected through the current sampling circuit. In a current cycle, that is, 20ms, 128 points are sampled regularly to calculate the effective value of the current.

[0076]

[0077] Among them, I s is the residual current effective value, N' is the total number of sampling points in a voltage cycle, that is, 128 sampling points, m is the mth sampling point, i sm The mth residual current sampling value; the specific calculation process is: first calculate the square of the residual current Then perform the sum operation The final square root calculation of all sampling points Then the average value of the residual current effective value within 1S is calculated to obtain the required current effective value, which is used as the feedback value and compared with the set current value. The output current amplitude is adjusted through the incremental PID algorithm.

Claims

1. A portable residual current electrical fire detector on-site detection device, characterized in that: Including housing, keypad and battery board; The shell is made of plastic, and is provided with a test port, a charging port, a current transformer, a switch button and a circuit. The test port has two red and black onboard banana sockets, of which the red one is the positive pole and the black one is the negative pole. The positive and negative poles of the test port are connected through a lantern banana plug connection line; one side of the primary side of the current transformer is connected to the positive pole of the banana socket, one end of the lantern banana plug is connected to the positive pole of the test port, and the other end is connected to the negative pole of the test port. One end of the switch button is connected to the battery panel, and the other end is connected to the circuit; The test port, charging port and switch button holes are arranged on the side baffle of the housing; The portable residual current electrical fire detector on-site detection device is used to implement a portable residual current electrical fire detector on-site detection method, comprising the following steps: Step 1: After the test port is connected through the banana plug, the circuit status on the LCD module display changes from "open" to "connected"; Step 2: After detecting that the "Function" button is pressed, enter the current setting state and set the desired output current value. Use the "+100", "+10", "+1", "-100", "-10", and "-1" buttons to set the current value; Step 3: After pressing the "Confirm" button, the current starts to output and eventually stabilizes at the current setting value; Step 4: After the "Cancel" button is pressed, the current stops outputting; Step 5: Press the "Select" button to enter the wireless communication state, select the 2.4G wireless communication mode, use the portable residual current generator field detection device as the host of the temperature generator to receive the information uploaded by it, or select the Bluetooth wireless communication mode to upload data to the mobile phone APP; The current setting state is specifically as follows: reading the current setting value stored in the EEPROM storage module, if a button is pressed to set the current value, the new current setting value is stored in the EEPROM storage module; the current setting value is generated by a sinusoidal current, divided, amplified, and converted into current through an inductive load, flows through the primary side of the current transformer, and the current value is collected by the current acquisition module. In one current cycle, i.e. 20ms, 128 points are sampled regularly to calculate the effective value of the current: ； in, I s is the residual current effective value, N' is the total number of sampling points in a voltage cycle, that is, 128 sampling points, m is the mth sampling point, i sm is the mth residual current sampling value; the average value of the residual current effective value within 1s is calculated to obtain the required current effective value as the feedback value, which is compared with the set current value, and the output current amplitude is adjusted through the incremental PID algorithm.

2. A portable residual current electrical fire detector on-site detection device according to claim 1, characterized in that: The key board comprises a key frame and a key membrane, the key membrane protrusion is arranged at the hollow part of the key frame, and the key frame is fixed on the housing through a bayonet; The battery panel is provided with a battery compartment inside, the battery compartment has a battery embedded therein, the battery panel is connected to the bottom of the housing through a buckle, and the battery is connected to a charging status indicator light and a charging completion indicator light; The circuit comprises a main control module, a battery charging module, a voltage boosting module, a current generating digital power amplifier module, a reference voltage module, a current acquisition module, a liquid crystal module, a key module, a voltage step-down module, a 2.4G wireless transmission module, a Bluetooth wireless transmission module, and an EEPROM storage module; wherein the main control module is respectively connected to the current digital power amplifier module, the current acquisition module, the liquid crystal module, the key module, the voltage step-down module, the 2.4G wireless transmission module, the Bluetooth wireless transmission module, and the EEPROM storage module; the battery charging module is connected to the battery in the battery panel, the switch button in the housing, and the voltage step-down module, and the voltage boosting module is connected to the switch button in the housing and the reference voltage module; The current acquisition module includes a current transformer and an amplifying and filtering unit. The amplifying and filtering unit receives a detection signal from the current transformer, amplifies and filters the detection signal result to obtain an amplifying and filtering result, and transmits the amplifying and filtering result to a current generating digital power amplifier module. One side of the primary side of the current transformer is connected to the current generating digital power amplifier module, and the other side of the primary side of the current transformer is connected to the positive pole of the banana socket.

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