Fault self-diagnosis system of high and low temperature damp heat test chamber

Abstract

The invention provides a fault self-diagnosis system of a high and low temperature damp heat test chamber, and relates to the technical field of environment test equipment and fault diagnosis. The system comprises a sensor module, a self-diagnosis system circuit board, a PLC (Programmable Logic Controller) and an alarm module, and the core has dual functions of self-checking and inspection: the self-checking function can be used for sequentially carrying out power-on detection on a circulating fan, an electromagnetic valve, a heating circuit and other parts before a test, and pre-judging potential faults; and the inspection function monitors basic parameters and states of all core components in real time in test operation, and carries out linkage troubleshooting according to preset logic. The system presets an adjustable threshold value, fault judgment is accurate to a single component, manual equipment disassembly is not needed, data loss and time waste caused by test interruption can be effectively avoided, the equipment operation reliability and maintenance efficiency are improved, and the method is suitable for fault diagnosis of high-low temperature damp heat test boxes in the fields of electronics, automobiles, aerospace and the like.

Description

Technical Field

[0001] This invention relates to the field of environmental testing equipment and fault diagnosis technology, specifically a fault self-diagnosis system for a high and low temperature humidity test chamber. Background Technology

[0002] High and low temperature humidity test chambers are key equipment used to simulate the high temperature, low temperature, and humid heat environments that products experience during storage, transportation, and use. They are widely used for product reliability testing in fields such as electronics, automotive, and aerospace. Existing high and low temperature humidity test chambers mainly consist of refrigeration, heating, and humidification systems. However, during long-term operation, components such as compressors, fans, solenoid valves, heating wires, and humidifying rods are prone to failure. Traditional fault detection methods mainly rely on periodic manual inspections or retrospective analysis after test interruptions, which presents the following problems: Delayed fault detection makes it impossible to predict potential faults before or during testing, which can easily lead to test interruptions, data loss, and wasted time. Inaccurate fault diagnosis relies on human experience, making it difficult to accurately locate faulty components and fault types, resulting in low maintenance efficiency. The operation is cumbersome, and manual troubleshooting requires disassembling the equipment or stopping the machine for testing, which increases maintenance costs and the risk of equipment damage.

[0003] Therefore, there is an urgent need to design a high and low temperature humidity test chamber with integrated fault self-diagnosis function to achieve early fault warning, accurate fault location and convenient maintenance, and solve the above-mentioned technical pain points. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides a fault self-diagnosis system for high and low temperature humidity test chambers, enabling pre-test component status verification and real-time fault monitoring during testing, thereby improving equipment reliability and maintenance efficiency. This system solves the problems of delayed fault detection, inaccurate diagnosis, and cumbersome operation in traditional high and low temperature humidity test chambers.

[0005] To achieve the above objectives, the present invention provides the following technical solution: A fault self-diagnosis system for a high and low temperature humidity test chamber includes a sensor module, a self-diagnosis system circuit board, a PLC controller and an alarm module, with the core functions being self-testing and inspection. The sensor module consists of a pressure sensor, a temperature sensor, a speed sensor, a conductivity sensor, and a current transformer. It collects operating signals from various components of the test chamber, specifically including: Pressure sensors detect the compressor's suction and discharge pressures; Temperature sensors detect ambient temperature, water temperature, condensation temperature, anti-dry-burning temperature, and expansion valve temperature; The speed sensor detects the fan frequency; A conductivity sensor detects the conductivity of water. Current transformers detect current signals from the compressor, heating circuit, and humidification circuit.

[0006] The self-diagnostic system circuit board is equipped with a standardized input channel. The channel numbering rule is "first digit (monitoring category) + second digit (component type) + third and fourth digits (serial number) + letter (signal type)". The monitoring categories include basic monitoring items, compressor, solenoid valve, expansion valve, fan, solid-state relay, and AC contactor, which are used to receive sensor signals and perform preprocessing. The PLC controller controls the self-test and inspection process, realizing functions such as sequential power-on of components, signal acquisition triggering, and fault logic judgment. The alarm module outputs fault information through sound and light prompts and text display, realizing visual reminders of faults.

[0007] The fault self-diagnosis system is used to diagnose faults in the high and low temperature humidity test chamber, which includes a cascade refrigeration system, a heating wire heating system, a boiler humidification system, and a circulating fan. The cascade refrigeration system adopts cascade refrigeration technology and includes a primary compressor, a secondary compressor, a compressor fan, a condenser, a plate heat exchanger, an evaporator, a solenoid valve (7 valves are provided, including a condensing expansion solenoid valve and a high-temperature stage compressor liquid distribution solenoid valve), and an expansion valve (including a condensing expansion valve and a high-temperature stage compressor liquid distribution expansion valve). The heating wire heating system adopts a heating wire heating method and includes a heating plate, a heating wire, a solid-state relay, and an AC contactor; The boiler humidification system adopts a boiler heating method and includes a humidification boiler water supply system, a humidification rod, and a solid-state relay; Two circulating fans are installed to agitate the air inside the test chamber and ensure uniform temperature and humidity.

[0008] Furthermore, the self-diagnostic function of the fault self-diagnosis system includes the following steps: S1. Receives a 12V self-test power switch signal and detects the fault status of the self-test circuit board; S2. If the self-test circuit board is fault-free, test the power-on signal of the test chamber; S3. When the power-on signal is high, the circulating fan, solenoid valve, heating circuit, humidification circuit and secondary compressor are powered on and tested in sequence, and the status of the components is judged according to the signals collected by the sensors and the preset standards. S4. When the power-on signal is low, wait for the test chamber to be powered on.

[0009] Furthermore, the self-testing steps of the circulating fan are as follows: S1. After the fan is powered on and running for 10 seconds, the fan frequency is detected. If the frequency is not within the range of

[1000] ±

[100] Hz, a fault prompt is output. S2. Detects the power-on signal of the test chamber. When the signal is low, it outputs a fan leakage warning.

[0010] Furthermore, the self-testing steps of the solenoid valve are as follows: S1.PLC energizes each solenoid valve coil sequentially, with an interval of 2 seconds between energizations. S2. Detect the voltage and current signals of the solenoid valve. If both are high or both are low, it is considered normal. Otherwise, output a solenoid valve abnormality prompt. S3. Synchronously detects the power-on signal of the test chamber, and outputs a solenoid valve leakage warning when the signal is not high.

[0011] Furthermore, the self-test steps of the heating circuit are as follows: S1. Detect the coil voltage of the heating solid-state relay, the coil voltage of the heating AC contactor, and the three-phase heating current, and determine the normal state or fault type based on the signal combination; S2. The fault types include heating solid-state relay faults, heating AC contactor faults, heating solid-state and AC contactor faults, and heating wire faults; S3. Synchronously detects the power-on signal of the test chamber. When the signal is low, it outputs a leakage warning for the heating circuit.

[0012] Furthermore, the inspection function of the fault self-diagnosis system includes basic parameter inspection, circulating fan inspection, heating circuit inspection, humidification circuit inspection, compressor current inspection, condenser fan inspection, solenoid valve inspection, expansion valve inspection and compressor pressure inspection. Each inspection module is linked sequentially according to preset logic to monitor the operating status of components in real time.

[0013] Furthermore, the preset thresholds of the self-diagnostic system circuit board include ambient temperature ≤

[30] ℃, condensation temperature ≤

[38] ℃, anti-dry burning temperature ≤

[110] ℃, water conductivity ≤

[20] μS / cm, secondary compressor exhaust pressure ≤

[20] bar, and suction pressure ≤ [2]bar. These thresholds can be adjusted by the installation engineer according to the actual situation.

[0014] Furthermore, the alarm module outputs fault information through audible and visual prompts and text display. The fault information includes "Please lower the ambient temperature or water temperature", "Please clean the condenser", "Humidifier box is short of water", "Please improve water quality", "Secondary compressor has no pressure", "Secondary compressor has low pressure", and abnormal prompts for various components, so as to achieve accurate fault tracing.

[0015] Furthermore, the core process of the fault self-diagnosis system is as follows: Self-test procedure: After the tester presses the self-test button, the system detects the 12V self-test power switch signal. If the signal is high within 5 minutes, the self-test will be started. First, check the fault status of the self-test circuit board. If there is no fault, then check the power-on signal of the test chamber. When the power-on signal is high, the power-on test is performed on the two circulating fans, seven solenoid valves, heating circuit, humidification circuit and secondary compressor in sequence. The status of the components is judged based on the signals collected by the sensors and the preset standards, and a fault prompt is output. After the self-test is completed, all components are powered off. When the fault signal of the self-test circuit board is detected to be low, the inspection mode is entered. Inspection process: During the trial operation, the system first performs basic parameter inspections (ambient temperature, water temperature, condensing temperature, etc.), and then sequentially performs inspections of the circulating fan, heating circuit, humidification circuit, compressor current, condenser fan, solenoid valve, expansion valve, and compressor pressure. Each module is linked according to preset logic, and the operating status of the components is monitored in real time. If any abnormality occurs, an alarm message is immediately output.

[0016] Furthermore, the fault judgment logic of the fault self-diagnosis system is as follows: Basic parameters: Ambient temperature / water temperature >

[30] ℃ prompts "Please lower the ambient temperature or water temperature"; A message appears indicating that the condenser should be cleaned if the condensing temperature is greater than 38°C. The anti-dry-burning temperature is greater than

[110] ℃, indicating "humidifier box is low on water"; A water conductivity value greater than 20 μS / cm indicates "Please improve water quality"; If the intake and exhaust pressures of the secondary compressor are both within [-1] to [1] bar, it indicates "no pressure in the secondary compressor"; if the difference between the two is ≤ [2] bar and both are < [9] bar, it indicates "low pressure in the secondary compressor". Fan: If the frequency is not within the range of

[1000] ±

[100] Hz after running for 10 seconds, prompt to check the corresponding fan; Solenoid valve: An abnormality is indicated when neither the voltage nor the current is both high or both are low. Heating / humidification circuit: Determine the fault type of the corresponding component based on the signal combination of solid-state relay coil voltage, AC contactor coil voltage and three-phase current; Expansion valve: When both the voltage and current of the solenoid valve are at a high level, the expansion temperature is detected after 2 seconds. If the temperature does not reach the preset threshold (e.g., ≤ [-20℃]), an abnormality is indicated. Compressor: If the discharge pressure of the secondary compressor is >

[20] bar after 2 minutes of current flow, it indicates that the primary compressor is short of refrigerant. If the suction pressure is > [2] bar, it indicates that the low-temperature compressor should be checked.

[0017] This invention provides a fault self-diagnosis system for a high and low temperature humidity test chamber. It has the following beneficial effects: 1. This invention provides a fault self-diagnosis system for a high and low temperature humidity test chamber. The self-test function checks for potential component faults before the test, and the patrol function monitors in real time during operation to avoid losses caused by test interruption. The fault location accuracy reaches a single component, reducing maintenance and troubleshooting time. Moreover, there is no need for manual disassembly of the equipment. The self-test can be started with one button, and the patrol process runs automatically. The alarm information is intuitive and easy to understand, reducing the reliance on the professional skills of the operators.

[0018] 2. This invention provides a fault self-diagnosis system for high and low temperature humidity test chambers. The threshold can be adjusted by the installation engineer according to the actual scenario to adapt to different test requirements and usage environments. It has a wide range of applications. Through full-process monitoring and timely alarm, it reduces excessive wear and tear on components, extends the service life of equipment, and reduces maintenance costs. Attached Figure Description

[0019] Figure 1 This is a block diagram of the fault self-diagnosis system of the high and low temperature humidity test chamber of the present invention; Figure 2 This is a schematic diagram of the structural composition of the high and low temperature humidity test chamber of the present invention; Figure 3 The fault self-diagnosis workflow of the JK system of the present invention Figure 1 ; Figure 4 The fault self-diagnosis workflow of the JK system of the present invention Figure 2 ; Figure 5 This is a circuit connection diagram for the fault self-diagnosis detection circuit of the JK system of the present invention. Detailed Implementation

[0020] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the present invention, and not all of the structures.

[0021] In the description of this invention, unless otherwise explicitly specified and limited, the terms "connected," "linked," and "fixed" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0022] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0023] In the description of this embodiment, the terms "upper," "lower," "right," etc., refer to the orientation or positional relationship shown in the accompanying drawings. They are used only for ease of description and simplification of operation, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the present invention. In addition, the terms "first" and "second" are used only for distinction in description and have no special meaning.

[0024] The technical solution of the present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0025] like Figures 1-2 As shown, this embodiment of the invention provides a fault self-diagnosis system for a high and low temperature humidity test chamber, including a sensor module, a self-diagnosis system circuit board, a PLC controller and an alarm module, the core functions of which are self-testing function and patrol inspection function; The sensors selected include a pressure sensor with an accuracy of ±0.1 bar, a temperature sensor with an accuracy of ±0.5℃, a speed sensor with a measurement range of 500-1500Hz, a conductivity sensor with an accuracy of ±1μS / cm, and a current transformer with a transformation ratio of 1:500. Pressure sensors detect the compressor's suction and discharge pressures; Temperature sensors detect ambient temperature, water temperature, condensation temperature, anti-dry-burning temperature, and expansion valve temperature; The speed sensor detects the fan frequency; A conductivity sensor detects the conductivity of water. Current transformers detect current signals from the compressor, heating circuit, and humidification circuit.

[0026] The self-diagnostic system circuit board uses an STM32F103 microcontroller as the core controller, with 32 input channels. The PLC controller selected is the Siemens S7-200 SMART; The alarm module uses a combination of an LED display screen and a buzzer. The display screen has a resolution of 320×240 pixels, and the buzzer volume is ≥80dB.

[0027] Threshold setting: Based on the actual usage scenario, the installation engineer sets the following thresholds through the debugging interface of the self-diagnostic system circuit board: normal threshold for ambient temperature / water temperature ≤30℃, normal threshold for condensing temperature ≤38℃, normal threshold for anti-dry burning temperature ≤110℃, normal threshold for water conductivity ≤20μS / cm, normal threshold for secondary compressor exhaust pressure ≤20bar, normal threshold for suction pressure ≤2bar, normal threshold for fan frequency

[1000] ±

[100] Hz, and normal threshold for expansion valve temperature ≤-20℃.

[0028] The self-check process is as follows: ① The tester presses the power button of the JK system, then presses the self-test button. The system detects that the 12V self-test power switch signal is high and starts the self-test. ②The self-test circuit board fault signal is detected to be low level (no fault), and then the power-on signal of the test chamber is detected to be high level. The PLC then powers on the two circulating fans in sequence. ③ After the first circulating fan is powered on and runs for 10 seconds, the speed sensor detects a frequency of 950Hz (within the normal threshold range), and the power-on signal of the test chamber remains at a high level, indicating normal operation; after the second circulating fan runs for 10 seconds, the frequency is 850Hz (below the lower threshold), and the system outputs "Please check the second circulating fan" through the alarm module. ④ After the circulating fan completes its self-test, the PLC powers on the 7 solenoid valves sequentially at 2-second intervals. When it detects that the voltage of the 3rd solenoid valve is high and the current is low (signal combination abnormal), it outputs "Please check the 3rd solenoid valve"; the signal combinations of the remaining solenoid valves are all high or low, which is considered normal. ⑤ After the solenoid valve completes its self-test, it starts the heating circuit. It detects that the heating solid-state relay coil voltage is low (0), the heating AC contactor coil voltage is high (1), and the three-phase heating current is high (111). The signal combination is 01111, and the output is "Please check the heating solid-state relay". ⑥ After the heating circuit completes its self-test, the humidification circuit is activated. The detection signal combination is 11111, indicating normal operation. ⑦ After the humidification circuit completes its self-test, it performs a self-test of the secondary compressor pressure. It detects that the suction pressure is 0.5 bar and the discharge pressure is 1.2 bar (both within the range of [-1] to [1] bar), and outputs "Secondary compressor has no pressure"; ⑧ After the self-test is completed, the CPU issues a power-off command, all components are powered off, and the self-test circuit board fault signal is detected as low level, and the system enters the inspection mode.

[0029] The inspection process is as follows: ① After the test is started, the system first performs basic parameter checks. It detects that the condensing temperature is 40℃, which is higher than the normal threshold of 38℃. It outputs "Please clean the condenser". After the operator cleans the condenser, the condensing temperature drops to 35℃ and the fault message is cleared. ② After the basic parameters are normal, current (high level) is detected in the first-stage compressor. After 10 seconds, the frequency of the circulating fan is detected. Both are within the normal threshold range, so it is judged to be normal. ③ Upon inspection of the heating circuit, the signal combination was found to be 11111, indicating normal operation; ④ Upon entering the humidification circuit inspection, it was detected that the second phase of the three-phase humidification current was at a low level, the signal combination was 11011, and the output was "Please check the humidifier rod"; ⑤ When the power-on signal of the test chamber is detected to be high level, the compressor current inspection is initiated. Both the first-stage and second-stage compressors have current. After 2 minutes, the discharge pressure of the second-stage compressor is measured to be 18 bar (normal) and the suction pressure is measured to be 1.5 bar (normal), which is considered normal. ⑥ The inspection is carried out in a loop according to the above logic, and the operating status of each component is monitored in real time until the test is completed.

[0030] As can be seen from the above embodiments, the present invention can effectively realize early fault detection and real-time monitoring of high and low temperature humidity test chambers, with accurate fault diagnosis and convenient operation, which can significantly improve the reliability of equipment operation and maintenance efficiency, and meet the stability requirements of various environmental tests.

[0031] Implementation Case: Fault Self-Diagnosis of the Health Management System (JK System) like Figures 3-5 As shown, the fault self-diagnosis process of the JK system is as follows: ①When the tester presses the power button of the JK system before the test, the ambient temperature or water temperature, condensation temperature, anti-dry burning temperature, water conductivity, suction pressure of the secondary compressor, and discharge pressure of the secondary compressor will be detected.

[0032] The test results are as follows: When the water temperature or ambient temperature is higher than the normal threshold setting

[30] ℃, the output fault message "Please lower the ambient temperature or water temperature" will be displayed. When the condensing temperature is higher than the normal threshold setting

[38] ℃, the output fault message "Please clean the condenser" will be displayed; When the anti-dry-burning temperature exceeds the normal threshold setting of

[110] ℃, the output fault message "humidifier box is short of water" will be displayed. When the water conductivity is higher than the normal threshold setting

[20] μS / cm, the output fault message "Please improve water quality" will be displayed. When the suction pressure and discharge pressure of the secondary compressor are both between -1 and 1 bar, the output fault message "Secondary compressor has no pressure" is displayed. When the difference between the intake pressure and the exhaust pressure does not exceed [2] bar and is simultaneously lower than [9] bar, the output fault message "Secondary compressor pressure is low" is displayed.

[0033] ② When the tester needs the JK system to perform a self-test, turn on the self-test button of the JK system. After the JK system detects that the 12V power switch signal is high, it will perform fault signal detection on the self-test circuit board. If the signal is low, it will prompt the tester to turn on the 12V self-test power switch. If the tester presses the self-test button of the JK system within 5 minutes (the 12V power switch signal is high), the JK system will perform fault signal detection on the self-test circuit board. If the tester does not press the self-test button of the JK system within 5 minutes (the 12V power switch signal is low), the JK system will enter the inspection mode. Detecting fault signals on the self-test circuit board: If there is no fault signal on the self-test circuit board, start the power-on signal detection of the test chamber; if there is a fault signal on the self-test circuit board, it indicates that the self-test circuit board is faulty. After shutting down the 12V self-test power supply, enter the inspection mode. Test chamber power-on signal detection: When the test chamber power-on signal is high, the test chamber self-test begins. The PLC sends power-on commands to each circulating fan in sequence. The self-test circuit board powers on two circulating fans in sequence to perform the self-test of the circulating fans. When the test chamber power-on signal is low, wait for the test chamber to be powered on.

[0034] ③ Self-test of circulating fans: Each time a fan is started, the power-on signal of the test chamber is checked. When the power-on signal of the test chamber is high, the frequency of the fan is checked after the fan runs for 10 seconds. If the frequency is not within the range of

[1000] ±

[100] Hz, the fan is prompted to be checked. A low-level power-on signal indicates that the fan is leaking electricity.

[0035] ④ Solenoid valve self-test: After the circulating fan completes its self-test, the PLC sends a power-on command to each solenoid valve coil (usually 7 in total) in sequence, with a power-on interval of 2 seconds between each solenoid valve. Normal operation occurs when both the voltage and current of the solenoid valve are at high or low levels. Otherwise, it indicates an abnormality in the solenoid valve, prompting you to check it. While each solenoid valve is activated, check if the power-on signal of the test chamber is at a high level. A high level indicates normal operation, while a non-high level indicates that the solenoid valve is leaking current.

[0036] ⑤ Heating circuit self-test: After the solenoid valve completes its self-test, the heating circuit is started for testing; The voltage of the solid-state relay coil is heated; a high level is represented by 1 when there is voltage and a low level is represented by 0 when there is no voltage. The voltage of the heating AC contactor coil is represented by 1 when there is voltage and 0 when there is no voltage. The three-phase heating currents are 1, 2, and 3. When there is current, the high level is represented by 1, and when there is no current, the low level is represented by 0. The above test results are normal when they are 00000, 11111, 01000, and 10000 respectively. When the value is 01111 / 01011 / 01101 / 01110 / 01001 / 01010 / 01100, a prompt will appear indicating that the heating solid-state relay needs to be checked. When the value is 10111 / 10011 / 10101 / 10110 / 10001 / 10010 / 10100, a prompt will appear indicating that the heating AC contactor needs to be checked. When the value is 00111 / 00011 / 00101 / 00110 / 00001 / 00010 / 00100, a prompt will appear indicating that the heating solid-state and AC contactors need to be checked. When the value is 11011 / 11101 / 11110 / 11001 / 11010 / 1110, a prompt will appear indicating that the heating wire needs to be checked. While the heating circuit is powered on for self-test, the power-on signal of the test chamber is detected. When the power-on signal of the test chamber is high (1), it is normal. When it is low (0), the output indicates that the heating circuit is leaking current.

[0037] ⑥ Humidification circuit self-test: After the heating circuit completes its self-test, the humidification circuit is activated for testing; The coil voltage of the humidifying solid-state relay is represented by 1 when there is voltage and 0 when there is no voltage. The humidifier AC contactor coil voltage is represented by 1 when there is voltage and 0 when there is no voltage. The three-phase humidification currents are 1, 2, and 3. When there is current, the level is high (represented by 1) and when there is no current, the level is low (represented by 0). The above test results are normal when they are 00000, 11111, 01000, and 10000 respectively. When the value is 01111 / 01011 / 01101 / 01110 / 01001 / 01010 / 01100, a prompt will appear indicating that the humidification solid-state relay needs to be checked. When the value is 10111 / 10011 / 10101 / 10110 / 10001 / 10010 / 10100, a prompt will appear indicating that the humidifying AC contactor needs to be checked. When the value is 00111 / 00011 / 00101 / 00110 / 00001 / 00010 / 00100, a prompt will appear indicating that the humidifier solid-state and AC contactor should be checked. When the value is 11011 / 11101 / 11110 / 11001 / 11010 / 1110, a prompt will appear indicating that the humidifier should be checked. While the humidification circuit is powered on for self-test, the power-on signal of the test chamber is detected. When the power-on signal of the test chamber is high (1), it is normal. When it is low (0), the output indicates that the humidification circuit is leaking current.

[0038] ⑦ Secondary compressor pressure self-check: After the humidification circuit self-check is completed, the secondary compressor pressure self-check is performed. When the suction pressure and discharge pressure of the secondary compressor are both between -1 and 1 bar, the output fault message "secondary compressor has no pressure" is displayed. When the suction pressure and discharge pressure are not more than 2 bar apart and are both lower than 9 bar, the output fault message "secondary compressor pressure is low" is displayed.

[0039] ⑧ Self-test ends: After the pressure self-test of the secondary compressor ends, the CPU sends a power-off command to the self-test circuit board. All components are powered off during the self-test process. In order to ensure that all components are powered off during the self-test process, monitor the fault signal of the self-test circuit board. When it is low level (0), proceed to the next inspection. When it is high level (1), indicate that the self-test circuit board is faulty and the 12V self-test power supply needs to be manually turned off.

[0040] Inspection of basic parameters of the test chamber: The system measures ambient temperature or water temperature, condensation temperature, anti-dry-burning temperature, water conductivity, suction pressure of the secondary compressor, and discharge pressure of the secondary compressor.

[0041] The test results are as follows: When the water temperature or ambient temperature is higher than the normal threshold setting

[30] ℃, the output fault message "Please lower the ambient temperature or water temperature" will be displayed. When the condensing temperature is higher than the normal threshold setting

[38] ℃, the output fault message "Please clean the condenser" will be displayed; When the anti-dry-burning temperature exceeds the normal threshold setting of

[110] ℃, the output fault message "humidifier box is short of water" will be displayed. When the water conductivity is higher than the normal threshold setting

[20] μS / cm, the output fault message "Please improve water quality" will be displayed. When the suction pressure and discharge pressure of the secondary compressor are both between -1 and 1 bar, the output fault message "Secondary compressor has no pressure" is displayed. When the difference between the intake pressure and the exhaust pressure does not exceed [2] bar and is simultaneously lower than [9] bar, the output fault message "Secondary compressor pressure is low" is displayed.

[0042] Circulating fan inspection: When the primary compressor has current, or the heating circuit has current, or the humidification circuit has current at a high level (1), check the frequency of the circulating fan after 10 seconds. If the frequency is not within the range of

[1000] ±

[100] Hz, prompt to check the circulating fan; When the current in the primary compressor, heating circuit, and humidification circuit is low (0), the heating circuit is inspected.

[0043] Heating circuit inspection: Detect the voltage of the heating solid-state relay coil. A high level is represented by 1 when there is voltage and a low level is represented by 0 when there is no voltage. The voltage of the heating AC contactor coil is represented by 1 when there is voltage and 0 when there is no voltage. The three-phase heating currents are 1, 2, and 3. When there is current, the high level is represented by 1, and when there is no current, the low level is represented by 0. The above test results are normal when they are 00000, 11111, 01000, and 10000 respectively. When the value is 01111 / 01011 / 01101 / 01110 / 01001 / 01010 / 01100, a prompt will appear indicating that the heating solid-state relay needs to be checked. When the value is 10111 / 10011 / 10101 / 10110 / 10001 / 10010 / 10100, a prompt will appear indicating that the heating AC contactor needs to be checked. When the value is 00111 / 00011 / 00101 / 00110 / 00001 / 00010 / 00100, a prompt will appear indicating that the heating solid-state and AC contactors need to be checked. When the value is 11011 / 11101 / 11110 / 11001 / 11010 / 1110, a prompt will appear indicating that the heating wire needs to be checked.

[0044] Humidifier circuit inspection: Detect the voltage of the humidifier solid-state relay coil. A high level is indicated by 1 when there is voltage and a low level is indicated by 0 when there is no voltage. The humidifier AC contactor coil voltage is represented by 1 when there is voltage and 0 when there is no voltage. The three-phase humidification currents are 1, 2, and 3. When there is current, the level is high (represented by 1) and when there is no current, the level is low (represented by 0). The above test results are normal when they are 00000, 11111, 01000, and 10000 respectively. When the value is 01111 / 01011 / 01101 / 01110 / 01001 / 01010 / 01100, a prompt will appear indicating that the humidification solid-state relay needs to be checked. When the value is 10111 / 10011 / 10101 / 10110 / 10001 / 10010 / 10100, a prompt will appear indicating that the humidifying AC contactor needs to be checked. When the value is 00111 / 00011 / 00101 / 00110 / 00001 / 00010 / 00100, a prompt will appear indicating that the humidifier solid-state and AC contactor should be checked. When the value is 11011 / 11101 / 11110 / 11001 / 11010 / 1110, a prompt will appear indicating that the humidifier rod needs to be checked.

[0045] Test chamber power-on detection: The test chamber is powered on when the power-on signal is high (1) and not powered on when the power-on signal is low (0). When the power-on signal of the test chamber is high (1), the next step of compressor current inspection is performed. When the power-on signal of the test chamber is low (0), the inspection ends.

[0046] Compressor current inspection: Detect the current of the primary compressor and the secondary compressor. When either compressor has current, perform a condenser fan inspection. When neither compressor has current, return to the start of the inspection and begin the next round of inspection.

[0047] Condenser fan inspection: If there is current in either the primary compressor or the secondary compressor, check the condenser fan frequency after 10 seconds. If the frequency is not within the range of

[1000] ±

[100] Hz, prompt to check the condenser fan. After the test is completed, perform a primary compressor fan inspection.

[0048] First-stage compressor fan inspection: Check if there is current in the first-stage compressor. If there is current, check the compressor fan frequency 10 seconds later. If the frequency is not within the range of

[1000] ±

[100] Hz, prompt to check the first-stage compressor fan; if there is no current in the first-stage compressor, proceed to the second-stage compressor fan inspection.

[0049] Secondary compressor fan inspection: Check if there is current in the secondary compressor. If there is current, check the compressor fan frequency 10 seconds later. If the frequency is not within the range of

[1000] ±

[100] Hz, prompt to check the secondary compressor fan; if there is no current in the secondary compressor, perform a primary compressor refrigeration solenoid valve inspection.

[0050] Inspection of the first-stage compressor refrigeration solenoid valve: Detect the current and voltage of the coil of the first-stage compressor refrigeration solenoid valve. When both the voltage and current of the solenoid valve are at a high level (current and voltage 11), perform an inspection of the first-stage compressor refrigeration expansion valve. When both the voltage and current of the solenoid valve are at low levels (no current, voltage 00), perform a routine inspection of the liquid-dispensing solenoid valve of the first-stage compressor. When the voltage and current of the solenoid valve are (01 / 10), it indicates that the first-stage compressor refrigeration solenoid valve should be checked.

[0051] Inspection of the first-stage compressor refrigeration expansion valve: Check that the voltage and current of the solenoid valve are both at a high level (current and voltage 11). After 2 seconds, check that the expansion temperature is ≤ [-20℃], which is normal. Proceed to the first-stage compressor liquid separator solenoid valve inspection. If the temperature is not within the range, prompt to check the first-stage compressor refrigeration expansion valve.

[0052] Inspection of the liquid distribution solenoid valve of the first stage compressor: Detect the current and voltage of the coil of the liquid distribution solenoid valve of the first stage compressor. When both the voltage and current of the solenoid valve are at a high level (current and voltage 11), perform an inspection of the liquid distribution expansion valve of the first stage compressor. When both the voltage and current of the solenoid valve are at low levels (no current, voltage 00), perform a routine inspection of the primary compressor's wet and hot refrigeration solenoid valve. When the voltage and current of the solenoid valve are (01 / 10), a prompt will appear indicating that the liquid distribution solenoid valve of the first-stage compressor needs to be checked.

[0053] Inspection of the liquid distribution expansion valve of the first-stage compressor: Check that the voltage and current of the solenoid valve are both at a high level (current and voltage 11). After 2 seconds, check that the expansion temperature is ≤ [-20℃], which is normal. Proceed to the inspection of the wet and hot refrigeration solenoid valve of the first-stage compressor. If the temperature is outside the range, check the liquid distribution expansion valve of the primary compressor.

[0054] Inspection of the solenoid valve for damp heat refrigeration of the first-stage compressor: Detect the current and voltage of the solenoid valve coil for damp heat refrigeration of the first-stage compressor. When both the voltage and current of the solenoid valve are at a high level (current and voltage 11), perform an inspection of the expansion valve for damp heat refrigeration of the first-stage compressor. When both the voltage and current of the solenoid valve are at low levels (no current, voltage 00), perform a routine inspection of the dehumidification solenoid valve of the first-stage compressor. When the voltage and current of the solenoid valve are (01 / 10), it indicates that the wet and hot refrigeration solenoid valve of the first-stage compressor needs to be checked.

[0055] Inspection of the expansion valve for damp heat refrigeration in the first stage compressor: Check that the voltage and current of the solenoid valve are both at a high level (current and voltage 11). After 2 seconds, check that the expansion temperature is ≤ [-20℃], which is normal. Proceed to the inspection of the dehumidification solenoid valve of the first stage compressor. If the temperature is outside the range, check the damp heat refrigeration expansion valve of the primary compressor.

[0056] Inspection of the dehumidification solenoid valve of the first-stage compressor: Detect the current and voltage of the coil of the dehumidification solenoid valve of the first-stage compressor. When both the voltage and current of the solenoid valve are at a high level (current and voltage 11), perform an inspection of the dehumidification expansion valve of the first-stage compressor. When both the voltage and current of the solenoid valve are at low levels (no current, voltage 00), perform a routine inspection of the main refrigeration solenoid valve of the secondary compressor. When the voltage and current of the solenoid valve are (01 / 10), a prompt will appear indicating that the dehumidification solenoid valve of the first-stage compressor needs to be checked.

[0057] Inspection of the dehumidification expansion valve of the first-stage compressor: Check that the voltage and current of the solenoid valve are both at a high level (current and voltage 11). After 2 seconds, check that the expansion temperature is ≤ [-20℃], which is normal. Proceed to the inspection of the main refrigeration solenoid valve of the second-stage compressor. If the temperature is outside the range, please check the dehumidification expansion valve of the primary compressor.

[0058] Inspection of the main refrigeration solenoid valve of the second-stage compressor: Detect the current and voltage of the coil of the main refrigeration solenoid valve of the second-stage compressor. When both the voltage and current of the solenoid valve are at a high level (current and voltage 11), perform an inspection of the main refrigeration expansion valve of the second-stage compressor. When both the voltage and current of the solenoid valve are at low levels (no current, voltage 00), perform a routine inspection of the auxiliary refrigeration solenoid valve of the secondary compressor. When the voltage and current of the solenoid valve are (01 / 10), a prompt will appear indicating that the main refrigeration solenoid valve of the secondary compressor needs to be checked.

[0059] Inspection of the main refrigeration expansion valve of the second-stage compressor: Check that the voltage and current of the solenoid valve are both at a high level (current and voltage 11). After 2 seconds, check that the expansion temperature is ≤ [-20℃], which is normal. Proceed to the inspection of the auxiliary refrigeration solenoid valve of the second-stage compressor. If the temperature is outside the range, check the main refrigeration expansion valve of the secondary compressor.

[0060] Inspection of the auxiliary refrigeration solenoid valve of the second-stage compressor: Detect the current and voltage of the coil of the auxiliary refrigeration solenoid valve of the second-stage compressor. When both the voltage and current of the solenoid valve are at a high level (current and voltage 11), perform an inspection of the expansion valve of the auxiliary refrigeration of the second-stage compressor. When both the voltage and current of the solenoid valve are at low levels (no current, voltage 00), perform a routine inspection of the liquid-dispensing solenoid valve of the secondary compressor. When the voltage and current of the solenoid valve are (01 / 10), it indicates that the auxiliary refrigeration solenoid valve of the first-stage compressor should be checked.

[0061] Secondary compressor auxiliary refrigeration expansion valve inspection: Check that the voltage and current of the solenoid valve are both at a high level (current and voltage 11). After 2 seconds, check that the expansion temperature is ≤ [-20℃], which is normal. Proceed to the secondary compressor liquid separator solenoid valve inspection. If the temperature is outside the range, check the auxiliary refrigeration expansion valve of the secondary compressor.

[0062] Inspection of the liquid distribution solenoid valve of the second-stage compressor: Detect the current and voltage of the coil of the liquid distribution solenoid valve of the second-stage compressor. When both the voltage and current of the solenoid valve are at a high level (current and voltage 11), perform an inspection of the liquid distribution expansion valve of the second-stage compressor. When the voltage and current of the solenoid valve are both at a low level (no current, voltage 00), the power-on signal of the test chamber is checked. When the voltage and current of the solenoid valve are (01 / 10), a prompt will appear indicating that the liquid distribution solenoid valve of the secondary compressor needs to be checked.

[0063] Inspection of the liquid distribution expansion valve of the secondary compressor: Check that the voltage and current of the solenoid valve are both at a high level with current and voltage of 11. After 2 seconds, check that the expansion temperature is ≤ [-20℃], which is normal. Then proceed to the power-on signal inspection of the test chamber. If the temperature is outside the range, check the liquid distribution expansion valve of the secondary compressor.

[0064] Test chamber power-on signal inspection: When the test chamber power-on signal is 0, the inspection ends because the chamber is not powered on. When the test chamber power-on signal is 1, the chamber is powered on normally and enters the compressor current inspection.

[0065] Compressor current inspection: Detect the current of the first-stage compressor and the second-stage compressor. When both the first-stage and second-stage compressors have current, perform a pressure inspection of the second-stage compressor. In all other cases, return to the start of the inspection and begin the next round of inspections.

[0066] Secondary compressor pressure inspection: After the secondary compressor has current for 2 minutes, check the discharge pressure. When the condensing temperature is normal and the primary compressor refrigeration solenoid valve and the primary compressor refrigeration expansion valve are normal, the discharge pressure ≤

[20] bar is normal. If it is not within the range, it indicates that the primary compressor is short of refrigerant. After the secondary compressor has current for 2 minutes, the suction pressure is checked. The suction pressure is ≤ [2] bar, which is normal. If it is not within the range, the low temperature compressor should be checked. After the test is completed, the power-on signal of the test chamber is checked.

[0067] Test chamber power-on signal inspection: When the test chamber power-on signal is 0, the inspection ends because the chamber is not powered on. When the test chamber power-on signal is 1, the chamber is powered on normally and the inspection returns to the beginning, starting the next round of inspection.

[0068] The following points should be noted in this article: 1. The accompanying drawings of the embodiments disclosed herein only relate to the structures involved in the embodiments disclosed herein; other structures can be referred to in general design.

[0069] 2. Where there is no conflict, the embodiments of this disclosure and the features in the embodiments can be combined with each other to obtain new embodiments.

[0070] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

Claims

1. A fault self-diagnosis system for a high and low temperature humidity test chamber, characterized in that, Includes sensor modules, self-diagnostic system circuit boards, PLC controllers, and alarm modules; The sensor module collects the working signals of each component of the test chamber and transmits them to the self-diagnostic system circuit board. The PLC controller controls the self-test and inspection process. The alarm module outputs prompt information based on the fault judgment result. The fault self-diagnosis system is used to diagnose faults in the high and low temperature humidity test chamber, which includes a cascade refrigeration system, a heating wire heating system, a boiler humidification system, and a circulating fan. The cascade refrigeration system includes a compressor, a compressor fan, a condenser, a plate heat exchanger, an evaporator, a solenoid valve, and an expansion valve; the heating wire system includes a heating plate, a heating wire, and a solid-state relay; and the boiler humidification system includes a humidification boiler water supply system, a humidification rod, and a solid-state relay.

2. The fault self-diagnosis system for the high and low temperature humidity test chamber according to claim 1, characterized in that, The sensor module includes a pressure sensor, a temperature sensor, a speed sensor, a conductivity sensor, and a current transformer. The pressure sensor is used to detect the compressor's suction pressure and discharge pressure; the temperature sensor is used to detect the ambient temperature, water temperature, condensing temperature, anti-dry burning temperature, and expansion valve temperature; the speed sensor is used to detect the fan frequency; the conductivity sensor is used to detect the water conductivity; and the current transformer is used to detect the current signals of the compressor, heating circuit, and humidification circuit.

3. The fault self-diagnosis system for the high and low temperature humidity test chamber according to claim 1, characterized in that, The self-diagnostic system circuit board is equipped with standardized input channels. The channel numbering rule is as follows: the first digit represents the monitoring category, the second digit represents the component type, the third and fourth digits represent the serial number, and the letter represents the signal type. The monitoring categories include basic monitoring items, compressors, solenoid valves, expansion valves, fans, solid-state relays, and AC contactors.

4. The fault self-diagnosis system for the high and low temperature humidity test chamber according to claim 1, characterized in that, The self-diagnosis function of the fault self-diagnosis system includes the following steps: S1. Receives a 12V self-test power switch signal and detects the fault status of the self-test circuit board; S2. If the self-test circuit board is fault-free, test the power-on signal of the test chamber; S3. When the power-on signal is high, the circulating fan, solenoid valve, heating circuit, humidification circuit and secondary compressor are powered on and tested in sequence, and the status of the components is judged according to the signals collected by the sensors and the preset standards. S4. When the power-on signal is low, wait for the test chamber to be powered on.

5. The fault self-diagnosis system for the high and low temperature humidity test chamber according to claim 4, characterized in that, The self-test steps for the circulating fan are as follows: S1. After the fan is powered on and running for 10 seconds, the fan frequency is detected. If the frequency is not within the range of [1000] ± [100] Hz, a fault prompt is output. S2. Detects the power-on signal of the test chamber. When the signal is low, it outputs a fan leakage warning.

6. The fault self-diagnosis system for the high and low temperature humidity test chamber according to claim 4, characterized in that, The self-test steps for the solenoid valve are as follows: S1.PLC energizes each solenoid valve coil sequentially, with an interval of 2 seconds between energizations. S2. Detect the voltage and current signals of the solenoid valve. If both are high or both are low, it is considered normal. Otherwise, output a solenoid valve abnormality prompt. S3. Synchronously detects the power-on signal of the test chamber, and outputs a solenoid valve leakage warning when the signal is not high.

7. The fault self-diagnosis system for the high and low temperature humidity test chamber according to claim 4, characterized in that, The self-test steps for the heating circuit are as follows: S1. Detect the coil voltage of the heating solid-state relay, the coil voltage of the heating AC contactor, and the three-phase heating current, and determine the normal state or fault type based on the signal combination; S2. The fault types include heating solid-state relay faults, heating AC contactor faults, heating solid-state and AC contactor faults, and heating wire faults; S3. Synchronously detects the power-on signal of the test chamber. When the signal is low, it outputs a leakage warning for the heating circuit.

8. The fault self-diagnosis system for the high and low temperature humidity test chamber according to claim 1, characterized in that, The self-diagnostic fault system's inspection functions include basic parameter inspection, circulating fan inspection, heating circuit inspection, humidification circuit inspection, compressor current inspection, condenser fan inspection, solenoid valve inspection, expansion valve inspection, and compressor pressure inspection. Each inspection module is linked sequentially according to preset logic to monitor the operating status of components in real time.

9. The fault self-diagnosis system for a high and low temperature humidity test chamber according to claim 1, characterized in that, The preset thresholds of the self-diagnostic system circuit board include ambient temperature ≤ [30]℃, condensation temperature ≤ [38]℃, anti-dry burning temperature ≤ [110]℃, water conductivity ≤ [20]μS / cm, secondary compressor exhaust pressure ≤ [20]bar, and suction pressure ≤ [2]bar. The thresholds can be adjusted by the installation engineer according to the actual situation.

10. A fault self-diagnosis system for a high and low temperature humidity test chamber according to claim 1, characterized in that, The alarm module outputs fault information through audible and visual prompts and text display. The fault information includes "Please lower the ambient temperature or water temperature", "Please clean the condenser", "Humidifier box is short of water", "Please improve water quality", "Secondary compressor has no pressure", "Secondary compressor has low pressure", and abnormal prompts for each component, so as to achieve accurate fault tracing.

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