High and low temperature environment testing device

Abstract

The utility model discloses a high low temperature environment testing arrangement, including main control unit, power module, communication module and test interface module, wherein power module electrically connected to main control unit, communication module is connected with main control unit signal, and communication module includes at least one way isolation RS485 communication circuit and at least one way isolation CAN communication circuit, test interface module is connected with main control unit signal, and test interface module includes at least two kinds of test circuit selected from following group: isolation passive output circuit, isolation active input sampling circuit and isolation passive input detection circuit, communication module and test interface module are electrically isolated with main control unit. The utility model discloses through wide temperature design and comprehensive electrical isolation, has guaranteed the high reliability and security of test system under high low temperature environment (-40 DEG C~85 DEG C), and has improved test efficiency through cascading architecture and automation process.

Description

Technical Field

[0001] This utility model belongs to the field of power terminal testing, and in particular, it is a high and low temperature environment testing device. Background Technology

[0002] Various power terminal equipment, such as concentrators, dedicated transformer terminals, and energy controllers, are widely deployed outdoors and must withstand harsh natural environments, ranging from extreme cold to extreme heat, and high humidity. Therefore, conducting comprehensive and rigorous testing and verification of the functional integrity and performance stability of products under extreme operating environments, especially high and low temperature environments (e.g., -40℃ to 85℃), before they leave the factory is a core element in ensuring product quality, reducing field failure rates, and ensuring power grid safety. This has extremely important engineering significance and research value.

[0003] Currently, testing and verification of power terminal equipment are primarily conducted on ambient temperature test platforms in a laboratory environment. A typical testing method involves setting up a test bench equipped with a standard power supply, load simulator, signal generator, and measuring instruments such as oscilloscopes and multimeters. During testing, the tester manually connects the terminal under test (DUT) to the test bench. Based on the test cases, the tester manually or via host computer software controls the instruments to input excitation signals to various functional interfaces of the DUT (such as remote signaling, remote control, and pulse signals). Simultaneously, measuring instruments are used to observe the signal waveforms, level states, or communication messages at the corresponding output ports to determine the correctness of its functional logic. For communication interfaces (such as RS485 and CAN), a PC is typically used with a corresponding interface converter for message transmission, reception, and verification. This test bench-based verification method effectively verifies the basic functions and electrical characteristics of terminal equipment under ambient temperature conditions and is a common functional verification method in product development and production stages.

[0004] However, existing testing methods suffer from several key technical challenges when addressing the need for large-scale, all-environment adaptability testing. These include insufficient environmental tolerance of testing equipment, lack of electrical isolation in testing systems, and difficulty in achieving automated closed-loop verification under high and low temperature environments. These issues collectively limit the depth, efficiency, and reliability of testing. Utility Model Content

[0005] Purpose of the utility model: To provide a high and low temperature environment testing device to solve the above-mentioned problems existing in the prior art.

[0006] Technical solution: A high and low temperature environment testing device, comprising:

[0007] Main control unit;

[0008] The power supply module is electrically connected to the main control unit;

[0009] A communication module is connected to the main control unit via signals, and the communication module includes at least one isolated RS485 communication circuit and at least one isolated CAN communication circuit.

[0010] The test interface module is connected to the main control unit via signals, and the test interface module includes at least two test circuits selected from the group consisting of: isolated passive output circuit, isolated active input sampling circuit, and isolated passive input detection circuit.

[0011] The communication module and the test interface module are electrically isolated from the main control unit.

[0012] According to one aspect of this application, the isolated passive output circuit includes an optocoupler; the input of the optocoupler is configured to receive a drive signal from a main control unit, and the output of the optocoupler is configured to connect to a passive input terminal of the terminal under test.

[0013] According to one aspect of this application, the isolated active input sampling circuit includes a voltage sampling circuit and an optocoupler;

[0014] The voltage sampling circuit has an input node configured to connect to the active output terminal of the terminal under test;

[0015] The input terminal of the optocoupler is connected to the output terminal of the voltage sampling circuit, and the output terminal of the optocoupler is connected to the analog-to-digital conversion input pin signal of the main control unit.

[0016] According to one aspect of this application, the isolated passive input detection circuit includes an isolated DC voltage source, a pull-up resistor, a voltage sampling circuit, and an optocoupler;

[0017] The pull-up resistor is connected to the isolated DC voltage source;

[0018] The voltage sampling circuit has a detection node configured to connect to a passive contact of the terminal under test, and the detection node is connected to a pull-up resistor.

[0019] The input terminal of the optocoupler is connected to the output terminal of the voltage sampling circuit, and the output terminal of the optocoupler is connected to the analog-to-digital conversion input pin signal of the main control unit.

[0020] According to one aspect of this application, the isolated RS485 communication circuit includes an RS485 transceiver, a signal isolator, and a first isolated power supply circuit.

[0021] The signal isolator is positioned between the main control unit and the logic pins of the RS485 transceiver;

[0022] The first isolation power supply circuit is configured to provide isolated power to the RS485 transceiver.

[0023] According to one aspect of this application, the isolated CAN communication circuit includes a CAN transceiver, a signal isolator, and a second isolated power supply circuit.

[0024] The signal isolator is positioned between the main control unit and the logic pins of the CAN transceiver;

[0025] The second isolation power supply circuit is configured to provide isolated power to the CAN transceiver.

[0026] According to one aspect of this application, the communication module includes at least two isolated RS485 communication circuits.

[0027] According to one aspect of this application, the power module includes a first input terminal connected to an external DC power input terminal, a non-isolated power conversion circuit, and an isolated DC-DC conversion circuit;

[0028] The non-isolated power conversion circuit is connected to the first input terminal, and the isolated DC-DC conversion circuit is connected to the first input terminal.

[0029] According to one aspect of this application, the output of the non-isolated power conversion circuit is connected to the main control unit to provide the main operating voltage to the main control unit.

[0030] According to one aspect of this application, the output terminal of the isolated DC-DC conversion circuit constitutes an isolated power supply output terminal, which is electrically connected to a communication module and / or a test interface module for supplying power to the isolated side of the isolated circuit.

[0031] Beneficial effects: This utility model ensures high reliability and safety of the test system in high and low temperature environments (-40℃~85℃) through wide temperature design and comprehensive electrical isolation, and improves test efficiency through cascaded architecture and automated processes. Attached Figure Description

[0032] Figure 1 A system architecture diagram of the high and low temperature environment testing device provided in this embodiment of the utility model.

[0033] Figure 2 A system flowchart of the high and low temperature environment testing device provided in this embodiment of the utility model.

[0034] Figure 3 The circuit diagram of the main control unit and its peripheral components provided in the embodiments of this utility model.

[0035] Figure 4 An isolated DC-DC conversion circuit diagram provided for an embodiment of this utility model.

[0036] Figure 5 An isolated passive output circuit diagram provided for an embodiment of this utility model. Detailed Implementation

[0037] The study revealed that the fundamental limitation of testing equipment is its severely insufficient environmental tolerance. Traditional testing instruments and control units (such as PCs and data acquisition cards) typically use commercial-grade or general industrial-grade components for their core processing and communication chips, with a rated operating temperature range of 0°C to 70°C. When high and low temperature tests are required, ranging from -40°C to 85°C, placing these control and measurement devices together in a temperature chamber risks a sharp decline in performance, data transmission errors, or even permanent damage due to exceeding their operating temperature range, leading to inaccurate test results or forced test interruption. Furthermore, existing testing systems generally lack effective electrical isolation, posing serious safety and reliability risks. In manually constructed testing environments, the control computer, instruments, and the terminal under test (DUT) are often directly connected via ordinary non-isolated interfaces (such as USB-to-RS485 converters), resulting in the entire testing system sharing a single ground wire. If the DUT generates high voltage or surges due to internal faults or external factors, this high-voltage signal can be reverse-propagated through the signal line or ground wire, directly damaging the control computer's motherboard or expensive testing instruments. The potential risks arising from this lack of isolation render the testing process itself unreliable and could lead to significant financial losses. These two issues together make true automated closed-loop verification difficult to achieve in high and low temperature environments. Because control equipment cannot enter the temperature chamber, testers must place the terminal under test inside, leaving the control and measurement components outside via long cables. This separate testing not only introduces signal attenuation and interference problems, but more importantly, it cannot achieve parallel, automated testing of multiple devices. The entire process still requires significant manual intervention, is inefficient and error-prone, and cannot meet the throughput requirements for high and low temperature aging and testing during mass production of terminal equipment, nor can it accurately verify the dynamic response of the equipment under extreme temperatures.

[0038] like Figure 1 and Figure 2 As shown, a high and low temperature environment testing device is provided. The system adopts a hierarchical architecture of main control + functional modules, consisting of a main control unit, a power supply module, a communication module, and a test interface module. The main control unit is the core of the entire device, responsible for receiving instructions from the host computer, controlling the functional modules to execute test actions, and processing and transmitting test data. In this embodiment, the main control unit can specifically be an STM32F412RET6 microcontroller (U100). This microcontroller is chosen because its operating junction temperature range is -40℃ to 125℃, which, compared to the 0℃ to 70℃ operating range of conventional industrial-grade chips, provides wider temperature adaptability. This ensures that the testing device can operate stably for a long time in harsh high and low temperature chamber environments ranging from -40℃ to 85℃, providing a fundamental guarantee for the accuracy and reliability of the tests.

[0039] Specifically, the functional modules include a power supply module that provides the required operating voltage for the entire system, a communication module responsible for data interaction with the host computer and the terminal under test, and a test interface module that connects directly to the low-voltage terminals of the terminal under test to perform specific test actions. This modular design decouples the main control unit from the specific functional execution units, which not only simplifies system maintenance but also facilitates subsequent functional expansion.

[0040] In a further embodiment of this invention, the workflow of the high and low temperature environment testing device forms an automated closed-loop testing system, specifically including the following steps:

[0041] Step one: The host computer, such as a personal computer (PC), sends test commands to the testing device through the communication interface according to the preset test items. For example, the host computer can send a command requesting the testing device to perform a simulated alarm function test on the connected Type III transformer terminal.

[0042] Step two: After receiving the instruction, the main control unit of the device parses it and drives the corresponding functional modules to execute specific test actions according to the instruction content. Optionally, the main control unit will control the isolated passive output circuit in the test interface module to generate a simulated alarm signal.

[0043] Step 3: After receiving the analog signal or a change in state, the terminal under test connected to the testing device will take corresponding actions and return data indicating its current state through its own communication port.

[0044] Step four: The communication module of the test device captures the data returned by the terminal under test and transmits it to the main control unit. The main control unit analyzes the data, determines whether it matches the expected results, and packages the final test results (e.g., alarm test passed or alarm test failed) and returns them to the host computer for recording and display.

[0045] Through the above steps, this device achieves automated closed-loop verification of terminal functions. Compared with traditional testing methods that rely on manual operation and oscilloscope observation, it improves testing efficiency, shortens the average testing time per terminal, and avoids data inaccuracies caused by human error or equipment failure under extreme temperatures.

[0046] According to one aspect of this application, a high and low temperature environment testing device is provided, the device comprising: a main control unit U100; a power supply module electrically connected to the main control unit U100; a communication module signal-connected to the main control unit U100, the communication module including at least one isolated RS485 communication circuit and at least one isolated CAN communication circuit; and a test interface module signal-connected to the main control unit U100, the test interface module including at least two test circuits selected from the group consisting of: an isolated passive output circuit, an isolated active input sampling circuit, and an isolated passive input detection circuit.

[0047] Specifically, such as Figure 3As shown, the main control unit U100 is the control center of the entire device. In this embodiment, it can preferably be an STM32F412RET6 microcontroller from STMicroelectronics. The VDD and VDDA power supply pins of the main control unit U100 are connected to the 3.3V operating voltage VDD3V3 output by the power supply module to obtain a stable power supply. Specifically, pin 1 of the main control unit U100 is connected to the power supply; pin 7 of the main control unit U100 is connected to one end of the voltage suppression diode F100, and the other end of the voltage suppression diode F100 is grounded; pin 12 of the main control unit U100 is grounded; pin 13 of the main control unit U100 is connected to the power supply; pin 18 of the main control unit U100 is grounded; pin 19 of the main control unit U100 is connected to the power supply; pin 30 of the main control unit U100 is simultaneously connected to one end of capacitors C109 and C111; and the other ends of capacitors C109 and C111 are simultaneously connected to the main control unit U100. Pin 31 of unit U100 is connected to ground, pin 32 of main control unit U100 is connected to power, pin 47 of main control unit U100 is grounded, pin 48 of main control unit U100 is connected to power, pin 61 of main control unit U100 is connected to one end of voltage suppression diode F103, pin 62 of main control unit U100 is connected to one end of voltage suppression diode F102, the other ends of voltage suppression diodes F103 and F102 are grounded, pin 63 of main control unit U100 is grounded, and pin 64 of main control unit U100 is connected to power. The peripherals of main control unit U100 include a crystal oscillator and reset circuit to provide a stable operating clock, as well as a debug interface for program writing and online debugging. Specifically, the crystal oscillator circuit includes crystal oscillator G100, capacitor C100, capacitor C105, and resistor R103. Pin 3 of crystal oscillator G100 is connected to one end of capacitor C105. The other end of capacitor C105 is connected to both pin 2 of crystal oscillator G100 and ground. Pin 4 of crystal oscillator G100 is connected to both capacitor C100 and ground. The other end of capacitor C100 is connected to both pin 1 of crystal oscillator G100 and one end of resistor R103. The reset circuit includes resistor R102 and capacitor C103. One end of resistor R102 is connected to the power supply, and the other end of resistor R102 is connected to one end of capacitor C103. The other end of capacitor C103 is grounded. The debugging interface X102 has pin 4 connected to the power supply and pin 1 grounded.

[0048] The power supply module is responsible for converting the externally input DC voltage (e.g., 12V) into various operating voltages required by the system, such as the 3.3V voltage VDD3V3 that powers the main control unit U100 and the 5V voltage VCC5V that powers some peripheral circuits.

[0049] The communication module is used to enable data communication between the main control unit, the host computer, and the terminal under test. This communication module includes at least one isolated RS485 communication circuit for command interaction with the host computer or for cascading multiple test modules to achieve parallel testing. In addition, the communication module also includes at least one isolated Controller Area Network (CAN) communication circuit for communication testing with terminals under test (such as energy controllers) equipped with a CAN interface.

[0050] The test interface module is the interface part that performs specific test functions. This module integrates various types of test circuits to adapt to different test requirements. For example, it includes an isolated passive output circuit for simulating switching signals, an isolated active input sampling circuit for acquiring active voltage signals output by the terminal under test, and an isolated passive input detection circuit for detecting the on / off state of the dry contacts of the terminal under test.

[0051] Furthermore, both the communication module and the test interface module are electrically isolated from the main control unit. Specifically, this electrical isolation is achieved by using digital signal isolators or optocouplers between the signal I / O ports of the main control unit U100 and the communication transceiver or test interface circuit. This electrical isolation design isolates the high voltage, surges, or electrical noise that may exist on the tested terminal side from the control side where the main control unit is located, effectively protecting the main control unit U100 from damage caused by external electrical faults. This enhances the safety, stability, and service life of the test device in complex industrial environments.

[0052] In some alternative implementations, the main control unit U100 can also be replaced with a microcontroller from another brand that also meets the wide operating temperature range requirements, such as certain automotive-grade MCUs. Furthermore, the method of achieving electrical isolation is not limited to optocouplers; for high-speed digital signals, digital isolation chips based on capacitive or magnetic isolation technologies (such as miniature transformers) can be used to achieve higher data transmission rates and lower transmission latency.

[0053] In a further embodiment, the power module includes a first input terminal X100 connected to an external DC power input, a non-isolated power conversion circuit, and an isolated DC-DC conversion circuit. In this embodiment, the first input terminal X100 is a DC power terminal for connecting an external 220VAC to 12VDC power adapter to provide DC 12V ± 5% input power to the entire device.

[0054] The non-isolated power conversion circuit is electrically connected to the first input terminal X100. This non-isolated power conversion circuit can be a high-efficiency switching buck circuit. This circuit steps down the input 12V DC voltage 12V2 to a 3.3V main operating voltage VDD3V3. Correspondingly, the output terminal of the non-isolated power conversion circuit (i.e., the VDD3V3 power network) is connected to multiple power supply pins (such as VDD, VDDA) of the main control unit U100 to provide the main operating voltage for the main control unit, ensuring its normal operation. This provides a stable and efficient power supply to the system's main controller.

[0055] The isolated DC-DC converter circuit is also connected to the first input terminal. It can be directly converted from a 12V input or converted from an intermediate voltage (such as 5V) generated by a non-isolated circuit. Figure 4 As shown, an exemplary isolated DC-DC converter circuit is constructed using an isolated power supply module D114, the specific model of which can be F0505S-2WR. The input terminal VIN (pin 1) of the isolated power supply module is connected to a non-isolated 5V power supply. Pin 2 of the isolated power supply module is simultaneously connected to one end of capacitor C152 and ground. The other end of capacitor C152 is connected to the input terminal VIN (pin 1) of the isolated power supply module. Pin 5 of the isolated power supply module is simultaneously connected to one end of capacitor C151 and ground. The other end of capacitor C151 is connected to the output terminal VOUT (pin 7) of the isolated power supply module. The output terminal VOUT (pin 7) of the isolated power supply module generates a 5V voltage that is electrically isolated from the input side. This output terminal constitutes the isolated power supply output terminal VCC485.

[0056] Optionally, the output terminal VCC485 of the isolated DC-DC converter circuit is electrically connected to the communication module and / or the test interface module to power the isolation side of the isolation circuit. For example, in the communication module, the isolated power supply output terminal VCC485 is specifically used to power the power supply pin VCC of the RS485 transceiver and CAN transceiver. Since these transceivers are interface chips that connect directly to external devices, providing them with an independent isolated power supply creates a floating ground plane (RGND) isolated from the ground plane (GND) of the main control unit U100, thereby cutting off ground loops caused by external ground interference or high voltage intrusion. This is the fundamental guarantee for achieving high-reliability electrical isolation. Similarly, in the test interface module, a similar isolated power supply can be used to power circuit sections that require isolated power supply (such as pull-up power supplies for passive input detection).

[0057] Alternatively, in addition to using a switching buck converter, non-isolated power conversion circuits can also employ linear regulators (LDOs) in scenarios where power consumption and efficiency requirements are not high. LDOs are simple in structure and have low noise. Furthermore, isolated DC-DC conversion circuits are not limited to using off-the-shelf power modules. In situations with specific cost or size requirements, isolated power supplies can be discretely built using a flyback controller chip, an isolation transformer, and external components, achieving greater design flexibility.

[0058] According to one aspect of this application, the communication module includes at least two isolated RS485 communication circuits and at least one isolated CAN communication circuit. The multiple RS485 circuits can provide a dedicated channel for stable command and data interaction with a host computer, and additional channels for connecting one or more terminals under test, or for cascading multiple high and low temperature environment testing devices via an RS485 bus, thereby enabling parallel testing of multiple terminals and improving test throughput.

[0059] Specifically, the isolated RS485 communication circuit includes an RS485 transceiver, a signal isolator, and a first isolation power supply circuit. The signal isolator is positioned between the main control unit and the logic pins of the RS485 transceiver. The first isolation power supply circuit is configured to provide isolated power to the RS485 transceiver. In a specific circuit implementation, the RS485 transceiver can be an HM308SEESA chip, whose A and B pins are connected to an external RS485 bus. The signal isolator can be a multi-channel digital isolation chip, such as the SP201AW-DSWVR. The UART serial port transmit pin (TX) and receive pin (RX) of the main control unit U100 are connected to the logic-side input terminal INA and output terminal OUTB of the signal isolator, respectively. Correspondingly, the isolated-side output terminal OUTA and input terminal INB of the signal isolator are connected to the logic data input pin DI and data output pin RO of the RS485 transceiver. Through this configuration, the digital logic signal path between the main control unit and the RS485 transceiver is isolated. The first isolated power supply circuit, namely the isolated 5V power supply VCC485 generated by the isolated power supply module D114 (F0505S-2WR), is used to supply power to the VCC pin of the RS485 transceiver. In summary, by combining signal isolation and power isolation, electrical isolation between the RS485 communication link and the main control unit is achieved.

[0060] Similarly, the isolated CAN communication circuit includes a CAN transceiver, a signal isolator, and a second isolated power supply circuit. The signal isolator is located between the main control unit and the logic pins of the CAN transceiver. The second isolated power supply circuit is configured to provide isolated power to the CAN transceiver. Specifically, the CAN transceiver can be a CA-IF1042LVS-Q1 chip, whose CANH and CANL pins are used to connect to an external CAN bus. The signal isolator can share the same multi-channel digital isolation chip with the RS485 circuit. Specifically, the CAN transmit pin CANI TX and receive pin CANI RX of the main control unit U100 are connected to the logic side of the signal isolator, and the corresponding pins on its isolation side are connected to the logic input pin TXD and logic output pin RXD of the CAN transceiver. In this embodiment, the second isolated power supply circuit can be the same isolated power supply as the first isolated power supply circuit, namely the isolated 5V power supply VCC485 generated by the isolated power supply module D114, which also powers the VCC pin of the CAN transceiver.

[0061] Research has found that in practical applications of industrial fieldbuses such as RS485 and CAN, ground potential differences may exist between different nodes, and various electromagnetic interferences are easily coupled onto the bus. Without isolation, ground potential differences and interference can be directly conducted to the main control unit through signal and ground lines, potentially causing communication errors or even burning out the main control unit's I / O ports or the entire chip. Therefore, this embodiment employs a dual signal and power isolation design. This isolation scheme effectively avoids ground loop problems and can withstand higher bus common-mode voltages, thus ensuring stable and reliable communication and improving the robustness and safety of the entire test setup.

[0062] In some alternative implementations, to further simplify circuit design and save printed circuit board (PCB) area, a single-chip isolated transceiver integrating signal and power isolation functions can be selected. For example, an integrated isolated RS485 transceiver module or an integrated isolated CAN transceiver module can be selected. Such modules already include a transceiver, isolation unit, and miniature isolated power supply, thereby replacing the discrete solution of signal isolator + transceiver + isolated DC-DC in this embodiment. Furthermore, although only RS485 and CAN communication interfaces are shown in this embodiment, the isolation design concept of this application can also be applied to other communication interfaces that require electrical isolation from external devices, such as SPI, I2C, or UART.

[0063] According to one aspect of this application, the test interface module integrates a variety of electrically isolated test circuits to meet the testing requirements of various low-voltage terminals on power terminal equipment (such as concentrators, dedicated transformer terminals, etc.), including: isolated passive output circuits, isolated active input sampling circuits, and isolated passive input detection circuits.

[0064] The isolated passive output circuit is used to output switching signals to the passive input terminals (such as remote signaling, pulse input, etc.) of the terminal under test. Specifically, the isolated passive output circuit includes an optocoupler; the input terminal of the optocoupler is configured to receive drive signals from the main control unit, and the output terminal of the optocoupler is configured to connect to the passive input terminals of the terminal under test. Figure 5 As shown, taking the EX_YX1 output branch used for simulating remote signals (telecommunications) as an example, the optocoupler D115 can be the LTV816S model. The anode of the input terminal of the optocoupler D115, i.e., the internal light-emitting diode (LED), is connected in series with the collector of a switching transistor V128 (MC9012ST) through a current-limiting resistor R181 (its resistance value is preferably 3.32 kΩ). The base of the transistor V128 is controlled by a general purpose input / output pin (GPIO) of the main control unit U100, i.e., the signal pin marked YX1. The base of the transistor V128 and the signal pin of YX1 are directly connected to resistor R174. The emitter of the transistor V128 is connected to the power supply, and the cathode of the input terminal of the optocoupler D115 is grounded. When the YX1 pin of the main control unit U100 outputs a control signal (e.g., high or low level, depending on the transistor type), transistor V128 conducts, driving current to flow through the input LED of optocoupler D115, causing it to light up. The output of optocoupler D115, i.e., the internal phototransistor, has its collector directly connected to the corresponding pin of terminal X106, forming the EX_YX1 interface for external connection. Users can connect this terminal to the passive input interface of the terminal under test. When the optocoupler is on, its output acts as a closed mechanical contact, thus simulating a switching signal. Utilizing the photoelectric conversion characteristics of the optocoupler, reliable electrical isolation is established between the low-voltage logic control domain of the main control unit (e.g., 3.3V) and the signal detection domain of the terminal under test (which may have unknown floating voltages or higher internal pull-up voltages, such as 12V or 24V), ensuring accurate transmission of control signals and the safety of both devices.

[0065] An isolated active input sampling circuit is used to safely detect and read active voltage signals (such as alarms, status indicators, etc.) output by the terminal under test (DUT). Specifically, the isolated active input sampling circuit includes a voltage sampling circuit and an optocoupler. The voltage sampling circuit has an input node configured to connect to the active output terminal of the DUT. The input of the optocoupler is connected to the output of the voltage sampling circuit, and the output of the optocoupler is connected to the analog-to-digital conversion input pin of the main control unit. Taking an alarm detection circuit as an example, its input node EGJ is used to connect to the active alarm output terminal of the DUT. The voltage sampling circuit mainly consists of voltage divider resistors R188 and R189. When the EGJ node receives a high voltage signal (e.g., DC24V), this voltage is divided by resistors R188 and R189, resulting in a reduced voltage suitable for driving the optocoupler at their connection point. This connection point serves as the output of the voltage sampling circuit and is connected to the LED input of the optocoupler D122 (LTV816S). The phototransistor at the output of optocoupler D122 is connected to a GPIO or analog-to-digital converter (ADC) input pin of the main control unit U100. This allows the main control unit to determine if the tested terminal outputs an alarm signal by monitoring the high or low level of this pin. The isolated active input sampling circuit can safely and isolatedly convert external active signals, which may be as high as tens of volts, into low-voltage logic signals that the microcontroller can recognize, effectively preventing damage to the main control unit from external high voltage.

[0066] An isolated passive input detection circuit is used to detect the on / off state (such as closed / open position feedback) of the passive contacts (or dry contacts) of the terminal under test. Specifically, the isolated passive input detection circuit includes an isolated DC voltage source, a pull-up resistor, a voltage sampling circuit, and an optocoupler; the pull-up resistor is connected to the isolated DC voltage source; the voltage sampling circuit has a detection node configured to connect to the passive contact of the terminal under test, and the detection node is connected to the pull-up resistor; the input terminal of the optocoupler is connected to the output terminal of the voltage sampling circuit, and the output terminal of the optocoupler is connected to the analog-to-digital conversion input pin signal of the main control unit. Taking the EHZ1 branch of the closed detection circuit as an example, the isolated DC voltage source is provided by an isolated DC-DC converter, such as an isolated 5V power supply. The detection node EHZ1 is connected to this isolated 5V power supply through a pull-up resistor R198 (preferably with a resistance value of 5.11kΩ). When the passive contact of the terminal under test connected to EHZ1 is open, the node is pulled up to a 12V high level; when the contact is closed (usually connected to the ground of the terminal under test), the node is pulled down to a low level. The voltage state of node EHZ1 drives the input of optocoupler D123 through a voltage sampling circuit (e.g., a simple current-limiting resistor). The output of optocoupler D123 is connected to the input pin of the main control unit U100. The main control unit can determine the continuity of the passive contact by reading the level state of this pin. Using a clean, isolated power supply (i.e., wet contact method) provided by the test device itself to detect external dry contacts avoids sharing power or ground with the terminal under test, achieving the highest level of electrical isolation and effectively eliminating misjudgments caused by complex external grounding or interference.

[0067] In some alternative implementations, for isolated passive output circuits, photoMOS relays can be used instead of traditional optocouplers. Their outputs are MOSFET switches, offering lower on-resistance, no contact bounce, and longer lifespan. For isolated active input sampling circuits, a voltage comparator can be added after the voltage divider circuit to shape the analog voltage signal into a clear digital signal before driving the optocoupler, improving anti-interference capability and signal judgment accuracy. For isolated passive input detection circuits, the internal isolated DC voltage source can be designed to be multi-adjustable (e.g., 5V / 12V / 24V) to meet the specific requirements of different industries or equipment for dry contact detection voltage (also known as wetting voltage).

[0068] In one embodiment of this application, the specific implementation steps of an automated testing method are as follows:

[0069] Step 1: Connecting and Configuring the Modules. Physically connect and configure one or more test modules described in the preceding embodiments. Specifically, when multiple devices under test (DUTs) need to be tested in parallel, a cascaded architecture can be used, connecting the RS485-I communication interfaces of each test module in parallel to the same RS485 bus. This bus is connected to a host computer (e.g., an industrial PC with test control software). To distinguish the modules on the bus, each module needs to be assigned a unique device address, which can be configured via a DIP switch on the module or through software commands. Simultaneously, connect the test interfaces (various terminals) of each module to the corresponding low-voltage terminals of one DUT using test cables. The entire connected system (including all modules and DUTs) is placed together in a high and low temperature chamber.

[0070] Step Two: Execute Automated Testing. The host computer sends test command frames to the downstream test modules via the RS485 bus according to the pre-edited test script. This command frame contains at least the device address of the target module and specific test operation instructions. Upon receiving the instruction, the test module at the corresponding address will have its main control unit U100 parse the instruction content and drive specific circuits on the test interface module to perform corresponding actions. For example, if the instruction is to simulate a circuit breaker closing, the main control unit will control the corresponding isolated passive output circuit to output a simulated contact closure signal to the terminal under test.

[0071] Step 3: Data Acquisition and Summarization. Upon receiving the test stimulus signal, the terminal under test (DUT) will respond, for example, by reporting a status change message or altering the level of an active output port. The test module captures these responses from the DUT through its communication module or test interface module. The main control unit U100 processes and encapsulates the captured response data or the status of its own actions, and returns the test result data frame to the host computer via the RS485 bus.

[0072] Step 4: Closed-Loop Verification and Report Generation. After receiving the data returned from the test module, the host computer compares it with the preset expected results in the test script. If the actual result matches the expected result, the test item is deemed to have passed; otherwise, it is deemed to have failed. The host computer automatically records each test result, including the test item, input stimulus, actual response, judgment result, and test time, into the test log and test report, thus completing a full automated closed-loop verification.

[0073] Furthermore, a specific application case illustrates the implementation process of this application: In a low-temperature environment of -40℃, two concentrator type I terminals (DUT-A and DUT-B) were tested in parallel for alarm input and door contact functions. Two test modules of this application were selected and labeled as Module A and Module B, respectively. Through software configuration, the RS485 address of Module A was set to 0x01, and the address of Module B was set to 0x02. The RS485-I interfaces of Module A and Module B were connected in parallel to the RS485 bus connected to the host computer. The isolated active input sampling circuit of Module A (such as the EGJ terminal) was connected to the alarm output terminal of DUT-A; the isolated passive output circuit of Module B (such as the EX_MEN terminal, used to simulate door contacts) was connected to the door magnetic input terminal of DUT-B. The entire system was placed in a high and low temperature chamber, and the temperature was set to -40℃ and allowed to stabilize. The host computer first sends a command to module B at address 0x02: [Addr: 0x02, Cmd: SetOutput, Port: EX_MEN, State: 1], meaning to control the EX_MEN port of module B to close, simulating the door of DUT-B being closed. After receiving the command, the main control unit of module B immediately drives the corresponding optocoupler to conduct, completing the simulated closing action. After detecting this state, DUT-B reports the door closed status information to the central station server through its own communication network (e.g., GPRS). After sending the first command, the host computer can immediately send a command to module A at address 0x01: [Addr: 0x01, Cmd: ReadInput, Port: EGJ], meaning to read the level status of the EGJ port of module A to monitor the alarm output of DUT-A. At this point, the tester manually triggers the alarm condition of DUT-A (e.g., by applying an undervoltage input). The alarm output terminal of DUT-A will output a 24V high-level signal. The isolated active input sampling circuit of module A detects this 24V signal, and after isolation and conversion, it is recognized by its main control unit. The main control unit then returns data to the host computer via the RS485 bus: [Addr: 0x01, Rsp: InputState, Port: EGJ, State: 1], indicating that a high level has been detected. After receiving the data returned by module A and confirming that the central station has also received the door-closed status information of DUT-B, the host computer automatically determines that both tests are successful and records the results.

[0074] As can be seen from this embodiment, the cascaded architecture and automated testing method of this application enable the testing of multiple different functions of multiple devices to be carried out in parallel or near parallel, thereby shortening the overall testing time and improving testing efficiency. At the same time, since the operating temperature range of all core hardware (-40℃~125℃) is better than the stringent testing environment requirements (-40℃~85℃), the success rate of the entire testing process is ensured.

[0075] Optionally, in addition to RS485, the communication bus used for cascading can also be a CAN bus with stronger anti-interference capabilities, or an Ethernet bus with a higher transmission rate, depending on the application scenario. Furthermore, the logic of the test scripts can be more complex, such as implementing advanced functions like automatically repeating the test or entering a specific diagnostic process after a test item fails, thereby further improving the automation and intelligence level of the test.

[0076] It should be noted that the component models mentioned above are merely examples, and those skilled in the art can select equivalent substitutes that meet the wide temperature range and functional requirements according to the actual situation. Furthermore, the various specific technical features described in the above embodiments can be combined in any suitable manner without contradiction. To avoid unnecessary repetition, this utility model will not describe the various possible combinations separately.

Claims

1. A high and low temperature environment testing device, characterized in that, include: Main control unit; The power supply module is electrically connected to the main control unit; A communication module is connected to the main control unit via signals, and the communication module includes at least one isolated RS485 communication circuit and at least one isolated CAN communication circuit; The test interface module is connected to the main control unit via signals, and the test interface module includes at least two test circuits selected from the group consisting of: isolated passive output circuit, isolated active input sampling circuit, and isolated passive input detection circuit. The communication module and the test interface module are electrically isolated from the main control unit.

2. The high and low temperature environment testing device according to claim 1, characterized in that, The isolated passive output circuit includes an optocoupler; the input of the optocoupler is configured to receive a drive signal from the main control unit, and the output of the optocoupler is configured to connect to the passive input terminal of the terminal under test.

3. The high and low temperature environment testing device according to claim 1, characterized in that, The isolated active input sampling circuit includes a voltage sampling circuit and an optocoupler; The voltage sampling circuit has an input node configured to connect to the active output terminal of the terminal under test; The input terminal of the optocoupler is connected to the output terminal of the voltage sampling circuit, and the output terminal of the optocoupler is connected to the analog-to-digital conversion input pin signal of the main control unit.

4. The high and low temperature environment testing device according to claim 1, characterized in that, The isolated passive input detection circuit includes an isolated DC voltage source, a pull-up resistor, a voltage sampling circuit, and an optocoupler. The pull-up resistor is connected to the isolated DC voltage source; The voltage sampling circuit has a detection node configured to connect to a passive contact of the terminal under test, and the detection node is connected to a pull-up resistor. The input terminal of the optocoupler is connected to the output terminal of the voltage sampling circuit, and the output terminal of the optocoupler is connected to the analog-to-digital conversion input pin signal of the main control unit.

5. The high and low temperature environment testing device according to claim 1, characterized in that, The isolated RS485 communication circuit includes an RS485 transceiver, a signal isolator, and a first isolated power supply circuit. The signal isolator is positioned between the main control unit and the logic pins of the RS485 transceiver; The first isolation power supply circuit is configured to provide isolated power to the RS485 transceiver.

6. The high and low temperature environment testing device according to claim 1, characterized in that, The isolated CAN communication circuit includes a CAN transceiver, a signal isolator, and a second isolated power supply circuit. The signal isolator is positioned between the main control unit and the logic pins of the CAN transceiver; The second isolation power supply circuit is configured to provide isolated power to the CAN transceiver.

7. The high and low temperature environment testing device according to claim 5, characterized in that, The communication module includes at least two isolated RS485 communication circuits.

8. The high and low temperature environment testing device according to claim 1, characterized in that, The power module includes a first input terminal connected to an external DC power input terminal, a non-isolated power conversion circuit, and an isolated DC-DC conversion circuit; The non-isolated power conversion circuit is connected to the first input terminal, and the isolated DC-DC conversion circuit is connected to the first input terminal.

9. The high and low temperature environment testing device according to claim 8, characterized in that, The output of the non-isolated power conversion circuit is connected to the main control unit to provide the main operating voltage to the main control unit.

10. The high and low temperature environment testing device according to claim 8, characterized in that, The output of the isolated DC-DC converter circuit forms an isolated power supply output terminal, which is electrically connected to the communication module and / or test interface module to supply power to the isolated side of the isolated circuit.

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