Automatic test system circuit for small-signal equipment

Abstract

According to the automatic test system circuit for the small-signal equipment, the switching-on and switching-off state signals output by the tested equipment are collected and isolated and converted through the switching-on and switching-off circuit, the state signals are input into the control unit, and the control unit carries out real-time processing and judgment according to the received state signals; according to the utility model, the switch-on and switch-off states of the tested equipment are automatically acquired and controlled, so that the whole test process has a relatively high automation degree; the switch-on and switch-off states of the tested equipment can be automatically acquired and controlled by the switch-on and switch-off states of the tested equipment, and the switch-on and switch-off states of the tested equipment can be automatically acquired and controlled by the switch-on and switch-off states; meanwhile, the input circuit and the output circuit both adopt a multi-stage electrical isolation design scheme, so that the interference of strong electric signals on the control unit is effectively prevented, the reliability of the test system is improved, and the safety of the test process is guaranteed; in addition, the system is simple in circuit structure, convenient for engineering realization, and suitable for automatic test application of various switch type small signal devices.

Description

Technical Field

[0001] The invention relates to the technical field of electronic circuits, and in particular to an automatic test system circuit for small signal equipment. Background Art

[0002] In existing automated test systems, testing of small signal devices often faces problems such as signal interference, insufficient isolation, and low automation. Test systems for small signal devices often require manual adjustment and configuration, resulting in low test efficiency and prone to errors. In addition, traditional circuit designs lack effective overvoltage protection and electrical isolation during signal acquisition and conversion, increasing the risk of device damage. Summary of the invention

[0003] The invention provides a small signal equipment automatic test system circuit, which improves the automation degree of the test process.

[0004] The present invention provides a small signal device automatic test system circuit, comprising:

[0005] An input circuit is used to receive the opening and closing state signal of the device under test and input the opening and closing state signal into the control unit;

[0006] A control unit, used for collecting and processing the opening and closing state signals of the device under test, and outputting opening and closing control instructions to the output circuit according to the opening and closing state signals;

[0007] The output circuit is used to output the opening and closing control instructions to the device under test.

[0008] Furthermore, the open-in circuit includes:

[0009] An opening and closing state signal acquisition and protection module is used to perform overvoltage protection on the opening and closing state signal, and input the opening and closing state signal of the device under test into the relay isolation conversion circuit;

[0010] A relay control circuit, used for receiving a control signal output by the control unit, and driving the relay isolation conversion circuit according to the control signal to electrically isolate the opening and closing state signal; the relay isolation conversion circuit is also used for converting the opening and closing state signal into a switching signal, and inputting the switching signal into a first photoelectric coupling isolation and signal conversion circuit;

[0011] The first photoelectric coupling isolation and signal conversion circuit is used to perform photoelectric isolation on the switch quantity signal, and convert the switch quantity signal into a level signal and input it into the control unit.

[0012] Furthermore, the opening and closing state signal acquisition and protection module includes a first varistor RX and a first transient suppression diode D1;

[0013] The input terminal of the input circuit is connected to the opening and closing state signal of the device under test;

[0014] The first varistor RX and the first transient suppression diode D1 are connected in sequence between the input terminal and the common terminal.

[0015] Furthermore, the relay control circuit includes: a transistor Q1, a first resistor R1, and a second resistor R2; the base of the transistor Q1 is grounded through the first resistor R1, and the base is also connected to the switch control port through the second resistor R2; the collector of the transistor Q1 is connected to the relay isolation conversion circuit; and the emitter of the transistor Q1 is grounded.

[0016] Further, the relay isolation conversion circuit includes: a third resistor R3, a fourth resistor R4, a first capacitor C1, a relay RL2, a first freewheeling diode D2 and a second freewheeling diode D3;

[0017] The opening and closing state signal outputted by the input terminal is inputted to the control input terminal of the relay RL2 after passing through the third resistor R3 and the first capacitor C1;

[0018] The power supply terminal of the relay RL2 is connected to a first power supply voltage;

[0019] The common end of the relay RL2 is connected between the relay control circuit and the anode of the second freewheeling diode D3, and the cathode of the second freewheeling diode D3 is connected between the power supply end of the relay RL2 and the first power supply voltage;

[0020] The switch contact of the relay is connected to the cathode of the first freewheeling diode D2, and the anode of the first freewheeling diode D2 is connected to the photoelectric coupling isolation and signal conversion circuit;

[0021] The fourth resistor R4 is connected in parallel between the common terminal and the switch contact of the relay.

[0022] Further, the first photoelectric coupling isolation and signal conversion circuit includes a first photoelectric coupler M1, a fifth resistor R5, a sixth resistor R6 and a seventh resistor R7;

[0023] The anode of the first freewheeling diode D2 is connected to the anode of the first photocoupler M1 through the fifth resistor R5;

[0024] The cathode of the first photocoupler M1 is connected to the switch contact of the relay through the fourth resistor R4.

[0025] The collector of the first photocoupler M1 is connected to the second power supply voltage through a sixth resistor R6, and is also connected to the input end of the control module through a seventh resistor R7;

[0026] The transmitting end of the first photoelectric coupler M1 is grounded.

[0027] Further, the output circuit includes a second photoelectric coupling isolation and signal conversion circuit;

[0028] The second photoelectric coupling isolation and signal conversion circuit is used to receive the opening and closing control instructions output by the control unit, and convert the opening and closing control instructions into a switching output signal that matches the device under test.

[0029] Further, the second photoelectric coupling isolation and signal conversion circuit includes: the second photoelectric coupling isolation and signal conversion circuit includes: a second transistor Q2, an eighth resistor R8, a ninth resistor R9, a second photocoupler M2, a tenth resistor R10, a second transient suppression diode D4 and a second varistor RX2;

[0030] The cathode of the second photocoupler M2 is connected to the collector of the second transistor Q2, the base of the second transistor Q2 is electrically connected to the control output terminal of the control unit through the eighth resistor R8, and the base of the second transistor Q2 is also grounded through the tenth resistor R10; the emitter of the second transistor Q2 is grounded;

[0031] The anode of the second photocoupler M2 is connected to the second power supply voltage; the collector of the second photocoupler M2 is connected to the output terminal through the tenth resistor R10, and the emitter of the second photocoupler M2 is connected to the common end; the second transient suppression diode D4 and the second varistor RX2 are sequentially connected in parallel between the other end of the tenth resistor R10 and the emitter.

[0032] Furthermore, the control module is an MCU.

[0033] Furthermore, it also includes a trialable operation module, and the trialable operation module is interconnected with the control module.

[0034] Compared with the prior art, the present invention has at least the following technical effects:

[0035] In the present invention, the opening and closing state signal output by the device under test is collected and isolated and converted through the open-in circuit, and the state signal is input into the control unit. The control unit performs real-time processing and judgment based on the received state signal, thereby outputting the corresponding opening and closing control instruction to the open-out circuit. The open-out circuit converts the control instruction into a switching signal matching the device under test and outputs it, thereby realizing the automatic collection and control of the opening and closing state of the device under test, so that the entire test process has a high degree of automation; at the same time, both the open-in circuit and the open-out circuit adopt a multi-level electrical isolation design, which effectively prevents the interference of strong electric signals on the control unit, improves the reliability of the test system, and ensures the safety of the test process; in addition, the system circuit structure is simple, easy to implement in engineering, and suitable for automated testing applications of various types of switch-type small signal equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 A schematic diagram of the structure of a circuit of an automated test system for small signal devices in Embodiment 1 of the present invention;

[0037] Figure 2 Schematic diagram of the structure of the input circuit in the first embodiment of the present invention;

[0038] Figure 3 It is a schematic diagram of the structure of the circuit in the first embodiment of the present invention. DETAILED DESCRIPTION

[0039] The following is a description of a circuit of a small signal device automated test system of the present invention in conjunction with a schematic diagram, wherein a preferred embodiment of the present invention is shown, and it should be understood that those skilled in the art can modify the present invention described herein and still achieve the advantageous effects of the present invention. Therefore, the following description should be understood as being widely known to those skilled in the art and not as a limitation of the present invention.

[0040] The present invention is described in more detail in the following paragraphs by way of example with reference to the accompanying drawings. The advantages and features of the present invention will become more apparent from the following description. It should be noted that the accompanying drawings are in very simplified form and in non-precise proportions, and are only used to facilitate and clearly assist in illustrating the purpose of the embodiments of the present invention.

[0041] Embodiment 1

[0042] Please refer to Figure 1-Figure 3 This embodiment provides a small signal device automatic test system circuit, including an input circuit, a control unit and an output circuit. The system circuit is used to perform automatic testing on switch-type small signal devices, and realize the collection and control of the opening and closing states of the tested device.

[0043] Specifically, it includes: an input circuit for receiving the opening and closing state signal of the device under test and inputting the opening and closing state signal into a control unit; a control unit for collecting and processing the opening and closing state signal of the device under test, and outputting an opening and closing control instruction to the output circuit according to the opening and closing state signal; and an output circuit for outputting the opening and closing control instruction to the device under test.

[0044] In this embodiment, the opening and closing status signal output by the device under test is collected and isolated and converted through the open-in circuit, and the status signal is input into the control unit. The control unit performs real-time processing and judgment based on the received status signal, thereby outputting the corresponding opening and closing control instruction to the open-out circuit. The open-out circuit converts the control instruction into a switching signal matching the device under test and outputs it, thereby realizing automatic collection and control of the opening and closing status of the device under test, and making the entire test process have a high degree of automation; at the same time, both the open-in circuit and the open-out circuit adopt a multi-level electrical isolation design, which effectively prevents the interference of strong electric signals on the control unit, improves the reliability of the test system, and ensures the safety of the test process; in addition, the system circuit structure is simple, easy to implement in engineering, and suitable for automated testing applications of various types of switch-type small signal equipment.

[0045] In this embodiment, a trialable operation module is also included, and the trialable operation module is interconnected with the control module.

[0046] In a specific embodiment, the testable operation module includes a touch screen, which communicates with the touch screen through the Ethernet physical layer (ETH) via the RMII interface, and the touch screen is driven by the chip RK3568B2 to realize data interaction; at the same time, the MCU is connected to the input circuit and the output circuit through the GPIO interface to complete the output of the opening and closing status signals and the opening and closing control instructions of the device under test, thereby forming a complete data acquisition and control system.

[0047] It uses Ethernet communication to communicate with the touch screen, and has the characteristics of high communication rate and strong anti-interference ability. In addition, the MCU manages the input and output circuits in a unified manner to achieve real-time and reliability of the system. At the same time, it adopts a modular design concept, and the interfaces of various functional modules are standardized, which has strong scalability and maintainability, and can meet the automated testing needs of different types of small signal equipment.

[0048] Specifically, the input circuit includes: an opening and closing state signal acquisition and protection module 100, which is used to perform overvoltage protection on the opening and closing state signal, and input the opening and closing state signal of the device under test into the relay isolation conversion circuit; a relay control circuit, which is used to receive the control signal output by the control unit, and drive the relay isolation conversion circuit according to the control signal to electrically isolate the opening and closing state signal; the relay isolation conversion circuit is also used to convert the opening and closing state signal into a switching signal, and input the switching signal into a first photoelectric coupling isolation and signal conversion circuit; the first photoelectric coupling isolation and signal conversion circuit is used to perform photoelectric isolation on the switching signal, and convert the switching signal into a level signal and input it into the control unit.

[0049] In a specific embodiment, the opening and closing state signal acquisition and protection module 100 includes a first varistor RX and a first transient suppression diode D1; the open-in terminal INPUT0 of the open-in circuit receives the opening and closing state signal of the device under test; the first varistor RX and the first transient suppression diode D1 are connected in sequence between the open-in terminal INPUT0 and the common terminal COM0.

[0050] In the above specific embodiment, the first varistor RX and the first transient voltage suppression diode D1 are used to protect the circuit from overvoltage and transient voltage spikes respectively. The varistor becomes low impedance when the voltage exceeds a certain threshold and absorbs excess current, while the transient voltage suppression diode can quickly clamp the voltage to prevent the transient voltage from damaging subsequent circuit components. The combination of the two provides effective voltage surge and transient voltage protection.

[0051] In another specific embodiment, the relay control circuit 200 includes: a transistor Q1, a first resistor R1, and a second resistor R2.

[0052] Specifically, the base of the transistor Q1 is grounded through the first resistor R1, and the base is also connected to the switch control port through the second resistor R2; the collector of the transistor Q1 is connected to the relay isolation conversion circuit; and the emitter of the transistor Q1 is grounded.

[0053] In the above relay control circuit 200, the transistor Q1 is used as a switch to control the activation of the relay.

[0054] In another specific embodiment, the relay isolation conversion circuit 300 includes: a third resistor R3, a fourth resistor R4, a first capacitor C1, a relay RL2, a first freewheeling diode D2 and a second freewheeling diode D3.

[0055] Specifically, the opening and closing state signal output by the input terminal INPUT0 is input to the control input terminal 2 of the relay RL2 after passing through the third resistor R3 and the first capacitor C1; the power supply terminal of the relay RL2 is connected to the first power supply voltage VDD_5V; the common terminal 4 of the relay RL2 is connected between the relay control circuit 200 and the anode of the second freewheeling diode D3, and the cathode of the second freewheeling diode D3 is connected between the power supply terminal 1 of the electrical appliance RL2 and the first power supply voltage VDD_5V; the switch contact 3 of the relay is connected to the cathode of the first freewheeling diode D2, and the anode of the first freewheeling diode D2 is connected to the photoelectric coupling isolation and signal conversion circuit; the fourth resistor R4 is connected in parallel between the common terminal COM0 and the switch contact 3 of the relay.

[0056] In the above-mentioned relay isolation conversion circuit 300, the third resistor R3 and the first capacitor C1 form a low-pass filter to filter and stabilize the opening and closing state signal. The relay RL2 realizes state switching by receiving the filtered signal. The first freewheeling diode D2 provides reverse current protection for the relay switch contact 3; the second freewheeling diode D3 is connected between the power supply terminal and the common terminal 4 of the relay to protect the power supply. The fourth resistor R4 is connected in parallel between the common terminal 4 and the relay switch contact 3 to provide current shunting.

[0057] When the input terminal INPUT0 receives the opening and closing state signal, the signal is filtered and stabilized through R2 and C1 to ensure that only valid signals activate the relay. Transistor Q1 receives the signal from the control unit and controls the conduction state of transistor Q1 through the second resistor R2, thereby controlling the activation of relay RL2 to physically isolate and convert the signal. After relay RL2 is activated, the switch contact 3 of relay RL2 transmits the signal to the subsequent photoelectric coupling isolation and signal conversion circuit through the first freewheeling diode D2 to achieve signal isolation and adaptation.

[0058] Furthermore, in the present embodiment, the first photoelectric coupling isolation and signal conversion circuit 400 includes a first photoelectric coupler M1 , a fifth resistor R5 , a sixth resistor R6 and a seventh resistor R7 .

[0059] The anode of the first freewheeling diode D2 is connected to the anode Anode of the first photocoupler M1 through the fifth resistor R5; the cathode Cathode of the first photocoupler M1 is connected to the switch contact 3 of the relay RL2 through the fourth resistor R4. The collector Drain1 of the first photocoupler M1 is connected to the second power supply voltage VCC_B_3.3V through the sixth resistor R6, and is also connected to the input terminal MCU_INPUT0 of the control module through the seventh resistor R7; the transmitter Drain2 of the first photocoupler M1 is grounded.

[0060] Furthermore, in this embodiment, the output circuit includes a second photoelectric coupling isolation and signal conversion circuit.

[0061] Specifically, the second photoelectric coupling isolation and signal conversion circuit is used to receive the opening and closing control instructions output by the control unit, and convert the opening and closing control instructions into a switching output signal that matches the device under test.

[0062] In a specific embodiment, the second photoelectric coupling isolation and signal conversion circuit includes: a second transistor Q2, an eighth resistor R8, a ninth resistor R9, a second photocoupler M2, a tenth resistor R10, a second transient suppression diode D4 and a second varistor RX2.

[0063] Specifically, the cathode of the second photocoupler M2 is connected to the collector of the second transistor Q2, the base of the second transistor Q2 is electrically connected to the control output terminal MCU_OUTPUT0 of the control unit through the eighth resistor R8, and the base of the second transistor Q2 is also grounded through the ninth resistor R9; the emitter of the second transistor Q2 is grounded; the anode Anode of the second photocoupler M2 is connected to the second power supply voltage VCC_B_3.3V; the collector Drain1 of the second photocoupler M2 is connected to the output terminal OUTPUT0 through the tenth resistor R10, and the emitter Drain2 of the second photocoupler M2 is connected to the common terminal COM 0; the second transient suppression diode D4 and the second varistor RX2 are sequentially arranged in parallel between the other end of the tenth resistor R10 and the emitter.

[0064] In the above specific embodiment, the opening and closing control command output by the control unit enters the base of the second transistor Q2 through the eighth resistor R8, and the base is grounded through the ninth resistor R9 to stabilize the base voltage. The collector of the second transistor Q2 is connected to the cathode of the second photocoupler M2, and the emitter is grounded. This connection mode acts as a switch in the circuit. When Q2 is turned on, it allows current to pass through M2, thereby activating the photocoupler to achieve signal isolation and transmission. The second transient suppression diode TVS2 and the second varistor RX2 are connected in parallel between the other end of the tenth resistor R10 and the emitter Drain2 of the second photocoupler M2 to protect the output signal. The entire path realizes the isolation and conversion of the control command, and outputs a switching signal that matches the device under test.

[0065] In a specific embodiment, the control module is an MCU.

[0066] The MCU program design adopts a modular parameter configuration method, and a parameter configuration area is reserved in the memory to store key parameters such as test-related thresholds, timing, sampling cycles, etc. The host computer can send new configuration parameters to the MCU through the Ethernet interface. After receiving, the MCU updates the parameters and stores them in the memory. For example, the signal sampling period of the input circuit, the action delay of the output circuit, the trigger threshold of the state judgment and other parameters can be adjusted to adapt to the test requirements of different types of small signal devices. Without modifying the hardware circuit, the test plan can be quickly switched and optimized.

[0067] Furthermore, this embodiment also includes a testable operation module,

[0068] An operation flow of the above-mentioned small signal device automatic test system circuit is:

[0069] When the device under test is in the open state, the open state signal output by it passes through the overvoltage protection of the open and close state signal acquisition and protection module 100, and is input to the relay RL2 through the RC filter circuit. At this time, the control unit outputs a low level through the MCU_SWITCH_0 port, turning off the transistor Q1, and the relay RL2 coil is energized and attracted. The relay contacts are closed, turning on the first photocoupler M1, and its collector outputs a low level signal to the control unit, indicating that the open state is detected.

[0070] When it is necessary to control the closing of the device under test, the control unit outputs the closing control instruction through the second photoelectric coupling isolation and signal conversion circuit of the output circuit. After photoelectric isolation and level conversion, the instruction is output to the device under test in the form of a switch signal, thereby realizing the control of the device under test.

[0071] Various changes and modifications do not depart from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these changes and modifications.

Claims

1. A small signal device automated test system circuit, characterized in that: include: An input circuit is used to receive the opening and closing state signal of the device under test and input the opening and closing state signal into the control unit; A control unit, used for collecting and processing the opening and closing state signals of the device under test, and outputting opening and closing control instructions to the output circuit according to the opening and closing state signals; The output circuit is used to output the opening and closing control instructions to the device under test.

2. The small signal device automated test system circuit according to claim 1, characterized in that: The open-in circuit comprises: An opening and closing state signal acquisition and protection module is used to perform overvoltage protection on the opening and closing state signal, and input the opening and closing state signal of the device under test into the relay isolation conversion circuit; A relay control circuit, used for receiving a control signal output by the control unit, and driving the relay isolation conversion circuit according to the control signal to electrically isolate the opening and closing state signal; the relay isolation conversion circuit is also used for converting the opening and closing state signal into a switching signal, and inputting the switching signal into a first photoelectric coupling isolation and signal conversion circuit; The first photoelectric coupling isolation and signal conversion circuit is used to perform photoelectric isolation on the switch quantity signal, and convert the switch quantity signal into a level signal and input it into the control unit.

3. The small signal device automated test system circuit according to claim 2, characterized in that: The opening and closing state signal acquisition and protection module includes a first varistor RX and a first transient suppression diode D1; The input terminal of the input circuit is connected to the opening and closing state signal of the device under test; The first varistor RX and the first transient suppression diode D1 are connected in sequence between the input terminal and the common terminal.

4. The small signal device automated test system circuit according to claim 2, characterized in that: The relay control circuit includes: a transistor Q1, a first resistor R1, and a second resistor R2; The base of the transistor Q1 is grounded via a first resistor R1, and the base is also connected to a switch control port via a second resistor R2; The collector of the transistor Q1 is connected to the relay isolation conversion circuit; The emitter of the transistor Q1 is grounded.

5. The small signal device automated test system circuit according to claim 4, characterized in that: The relay isolation conversion circuit includes: a third resistor R3, a fourth resistor R4, a first capacitor C1, a relay RL2, a first freewheeling diode D2 and a second freewheeling diode D3; The opening and closing state signal outputted by the input terminal is inputted to the control input terminal of the relay RL2 after passing through the third resistor R3 and the first capacitor C1; The power supply terminal of the relay RL2 is connected to a first power supply voltage; The common end of the relay RL2 is connected between the relay control circuit and the anode of the second freewheeling diode D3, and the cathode of the second freewheeling diode D3 is connected between the power supply end of the relay RL2 and the first power supply voltage; The switch contact of the relay is connected to the cathode of the first freewheeling diode D2, and the anode of the first freewheeling diode D2 is connected to the photoelectric coupling isolation and signal conversion circuit; The fourth resistor R4 is connected in parallel between the common terminal and the switch contact of the relay.

6. The small signal device automated test system circuit according to claim 5, characterized in that: The first photoelectric coupling isolation and signal conversion circuit includes a first photoelectric coupler M1, a fifth resistor R5, a sixth resistor R6 and a seventh resistor R7; The anode of the first freewheeling diode D2 is connected to the anode of the first photocoupler M1 through the fifth resistor R5; The cathode of the first photocoupler M1 is connected to the switch contact of the relay through the fourth resistor R4; The collector of the first photoelectric coupler M1 is connected to the second power supply voltage through a sixth resistor R6, and is also connected to the input end of the control module through a seventh resistor R7; The transmitting end of the first photoelectric coupler M1 is grounded.

7. The small signal device automated test system circuit according to claim 1, characterized in that: The output circuit includes a second photoelectric coupling isolation and signal conversion circuit; The second photoelectric coupling isolation and signal conversion circuit is used to receive the opening and closing control instructions output by the control unit, and convert the opening and closing control instructions into a switching output signal that matches the device under test.

8. The small signal device automated test system circuit according to claim 7, characterized in that: The second photoelectric coupling isolation and signal conversion circuit includes: a second transistor Q2, an eighth resistor R8, a ninth resistor R9, a second photocoupler M2, a tenth resistor R10, a second transient suppression diode D4, and a second varistor RX2; The cathode of the second photocoupler M2 is connected to the collector of the second transistor Q2, the base of the second transistor Q2 is electrically connected to the control output terminal of the control unit through the eighth resistor R8, and the base of the second transistor Q2 is also grounded through the ninth resistor R9; the emitter of the second transistor Q2 is grounded The anode of the second photocoupler M2 is connected to the second power supply voltage; the collector of the second photocoupler M2 is connected to the output terminal through the tenth resistor R10, and the emitter of the second photocoupler M2 is connected to the common end; the second transient suppression diode D4 and the second varistor RX2 are sequentially connected in parallel between the other end of the tenth resistor R10 and the emitter.

9. The small signal device automated test system circuit according to claim 1, characterized in that: The control module is MCU.

10. The small signal device automated test system circuit according to claim 1, characterized in that: It also includes a trialable operation module, which is interconnected with the control module.

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