Short circuit and resistance value detection device and detection method

Abstract

This invention discloses a short-circuit and resistance detection device, comprising a circuit board assembly electrically connected to a rectangular connector. The circuit board assembly includes an MCU, which is electrically connected to a power supply unit, a switching unit, and a detection unit. The switching unit includes a short-circuit detection switch unit, a short-circuit detection interrupt switch unit, a resistance detection switch unit, and a resistance detection interrupt switch unit. The detection unit includes a short-circuit detection unit and a resistance detection unit. The MCU includes several PA pins and several PC pins. The PA pins include PA0 pins and PAn pins, and the PC pins include PCi pins; n=1…n, i=0…i. This invention can simultaneously detect whether any signal is short-circuited to multiple other signals, can detect the resistance of multiple products, reduces personnel requirements, improves product detection accuracy, and shortens detection time. This invention also discloses a detection method for the short-circuit and resistance detection device.

Description

Technical Field

[0001] This invention belongs to the field of circuit testing technology, and relates to a short circuit and resistance detection device. This invention also relates to a detection method of the above-mentioned short circuit and resistance detection device. Background Technology

[0002] Currently, the main tool on the market for detecting short circuits between signals is the multimeter. While a multimeter can meet the requirements for detecting short circuits between two signals, it cannot simultaneously detect short circuits between any two pairs of multiple signals. Furthermore, when testing the input and output resistance of multiple signals, it relies on manually touching the input and output terminals of the signals one by one with the probes, which is prone to errors and affects the efficiency and accuracy of the test results. Summary of the Invention

[0003] The purpose of this invention is to provide a short circuit and resistance detection device, which solves the problems in the prior art that can only detect whether there is a short circuit between two signals at a time, and that poor connection is easy to occur when manually touching the signals one by one with the probes for short circuit detection and resistance detection.

[0004] Another object of the present invention is to provide a detection method for the above-mentioned short circuit and resistance detection device.

[0005] The technical solution adopted in this invention is a short circuit and resistance detection device, including a circuit board assembly, which is electrically connected to a rectangular connector. The circuit board assembly includes a microcontroller (MCU), which is electrically connected to a power supply unit, a switching unit, and a detection unit. The switching unit includes a short circuit detection switch unit, a short circuit detection interruption switch unit, a resistance detection switch unit, and a resistance detection interruption switch unit. The detection unit includes a short circuit detection unit and a resistance detection unit. The MCU includes several PA pins and several PC pins. The PA pins include PA0 pins and PAn pins, and the PC pins include PCi pins; n=1……n, i=0……i.

[0006] The invention is further characterized by:

[0007] There are two sets of rectangular connectors, including a first rectangular connector and a second rectangular connector. The first rectangular connector includes an X1 connector and a J1 connector, and the second rectangular connector includes an X2 connector and a J2 connector. The J1 connector includes several input terminals Ai, and the J2 connector includes several output terminals Ai_O.

[0008] The short-circuit detection switch unit includes a toggle switch SW2. The normally open terminal T1 of the toggle switch SW2 is electrically connected to a resistor R2. The other end of the resistor R2 is electrically connected to the power supply VCC3.3. The common terminal S1 of the toggle switch SW2 is electrically connected to a capacitor C7, a pin 58 of the MCU, and the common terminal S1 of the toggle switch SW1. The normally closed terminal T2 of the toggle switch SW2 and the other end of the capacitor C7 are both grounded.

[0009] The short-circuit detection interrupt switch unit includes a toggle switch SW3. The normally open terminal T1 of the toggle switch SW3 is electrically connected to a resistor R5. The other end of the resistor R5 is electrically connected to the power supply VCC3.3. The common terminal S1 of the toggle switch SW3 is electrically connected to a capacitor C9, pin 59 of the MCU, and the common terminal S1 of the toggle switch SW2. The normally closed terminal T2 of the toggle switch SW3 and the other end of the capacitor C9 are both grounded.

[0010] The resistance detection switch unit includes a toggle switch SW4. The normally open terminal T1 of the toggle switch SW4 is electrically connected to a resistor R10. The other end of the resistor R10 is electrically connected to the power supply VCC3.3. The common terminal S1 of the toggle switch SW4 is electrically connected to a capacitor C12, a pin 61 of the MCU, and the common terminal S1 of the toggle switch SW3. The normally closed terminal of the toggle switch SW4 and the other end of the capacitor C12 are both grounded.

[0011] The resistance detection interrupt switch unit includes a toggle switch SW5. The normally open terminal T1 of the toggle switch SW5 is electrically connected to a resistor R11. The other end of the resistor R11 is electrically connected to the power supply VCC3.3. The common terminal S1 of the toggle switch SW5 is electrically connected to a capacitor C22, a pin 62 of the MCU, and the common terminal S1 of the toggle switch SW4. The normally closed terminal T2 of the toggle switch SW5 and the other end of the capacitor C22 are both grounded.

[0012] The power supply unit includes a toggle switch SW1. The normally open terminal T1 of the toggle switch SW1 is electrically connected to pin 1 of the P1 interface. The common terminal S1 of the toggle switch SW1 is electrically connected to the transient suppression diode D1 and the fuse F1. The other end of the fuse F1 is electrically connected to capacitors C1 and C2 and the Vin pin of the voltage regulator chip U1. The Vout pin of the voltage regulator chip U1 is electrically connected to capacitors C3 and C4 and the Vin pin of the voltage regulator chip U2. The Vout pin of the voltage regulator chip U2 is electrically connected to capacitors C5 and C6. Capacitors C3 and C4 are electrically connected to power supply VCC5, and capacitors C5 and C6 are electrically connected to power supply VCC3.3.

[0013] Pins 2 and 3 of P1, normally closed terminal T2 of toggle switch SW1, capacitors C1 and C2, GND pin of voltage regulator chip U1, capacitors C3 and C4, GND pin of voltage regulator chip U2, capacitors C5 and C6 are all grounded.

[0014] Power supply VCC3.3 is connected in sequence to resistor R1 and the positive terminal of LED1, while the negative terminal of LED1 is grounded.

[0015] The short-circuit detection unit includes a PA0 short-circuit detection unit and a PAn short-circuit detection unit. The PA0 short-circuit detection unit includes a field-effect transistor Q1. The collector S of the field-effect transistor Q1 is electrically connected to a resistor R13, a capacitor C23, and a power supply VCC5. The gate G is electrically connected to a resistor R14 and the collector 3 of a transistor Q2. The drain D is electrically connected to a resistor R12 and the A0 input terminal of the J1 connector. The other end of the resistor R13 and the other end of the capacitor C23 are electrically connected together between the gate G and the resistor R14. The base 1 of the transistor Q2 is electrically connected to a resistor R15 and a resistor R16. The other end of the resistor R15 is electrically connected to a light-emitting diode (LED). a The other end of resistor R16 is grounded together with pin PA0 of the MCU and emitter 2;

[0016] The PAn short-circuit detection unit includes a field-effect transistor Q. a Q-type field-effect transistor a The collector S is electrically connected to resistor R respectively. a Capacitor C a The power supply VCC5 and the gate G are electrically connected in sequence to resistor R. b and transistor Q b The collector 3 and drain D are connected in sequence to resistor R. e The An output terminal is electrically connected to the corresponding Ai input terminal of connector J1. The An output terminal is also electrically connected to the positive terminal of LEDn+1, and the negative terminal of LEDn+1 is grounded; resistor R... a The other end and capacitor C a The other end is electrically connected to the gate G and the resistor R. b Between; transistor Q b The base 1 is electrically connected to resistor R. c and resistance R d resistance R c The other end is electrically connected to pin PAn on the MCU, and resistor R d The other end is grounded together with emitter 2.

[0017] The resistance detection unit includes an Ai input terminal unit and an Ai_O output terminal unit. The Ai input terminal unit includes a light-emitting diode (LED). b Light Emitting Diode (LED) b The positive terminal is electrically connected to the PCi pin on the MCU, and the negative terminal is electrically connected to resistor R. f resistance R f Connect resistor R respectively g and transistor Q c The base b, resistor Rg The other end is connected to transistor Q. c The emitter (e) of the transistor is grounded; transistor Q c The collectors c are electrically connected to diode D respectively. a The positive terminal and relay JK a Contact 1, diode D a The negative terminal and relay JK a Contact 2 is connected to power supply VCC5; Relay JK a Contact 4 is electrically connected to the corresponding Ai input terminal of connector J1, and contact 3 is electrically connected to the positive terminal of the ohmmeter.

[0018] The Ai_O output unit includes a resistor R. h resistance R h One end is electrically connected to the PCi pin on the MCU, and the resistor R h The other end is electrically connected to resistor R. j and transistor Q d The base b, resistor R j The other end is connected to transistor Q. d The emitter (e) of the transistor is grounded; transistor Q d The collectors c are electrically connected to diode D respectively. b The positive terminal and relay JK b Contact 1, diode D b The negative terminal and relay JK b Contact 2 is connected to power supply VCC5; Relay JK b Contact 4 is electrically connected to the corresponding Ai_O output terminal of the J2 connector, and contact 3 is electrically connected to the negative terminal of the ohmmeter.

[0019] Pin 5 of the MCU is electrically connected to capacitor C8 and the input terminal of dual-electrode crystal oscillator Y1 respectively. The output terminal of dual-electrode crystal oscillator Y1 is connected to capacitor C10 and resistor R7 respectively. The other end of resistor R7 is connected to pin 6 of the MCU. The connection point of capacitor C8 and capacitor C10 is grounded together.

[0020] Pin 43 of the MCU is electrically connected to pin 3 of P2, pin 42 of the MCU is electrically connected to pin 2 of P2, and pin 1 of P2 is grounded; pin 60 of the MCU is electrically connected to resistor R8 and power supply VCC3.3, with the other end of resistor R8 grounded; pin 7 of the MCU is electrically connected to the reset signal node RESET, which is electrically connected to resistor R9 and capacitor C11, with the other end of R9 connected to power supply VCC3.3 and the other end of capacitor C11 grounded; pin 13 of the MCU is electrically connected to ferrite bead FB1 and capacitors C15 and C16, with the other end of ferrite bead FB1 connected to power supply VCC3.3, and the other ends of capacitors C15 and C16 grounded; pin 28 of the MCU is electrically connected to pin BOOT1, resistor R4, and power supply VCC3.3, with the other end of resistor R4 grounded; MCU Pin 31 of the MCU is electrically connected to capacitor C14, with the other end of capacitor C14 grounded; pin 47 of the MCU is electrically connected to capacitor C13, with the other end of capacitor C13 grounded; pins 63, 18, and 12 of the MCU are all grounded; pins 1, 32, 48, 64, and 19 of the MCU are all electrically connected to power supply VCC3.3; pins 49 and 46 of the MCU are electrically connected to download port P3; pin 1 of download port P3 is electrically connected to diode D7 and power supply VCC3.3, with the other end of diode D7 grounded; pin 2 of download port P3 is grounded; pin 3 of download port P3 is electrically connected to diode D6 and pin 49 of the MCU, with the other end of diode D6 grounded; pin 4 of download port P3 is electrically connected to diode D5 and pin 46 of the MCU, with the other end of diode D5 grounded.

[0021] The power supply VCC3.3 is also electrically connected to a filter circuit, which includes several capacitors. One end of capacitors C17, C18, C19, C20, and C21 is electrically connected to the power supply VCC3.3, and the other end is grounded together.

[0022] Capacitor C4 is electrically connected to diode D2 between it and the Vin pin of voltage regulator chip U2. Capacitor C6 is also electrically connected to diode D3. Both diodes D2 and D3 are grounded. Pin 60 of the MCU is electrically connected to resistors R6 and R8 respectively. The other end of resistor R6 is electrically connected to power supply VCC3.3. Pin 28 of the MCU is electrically connected to pin BOOT1, resistor R3 and resistor R4 respectively. The other end of resistor R3 is electrically connected to power supply VCC3.3.

[0023] Another technical solution adopted in this invention is a detection method for a short circuit and resistance detection device, which includes a short circuit detection method and a resistance detection method.

[0024] Another feature of the technical solution of the present invention is that:

[0025] The short-circuit detection method is implemented according to the following steps:

[0026] Step 1: Connect the signal input terminal of the device under test (DUT) to connector X1 and the signal output terminal of the DUT to connector X2; connect connector X1 to connector J1 and connector X2 to connector J2.

[0027] Step 2: Close the power switch SW1;

[0028] Step 3, short circuit detection;

[0029] When the short-circuit detection switch SW2 is closed, PA0, PA1...PAn output high levels in sequence;

[0030] When PA0 outputs a high level, the A0 signal sequentially performs short-circuit detection on the A1 signal...An signal, and ground signal; when the A0 signal does not short-circuit any other signal, the LED... a When the LED is lit, PA1 outputs a high level; when the A0 signal is short-circuited to the An signal, the LED... a Only LEDn+1 is lit, while the other LEDs are not lit.

[0031] When PAm outputs a high level, the Am signal sequentially performs short-circuit detection on the Am+1 signal...An signal, and ground signal; when the Am signal does not short-circuit other signals, LEDm+1 lights up, and then it is PAm+1's turn to output a high level; if the Am signal short-circuits the An signal, LEDm+1 and LEDn+1 light up, while other LEDs do not light up; n is greater than m+1;

[0032] Step 4, short circuit detection interrupted;

[0033] When a short circuit occurs between two signals, close SW3 switch to interrupt the short circuit detection, record the fault, and then open SW3 switch to continue the detection.

[0034] The resistance testing method is implemented according to the following steps:

[0035] Step 1: Connect the signal input terminal of the device under test (DUT) to connector X1, and connect the signal output terminal of the DUT to connector X2; connect connector X1 to connector J1, and connector X2 to connector J2; connect the positive terminal of the ohmmeter to the i relays JK in the Ai input unit. a Contact 3 connects the negative terminal of the ohmmeter to the i-th relay JK in the Ai_O output terminal. b Contact point 3;

[0036] Step 2: Close the power switch SW1;

[0037] Step 3, resistance detection;

[0038] When the resistance detection switch SW4 is closed, the MCU's PC0 to PCi output high levels sequentially.

[0039] Connect signals A0, A0_O, ..., Ai, Ai_O sequentially between the positive and negative terminals of the ohmmeter. When the i-th group of signals is detected, the corresponding LED will... b Light it up; read the resistance value of group i using an ohmmeter;

[0040] Step 4, resistance interruption detection;

[0041] If any abnormality occurs in the resistance detection of any signal, close the SW5 switch to interrupt the resistance detection, record the fault, and then open the SW5 switch to continue the resistance detection.

[0042] The beneficial effects of this invention are:

[0043] (1) The short circuit and resistance detection device provided by the present invention can simultaneously detect whether any signal is short-circuited to other multiple signals. When two signals are short-circuited, the lights on the two signals will light up. The tester can intuitively judge which two signals are short-circuited, realize the rapid switching of different signals from input to output resistance detection, and the detection data is stable and accurate, avoiding the uncontrollable factors of manual detection.

[0044] (2) The short circuit and resistance detection device provided by the present invention can be used for detection simply by connecting the product's input and output interfaces to the input and output interfaces of the detection device via cables. When the product's input and output interfaces are not designed on the same side, multiple people are not required to use a multimeter for testing, which can reduce the number of personnel required.

[0045] (3) The short circuit and resistance detection device provided by the present invention can greatly shorten the detection time. It takes 2 people 20 minutes to manually detect the short circuit and resistance of 17 signals and record the data. With this detection device, it only takes 1 person 3.5 minutes, and the detection efficiency is increased by about 11 times. Attached Figure Description

[0046] Figure 1 This is a diagram of the MCU of the present invention;

[0047] Figure 2 This is the filter circuit diagram of the present invention;

[0048] Figure 3 This is a circuit diagram of the short-circuit detection switch unit of the present invention;

[0049] Figure 4 This is a circuit diagram of the short-circuit detection interrupt switch unit of the present invention;

[0050] Figure 5 This is a circuit diagram of the resistance detection switch unit of the present invention;

[0051] Figure 6 This is a circuit diagram of the resistance detection interrupt switch unit of the present invention;

[0052] Figure 7 This is a circuit diagram of the PA0 short-circuit detection unit of the present invention;

[0053] Figure 8 This is a circuit diagram of the PAn short-circuit detection unit of the present invention;

[0054] Figure 9 This is a circuit diagram showing the connection between the output terminal of the short-circuit detection unit An and the light-emitting diode of the present invention;

[0055] Figure 10 This is a circuit diagram of the Ai input terminal unit of the present invention;

[0056] Figure 11 This is the circuit diagram of the Ai_O output unit of the present invention;

[0057] Figure 12 This is a block diagram illustrating the principle of resistance detection between the input and output signals of the device under test according to the present invention.

[0058] Figure 13 This is a circuit diagram of the power supply unit of the present invention;

[0059] Figure 14 This is a circuit diagram showing the connection of light-emitting diodes in the power supply unit of the present invention;

[0060] Figure 15 This is a front view of the casing of the present invention;

[0061] Figure 16 This is a planar schematic diagram of the J1 connector of the present invention;

[0062] Figure 17 This is a planar schematic diagram of the J2 connector of the present invention;

[0063] Figure 18 This is a flowchart of the short-circuit detection and resistance detection method of the present invention. Detailed Implementation

[0064] The following detailed description is provided in conjunction with specific implementation methods.

[0065] A short-circuit and resistance detection device includes a circuit board assembly electrically connected to a rectangular connector. The circuit board assembly includes an MCU, which is electrically connected to a power supply unit, a switching unit, and a detection unit. The switching unit includes a short-circuit detection switch unit, a short-circuit detection interrupt switch unit, a resistance detection switch unit, and a resistance detection interrupt switch unit. The detection unit includes a short-circuit detection unit and a resistance detection unit. The MCU includes several PA pins and several PC pins. The PA pins include PA0 pins and PAn pins, and the PC pins include PCi pins; n=1……n, i=0……i.

[0066] The device includes two sets of rectangular connectors: a first rectangular connector and a second rectangular connector. The first rectangular connector comprises an X1 connector and a J1 connector, while the second rectangular connector comprises an X2 connector and a J2 connector. The J1 connector includes several input terminals Ai, and the J2 connector includes several output terminals Ai_O. The X1 connector connects to the signal input terminals of the device under test (DUT), and the X2 connector connects to the signal output terminals of the DUT. Connecting the X1 connector to the J1 connector and the X2 connector to the J2 connector connects all signals from the DUT to the short-circuit and resistance detection device, thus completing the detection path between the DUT and the short-circuit and resistance detection device.

[0067] like Figure 1 As shown, the MCU includes several PA pins, PB pins, and PC pins. PA pins include PA0 and PAn pins, and PC pins include PCi pins. The MCU's PA pins are connected to corresponding short-circuit detection circuits. When the number of PA pins is less than the number of short-circuit detection circuits, the PB pin is used as a spare terminal for the PA pins, and the remaining short-circuit detection circuits are connected to the PB pin.

[0068] like Figure 1 In the short circuit detection circuit unit, there are a total of 16 units. The MCU has 12 PA pins, and the remaining 4 short circuit detection circuit units A12, A13, A14, and A15 are electrically connected to the MCU's PB0, PB1, PB3, and PB4 pins, respectively.

[0069] Pin 43 of the MCU is electrically connected to pin 3 of P2, pin 42 of the MCU is electrically connected to pin 2 of P2, and pin 1 of P2 is grounded.

[0070] Pin 5 of the MCU is electrically connected to capacitor C8 and the input terminal of the dual-electrode crystal oscillator Y1. The output terminal of the dual-electrode crystal oscillator Y1 is connected to capacitor C10 and resistor R7. The other end of resistor R7 is connected to pin 6 of the MCU. The connection point of capacitors C8 and C10 is grounded together. Specifically, capacitor C8 has a capacitance of 30 picofarads and an accuracy of 1%; capacitor C10 has a capacitance of 20 picofarads and an accuracy of 1%; and resistor R7 has a resistance of 200 ohms and an accuracy of 1%.

[0071] Pin 60 of the MCU is electrically connected to resistors R6 and R8 respectively. The other end of resistor R6 is electrically connected to power supply VCC3.3, and the other end of resistor R8 is grounded. Resistor R6 has a resistance of 10 kΩ and a tolerance of 1%; resistor R8 has a resistance of 10 kΩ and a tolerance of 1%. Resistor R6 is not installed by default.

[0072] Pin 7 of the MCU is electrically connected to the reset signal node RESET. The reset signal node RESET is electrically connected to resistor R9 and capacitor C11. The other end of R9 is electrically connected to the power supply VCC3.3, and the other end of capacitor C11 is grounded. Among them, resistor R9 has a resistance of 10 kΩ and a tolerance of 1%; capacitor C11 has a capacitance of 100 nanofarads and a rated voltage of 50 volts.

[0073] Pin 13 of the MCU is electrically connected to ferrite bead FB1 and capacitors C15 and C16. The other end of ferrite bead FB1 is electrically connected to power supply VCC3.3. The other ends of capacitors C15 and C16 are grounded together. Among them, capacitor C15 has a capacitance of 1uF and capacitor C16 has a capacitance of 100nF.

[0074] 6. Pin 28 of the MCU is electrically connected to pin BOOT1, resistor R3, and resistor R4 respectively. The other end of resistor R3 is electrically connected to power supply VCC3.3, and the other end of resistor R4 is grounded. Resistor R3 has a resistance of 10 kΩ and a tolerance of 1%, and is not installed by default; resistor R4 has a resistance of 10 kΩ and a tolerance of 1%.

[0075] Pin 31 of the MCU is electrically connected to capacitor C14, and the other end of capacitor C14 is grounded. Capacitor C14 has a capacitance of 2.2µF and a tolerance of 5%.

[0076] Pin 47 of the MCU is electrically connected to capacitor C13, and the other end of capacitor C13 is grounded. Capacitor C13 has a capacitance of 2.2µF and a tolerance of 5%.

[0077] Pins 63, 18, and 12 of the MCU are grounded together.

[0078] Pins 1, 32, 48, 64, and 19 of the MCU are all connected to the power supply VCC3.3.

[0079] The MCU is also electrically connected to the download port P3. Pin 1 of download port P3 is electrically connected to diode D7 and power supply VCC3.3, and the other end of diode D7 is grounded. Pin 2 of download port P3 is grounded. Pin 3 of download port P3 is electrically connected to diode D6 and MCU pin 49, and the other end of diode D6 is grounded. Pin 4 of download port P3 is electrically connected to diode D5 and MCU pin 46, and the other end of diode D5 is grounded.

[0080] like Figure 2As shown, power supply VCC3.3 is also electrically connected to a filter circuit. The filter circuit includes several capacitors: capacitors C17, C18, C19, C20, and C21 are all electrically connected to power supply VCC3.3 at one end, and the other ends are grounded together. The main function of the capacitors is filtering, providing the MCU with a power supply free from electromagnetic interference. Among these, capacitors C17, C18, C19, C20, and C21 can all have a capacitance of 100nF and a rated voltage of 50 volts.

[0081] like Figure 3 As shown, the short-circuit detection switch unit includes a toggle switch SW2. The normally open terminal T1 of toggle switch SW2 is electrically connected to resistor R2. The other end of resistor R2 is electrically connected to power supply VCC3.3. The common terminal S1 of toggle switch SW2 is electrically connected to capacitor C7, pin 58 of the MCU, and the common terminal S1 of toggle switch SW1. The normally closed terminal T2 of toggle switch SW2 and the other end of capacitor C7 are both grounded. The resistance of resistor R2 can be selected as 1000 ohms; the capacitance of capacitor C7 is 100nF, and the rated voltage is 50 volts.

[0082] like Figure 4 As shown, the short-circuit detection interrupt switch unit includes a toggle switch SW3. The normally open terminal T1 of toggle switch SW3 is electrically connected to resistor R5. The other end of resistor R5 is electrically connected to power supply VCC3.3. The common terminal S1 of toggle switch SW3 is electrically connected to capacitor C9, pin 59 of the MCU, and the common terminal S1 of toggle switch SW2. The normally closed terminal T2 of toggle switch SW3 and the other end of capacitor C9 are both grounded. The resistance of resistor R5 can be selected as 1000 ohms; the capacitance of capacitor C9 is 100nF, and the rated voltage is 50 volts.

[0083] like Figure 5 As shown, the resistance detection switch unit includes a toggle switch SW4. The normally open terminal T1 of toggle switch SW4 is electrically connected to resistor R10. The other end of resistor R10 is electrically connected to power supply VCC3.3. The common terminal S1 of toggle switch SW4 is electrically connected to capacitor C12, pin 61 of the MCU, and the common terminal S1 of toggle switch SW3. The normally closed terminal of toggle switch SW4 and the other end of capacitor C12 are both grounded. The selectable resistance value of resistor R10 is 1000 ohms; the capacitance value of capacitor C12 is 100nF, and the rated voltage is 50 volts.

[0084] like Figure 6As shown, the resistance detection interrupt switch unit includes a toggle switch SW5. The normally open terminal T1 of toggle switch SW5 is electrically connected to resistor R11. The other end of resistor R11 is electrically connected to power supply VCC3.3. The common terminal S1 of toggle switch SW5 is electrically connected to capacitor C22, pin 62 of the MCU, and the common terminal S1 of toggle switch SW4. The normally closed terminal T2 of toggle switch SW5 and the other end of capacitor C22 are both grounded. The selectable resistor R11 has a resistance of 1000 ohms; the capacitor C22 has a capacitance of 100nF and a rated voltage of 50 volts.

[0085] The short-circuit detection unit includes the PA0 short-circuit detection unit and the PAn short-circuit detection unit.

[0086] like Figure 7 As shown, the PA0 short-circuit detection unit includes a field-effect transistor Q1. The collector S of the field-effect transistor Q1 is electrically connected to resistor R13, capacitor C23, and power supply VCC5. The gate G is electrically connected to resistor R14 and the collector 3 of transistor Q2. The drain D is electrically connected to resistor R12 and the A0 input terminal of connector J1. The other ends of resistor R13 and capacitor C23 are electrically connected together between the gate G and resistor R14. The base 1 of transistor Q2 is electrically connected to resistors R15 and R16. The other end of resistor R15 is electrically connected to a light-emitting diode (LED). a The other end of resistor R16 is grounded together with pin PA0 of the MCU and emitter 2.

[0087] Among them, the selectable resistors are: R12 with a resistance of 680Ω and a tolerance of 1%; R13 with a resistance of 100kΩ and a tolerance of 1%; R14 with a resistance of 1kΩ and a tolerance of 1%; R15 with a resistance of 680Ω and a tolerance of 1%; R16 with a resistance of 47kΩ and a tolerance of 1%; and C23 with a capacitance of 100nF and a rated voltage of 50V.

[0088] like Figure 8 As shown, the PAn short-circuit detection unit includes a field-effect transistor Q. a Q-type field-effect transistor a The collector S is electrically connected to resistor R respectively. a Capacitor C a The power supply VCC5 and the gate G are electrically connected in sequence to resistor R. b and transistor Q b The collector 3 and drain D are connected in sequence to resistor R. e The An output terminal is electrically connected to the corresponding Ai input terminal of connector J1; resistor R a The other end and capacitor C a The other end is electrically connected to the gate G and the resistor R. b Between. Transistor Q bThe base 1 is electrically connected to resistor R. c and resistance R d resistance R c The other end is electrically connected to pin PAn on the MCU, and resistor R d The other end is grounded together with emitter 2. For example... Figure 9 As shown, the output terminal of An is also electrically connected to the positive terminal of LEDn+1, and the negative terminal of LEDn+1 is grounded.

[0089] Among them, resistor R can be selected c The resistance is 10 kΩ, and the tolerance is 1%; resistor R a The resistance is 100 kΩ, and the tolerance is 1%; resistor R b Resistance is 1 kΩ, tolerance is 1%; resistor R e The resistance is 680Ω, and the tolerance is 1%; resistor R d Resistance is 47 kΩ, tolerance is 1%; capacitor C a The capacitance is 100nF and the rated voltage is 50 volts.

[0090] The resistance detection circuit unit includes an Ai input terminal unit and an Ai_O output terminal unit. For example... Figure 10 As shown, the Ai input unit includes a light-emitting diode (LED). b Light Emitting Diode (LED) b The positive terminal is electrically connected to the PCi pin on the MCU, and the negative terminal is electrically connected to resistor R. f resistance R f Connect resistor R respectively g and transistor Q c The base b, resistor R g The other end is connected to transistor Q. c The emitter (e) of the transistor is grounded; transistor Q c The collectors c are electrically connected to diode D respectively. a The positive terminal and relay JK a Contact 1, diode D a The negative terminal and relay JK a Contact 2 is connected to power supply VCC5. Relay JK a Contact 4 is electrically connected to the corresponding Ai input terminal of connector J1, and contact 3 is electrically connected to the positive terminal of the ohmmeter.

[0091] Among them, resistor R can be selected f The resistance is 680 ohms, and the tolerance is 1%; resistor R g The resistance is 47 kΩ and the tolerance is 1%.

[0092] like Figure 11 As shown, the Ai_O output unit includes a resistor R. h resistance Rh One end is electrically connected to the PCi pin on the MCU, and the resistor R h The other end is electrically connected to resistor R. j and transistor Q d The base b, resistor R j The other end is connected to transistor Q. d The emitter (e) of the transistor is grounded; transistor Q d The collectors c are electrically connected to diode D respectively. b The positive terminal and relay JK b Contact 1, diode D b The negative terminal and relay JK b Contact 2 is connected to power supply VCC5. Relay JK b Contact 4 is electrically connected to the corresponding Ai_O output terminal of the J2 connector, and contact 3 is electrically connected to the negative terminal of the ohmmeter.

[0093] Among them, resistor R can be selected h The resistance is 10 kΩ, and the tolerance is 1%; resistor R j The resistance is 47 kΩ and the tolerance is 1%.

[0094] like Figure 12 As shown, the principle of resistance detection between the Ai signal input and the Ai_O signal output is as follows: the Ai signal of the device under test (DUT) is input to the positive terminal of the ohmmeter via a short-circuit detection and resistance detection device; the negative terminal of the ohmmeter outputs the Ai_O signal, which is then output to the DUT via the short-circuit detection and resistance detection device. The detection principle for other signals A1, A2, A3, etc., is similar. The detection device can perform resistance switching detection between multiple signals of the DUT from input to output.

[0095] like Figure 13 As shown, the power supply unit includes a toggle switch SW1. The normally open terminal T1 of the toggle switch SW1 is electrically connected to pin 1 of the P1 interface; the normally closed terminal T2 of the toggle switch SW1 is grounded; the common terminal S1 of the toggle switch SW1 is electrically connected to the transient suppression diode D1 and the fuse F1; the other end of the fuse F1 is electrically connected to capacitors C1 and C2 and the Vin pin of the voltage regulator chip U1; the Vout pin of the voltage regulator chip U1 is electrically connected to capacitors C3 and C4, diode D2 and the Vin pin of the voltage regulator chip U2; the Vout pin of the voltage regulator chip U2 is electrically connected to capacitors C5 and C6 and diode D3. Capacitors C3 and C4 are electrically connected to power supply VCC5, and capacitors C5 and C6 are electrically connected to power supply VCC3.3. Pins 2 and 3 of P1, capacitors C1 and C2, the GND pin of voltage regulator chip U1, capacitors C3 and C4, diode D2, the GND pin of voltage regulator chip U2, capacitors C5 and C6, and diode D3 are all grounded.

[0096] like Figure 14 As shown, power supply VCC3.3 is connected in sequence to resistor R1 and the positive terminal of LED1, while the negative terminal of LED1 is grounded. After the power is turned on, LED1 lights up.

[0097] Pin 1 of the P1 interface is 12V+. Selectable capacitors C1, C3, and C5 are all 100nF with a rated voltage of 50V; capacitors C2, C4, and C6 are all 10μF with a rated voltage of 50V; resistor R1 has a resistance of 1kΩ and a tolerance of 1%. Diodes D2 and D3 are reserved diodes and are not installed by default.

[0098] like Figure 15 As shown, the circuit board assembly is located inside the housing. On the housing surface are the main power switch (SW1), short-circuit detection switch (SW2), short-circuit detection pause switch (SW3), resistance detection switch (SW4), and resistance detection pause switch (SW5). The housing surface also has i+1 short-circuit detection indicator lights and i capacitance detection indicator lights, where the short-circuit detection indicator light A0 is a light-emitting diode (LED). a The Ai signal light is LEDn+1; the capacitance detection signal light Ai is the LED corresponding to group i. b .

[0099] The casing surface has positive and negative input ports for the ohmmeter, as well as an IN terminal (external input) and an OUT terminal (external output). The ohmmeter's positive terminal is connected to the i-th relay JK in the Ai input terminal. a Contact 3 is electrically connected, and the negative terminal of the ohmmeter is connected to the i-th relay JK in the Ai_O output terminal. b The device has three electrical contacts. The IN terminal is the J1 connector, and the OUT terminal is the J2 connector. The signal input terminal X1 connector of the device under test (DUT) is inserted into the IN terminal, and the signal output terminal X2 connector of the DUT is inserted into the OUT terminal. Handles are also provided on both sides of the housing.

[0100] The detection method using a short-circuit and resistance detection device includes a short-circuit detection method and a resistance detection method. The short-circuit detection method specifically includes the following steps:

[0101] Step 1: Connect the signal input terminal of the device under test (DUT) to connector X1 and the signal output terminal of the DUT to connector X2; connect connector X1 to connector J1 and connector X2 to connector J2; thereby connecting all signals of the DUT to the short circuit and resistance detection device.

[0102] Step 2: Close the power switch SW1 to supply power to the system. When the light-emitting diode LED1 lights up, it indicates that the system power supply is normal.

[0103] Step 3, short circuit detection.

[0104] When the short-circuit detection switch SW2 is closed, PA0, PA1...PAn sequentially output high-level signals. When PA0 outputs a high-level signal, the A0 signal sequentially performs short-circuit detection on the A1...An signals and the ground signal. When the A0 signal shows no short circuit to any other signal, the LED... a When the LED is lit, PA1 outputs a high level; when the A0 signal is short-circuited to the An signal, the LED... a Only LEDn+1 is lit, while the other LEDs are not lit.

[0105] When PAm outputs a high level, the Am signal sequentially performs short-circuit detection on the Am+1 signal...An signal and ground signal; when the Am signal has no short circuit to other signals, LEDm+1 lights up, and then it is PAm+1's turn to output a high level; if the Am signal short-circuits the An signal, LEDm+1 and LEDn+1 light up, and other LEDs do not light up; n is greater than m+1.

[0106] By analogy, the detection of whether any pair of signals A0...An and ground signals are short-circuited is completed, for a total of n+2 signals.

[0107] Step 4, short circuit detection interruption.

[0108] When a short circuit occurs between two signals, close SW3 switch to interrupt the short circuit detection, record the fault, and then open SW3 switch to continue the detection.

[0109] The resistance testing method is implemented according to the following steps:

[0110] Step 1: Connect the signal input terminal of the device under test (DUT) to connector X1, and connect the signal output terminal of the DUT to connector X2; connect connector X1 to connector J1, and connector X2 to connector J2; connect the positive terminal of the ohmmeter to the positive terminal of the ohmmeter in the short circuit and resistance detection device, i.e., to the i relays JK in the Ai input unit. a Contact 3; connect the negative terminal of the ohmmeter to the negative terminal of the ohmmeter in the short-circuit and resistance detection device, i.e., the i relays JK in the Ai_O output terminal. b Contact point 3.

[0111] Step 2: Close the power switch SW1 to supply power to the system. When the light-emitting diode LED1 lights up, it indicates that the system power supply is normal.

[0112] Step 3, resistance detection.

[0113] When the resistance detection switch SW4 is closed, PC0 through PCi of the MCU output high levels sequentially. Signals A0 (input), A0_O (output), ..., Ai (input), Ai_O (output) are connected sequentially between the positive and negative terminals of an ohmmeter. When the i-th signal is detected, the corresponding LED... b Light up. The resistance value of group i can be read using an ohmmeter.

[0114] Step 4, resistance interruption detection.

[0115] If any abnormality occurs in the resistance detection of any signal, close the SW5 switch to interrupt the resistance detection, record the fault, and then open the SW5 switch to continue the resistance detection.

[0116] When the external signals are A0 to A15 (a total of 16), the signal connection method of the short-circuit and resistance detection device is as follows: Figure 1 As shown, the rectangular connector can be a J29A series rectangular connector. Figure 16 As shown, the input terminal of connector J1 of the short-circuit and resistance detection device is connected to 16 input signals, A0 to A15. Figure 17 As shown, the output terminal of the J2 connector of the short circuit and resistance detection device is connected to a total of 16 output signals from A0_O to A15_O.

[0117] like Figure 18 As shown, during short circuit detection, after the short circuit detection switch SW2 is closed and grounded, the MCU's PA0~PA8, PA11~PA12, PA15, PB0~PB1, and PB3~PB4 output high levels in sequence.

[0118] When PA0 outputs a high level, the corresponding transistor + MOS switch combination circuit turns on. Simultaneously, it checks whether the A0 signal is short-circuited to signals A1-A15 and ground (A16). If the A0 signal is not short-circuited to any other signals, only the LED is activated. a If signal A0 is short-circuited only to signal A1, then the LED will light up. a LED2 is lit, while the other LEDs are not lit.

[0119] When PA1 outputs a high level, the corresponding transistor + MOS switch combination circuit is turned on. At the same time, it detects whether the A1 signal is short-circuited to signals A2 to A15 and ground signal (A16). If the A1 signal is not short-circuited to other signals, only LED2 lights up. If the A1 signal is short-circuited only to signal A4, LED2 and LED5 light up, and the other LEDs do not light up. This process is repeated to detect whether any two of the 17 signals are short-circuited.

[0120] During resistance detection, the resistance detection switch SW4 is closed to ground. The MCU's PC0 to PC15 output high levels sequentially, VCC5 outputs 5V, the transistor conducts, and the relays (JK1 and JK3) contacts close. Signals A0 (input), A0_O (output), A1 (input), A1_O (output), A2 (input), A2_O (output), ..., A15 (input), A15_O (output) are sequentially connected between the positive and negative terminals of an ohmmeter. This allows for resistance detection of all input signals to the output terminals. The LED corresponding to the detected signal illuminates, and the resistance value is read from the ohmmeter.

[0121] Example 1

[0122] A short-circuit and resistance detection device includes a circuit board assembly electrically connected to a rectangular connector. The circuit board assembly includes an MCU, which is electrically connected to a power supply unit, a switching unit, and a detection unit. The switching unit includes a short-circuit detection switch unit, a short-circuit detection interrupt switch unit, a resistance detection switch unit, and a resistance detection interrupt switch unit. The detection unit includes a short-circuit detection unit and a resistance detection unit. The MCU includes several PA pins and several PC pins. The PA pins include PA0 pins and PAn pins, and the PC pins include PCi pins; n=1……n, i=0……i.

[0123] Example 2

[0124] A short-circuit and resistance detection device includes a circuit board assembly electrically connected to a rectangular connector. The circuit board assembly includes an MCU, which is electrically connected to a power supply unit, a switching unit, and a detection unit. The switching unit includes a short-circuit detection switch unit, a short-circuit detection interrupt switch unit, a resistance detection switch unit, and a resistance detection interrupt switch unit. The detection unit includes a short-circuit detection unit and a resistance detection unit. The MCU includes several PA pins and several PC pins. The PA pins include PA0 pins and PAn pins, and the PC pins include PCi pins; n=1……n, i=0……i.

[0125] There are two sets of rectangular connectors, including a first rectangular connector and a second rectangular connector. The first rectangular connector includes an X1 connector and a J1 connector, and the second rectangular connector includes an X2 connector and a J2 connector. The J1 connector includes several input terminals Ai, and the J2 connector includes several output terminals Ai_O.

[0126] The short-circuit detection switch unit includes a toggle switch SW2. The normally open terminal T1 of the toggle switch SW2 is electrically connected to a resistor R2. The other end of the resistor R2 is electrically connected to the power supply VCC3.3. The common terminal S1 of the toggle switch SW2 is electrically connected to a capacitor C7, a pin 58 of the MCU, and the common terminal S1 of the toggle switch SW1. The normally closed terminal T2 of the toggle switch SW2 and the other end of the capacitor C7 are both grounded.

[0127] The short-circuit detection interrupt switch unit includes a toggle switch SW3. The normally open terminal T1 of the toggle switch SW3 is electrically connected to a resistor R5. The other end of the resistor R5 is electrically connected to the power supply VCC3.3. The common terminal S1 of the toggle switch SW3 is electrically connected to a capacitor C9, pin 59 of the MCU, and the common terminal S1 of the toggle switch SW2. The normally closed terminal T2 of the toggle switch SW3 and the other end of the capacitor C9 are both grounded.

[0128] The resistance detection switch unit includes a toggle switch SW4. The normally open terminal T1 of the toggle switch SW4 is electrically connected to a resistor R10. The other end of the resistor R10 is electrically connected to the power supply VCC3.3. The common terminal S1 of the toggle switch SW4 is electrically connected to a capacitor C12, a pin 61 of the MCU, and the common terminal S1 of the toggle switch SW3. The normally closed terminal of the toggle switch SW4 and the other end of the capacitor C12 are both grounded.

[0129] The resistance detection interrupt switch unit includes a toggle switch SW5. The normally open terminal T1 of the toggle switch SW5 is electrically connected to a resistor R11. The other end of the resistor R11 is electrically connected to the power supply VCC3.3. The common terminal S1 of the toggle switch SW5 is electrically connected to a capacitor C22, a pin 62 of the MCU, and the common terminal S1 of the toggle switch SW4. The normally closed terminal T2 of the toggle switch SW5 and the other end of the capacitor C22 are both grounded.

[0130] Example 3

[0131] A short-circuit and resistance detection device includes a circuit board assembly electrically connected to a rectangular connector. The circuit board assembly includes an MCU, which is electrically connected to a power supply unit, a switching unit, and a detection unit. The switching unit includes a short-circuit detection switch unit, a short-circuit detection interrupt switch unit, a resistance detection switch unit, and a resistance detection interrupt switch unit. The detection unit includes a short-circuit detection unit and a resistance detection unit. The MCU includes several PA pins and several PC pins. The PA pins include PA0 pins and PAn pins, and the PC pins include PCi pins; n=1……n, i=0……i.

[0132] There are two sets of rectangular connectors, including a first rectangular connector and a second rectangular connector. The first rectangular connector includes an X1 connector and a J1 connector, and the second rectangular connector includes an X2 connector and a J2 connector. The J1 connector includes several input terminals Ai, and the J2 connector includes several output terminals Ai_O.

[0133] The short-circuit detection switch unit includes a toggle switch SW2. The normally open terminal T1 of the toggle switch SW2 is electrically connected to a resistor R2. The other end of the resistor R2 is electrically connected to the power supply VCC3.3. The common terminal S1 of the toggle switch SW2 is electrically connected to a capacitor C7, a pin 58 of the MCU, and the common terminal S1 of the toggle switch SW1. The normally closed terminal T2 of the toggle switch SW2 and the other end of the capacitor C7 are both grounded.

[0134] The short-circuit detection interrupt switch unit includes a toggle switch SW3. The normally open terminal T1 of the toggle switch SW3 is electrically connected to a resistor R5. The other end of the resistor R5 is electrically connected to the power supply VCC3.3. The common terminal S1 of the toggle switch SW3 is electrically connected to a capacitor C9, pin 59 of the MCU, and the common terminal S1 of the toggle switch SW2. The normally closed terminal T2 of the toggle switch SW3 and the other end of the capacitor C9 are both grounded.

[0135] The resistance detection switch unit includes a toggle switch SW4. The normally open terminal T1 of the toggle switch SW4 is electrically connected to a resistor R10. The other end of the resistor R10 is electrically connected to the power supply VCC3.3. The common terminal S1 of the toggle switch SW4 is electrically connected to a capacitor C12, a pin 61 of the MCU, and the common terminal S1 of the toggle switch SW3. The normally closed terminal of the toggle switch SW4 and the other end of the capacitor C12 are both grounded.

[0136] The resistance detection interrupt switch unit includes a toggle switch SW5. The normally open terminal T1 of the toggle switch SW5 is electrically connected to a resistor R11. The other end of the resistor R11 is electrically connected to the power supply VCC3.3. The common terminal S1 of the toggle switch SW5 is electrically connected to a capacitor C22, a pin 62 of the MCU, and the common terminal S1 of the toggle switch SW4. The normally closed terminal T2 of the toggle switch SW5 and the other end of the capacitor C22 are both grounded.

[0137] The power supply unit includes a toggle switch SW1. The normally open terminal T1 of the toggle switch SW1 is electrically connected to pin 1 of the P1 interface. The common terminal S1 of the toggle switch SW1 is electrically connected to the transient suppression diode D1 and the fuse F1. The other end of the fuse F1 is electrically connected to capacitors C1 and C2 and the Vin pin of the voltage regulator chip U1. The Vout pin of the voltage regulator chip U1 is electrically connected to capacitors C3 and C4 and the Vin pin of the voltage regulator chip U2. The Vout pin of the voltage regulator chip U2 is electrically connected to capacitors C5 and C6. Capacitors C3 and C4 are electrically connected to power supply VCC5, and capacitors C5 and C6 are electrically connected to power supply VCC3.3.

[0138] Pins 2 and 3 of P1, normally closed terminal T2 of toggle switch SW1, capacitors C1 and C2, GND pin of voltage regulator chip U1, capacitors C3 and C4, GND pin of voltage regulator chip U2, capacitors C5 and C6 are all grounded.

[0139] Power supply VCC3.3 is connected in sequence to resistor R1 and the positive terminal of LED1, while the negative terminal of LED1 is grounded.

[0140] Example 4

[0141] A short-circuit and resistance detection device includes a circuit board assembly electrically connected to a rectangular connector. The circuit board assembly includes an MCU, which is electrically connected to a power supply unit, a switching unit, and a detection unit. The switching unit includes a short-circuit detection switch unit, a short-circuit detection interrupt switch unit, a resistance detection switch unit, and a resistance detection interrupt switch unit. The detection unit includes a short-circuit detection unit and a resistance detection unit. The MCU includes several PA pins and several PC pins. The PA pins include PA0 pins and PAn pins, and the PC pins include PCi pins; n=1……n, i=0……i.

[0142] There are two sets of rectangular connectors, including a first rectangular connector and a second rectangular connector. The first rectangular connector includes an X1 connector and a J1 connector, and the second rectangular connector includes an X2 connector and a J2 connector. The J1 connector includes several input terminals Ai, and the J2 connector includes several output terminals Ai_O.

[0143] The short-circuit detection switch unit includes a toggle switch SW2. The normally open terminal T1 of the toggle switch SW2 is electrically connected to a resistor R2. The other end of the resistor R2 is electrically connected to the power supply VCC3.3. The common terminal S1 of the toggle switch SW2 is electrically connected to a capacitor C7, a pin 58 of the MCU, and the common terminal S1 of the toggle switch SW1. The normally closed terminal T2 of the toggle switch SW2 and the other end of the capacitor C7 are both grounded.

[0144] The short-circuit detection interrupt switch unit includes a toggle switch SW3. The normally open terminal T1 of the toggle switch SW3 is electrically connected to a resistor R5. The other end of the resistor R5 is electrically connected to the power supply VCC3.3. The common terminal S1 of the toggle switch SW3 is electrically connected to a capacitor C9, pin 59 of the MCU, and the common terminal S1 of the toggle switch SW2. The normally closed terminal T2 of the toggle switch SW3 and the other end of the capacitor C9 are both grounded.

[0145] The resistance detection switch unit includes a toggle switch SW4. The normally open terminal T1 of the toggle switch SW4 is electrically connected to a resistor R10. The other end of the resistor R10 is electrically connected to the power supply VCC3.3. The common terminal S1 of the toggle switch SW4 is electrically connected to a capacitor C12, a pin 61 of the MCU, and the common terminal S1 of the toggle switch SW3. The normally closed terminal of the toggle switch SW4 and the other end of the capacitor C12 are both grounded.

[0146] The resistance detection interrupt switch unit includes a toggle switch SW5. The normally open terminal T1 of the toggle switch SW5 is electrically connected to a resistor R11. The other end of the resistor R11 is electrically connected to the power supply VCC3.3. The common terminal S1 of the toggle switch SW5 is electrically connected to a capacitor C22, a pin 62 of the MCU, and the common terminal S1 of the toggle switch SW4. The normally closed terminal T2 of the toggle switch SW5 and the other end of the capacitor C22 are both grounded.

[0147] The power supply unit includes a toggle switch SW1. The normally open terminal T1 of the toggle switch SW1 is electrically connected to pin 1 of the P1 interface. The common terminal S1 of the toggle switch SW1 is electrically connected to the transient suppression diode D1 and the fuse F1. The other end of the fuse F1 is electrically connected to capacitors C1 and C2 and the Vin pin of the voltage regulator chip U1. The Vout pin of the voltage regulator chip U1 is electrically connected to capacitors C3 and C4 and the Vin pin of the voltage regulator chip U2. The Vout pin of the voltage regulator chip U2 is electrically connected to capacitors C5 and C6. Capacitors C3 and C4 are electrically connected to power supply VCC5, and capacitors C5 and C6 are electrically connected to power supply VCC3.3.

[0148] Pins 2 and 3 of P1, normally closed terminal T2 of toggle switch SW1, capacitors C1 and C2, GND pin of voltage regulator chip U1, capacitors C3 and C4, GND pin of voltage regulator chip U2, capacitors C5 and C6 are all grounded.

[0149] Power supply VCC3.3 is connected in sequence to resistor R1 and the positive terminal of LED1, while the negative terminal of LED1 is grounded.

[0150] The short-circuit detection unit includes a PA0 short-circuit detection unit and a PAn short-circuit detection unit. The PA0 short-circuit detection unit includes a field-effect transistor Q1. The collector S of the field-effect transistor Q1 is electrically connected to a resistor R13, a capacitor C23, and a power supply VCC5. The gate G is electrically connected to a resistor R14 and the collector 3 of a transistor Q2. The drain D is electrically connected to a resistor R12 and the A0 input terminal of the J1 connector. The other end of the resistor R13 and the other end of the capacitor C23 are electrically connected together between the gate G and the resistor R14. The base 1 of the transistor Q2 is electrically connected to a resistor R15 and a resistor R16. The other end of the resistor R15 is electrically connected to a light-emitting diode (LED). a The other end of resistor R16 is grounded together with pin PA0 of the MCU and emitter 2;

[0151] The PAn short-circuit detection unit includes a field-effect transistor Q. a Q-type field-effect transistor a The collector S is electrically connected to resistor R respectively. a Capacitor C a The power supply VCC5 and the gate G are electrically connected in sequence to resistor R.b and transistor Q b The collector 3 and drain D are connected in sequence to resistor R. e The An output terminal is electrically connected to the corresponding Ai input terminal of connector J1. The An output terminal is also electrically connected to the positive terminal of LEDn+1, and the negative terminal of LEDn+1 is grounded; resistor R... a The other end and capacitor C a The other end is electrically connected to the gate G and the resistor R. b Between; transistor Q b The base 1 is electrically connected to resistor R. c and resistance R d resistance R c The other end is electrically connected to pin PAn on the MCU, and resistor R d The other end is grounded together with emitter 2.

[0152] Example 5

[0153] The detection method of the short circuit and resistance detection device includes a short circuit detection method and a resistance detection method.

[0154] Example 6

[0155] The detection method of the short circuit and resistance detection device includes a short circuit detection method and a resistance detection method.

[0156] The short-circuit detection method is implemented according to the following steps:

[0157] Step 1: Connect the signal input terminal of the device under test (DUT) to connector X1 and the signal output terminal of the DUT to connector X2; connect connector X1 to connector J1 and connector X2 to connector J2.

[0158] Step 2: Close the power switch SW1;

[0159] Step 3, short circuit detection;

[0160] When the short-circuit detection switch SW2 is closed, PA0, PA1...PAn sequentially output high-level signals. When PA0 outputs a high-level signal, the A0 signal sequentially performs short-circuit detection on the A1...An signals and the ground signal. When the A0 signal shows no short circuit to any other signal, the LED... a When the LED is lit, PA1 outputs a high level; when the A0 signal is short-circuited to the An signal, the LED... a Only LEDn+1 is lit, while the other LEDs are not lit.

[0161] When PAm outputs a high level, the Am signal sequentially performs short-circuit detection on the Am+1 signal...An signal, and ground signal; when the Am signal does not short-circuit other signals, LEDm+1 lights up, and then it is PAm+1's turn to output a high level; if the Am signal short-circuits the An signal, LEDm+1 and LEDn+1 light up, while other LEDs do not light up; n is greater than m+1;

[0162] Step 4, short circuit detection interrupted;

[0163] When a short circuit occurs between two signals, close SW3 switch to interrupt the short circuit detection, record the fault, and then open SW3 switch to continue the detection.

[0164] The resistance testing method is implemented according to the following steps:

[0165] Step 1: Connect the signal input terminal of the device under test (DUT) to connector X1, and connect the signal output terminal of the DUT to connector X2; connect connector X1 to connector J1, and connector X2 to connector J2; connect the positive terminal of the ohmmeter to the i relays JK in the Ai input unit. a Contact 3 connects the negative terminal of the ohmmeter to the i-th relay JK in the Ai_O output terminal. b Contact point 3;

[0166] Step 2: Close the power switch SW1;

[0167] Step 3, resistance detection;

[0168] When the resistance detection switch SW4 is closed, PC0 to PCi of the MCU output high levels sequentially. Signals A0, A0_O, ..., Ai, Ai_O are then connected between the positive and negative terminals of an ohmmeter. When the i-th group of signals is detected, the corresponding LED... b Light it up; read the resistance value of group i using an ohmmeter;

[0169] Step 4, resistance interruption detection;

[0170] If any abnormality occurs in the resistance detection of any signal, close the SW5 switch to interrupt the resistance detection, record the fault, and then open the SW5 switch to continue the resistance detection.

Claims

1. A short-circuit and resistance detection device, characterized in that, The device includes a circuit board assembly electrically connected to a rectangular connector. The circuit board assembly includes an MCU, which is electrically connected to a power supply unit, a switching unit, and a detection unit. The switching unit includes a short-circuit detection switch unit, a short-circuit detection interrupt switch unit, a resistance detection switch unit, and a resistance detection interrupt switch unit. The detection unit includes a short-circuit detection unit and a resistance detection unit. The MCU includes several PA pins and several PC pins. The PA pins include PA0 pins and PAn pins, and the PC pins include PCi pins; n=1…n, i=0…i. The rectangular connectors consist of two sets, including a first rectangular connector and a second rectangular connector. The first rectangular connector includes an X1 connector and a J1 connector, and the second rectangular connector includes an X2 connector and a J2 connector. The J1 connector includes several input terminals Ai, and the J2 connector includes several output terminals Ai_O. The short-circuit detection switch unit includes a toggle switch SW2. The normally open terminal T1 of the toggle switch SW2 is electrically connected to a resistor R2. The other end of the resistor R2 is electrically connected to the power supply VCC3.

3. The common terminal S1 of the toggle switch SW2 is electrically connected to a capacitor C7, a pin 58 of the MCU, and the common terminal S1 of the toggle switch SW1. The normally closed terminal T2 of the toggle switch SW2 and the other end of the capacitor C7 are both grounded. The short-circuit detection interrupt switch unit includes a toggle switch SW3. The normally open terminal T1 of the toggle switch SW3 is electrically connected to a resistor R5. The other end of the resistor R5 is electrically connected to the power supply VCC3.

3. The common terminal S1 of the toggle switch SW3 is electrically connected to a capacitor C9, a pin 59 of the MCU, and the common terminal S1 of the toggle switch SW2. The normally closed terminal T2 of the toggle switch SW3 and the other end of the capacitor C9 are both grounded. The resistance detection switch unit includes a toggle switch SW4. The normally open terminal T1 of the toggle switch SW4 is electrically connected to a resistor R10. The other end of the resistor R10 is electrically connected to the power supply VCC3.

3. The common terminal S1 of the toggle switch SW4 is electrically connected to a capacitor C12, a pin 61 of the MCU, and the common terminal S1 of the toggle switch SW3. The normally closed terminal of the toggle switch SW4 and the other end of the capacitor C12 are both grounded. The resistance detection interruption switch unit includes a toggle switch SW5. The normally open terminal T1 of the toggle switch SW5 is electrically connected to a resistor R11. The other end of the resistor R11 is electrically connected to the power supply VCC3.

3. The common terminal S1 of the toggle switch SW5 is electrically connected to a capacitor C22, a pin 62 of the MCU, and the common terminal S1 of the toggle switch SW4. The normally closed terminal T2 of the toggle switch SW5 and the other end of the capacitor C22 are both grounded. The power supply unit includes a toggle switch SW1. The normally open terminal T1 of the toggle switch SW1 is electrically connected to pin 1 of the P1 interface. The common terminal S1 of the toggle switch SW1 is electrically connected to the transient suppression diode D1 and the fuse F1. The other end of the fuse F1 is electrically connected to capacitors C1 and C2 and the Vin pin of the voltage regulator chip U1. The Vout pin of the voltage regulator chip U1 is electrically connected to capacitors C3 and C4 and the Vin pin of the voltage regulator chip U2. The Vout pin of the voltage regulator chip U2 is electrically connected to capacitors C5 and C6. Capacitors C3 and C4 are electrically connected to power supply VCC5, and capacitors C5 and C6 are electrically connected to power supply VCC3.

3. Pins 2 and 3 of P1, normally closed terminal T2 of toggle switch SW1, capacitors C1 and C2, GND pin of voltage regulator chip U1, capacitors C3 and C4, GND pin of voltage regulator chip U2, capacitors C5 and C6 are all grounded. Power supply VCC3.3 is connected in sequence to resistor R1 and the positive terminal of LED1, and the negative terminal of LED1 is grounded; The short-circuit detection unit includes a PA0 short-circuit detection unit and a PAn short-circuit detection unit. The PA0 short-circuit detection unit includes a field-effect transistor Q1. The collector S of the field-effect transistor Q1 is electrically connected to a resistor R13, a capacitor C23, and a power supply VCC5. The gate G is electrically connected to a resistor R14 and the collector 3 of a transistor Q2. The drain D is electrically connected to a resistor R12 and the A0 input terminal of the J1 connector. The other end of the resistor R13 and the other end of the capacitor C23 are electrically connected together between the gate G and the resistor R14. The base 1 of the transistor Q2 is electrically connected to a resistor R15 and a resistor R16. The other end of the resistor R15 is electrically connected to a light-emitting diode (LED). a The other end of resistor R16 is grounded together with pin PA0 of the MCU and emitter 2; The PAn short-circuit detection unit includes a field-effect transistor Q. a The field-effect transistor Q a The collector S is electrically connected to resistor R respectively. a Capacitor C a The power supply VCC5 and the gate G are connected in sequence to resistor R. b and transistor Q b The collector 3 and drain D are connected in sequence to resistor R. e The An output terminal is electrically connected to the corresponding Ai input terminal of connector J1. The An output terminal is also electrically connected to the positive terminal of LEDn+1, and the negative terminal of LEDn+1 is grounded; resistor R... a The other end and capacitor C a The other end is electrically connected to the gate G and the resistor R. b Between; transistor Q b The base 1 is electrically connected to resistor R. c and resistance R d resistance R c The other end is electrically connected to pin PAn on the MCU, and resistor R d The other end is grounded together with emitter 2.

2. The short-circuit and resistance detection device according to claim 1, characterized in that, The resistance detection unit includes an Ai input terminal unit and an Ai_O output terminal unit. The Ai input terminal unit includes a light-emitting diode (LED). b The light-emitting diode (LED) b The positive terminal is electrically connected to the PCi pin on the MCU, and the negative terminal is electrically connected to resistor R. f resistance R f Connect resistor R respectively g and transistor Q c The base b, resistor R g The other end is connected to transistor Q. c The emitter (e) of the transistor is grounded; transistor Q c The collectors c are electrically connected to diode D respectively. a The positive terminal and relay JK a Contact 1, diode D a The negative terminal and relay JK a Contact 2 is connected to power supply VCC5; Relay JK a Contact 4 is electrically connected to the corresponding Ai input terminal of connector J1, and contact 3 is electrically connected to the positive terminal of the ohmmeter. The Ai_O output terminal unit includes a resistor R. h resistance R h One end is electrically connected to the PCi pin on the MCU, and the resistor R h The other end is electrically connected to resistor R. j and transistor Q d The base b, resistor R j The other end is connected to transistor Q. d The emitter (e) of the transistor is grounded; transistor Q d The collectors c are electrically connected to diode D respectively. b The positive terminal and relay JK b Contact 1, diode D b The negative terminal and relay JK b Contact 2 is connected to power supply VCC5; Relay JK b Contact 4 is electrically connected to the corresponding Ai_O output terminal of the J2 connector, and contact 3 is electrically connected to the negative terminal of the ohmmeter.

3. The short-circuit and resistance detection device according to claim 2, characterized in that, Pin 5 of the MCU is electrically connected to capacitor C8 and the input terminal of dual-electrode crystal oscillator Y1 respectively. The output terminal of dual-electrode crystal oscillator Y1 is connected to capacitor C10 and resistor R7 respectively. The other end of resistor R7 is connected to pin 6 of the MCU. The connection point of capacitor C8 and capacitor C10 is grounded together. Pin 43 of the MCU is electrically connected to pin 3 of P2, pin 42 of the MCU is electrically connected to pin 2 of P2, and pin 1 of P2 is grounded; pin 60 of the MCU is electrically connected to resistor R8 and power supply VCC3.3, with the other end of resistor R8 grounded; pin 7 of the MCU is electrically connected to the reset signal node RESET, which is electrically connected to resistor R9 and capacitor C11, with the other end of R9 connected to power supply VCC3.3 and the other end of capacitor C11 grounded; pin 13 of the MCU is electrically connected to ferrite bead FB1 and capacitors C15 and C16, with the other end of ferrite bead FB1 connected to power supply VCC3.3, and the other ends of capacitors C15 and C16 grounded; pin 28 of the MCU is electrically connected to pin BOOT1, resistor R4, and power supply VCC3.3, with the other end of resistor R4 grounded; MCU Pin 31 of the MCU is electrically connected to capacitor C14, with the other end of capacitor C14 grounded; pin 47 of the MCU is electrically connected to capacitor C13, with the other end of capacitor C13 grounded; pins 63, 18, and 12 of the MCU are all grounded; pins 1, 32, 48, 64, and 19 of the MCU are all electrically connected to power supply VCC3.3; pins 49 and 46 of the MCU are electrically connected to download port P3; pin 1 of download port P3 is electrically connected to diode D7 and power supply VCC3.3, with the other end of diode D7 grounded; pin 2 of download port P3 is grounded; pin 3 of download port P3 is electrically connected to diode D6 and pin 49 of the MCU, with the other end of diode D6 grounded; pin 4 of download port P3 is electrically connected to diode D5 and pin 46 of the MCU, with the other end of diode D5 grounded.

4. The short-circuit and resistance detection device according to claim 3, characterized in that, The power supply VCC3.3 is also electrically connected to a filter circuit, which includes several capacitors. One end of capacitors C17, C18, C19, C20, and C21 is electrically connected to the power supply VCC3.3, and the other end is grounded together.

5. The short-circuit and resistance detection device according to claim 3, characterized in that, The capacitor C4 is electrically connected to the Vin pin of the voltage regulator chip U2 via diode D2. The capacitor C6 is also electrically connected to diode D3. Both diodes D2 and D3 are grounded. The pin 60 of the MCU is electrically connected to resistors R6 and R8, respectively. The other end of resistor R6 is electrically connected to power supply VCC3.

3. The pin 28 of the MCU is electrically connected to pin BOOT1, resistors R3 and R4, respectively. The other end of resistor R3 is electrically connected to power supply VCC3.

3.

6. A detection method for a short circuit and resistance detection device, characterized in that, The short-circuit and resistance detection device as described in claims 4-5 includes a short-circuit detection method and a resistance detection method.

7. The detection method of the short circuit and resistance detection device as described in claim 6, characterized in that, The short-circuit detection method is implemented according to the following steps: Step 1: Connect the signal input terminal of the device under test (DUT) to connector X1 and the signal output terminal of the DUT to connector X2; connect connector X1 to connector J1 and connector X2 to connector J2. Step 2: Close the power switch SW1; Step 3, short circuit detection; When the short-circuit detection switch SW2 is closed, PA0, PA1...PAn output high levels in sequence; When PA0 outputs a high level, the A0 signal sequentially performs short-circuit detection on the A1 signal...An signal, and ground signal; when the A0 signal does not short-circuit any other signal, the LED... a When the LED is lit, PA1 outputs a high level; when the A0 signal is short-circuited to the An signal, the LED... a Only LEDn+1 is lit, while the other LEDs are not lit. When PAm outputs a high level, the Am signal sequentially performs short-circuit detection on the Am+1 signal...An signal, and ground signal; when the Am signal does not short-circuit other signals, LEDm+1 lights up, and then it is PAm+1's turn to output a high level; if the Am signal short-circuits the An signal, LEDm+1 and LEDn+1 light up, while other LEDs do not light up; n is greater than m+1; Step 4, short circuit detection interrupted; When a short circuit occurs between two signals, close SW3 switch to interrupt the short circuit detection, record the fault, and then open SW3 switch to continue the detection. The resistance detection method is implemented according to the following steps: Step 1: Connect the signal input terminal of the device under test (DUT) to connector X1, and connect the signal output terminal of the DUT to connector X2; connect connector X1 to connector J1, and connector X2 to connector J2; connect the positive terminal of the ohmmeter to the i relays JK in the Ai input unit. a Contact 3 connects the negative terminal of the ohmmeter to the i-th relay JK in the Ai_O output terminal. b Contact point 3; Step 2: Close the power switch SW1; Step 3, resistance detection; When the resistance detection switch SW4 is closed, the MCU's PC0 to PCi output high levels sequentially. Signals A0, A0_O, ..., Ai, Ai_O are sequentially connected between the positive and negative terminals of an ohmmeter. When the i-th group of signals is detected, the corresponding LED is activated. b Light it up; read the resistance value of group i using an ohmmeter; Step 4, resistance interruption detection; If any abnormality occurs in the resistance detection of any signal, close the SW5 switch to interrupt the resistance detection, record the fault, and then open the SW5 switch to continue the resistance detection.

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