A joint resistance measuring device

Abstract

The present invention relates to a joint resistance measurement device, comprising: a control unit, a constant current source, a constant voltage source, a first connection end, a second connection end, a first switching switch, a second switching switch, a first voltage detection unit, a second voltage detection unit, a digital-to-analog conversion unit and a control unit; the first connection end and the second connection end are used to correspondingly connect the inner core and the outer core of the joint to be measured; the control unit is configured to output the continuous resistance value of the joint to be measured when receiving a first trigger instruction. Implementing the present invention can effectively improve the joint test efficiency and reduce the labor input cost.

Description

Technical Field

[0001] The present invention relates to the technical field of joint resistance measurement, and more particularly to a joint resistance measurement device. Background Art

[0002] Nuclear power units mostly use aviation plugs or coaxial cables on site, but with the increase of usage time or frequent disassembly and assembly of equipment, poor contact often occurs. Abnormal contact of this type of connector greatly affects the transmission of signals, has a negative impact on the reliability and stability of the equipment, and affects the normal monitoring of important signals and the control and protection system. At present, there are many scenarios for instrument resistance and insulation measurement on site of nuclear power units. The current test method requires frequent alternation of insulation meters and multimeters during the test process, which is cumbersome, time-consuming and labor-intensive. At the same time, its interface matching is poor. For example, the measurement of the main pump displacement probe and the main pump speed probe requires the use of an adapter, which has a negative impact on the reliability of the maintenance of key and important sensitive equipment. The level of intelligence is low, and the display and operation are not intuitive. Summary of the invention

[0003] The technical problem to be solved by the present invention is to provide a joint resistance measuring device in view of the above-mentioned partial technical defects of the prior art.

[0004] The technical solution adopted by the present invention to solve the technical problem is: construct a joint resistance measuring device, including: a control unit, a constant current source, a first connection end, a second connection end, a first switch, a second switch, a first voltage detection unit, a second voltage detection unit, a digital-to-analog conversion unit and a control unit;

[0005] The first connection end and the second connection end are used to connect the inner core and the outer core of the tested connector respectively, the first switching switch is respectively connected to the control unit, the first connection end, the constant current source and the first voltage detection unit, and the second switching switch is respectively connected to the control unit, the second connection end and the second voltage detection unit;

[0006] The constant current source is connected to the control unit and is used to generate a stable current when the control unit receives a first trigger instruction; the first switching switch and the second switching switch are configured to be controlled to be turned on by the control unit when the control unit receives the first trigger instruction; the digital-to-analog conversion unit is connected to the first voltage detection unit, the second voltage detection unit and the control unit, and is used to obtain the detection results of the first voltage detection unit and the second voltage detection unit and output the corresponding first conversion value, and the control unit is configured to output the continuous resistance value of the measured joint according to the first conversion value when receiving the first trigger instruction.

[0007] Preferably, in the joint resistance measuring device of the present invention, it further includes: a constant voltage source, a third connection terminal, a first voltage dividing unit, a second voltage dividing unit, a third switching switch, a fourth switching switch, a third voltage detecting unit, and a fourth voltage detecting unit;

[0008] The third connection terminal is used to connect the insulating layer of the joint to be measured;

[0009] The constant voltage source is connected to the second connection terminal and the control unit, and is used to output a stable voltage when the control unit receives a second trigger instruction;

[0010] The third switching switch is respectively connected to the control unit, the first connection terminal, and the first voltage dividing unit. The fourth switching switch is respectively connected to the control unit, the second connection terminal, and the second voltage dividing unit. The third voltage detecting unit is connected to the first voltage dividing unit, and the fourth voltage detecting unit is connected to the second voltage dividing unit; and the third switching switch and the fourth switching switch are configured to be controlled to conduct by the control unit when the control unit receives a second trigger instruction;

[0011] The analog-to-digital conversion unit is connected to the third voltage detecting unit, the fourth voltage detecting unit, and the control unit, and is used to respectively obtain the detection results of the third voltage detecting unit and the fourth voltage detecting unit and output corresponding second conversion values. The control unit is configured to output the insulation resistance value of the joint to be measured according to the second conversion values when receiving the second trigger instruction.

[0012] Preferably, in the joint resistance measuring device of the present invention, it further includes a discharging unit connected to the third connection terminal. The discharging unit is used to discharge the insulating layer of the joint to be measured when the constant voltage source is in an off state.

[0013] Preferably, in the joint resistance measuring device of the present invention, it further includes an execution unit. The execution unit is used to control the joint to be measured to shake evenly. The control unit is used to obtain the maximum value and the minimum value of the continuous resistance values during the shaking process of the joint to be measured, and obtain the difference obtained by subtracting the minimum value from the maximum value as the shaking resistance value of the joint to be measured.

[0014] Preferably, in the joint resistance measuring device of the present invention, the control unit is further used to obtain the average value of the continuous resistance values within a preset time period as the average resistance value of the joint to be measured.

[0015] Preferably, in the joint resistance measuring device of the present invention, a resistance calibration unit is further included. The first end of the resistance calibration unit is connected to the constant current source, the second end of the resistance calibration unit is connected to the second voltage detection unit, the third end of the resistance calibration unit is connected to the first voltage detection unit, and the fourth end of the resistance calibration unit is connected to the control unit, and is controlled to be turned on or off by the control unit.

[0016] Preferably, in the joint resistance measuring device of the present invention, a zero-point calibration unit is further included. The first end of the zero-point calibration unit is connected to the first voltage detection unit, the second end of the zero-point calibration unit is connected to the second voltage detection unit, and the third end of the zero-point calibration unit is connected to the control unit, and is controlled to be turned on or off by the control unit.

[0017] Preferably, in the joint resistance measuring device of the present invention, the constant current source includes a power supply unit, a first operational amplifier, a first capacitor, a first bidirectional diode, a first resistor, a second resistor, a first relay switch, a first diode, and a first MOS transistor;

[0018] The first pin of the first operational amplifier is connected to the input end of the first relay switch, the second pin of the first operational amplifier is grounded, the third pin of the first operational amplifier is connected to the first end of the first resistor, the second end of the first resistor is used to input a reference voltage, the fourth pin of the first operational amplifier is connected to the third end of the first bidirectional diode, the first end of the first bidirectional diode is used to input a first voltage, the second end of the first bidirectional diode is used to input a second voltage, and the fifth pin of the first operational amplifier is connected to the power supply unit;

[0019] The output end of the first relay switch is connected to the anode of the first diode, the cathode of the first diode is connected to the drain of the first MOS transistor, the source of the first MOS transistor is connected to the first end of the second resistor, the second end of the second resistor is connected to the first switching switch, the control end of the first relay switch is connected to the control unit, and the first relay switch is configured to be controlled to be turned on by the control unit when the control unit receives the first trigger instruction.

[0020] Preferably, in the joint resistance measuring device of the present invention, the first voltage detection unit includes a second relay switch and a third resistor; the input end of the second relay switch is connected to the first switching switch, the output of the second relay switch is connected to the first end of the third resistor, the second end of the third resistor is connected to the analog-to-digital conversion unit, the control end of the second relay switch is connected to the control unit, and the second relay switch is configured to be controlled to be turned on by the control unit when the control unit receives the first trigger instruction; and / or

[0021] The second voltage detection unit includes a fourth resistor and a fifth resistor. The first end of the fourth resistor is connected to the second switching switch, the second end of the fourth resistor is connected to the digital-to-analog conversion unit, the first end of the fifth resistor is connected to the second switching switch, and the second end of the fifth resistor is grounded.

[0022] Preferably, in the joint resistance measuring device of the present invention, the first voltage dividing unit includes a sixth resistor, a seventh resistor R1, and a second diode. The first end of the sixth resistor is connected to the third switching switch, the second end of the sixth resistor is connected to the first end of the seventh resistor and the third voltage detection unit, the second end of the seventh resistor is connected to the anode of the second diode D7, and the cathode of the second diode is grounded;

[0023] The second voltage dividing unit includes an eighth resistor and a ninth resistor. The first end of the eighth resistor is connected to the fourth switching switch, the second end of the eighth resistor is connected to the first end of the ninth resistor and the fourth voltage detection unit, and the second end of the ninth resistor is connected to the anode of the second diode.

[0024] Preferably, in the joint resistance measuring device of the present invention, the third voltage detection unit includes a second operational amplifier, a third relay switch, a tenth resistor, and an eleventh resistor. The third pin of the second operational amplifier is connected to the second end of the seventh resistor, the fourth pin of the second operational amplifier is connected to the first pin of the second operational amplifier and the first end of the tenth resistor, the second end of the tenth resistor is connected to the input end of the third relay switch, the output end of the third relay switch is connected to the first end of the eleventh resistor, and the second end of the eleventh resistor is connected to the digital-to-analog conversion unit; the control end of the third relay switch is connected to the control unit, and the third relay switch is configured to be controlled to conduct by the control unit when the control unit receives the second trigger instruction;

[0025] The fourth voltage detection unit includes a third operational amplifier, a fourth relay switch, and a twelfth resistor. The third pin of the third operational amplifier is connected to the second end of the ninth resistor, the fourth pin of the third operational amplifier is connected to the first pin of the third operational amplifier and the first end of the twelfth resistor, the second end of the twelfth resistor is connected to the input end of the fourth relay switch, and the output end of the fourth relay switch is connected to the first end of the eleventh resistor; the control end of the fourth relay switch is connected to the control unit, and the fourth relay switch is configured to be controlled to conduct by the control unit when the control unit receives the second trigger instruction.

[0026] Implementing a joint resistance measuring device of the present invention has the following beneficial effects: By means of a simple circuit design, one-key trigger testing of the joint resistance can be achieved, which can effectively improve the joint testing efficiency and reduce the labor input cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The present invention will be further described below in conjunction with the drawings and embodiments. In the drawings:

[0028] Figure 1 is a schematic structural diagram of an embodiment of a joint resistance testing device of the present invention;

[0029] Figure 2 is a schematic structural diagram of another embodiment of a joint resistance testing device of the present invention;

[0030] Figure 3 is a partial circuit schematic diagram of an embodiment of a joint resistance testing device of the present invention;

[0031] Figure 4 is a partial circuit schematic diagram of another embodiment of a joint resistance testing device of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0032] For a clearer understanding of the technical features, objectives, and effects of the present invention, the specific embodiments of the present invention will now be described in detail with reference to the drawings.

[0033] As Figure 1As shown, in the first embodiment of a joint resistance measurement device of the present invention, it includes: a control unit 160, a constant current source 140, a first connection end 111, a second connection end 112, a first switch 121, a second switch 122, a first voltage detection unit 131, a second voltage detection unit 132, a digital-to-analog conversion unit 150, and a control unit 160; the first connection end 111 and the second connection end 112 are used to correspondingly connect the inner core and the outer core of the joint to be measured, the first switch 121 is respectively connected to the control unit 160, the first connection end 111, the constant current source 140, and the first voltage detection unit 131, and the second switch 122 is respectively connected to the control unit 160, the second connection end 112, and the second voltage detection unit 132; the constant current source 140 is connected to the control unit 160 and is used to generate a stable current when the control unit 160 receives a first trigger instruction; the first switch 121 and the second switch 122 are configured to be controlled to conduct by the control unit 160 when the control unit 160 receives the first trigger instruction; the digital-to-analog conversion unit 150 is connected to the first voltage detection unit 131, the second voltage detection unit 132, and the control unit 160, and is used to obtain the detection results of the first voltage detection unit 131 and the second voltage detection unit 132 and output corresponding first conversion values, and the control unit 160 is configured to output the continuous resistance value of the joint to be measured according to the first conversion value when receiving the first trigger instruction.

[0034] Specifically, the first connection end 111 and the second connection end 112 are respectively used to connect the inner core and the outer core of the joint to be measured. When measuring the continuous resistance of the joint to be measured, the control unit 160 triggers the constant current source 140 to output a stable current according to the first trigger instruction. At the same time, the first switch 121 and the second switch 122 are controlled to conduct. When the first switch 121 conducts, the stable current output by the constant current source 140 generates a voltage at the first connection end 111, and this voltage is obtained through the first voltage detection unit 131. The constant current output by the constant current source 140 passes through the inner core and the outer core of the joint to be measured (at this time, the inner core and the outer core are equivalent to being connected through a resistor with a certain resistance value), and then is connected to the second voltage detection unit 132 through the conducting second switch 122, and the output voltage of the second switch 122 is obtained through the second voltage detection unit 132. At this time, it can be understood that the voltages on the inner core and the outer core of the joint to be measured are respectively obtained. By obtaining the voltage difference between the two voltages and according to the constant current provided by the constant current source 140, the continuous resistance value of the joint to be measured can be obtained. Among them, the voltage values obtained by the first voltage detection unit 131 and the second voltage detection unit 132 are both subjected to digital-to-analog conversion by the digital-to-analog conversion unit 150, and the main control unit obtains the corresponding continuous resistance value based on this digital-to-analog conversion value. The first trigger instruction can be understood as an instruction for triggering the control unit 160 to measure the continuous resistance value, that is, through this process, the measurement result of the continuous resistance of the joint to be measured with one key can be realized.

[0035] Optionally, in a first embodiment of the joint resistance measuring device of the present invention, it further includes: a constant voltage source 180, a third connection end 113, a first voltage dividing unit 171, a second voltage dividing unit 172, a third switching switch 123, a fourth switching switch 124, a third voltage detection unit 133, and a fourth voltage detection unit 134. The third connection end 113 is used to connect the insulating layer of the joint to be measured; the constant voltage source 180 is connected to the second connection end 112 and the control unit 160, and is used to output a stable voltage when the control unit 160 receives a second trigger instruction; the third switching switch 123 is respectively connected to the control unit 160, the first connection end 111, and the first voltage dividing unit 171, the fourth switching switch 124 is respectively connected to the control unit 160, the second connection end 112, and the second voltage dividing unit 172, the third voltage detection unit 133 is connected to the first voltage dividing unit 171, and the fourth voltage detection unit 134 is connected to the second voltage dividing unit 172; and the third switching switch 123 and the fourth switching switch 124 are configured to be controlled by the control unit 160 to conduct when the control unit 160 receives a second trigger instruction; the analog-to-digital conversion unit 150 is connected to the third voltage detection unit 133, the fourth voltage detection unit 134, and the control unit 160, and is used to respectively obtain the detection results of the third voltage detection unit 133 and the fourth voltage detection unit 134 and output corresponding second conversion values. The control unit 160 is configured to output the insulation resistance value of the joint to be measured according to the second conversion value when receiving a second trigger instruction.

[0036] The third connection terminal 113 is used to connect the insulating layer of the joint under test. When measuring the insulation resistance of the joint under test, the control unit 160 triggers the constant voltage source 180 to generate a stable voltage according to the second trigger instruction, and at the same time controls the third switch 123 and the fourth switch 124 to conduct respectively. Taking the first connection terminal 111 connected to the inner core of the joint under test and the second connection terminal 112 connected to the inner core of the joint under test as an example. The stable voltage generated by the constant voltage source 180 forms a leakage current between the third connection terminal 113 and the first connection terminal 111. Due to the action of this leakage current, an output voltage corresponding to the output voltage is formed at the output terminal of the first voltage dividing unit 171. The output voltage is obtained through the third voltage detecting unit 133, and the detection value of the output voltage is converted by the analog-to-digital conversion unit 150 to obtain a conversion value. The control unit 160 obtains the detection value of the leakage current based on this conversion value, and based on this detection value and the stable voltage output by the constant voltage source 180, the insulation resistance between the insulating layer of the joint under test and its inner core can be obtained. The stable voltage generated by the constant voltage source 180 forms a leakage current between the third connection terminal 113 and the second connection terminal 112. Due to the action of this leakage current, an output voltage corresponding to the output voltage is formed at the output terminal of the second voltage dividing unit 172. The output voltage is obtained through the fourth voltage detecting unit 134, and the detection value of the output voltage is converted by the analog-to-digital conversion unit 150 to obtain a conversion value. The control unit 160 obtains the detection value of the leakage current based on this conversion value, and based on this detection value and the stable voltage output by the constant voltage source 180, the insulation resistance between the insulating layer of the joint under test and its outer core can be obtained. Finally, the insulation resistance test value of the joint under test is obtained. The second trigger instruction can be understood as an instruction for triggering the control unit 160 to perform continuous resistance value measurement, that is, through this process, the measurement result of the insulation resistance of the joint under test with one key can be realized.

[0037] Optionally, as Figure 2 shown, in the joint resistance measuring device of the present invention, a discharging unit 210 connected to the third connection terminal 113 is further included. The discharging unit is used to discharge the insulating layer of the joint under test when the constant voltage source 180 is in the off state. Specifically, when the insulation resistance test of the joint under test is completed, due to the power supply voltage of the constant current source 140, a large amount of charge is left on the insulating layer of the joint under test. Due to the insulating effect of the insulating layer, this charge cannot be released externally. In order to avoid damage to the internal circuit of the measuring device by this charge, a discharging unit is provided at the third connection terminal 113. The discharging unit discharges the insulating layer of the joint under test when the constant voltage source 180 is in the off state. In one embodiment, as Figure 4 shown, the discharging unit 210 includes a resistor R22, a resistor R23, and a capacitor C12.

[0038] Optionally, in the joint resistance measurement device of the present invention, an execution unit is further included. The execution unit is used to control the joint under test to shake evenly. The control unit 160 is used to obtain the maximum and minimum values of the continuous resistance values during the shaking of the joint under test, and obtain the difference obtained by subtracting the minimum value from the maximum value as the shaking resistance value of the joint under test. Specifically, the joint under test can be controlled to shake evenly through a mechanical or electrical execution unit. During the shaking of the joint under test, the maximum and minimum values of the measured continuous resistance are obtained, and the difference between the maximum value and the minimum value is used as the shaking resistance value of the joint under test. It can be understood that the magnitude of the shaking resistance value may be related to the measurement duration of the continuous resistance value. The duration of the execution unit can be set to obtain the shaking resistance value corresponding to the corresponding time.

[0039] Optionally, the control unit 160 is further used to obtain the average value of the continuous resistance values within a preset duration as the average resistance value of the joint under test. Specifically, for the continuous resistance value of the joint, since the continuous resistance value may change, in practical applications, it is more inclined to obtain the average value of the joint under test as the calculation parameter used. The measurement of the average resistance value can be obtained based on the average value of the continuous resistance values of the joint over a period of time. By setting a reasonable preset duration, the obtained average resistance value can more truly reflect the state of the joint under test.

[0040] Such as Figure 3As shown, the constant current source 140 includes a power supply unit, a first operational amplifier U12, a first capacitor C3, a first bidirectional diode D2, a first resistor R12, a second resistor R3, a first relay switch U7, a first diode D1, and a first MOS transistor Q2; the first pin of the first operational amplifier U12 is connected to the input terminal of the first relay switch, the second pin of the first operational amplifier U12 is grounded, the third pin of the first operational amplifier U12 is connected to the first end of the first resistor, the second end of the first resistor is used to input a reference voltage, the fourth pin of the first operational amplifier U12 is connected to the third end of the first bidirectional diode D2, the first end of the first bidirectional diode D2 is used to input a first voltage, the second end of the first bidirectional diode D2 is used to input a second voltage, and the fifth pin of the first operational amplifier U12 is connected to the power supply unit; the output terminal of the first relay switch U7 is connected to the anode of the first diode D1, the cathode of the first diode D1 is connected to the drain of the first MOS transistor, the source of the first MOS transistor Q2 is connected to the first end of the second resistor R3, the second end of the second resistor R3 is connected to the first switching switch 121, the control terminal of the first relay switch U7 is connected to the control unit 160, and the first relay switch U7 is configured to be controlled to conduct by the control unit 160 when the control unit 160 receives a first trigger instruction. Specifically, in the constant current source 140 circuit, a constant current source is generated by the first operational amplifier U12. In one embodiment, the constant current is 1 mA. This constant current passes through the first relay switch and is input to the first switching switch 121 through the first diode D1 and the first MOS transistor Q2. When the first switching switch 121 is conducting, it directly acts on the outer core or the inner core of the measured joint. Among them, the function of the first bidirectional diode D2 is to limit the voltage of the fourth pin of the first operational amplifier U12, prevent a voltage higher than the power supply voltage from being introduced during resistance measurement, and damage the first operational amplifier U12. By setting the first voltage to 0.7 V and the second voltage to 2.7 V, the voltage of the fourth pin of the first operational amplifier U12 can be limited between 0 V and 3.4 V. Among them, the conduction or cut-off of the first relay switch can be controlled by the control unit 160 to control whether the constant current source 140 participates in the measurement process.

[0041] Optionally, the first voltage detection unit 131 includes a second relay switch U6 and a third resistor R5; the input end of the second relay switch U6 is connected to the first switch 121, the output of the second relay switch U6 is connected to the first end of the third resistor R5, the second end of the third resistor R5 is connected to the analog-to-digital conversion unit 150, the control end of the second relay switch U6 is connected to the control unit 160, and the second relay switch U6 is configured to be controlled by the control unit 160 to conduct when the control unit 160 receives the first trigger instruction. Specifically, in the first voltage detection unit 131, the detection voltage is obtained by voltage division through the third resistor R5. The voltage detection unit can participate in the circuit operation according to the control instruction of the control unit 160. In one embodiment, a bidirectional diode D3 is connected to the second end of the third resistor R5 at the same time, and voltage limiting protection is performed through the bidirectional diode to prevent the output voltage at the second end of the third resistor R5 from being too high and damaging the analog-to-digital conversion unit 150.

[0042] Optionally, the second voltage detection unit 132 includes a fourth resistor R49 and a fifth resistor R9. The first end of the fourth resistor R49 is connected to the second switch 122, the second end of the fourth resistor R49 is connected to the analog-to-digital conversion unit 150, the first end of the fifth resistor R9 is connected to the second switch 122, and the second end of the fifth resistor R9 is grounded. Specifically, the voltage division can be obtained by forming a series connection between the fifth resistor R9 and the measured joint, and the voltage detection result of the voltage division can be obtained through the fourth resistor R49.

[0043] Optionally, in the joint resistance measuring device of the present invention, a resistance calibration unit 220 is further included. The first end of the resistance calibration unit 220 is connected to the constant current source 140, the second end of the resistance calibration unit 220 is connected to the second voltage detection unit 132, the third end of the resistance calibration unit 220 is connected to the first voltage detection unit 131, and the fourth end of the resistance calibration unit 220 is connected to the control unit 160, and is controlled by the control unit 160 to conduct or turn off. Specifically, the control unit 160 can control the resistance calibration unit 220 to conduct, and the measurement result can be calibrated through the resistance calibration unit 200. In one embodiment, as Figure 3 shown, the resistance calibration unit 220 includes a relay switch U13, a relay switch U10, and a standard resistor R10. When calibrating the test resistance value, the control unit 160 controls the relay switch U10 and the relay switch U13 to conduct, so that the voltages obtained by the first voltage detection unit 131 and the second voltage detection unit 132 are the voltages across the standard resistor R10. The calibration value is obtained according to the comparison result between the measured value and the actual value of the standard resistor R10, and the measurement result of the measured joint is calibrated through the calibration value. At the same time, when the relay switch U13 conducts, the first voltage detection unit 131 can obtain the maximum value of the corresponding measured voltage, that is, the full-scale test value.

[0044] Optionally, in the joint resistance measuring device of the present invention, a zero-point calibration unit 230 is further included. The first end of the zero-point calibration unit 230 is connected to the first voltage detection unit 131, the second end of the zero-point calibration unit 230 is connected to the second voltage detection unit 132, and the third end of the zero-point calibration unit 230 is connected to the control unit 160, and is controlled by the control unit 160 to be turned on or off. Specifically, the zero-point calibration of the voltage difference between the first voltage detection unit 131 and the second voltage detection unit 132 is realized through the zero-point calibration unit 230. It can be controlled by the control unit 160 to turn on the zero-point calibration unit. At this time, the first voltage detection unit 131 and the second voltage detection unit 132 are directly connected. According to the resistance values obtained by the first voltage detection unit 131 and the second voltage detection unit 132, it should be zero. The difference between the theoretical value and the actual measurement result is obtained, and this difference is calibrated so that the measured value is zero. Finally, the zero-point calibration result is obtained.

[0045] Optionally, the first voltage dividing unit 171 includes a sixth resistor R38, a seventh resistor R1, and a second diode D7. The first end of the sixth resistor is connected to the third switching switch 123. The second end of the sixth resistor is connected to the first end of the seventh resistor and the third voltage detection unit 133. The second end of the seventh resistor is connected to the anode of the second diode D7, and the cathode of the second diode D7 is grounded. Specifically, a voltage division is formed at the second end of the sixth resistor R38 through the combined action of the sixth resistor R38, the seventh resistor R1, and the second diode D7. The third voltage detection unit 133 is used to detect the voltage division and finally obtain the corresponding conversion value. Simply understood, the measured value of the leakage current is obtained by measuring the voltage.

[0046] Optionally, the second voltage dividing unit 172 includes an eighth resistor R37 and a ninth resistor R2. The first end of the eighth resistor R37 is connected to the fourth switching switch 124. The second end of the eighth resistor R37 is connected to the first end of the ninth resistor R2 and the fourth voltage detection unit 134. The second end of the ninth resistor R2 is connected to the anode of the second diode D7. Specifically, a voltage division is formed at the second end of the eighth resistor R37 through the combined action of the eighth resistor R37, the ninth resistor R2, and the second diode D7. The fourth voltage detection unit 134 is used to detect the voltage division and finally obtain the corresponding conversion value. Simply understood, the measured value of the leakage current is obtained by measuring the voltage.

[0047] Optionally, the third voltage detection unit 133 includes a second operational amplifier U8, a third relay switch U15, a tenth resistor R7, and an eleventh resistor R4. The third pin of the second operational amplifier U8 is connected to the second end of the seventh resistor. The fourth pin of the second operational amplifier U8 is connected to the first pin of the second operational amplifier U8 and the first end of the tenth resistor R7. The second end of the tenth resistor R7 is connected to the input end of the third relay switch U15. The output end of the third relay switch U15 is connected to the first end of the eleventh resistor R4. The second end of the eleventh resistor R4 is connected to the analog-to-digital conversion unit 150. The control end of the third relay switch U15 is connected to the control unit 160, and the third relay switch U15 is configured to be controlled to conduct by the control unit 160 when the control unit 160 receives the second trigger instruction. Specifically, a corresponding voltage value generated based on the detected leakage current is obtained through the second operational amplifier U8. The third relay switch U15 is controlled to conduct by the control unit 160, and a corresponding detection value is obtained and converted in the analog-to-digital conversion unit 150. Among them, a bidirectional diode D4 is provided at the first pin of the second operational amplifier U8, and the bidirectional diode D4 is used to limit the input voltage of the first pin of the second operational amplifier U8 to protect the operational amplifier.

[0048] The fourth voltage detection unit 134 includes a third operational amplifier U16, a fourth relay switch U14, and a twelfth resistor R6. The third pin of the third operational amplifier U16 is connected to the second end of the ninth resistor. The fourth pin of the third operational amplifier U16 is connected to the first pin of the third operational amplifier U16 and the first end of the twelfth resistor R6. The second end of the twelfth resistor R6 is connected to the input end of the fourth relay switch U14. The output end of the fourth relay switch U14 is connected to the first end of the eleventh resistor R4. The control end of the fourth relay switch U14 is connected to the control unit 160, and the fourth relay switch U14 is configured to be controlled to conduct by the control unit 160 when the control unit 160 receives the second trigger instruction. Specifically, a corresponding voltage value generated based on the detected leakage current is obtained through the third operational amplifier U16. The fourth relay switch U14 is controlled to conduct by the control unit 160, and a corresponding detection value is obtained and converted in the analog-to-digital conversion unit 150. Among them, a bidirectional diode D5 is provided at the first pin of the third operational amplifier U16, and the bidirectional diode D5 is used to limit the input voltage of the first pin of the third operational amplifier U16 to protect the operational amplifier.

[0049] Optionally, in the joint resistance measuring device of the present invention, a user input unit is further provided, and the user input unit can be a button or a touch screen. In this measuring device, a display unit is further provided for displaying the measurement result, and the display unit can be a touch screen. Among them, the touch screen can be used as both an input or output unit at the same time.

[0050] Optionally, in the joint resistance measuring device of the present invention, the first switching switch 121, the second switching switch 122, the third switching switch 123, and the fourth switching switch 124 are integrated on the same switch chip, and the conduction or cut-off of the connection end is realized through different pins of the switch chip. As Figure 3 shown, the third and fourth pins of the switch chip K1 are the first switching switch 121, the ninth and tenth pins of the switch chip K1 are the second switching switch 122, the fourth and fifth pins of the switch chip K1 are the third switching switch 123, and the eighth and ninth pins of the switch chip K1 are the fourth switching switch 124. The ninth and fourth pins of the switch chip K1 are respectively used to connect the inner core and the outer core of the joint to be measured.

[0051] Optionally, in the joint resistance measuring device of the present invention, the constant voltage source may be composed of a power supply chip U9 and its peripheral circuit. It can output a constant voltage with a constant voltage source of 100V or 50V.

[0052] It can be understood that the above embodiments only express the preferred embodiments of the present invention, and the description is relatively specific and detailed, but it cannot be understood as a limitation to the scope of the patent of the present invention; it should be pointed out that for those of ordinary skill in the art, without departing from the concept of the present invention, the above technical features can be freely combined, and several deformations and improvements can also be made, which all belong to the protection scope of the present invention; therefore, all equivalent transformations and modifications made to the scope of the claims of the present invention shall fall within the scope covered by the claims of the present invention.

Claims

1. A joint resistance measuring device, characterized in that, Comprising: A control unit, a constant current source, a first connection terminal, a second connection terminal, a first switching switch, a second switching switch, a first voltage detection unit, a second voltage detection unit, a digital-to-analog conversion unit, and a control unit; The first connection terminal and the second connection terminal are used to correspondingly connect the inner core and the outer core of the measured joint. The first switching switch is respectively connected to the control unit, the first connection terminal, the constant current source, and the first voltage detection unit. The second switching switch is respectively connected to the control unit, the second connection terminal, and the second voltage detection unit; The constant current source is connected to the control unit and is used to generate a stable current when the control unit receives a first trigger instruction; the first switching switch and the second switching switch are configured to be controlled to conduct by the control unit when the control unit receives the first trigger instruction; The digital-to-analog conversion unit is connected to the first voltage detection unit, the second voltage detection unit, and the control unit, and is used to obtain the detection results of the first voltage detection unit and the second voltage detection unit and output corresponding first conversion values. The control unit is configured to output the continuous resistance value of the measured joint according to the first conversion values when receiving the first trigger instruction.

2. The joint resistance measuring device according to claim 1, wherein The joint resistance measuring device further comprises: a constant voltage source, a third connection terminal, a first voltage dividing unit, a second voltage dividing unit, a third switching switch, a fourth switching switch, a third voltage detection unit, and a fourth voltage detection unit; The third connection terminal is used to connect the insulating layer of the measured joint; The constant voltage source is connected to the second connection terminal and the control unit and is used to output a stable voltage when the control unit receives a second trigger instruction; The third switching switch is respectively connected to the control unit, the first connection terminal, and the first voltage dividing unit. The fourth switching switch is respectively connected to the control unit, the second connection terminal, and the second voltage dividing unit. The third voltage detection unit is connected to the first voltage dividing unit. The fourth voltage detection unit is connected to the second voltage dividing unit; and the third switching switch and the fourth switching switch are configured to be controlled to conduct by the control unit when the control unit receives the second trigger instruction; The digital-to-analog conversion unit is connected to the third voltage detection unit, the fourth voltage detection unit, and the control unit, and is used to respectively obtain the detection results of the third voltage detection unit and the fourth voltage detection unit and output corresponding second conversion values. The control unit is configured to output the insulation resistance value of the measured joint according to the second conversion values when receiving the second trigger instruction.

3. The joint resistance measuring device according to claim 2, characterized in that, The joint resistance measuring device further comprises a discharge unit connected to the third connection terminal. The discharge unit is used to discharge the insulating layer of the measured joint when the constant voltage source is in an off state.

4. The joint resistance measuring device according to claim 1, wherein The joint resistance measuring device further includes an execution unit for controlling the uniform shaking of the joint to be measured, and a control unit for obtaining the maximum and minimum values of the continuous resistance values during the shaking of the joint to be measured, and obtaining the difference between the maximum value and the minimum value as the shaking resistance value of the joint to be measured.

5. The joint resistance measuring device according to claim 4, wherein The control unit is further configured to obtain the average value of the continuous resistance values within a preset time period as the average resistance value of the joint to be measured.

6. The joint resistance measuring device according to claim 1, wherein the joint resistance measuring device further includes a resistance calibration unit, the first end of the resistance calibration unit is connected to the constant current source, the second end of the resistance calibration unit is connected to the second voltage detection unit, the third end of the resistance calibration unit is connected to the first voltage detection unit, and the fourth end of the resistance calibration unit is connected to the control unit, and is controlled to be turned on or off by the control unit; and / or further includes a zero point calibration unit, the first end of the zero point calibration unit is connected to the first voltage detection unit, the second end of the zero point calibration unit is connected to the second voltage detection unit, and the third end of the zero point calibration unit is connected to the control unit, and is controlled to be turned on or off by the control unit.

7. The joint resistance measuring device according to claim 1, characterized in that The constant current source includes a power supply unit, a first operational amplifier, a first capacitor, a first bidirectional diode, a first resistor, a second resistor, a first relay switch, a first diode, and a first MOS transistor; the first pin of the first operational amplifier is connected to the input end of the first relay switch, the second pin of the first operational amplifier is grounded, the third pin of the first operational amplifier is connected to the first end of the first resistor, the second end of the first resistor is used to input a reference voltage, the fourth pin of the first operational amplifier is connected to the third end of the first bidirectional diode, the first end of the first bidirectional diode is used to input a first voltage, the second end of the first bidirectional diode is used to input a second voltage, and the fifth pin of the first operational amplifier is connected to the power supply unit; the output end of the first relay switch is connected to the anode of the first diode, the cathode of the first diode is connected to the drain of the first MOS transistor, the source of the first MOS transistor is connected to the first end of the second resistor, the second end of the second resistor is connected to the first switching switch, the control end of the first relay switch is connected to the control unit, and the first relay switch is configured to be controlled to be turned on by the control unit when the control unit receives the first trigger instruction.

8. The joint resistance measuring device according to claim 1, wherein the first voltage detection unit includes a second relay switch and a third resistor; the input end of the second relay switch is connected to the first switching switch, the output of the second relay switch is connected to the first end of the third resistor, the second end of the third resistor is connected to the analog-to-digital conversion unit, the control end of the second relay switch is connected to the control unit, and the second relay switch is configured to be controlled to be turned on by the control unit when the control unit receives the first trigger instruction; and / or The second voltage detection unit includes a fourth resistor and a fifth resistor. The first end of the fourth resistor is connected to the second switching switch, the second end of the fourth resistor is connected to the digital-to-analog conversion unit, the first end of the fifth resistor is connected to the second switching switch, and the second end of the fifth resistor is grounded.

9. The joint resistance measuring device according to claim 2, wherein The first voltage dividing unit includes a sixth resistor, a seventh resistor R1, and a second diode. The first end of the sixth resistor is connected to the third switching switch, the second end of the sixth resistor is connected to the first end of the seventh resistor and the third voltage detection unit, the second end of the seventh resistor is connected to the anode of the second diode D7, and the cathode of the second diode is grounded; The second voltage dividing unit includes an eighth resistor and a ninth resistor. The first end of the eighth resistor is connected to the fourth switching switch, the second end of the eighth resistor is connected to the first end of the ninth resistor and the fourth voltage detection unit, and the second end of the ninth resistor is connected to the anode of the second diode.

10. The joint resistance measuring device according to claim 9, wherein The third voltage detection unit includes a second operational amplifier, a third relay switch, a tenth resistor, and an eleventh resistor. The third pin of the second operational amplifier is connected to the second end of the seventh resistor, the fourth pin of the second operational amplifier is connected to the first pin of the second operational amplifier and the first end of the tenth resistor, the second end of the tenth resistor is connected to the input end of the third relay switch, the output end of the third relay switch is connected to the first end of the eleventh resistor, and the second end of the eleventh resistor is connected to the digital-to-analog conversion unit; the control end of the third relay switch is connected to the control unit, and the third relay switch is configured to be controlled to conduct by the control unit when the control unit receives the second trigger instruction; The fourth voltage detection unit includes a third operational amplifier, a fourth relay switch, and a twelfth resistor. The third pin of the third operational amplifier is connected to the second end of the ninth resistor, the fourth pin of the third operational amplifier is connected to the first pin of the third operational amplifier and the first end of the twelfth resistor, the second end of the twelfth resistor is connected to the input end of the fourth relay switch, and the output end of the fourth relay switch is connected to the first end of the eleventh resistor; the control end of the fourth relay switch is connected to the control unit, and the fourth relay switch is configured to be controlled to conduct by the control unit when the control unit receives the second trigger instruction.

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