Equipment ground wire monitoring device

Abstract

The present invention discloses a device for monitoring the ground wire of an equipment, which includes a power supply circuit, a constant current source circuit, a ground wire impedance sampling circuit, a comparison circuit, an indicator light display circuit and a buzzer circuit; the power supply circuit is used to supply power to the constant current source circuit and the ground wire impedance sampling circuit; the constant current source circuit is used to supply power to the ground wire of the monitored equipment; the ground wire impedance sampling circuit is used to collect the voltage at both ends of the ground wire of the monitored equipment; the comparison circuit is connected to the indicator light display circuit, which is used to compare the collected voltage at both ends of the ground wire of the monitored equipment with the preset voltage, and output a high level or a low level according to the comparison result; the indicator light display circuit is used to receive the high level or the low level output by the comparison circuit, and control the indicator light to display different colors according to the different levels received. The present invention improves the safety of the device and avoids the occurrence of safety accidents caused by the ground wire not being connected properly.

Description

Technical Field

[0001] The invention relates to the field of electrical equipment protection circuits, and more specifically to an equipment ground line monitoring device. Background Art

[0002] With the progress of the times, electronic equipment is used more and more widely, especially in production lines, where semi-automation and automation are used more and more, and production efficiency is getting higher and higher. However, production efficiency is not the first factor of the production line. The first factor of the production line is safety. Only when the safety of the production line is guaranteed can production efficiency be achieved. Otherwise, once a safety accident occurs, everything will be in vain. In the production line, in order to ensure safety, one of the items is to ensure that the equipment must be grounded to prevent the metal shell equipment from being electrified due to insulation damage and endangering personal safety.

[0003] Existing detection equipment is connected to the ground by measuring the on-off position of a multimeter to determine whether the equipment is well grounded. However, this method has the following problems: each time before using the equipment, a multimeter must be used to measure whether it is connected to the ground, but due to negligence or fluke, it is easy to forget to measure; or the ground wire is well connected during measurement but falls off during the production process; or the ground wire is aged, resulting in poor contact, etc. Therefore, this measurement method has loopholes, which may cause major safety hazards to the production line. Summary of the invention

[0004] The purpose of the present invention is to overcome the deficiencies of the prior art and provide an equipment ground line monitoring device.

[0005] To achieve the above object, the present invention adopts the following technical scheme: an equipment ground monitoring device, including a power supply circuit, a constant current source circuit, a ground impedance sampling circuit, a comparison circuit and an indicator light display circuit;

[0006] The power supply circuit is connected to the constant current source circuit and the ground impedance sampling circuit, and is used to supply power to the constant current source circuit and the ground impedance sampling circuit;

[0007] The constant current source circuit is connected to the ground line impedance sampling circuit and is used to supply power to the ground line of the monitored device;

[0008] The ground line impedance sampling circuit is connected to the ground line of the monitored device and the comparison circuit, and is used to collect the voltage at both ends of the ground line of the monitored device;

[0009] The comparison circuit is connected to the indicator light display circuit, and is used to compare the collected voltage at both ends of the ground wire of the monitored device with a preset voltage, and output a high level or a low level according to the comparison result;

[0010] The indicator light display circuit is used to receive the high level or low level output by the comparison circuit, and control the indicator light to display different colors according to the different levels received.

[0011] Its further technical solution is: it also includes a buzzer circuit; the buzzer circuit is connected to the comparison circuit, used to receive the high level or low level output by the comparison circuit, and control the buzzer to emit or not emit an alarm sound according to the different levels received.

[0012] Its further technical solution is: the power supply circuit includes a DCDC converter U1 and a low-voltage difference linear regulator U2 connected to the DCDC converter U1; the DCDC converter U1 is used to boost the DC voltage provided by the external power supply end, and the low-voltage difference linear regulator U2 is used to step down the voltage after the DC voltage is boosted by the DCDC converter U1.

[0013] Its further technical solution is: the constant current source circuit includes a controllable voltage regulator U3, an operational amplifier U4A and a MOS tube Q1 connected in sequence; the controllable voltage regulator U3 is used to output a reference voltage, and the operational amplifier U4A and the MOS tube Q1 constitute a constant current source to output a current for the ground line of the monitored device.

[0014] Its further technical solution is: the ground line impedance sampling circuit includes an anti-reverse diode D1, an operational amplifier U5A, an operational amplifier U5B, and an operational amplifier U6A; the anode of the anti-reverse diode D1 is connected to the MOS tube Q1, the cathode of the anti-reverse diode D1 is connected to the non-inverting input terminal of the operational amplifier U5B through a resistor R12, the inverting input terminal of the operational amplifier U5B is connected to the inverting input terminal of the operational amplifier U5A through a resistor R18, and the output terminal of the transport amplifier U5B is connected to the non-inverting input terminal of the operational amplifier U6A through a resistor R21; the non-inverting input terminal of the operational amplifier U5A is connected to the cathode of the anti-reverse diode D1 through a capacitor C16, and the output terminal of the operational amplifier U5A is connected to the inverting input terminal of the operational amplifier U6A through a resistor R10.

[0015] Its further technical solution is: the comparison circuit includes a variable resistor RV1 and a comparator U6B; the first pin of the variable resistor RV1 is respectively connected to the output end of the transport amplifier U5B and the non-inverting input end of the operational amplifier U6A, and the second pin of the variable resistor RV1 is connected to the reverse input end of the comparator U6B; the non-inverting input end of the comparator U6B is connected to the output end of the operational amplifier U6A through a resistor R16.

[0016] Its further technical solution is: the indicator light display circuit includes an optocoupler U7, a transistor Q4, a transistor Q5 and a transistor Q6; the first pin of the optocoupler U7 is connected to the output end of the comparator U6B, and the third pin of the optocoupler U7 is connected to the base of the transistor Q5 through a resistor R27 and to the base of the transistor Q4 through a resistor R28; the emitter of the transistor Q5 is grounded, and the collector of the transistor Q5 is connected to the base of the transistor Q6; the emitter of the transistor Q4 is grounded, and the collector of the transistor Q4 is connected to the third pin of the indicator light through a resistor R31; the collector of the transistor Q6 is connected to the second pin of the indicator light through a resistor R32, and the emitter of the transistor Q6 is grounded.

[0017] Its further technical solution is: the buzzer circuit includes a toggle switch K1 and a timing chip U8; the first pin of the toggle switch K1 is connected to the fourth pin of the optocoupler U7, and the second pin of the toggle switch K1 is connected to the eighth pin of the timing chip U8; the output end of the timing chip U8 is connected to the buzzer.

[0018] The beneficial effects of the present invention compared with the prior art are as follows: the present invention provides an equipment ground wire monitoring device, which supplies power to the ground wire of the monitored equipment through a constant current source circuit, and then measures the voltage at both ends of the ground wire of the monitored equipment through a ground wire impedance sampling circuit. When the voltage at both ends of the ground wire is greater than a preset voltage, the indicator light of the equipment ground wire monitoring device will display a red light and send out an alarm sound through a beeper, thereby enabling real-time monitoring of the ground wire connection status of the monitored equipment, thereby improving the safety of the device and avoiding the occurrence of safety accidents caused by improper ground wire connection.

[0019] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present invention more obvious and easy to understand, the following preferred embodiments are specifically cited and described in detail as follows. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a structural schematic diagram of a specific embodiment of a device ground line monitoring device of the present invention;

[0021] Figure 2 The present invention is a circuit diagram of a specific embodiment of a device ground monitoring device.

[0022] Reference numerals

[0023] 10. Power supply circuit; 20. Constant current source circuit; 30. Ground impedance sampling circuit; 40. Comparison circuit; 50. Indicator light display circuit; 60. Buzzer circuit. DETAILED DESCRIPTION

[0024] In order to more fully understand the technical content of the present invention, the technical solution of the present invention is further introduced and illustrated in conjunction with specific embodiments below, but is not limited thereto.

[0025] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0026] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0027] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0028] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be connected, detachably connected, or integrated; it can be mechanically connected or electrically connected; it can be directly connected or indirectly connected through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0029] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0030] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms should not be understood as necessarily referring to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification.

[0031] The present invention provides a device for monitoring the ground wire of an equipment. Figure 1 , 2 The device includes a power supply circuit 10, a constant current source circuit 20, a ground impedance sampling circuit 30, a comparison circuit 40 and an indicator light display circuit 50; the power supply circuit 10 is connected to the constant current source circuit 20 and the ground impedance sampling circuit 30, and is used to supply power to the constant current source circuit 20 and the ground impedance sampling circuit 30; the constant current source circuit 20 is connected to the ground impedance sampling circuit 30, and is used to supply power to the ground of the monitored device; the ground impedance sampling circuit 30 is connected to the ground of the monitored device and the comparison circuit 40, and is used to collect the voltage at both ends of the ground of the monitored device; the comparison circuit 40 is connected to the indicator light display circuit 50, and is used to compare the collected voltage at both ends of the ground of the monitored device with the preset voltage, and output a high level or a low level according to the comparison result; the indicator light display circuit 50 is used to receive the high level or the low level output by the comparison circuit 40, and control the indicator light to display different colors according to the different levels received.

[0032] In some embodiments, the equipment ground monitoring device also includes a buzzer circuit 60; the buzzer circuit 60 is connected to the comparison circuit 40, and is used to receive a high level or a low level output by the comparison circuit 40, and control the buzzer to emit or not emit an alarm sound according to the different levels received.

[0033] The function of the equipment ground monitoring device is to monitor whether the equipment ground is well connected to the ground. Its principle is to provide a constant current source to the ground of the monitored equipment to measure the impedance of the equipment ground, and then compare it with the preset impedance value. When the impedance value of the equipment ground is greater than the preset impedance value, it means that the equipment is not well connected to the ground. At this time, the equipment ground monitoring device will alarm. The size of the preset impedance value can be set. The equipment ground monitoring device can be set in the range of 0.0~80.0Ω, and the general equipment grounding resistance is not greater than 4.0Ω, which fully meets the impedance monitoring of all equipment grounds at this stage.

[0034] Further, such as Figure 2 As shown, the power supply circuit 10 includes a DCDC converter U1 and a low-voltage dropout linear regulator U2 connected to the DCDC converter U1; the DCDC converter U1 is used to boost the DC voltage provided by the external power supply end, and the low-voltage dropout linear regulator U2 is used to step down the voltage after the DC boost of the DCDC converter U1. In this embodiment, the model used by the DCDC converter U1 is B0509XT-1WR3, and the model used by the low-voltage dropout linear regulator U2 is AMS1117-5.0. Figure 2 In the example, SYS_5V is an external power supply, which comes from the 5V on the device, enters the board from J3, and is converted into 9V by DCDC converter U1, and then passes through Figure 2 The low-dropout linear regulator (LDO) U2 converts 5V (ISO_5V) to power the constant current source motor and the ground impedance sampling circuit 30, etc.

[0035] Further, such as Figure 2 As shown, the constant current source circuit 20 includes a controllable voltage regulator U3, an operational amplifier U4A and a MOS tube Q1 connected in sequence; the controllable voltage regulator U3 is used to output a reference voltage, and the operational amplifier U4A and the MOS tube Q1 constitute a constant current source to output a current for the ground line of the monitored device. In this embodiment, the model of the controllable voltage regulator U3 is TL431ACDBZR, the model of the operational amplifier U4A is LMC6482, and the model of the MOS tube Q1 is WNM3003-3 / TR. Figure 2 In the circuit, the 2.5V provided by the controllable voltage regulator U3 is used as the reference voltage. The operational amplifier U4A and the MOS tube Q1 form a constant current source with an output current of 10mA to supply power to the ground line of the monitored device.

[0036] Further, such as Figure 2As shown, the ground impedance sampling circuit 30 includes an anti-reverse diode D1, an operational amplifier U5A, an operational amplifier U5B, and an operational amplifier U6A; the anode of the anti-reverse diode D1 is connected to the MOS tube Q1, the cathode of the anti-reverse diode D1 is connected to the non-inverting input terminal of the operational amplifier U5B through a resistor R12, the inverting input terminal of the operational amplifier U5B is connected to the inverting input terminal of the operational amplifier U5A through a resistor R18, and the output terminal of the transport amplifier U5B is connected to the non-inverting input terminal of the operational amplifier U6A through a resistor R21; the non-inverting input terminal of the operational amplifier U5A is connected to the cathode of the anti-reverse diode D1 through a capacitor C16, and the output terminal of the operational amplifier U5A is connected to the inverting input terminal of the operational amplifier U6A through a resistor R10. The comparison circuit 40 includes a variable resistor RV1 and a comparator U6B; the first pin of the variable resistor RV1 is respectively connected to the output end of the transport amplifier U5B and the non-inverting input end of the operational amplifier U6A, and the second pin of the variable resistor RV1 is connected to the reverse input end of the comparator U6B; the non-inverting input end of the comparator U6B is connected to the output end of the operational amplifier U6A through a resistor R16. In this embodiment, the models of the operational amplifiers U5A, U5B, U6A and U6B are all LMC6482. Figure 2 In the figure, the two ports of J2 are used to connect the ground wire of the monitored device. The 10mA constant current source passes through J2 (the ground wire of the monitored device) through the anti-reverse diode D1, and then passes through the resistor R4 to form a loop. The current flows through the ground wire of the device, generating a voltage difference. This design uses a 2x instrument amplifier composed of three operational amplifiers (i.e., operational amplifiers U5A, U5B and U6A) to collect the voltage at both ends of the device ground wire, and then compare it with a voltage adjustable by a variable resistor RV1. When the impedance at both ends of the ground wire is higher than the preset value, the comparator U6B outputs a high level.

[0037] Further, such as Figure 2As shown, the indicator light display circuit 50 includes an optocoupler U7, a transistor Q4, a transistor Q5 and a transistor Q6; the first pin of the optocoupler U7 is connected to the output end of the comparator U6B, the third pin of the optocoupler U7 is connected to the base of the transistor Q5 through a resistor R27 and to the base of the transistor Q4 through a resistor R28; the emitter of the transistor Q5 is grounded, and the collector of the transistor Q5 is connected to the base of the transistor Q6; the emitter of the transistor Q4 is grounded, and the collector of the transistor Q4 is connected to the third pin of the indicator light through a resistor R31; the collector of the transistor Q6 is connected to the second pin of the indicator light through a resistor R32, and the emitter of the transistor Q6 is grounded. The buzzer circuit 60 includes a toggle switch K1 and a timing chip U8; the first pin of the toggle switch K1 is connected to the fourth pin of the optocoupler U7, the second pin of the toggle switch K1 is connected to the eighth pin of the timing chip U8; the output end of the timing chip U8 is connected to the buzzer. In this embodiment, the model used by the optocoupler U7 is K10104C, the model used by the transistors Q4, Q5 and Q6 is MMBT2222, the model used by the toggle switch K1 is SK12F14G7, and the model used by the timing chip U8 is NE555D. Figure 2 In the figure, a comparison voltage output by the comparison circuit 40 passes through the optocoupler U7. When the impedance of the ground line of the monitored device is greater than the preset value, the indicator light D2 lights up red and the buzzer emits an alarm sound of "beep, beep, beep..." The alarm sound of the buzzer can be turned off by the wave switch K1. The indicator light is driven by a transistor, and the buzzer is a DC buzzer, which is controlled by NE555 to output a square wave with a frequency of about 2Hz.

[0038] In addition, according to the demand for the preset voltage, the variable resistor RV1 can be adjusted, and the adjustment process is as follows:

[0039] The large 4-pin socket (J1) is connected to a 5V power supply with a supply current greater than 150mA;

[0040] Connect a standard resistance to the fence terminal (J2), which is the limit value of the ground impedance of the monitored equipment (0~80Ω); observe the indicator light D2 to adjust the variable resistor RV1. There are two situations when the indicator light D2 is powered on: Ⅰ If the green light is on, adjust the variable resistor RV1 counterclockwise until the indicator light just turns red, indicating that it has been adjusted; Ⅱ If the red light is on, adjust the variable resistor RV1 clockwise until the indicator light turns green, and then adjust RV1 counterclockwise until the indicator light just turns red, indicating that it has been adjusted.

[0041] This device can monitor the equipment ground wire in the range of 0.0~80.0Ω, and its accuracy can be adjusted to ±0.5%. Any poor connection of the monitored equipment ground wire can be tested and an alarm will be issued, ensuring that the connection of the equipment ground wire is foolproof, perfectly solving the potential safety hazards caused by poor ground wire connection of production line equipment.

[0042] The above examples are only used to further illustrate the technical content of the present invention, so that readers can understand it more easily, but they do not mean that the implementation of the present invention is limited to this. Any technical extension or re-creation made according to the present invention is protected by the present invention. The protection scope of the present invention shall be subject to the claims.

Claims

1. A device for monitoring equipment ground wire, characterized in that: It includes a power supply circuit, a constant current source circuit, a ground line impedance sampling circuit, a comparison circuit and an indicator light display circuit; The power supply circuit is connected to the constant current source circuit and the ground impedance sampling circuit, and is used to supply power to the constant current source circuit and the ground impedance sampling circuit; The constant current source circuit is connected to the ground line impedance sampling circuit and is used to supply power to the ground line of the monitored device; The ground line impedance sampling circuit is connected to the ground line of the monitored device and the comparison circuit, and is used to collect the voltage at both ends of the ground line of the monitored device; The comparison circuit is connected to the indicator light display circuit, and is used to compare the collected voltage at both ends of the ground wire of the monitored device with a preset voltage, and output a high level or a low level according to the comparison result; The indicator light display circuit is used to receive the high level or low level output by the comparison circuit, and control the indicator light to display different colors according to the different levels received; The power supply circuit includes a DCDC converter U1 and a low-voltage difference linear regulator U2 connected to the DCDC converter U1; the DCDC converter U1 is used to boost the DC voltage provided by the external power supply end, and the low-voltage difference linear regulator U2 is used to step down the voltage after the DC boost of the DCDC converter U1; the constant current source circuit includes a controllable voltage regulator U3, an operational amplifier U4A and a MOS tube Q1 connected in sequence; the controllable voltage regulator U3 is used to output a reference voltage, and the operational amplifier U4A and the MOS tube Q1 constitute a constant current source to output a current for the ground line of the monitored device; the ground line impedance sampling circuit includes an anti-reverse diode D1, an operational amplifier U4A and a MOS tube Q1. Operational amplifier U5A, operational amplifier U5B, operational amplifier U6A; the anode of the anti-reverse diode D1 is connected to the MOS tube Q1, the cathode of the anti-reverse diode D1 is connected to the non-inverting input terminal of the operational amplifier U5B through the resistor R12, the inverting input terminal of the operational amplifier U5B is connected to the inverting input terminal of the operational amplifier U5A through the resistor R18, and the output terminal of the transport amplifier U5B is connected to the non-inverting input terminal of the operational amplifier U6A through the resistor R21; the non-inverting input terminal of the operational amplifier U5A is connected to the cathode of the anti-reverse diode D1 through the capacitor C16, and the output terminal of the operational amplifier U5A is connected to the inverting input terminal of the operational amplifier U6A through the resistor R10.

2. The equipment ground monitoring device according to claim 1, characterized in that: It also includes a buzzer circuit; the buzzer circuit is connected to the comparison circuit, and is used to receive the high level or low level output by the comparison circuit, and control the buzzer to emit or not emit an alarm sound according to the different levels received.

3. The equipment ground monitoring device according to claim 2, characterized in that: The comparison circuit includes a variable resistor RV1 and a comparator U6B; the first pin of the variable resistor RV1 is respectively connected to the output end of the transport amplifier U5B and the non-inverting input end of the operational amplifier U6A, and the second pin of the variable resistor RV1 is connected to the reverse input end of the comparator U6B; the non-inverting input end of the comparator U6B is connected to the output end of the operational amplifier U6A through a resistor R16.

4. The equipment ground monitoring device according to claim 3, characterized in that: The indicator light display circuit includes an optocoupler U7, a transistor Q4, a transistor Q5 and a transistor Q6; the first pin of the optocoupler U7 is connected to the output end of the comparator U6B, and the third pin of the optocoupler U7 is connected to the base of the transistor Q5 through a resistor R27 and to the base of the transistor Q4 through a resistor R28; the emitter of the transistor Q5 is grounded, and the collector of the transistor Q5 is connected to the base of the transistor Q6; the emitter of the transistor Q4 is grounded, and the collector of the transistor Q4 is connected to the third pin of the indicator light through a resistor R31; the collector of the transistor Q6 is connected to the second pin of the indicator light through a resistor R32, and the emitter of the transistor Q6 is grounded.

5. The equipment ground monitoring device according to claim 4, characterized in that: The buzzer circuit includes a toggle switch K1 and a timing chip U8; the first pin of the toggle switch K1 is connected to the fourth pin of the optocoupler U7, and the second pin of the toggle switch K1 is connected to the eighth pin of the timing chip U8; the output end of the timing chip U8 is connected to the buzzer.

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