Dry and wet contact acquisition circuit and industrial control equipment

Abstract

The utility model provides a dry and wet contact acquisition circuit and industrial control equipment, and relates to the technical field of industrial control. The dry and wet contact acquisition circuit comprises a dry and wet contact detection module and a level transmission module, and the dry and wet contact detection module comprises a comparison unit. The comparison unit is used for comparing voltage amplitudes between the dry contact signal or the wet contact signal and a preset signal to obtain a first level signal or a second level signal; the level transmission module is used for transmitting the first level signal or the second level signal to the main control circuit. According to the embodiment of the utility model, the comparison unit is used for converting dry and wet contact signals into voltage amplitudes so as to output different level signals; and the level transmission module is used for transmitting the level signal to the main control circuit so as to provide an accurate output signal for identifying the current working state of the contact for the main control circuit.

Description

Technical Field

[0001] The utility model relates to the field of industrial control, in particular to a dry and wet contact acquisition circuit and industrial control equipment. Background Art

[0002] In the field of industrial control, dry contacts and wet contacts are widely used. There are many control methods in industrial control circuits. For example, the first is a circuit control loop with dry contacts as input signals, the second is a control loop with low voltage wet contacts as input signals, and the third is a control loop with high voltage wet contacts as input signals. Since dry contacts are passive switches with two states of closed and open, there is no polarity between the two contacts and they can be interchanged. Wet contacts are active switches with two states of energized and unenergized, and there is polarity between the two contacts and they cannot be connected in reverse. Among them, for dry contacts, when the output signal of the dry contacts in the open state is collected, the digital signal "1" is usually collected; when the output signal of the dry contacts in the closed state is collected, the digital signal "0" is usually collected. For wet contacts, when the high voltage wet contacts are collected, the digital signal "1" is usually collected; when the low voltage wet contacts are collected, the digital signal "0" is usually collected. In the prior art, a signal acquisition circuit usually acquires an output signal representing the current working state of a dry contact or a wet contact, and a CPU performs a logic conversion on the acquired output signal voltage value to determine a digital signal value.

[0003] Since dry contacts and wet contacts have different applications and they coexist for a long time, the general circuit of the device to collect the contact input signal usually needs to determine the type of dry contact or wet contact first. In the prior art, manual confirmation is usually used, and a digital detector is used in the process to determine the type of dry contact. This process is cumbersome and prone to errors.

[0004] Based on this, there is an urgent need for a detection circuit with a simple structure, convenience and high efficiency, which can automatically be compatible with dry and wet node types and provide the main control circuit with an accurate output signal that identifies the current working state of the contact. Utility Model Content

[0005] The purpose of the utility model is to provide a dry-wet contact acquisition circuit and industrial control equipment. A comparison unit is used to convert different dry-wet contact signals into voltage amplitudes to output different level signals; and a level transmission module is used to transmit the level signal to the main control circuit to provide the main control circuit with an accurate output signal that identifies the current working state of the contact. The dry-wet contact acquisition circuit of the utility model has a wide range of applications and can be applied to control circuits with both high voltage and low voltage.

[0006] Specifically, on one hand, the utility model provides a dry-wet contact acquisition circuit, the dry-wet contact acquisition circuit comprising: a dry-wet contact detection module, a level transmission module;

[0007] The dry-wet contact detection module includes a comparison unit, the output end of the comparison unit is connected to the input end of the level transmission module; the first input end of the comparison unit is used as the input end of the dry-wet contact acquisition circuit to receive a dry contact signal or a wet contact signal; the second input end of the comparison unit is connected to a preset signal generator to receive a preset signal; the output end of the level transmission module is connected to the main control circuit;

[0008] Among them, the comparison unit is used to compare the voltage amplitude between the dry contact signal or the wet contact signal and the preset signal to obtain a first level signal or a second level signal; the level transmission module is used to transmit the first level signal or the second level signal to the main control circuit.

[0009] Optionally, the comparison unit includes a comparator, a first voltage dividing unit and a second voltage dividing unit;

[0010] The output end of the first voltage divider unit is connected to the first input end of the comparator; the input end of the first voltage divider unit serves as the input end of the dry-wet contact acquisition circuit, and is used to receive the dry contact signal or the wet contact signal; the output end of the second voltage divider unit is connected to the second input end of the comparator, and the input end of the second voltage divider unit is connected to the preset signal generator; the output end of the comparator serves as the output end of the comparison unit, and is connected to the input end of the level transmission module.

[0011] Optionally, the first voltage dividing unit includes a first resistor and a second resistor; the second voltage dividing unit includes a third resistor and a fourth resistor;

[0012] The first end of the first resistor is used as the input end of the dry-wet contact acquisition circuit to receive the dry contact signal or the wet contact signal; the second end of the first resistor is respectively connected to the first end of the second resistor and the first input end of the comparator; the second end of the second resistor is grounded;

[0013] The first end of the third resistor serves as the input end of the preset signal and is used to receive the preset signal; the second end of the third resistor is respectively connected to the first end of the fourth resistor and the second input end of the comparator; and the second end of the fourth resistor is grounded.

[0014] Optionally, the comparison unit further includes a filtering subunit; the filtering subunit is connected to the power input of the comparator.

[0015] Optionally, the filtering subunit includes at least two capacitors arranged in parallel;

[0016] Wherein, the first end of the capacitor is connected to the power input end of the comparator; and the second end of the capacitor is grounded.

[0017] Optionally, the dry-wet contact detection module further includes an isolation unit; a first end of the isolation unit is connected to the output end of the comparison unit; and a second end of the isolation unit is connected to the input end of the level transmission module.

[0018] Optionally, the dry-wet contact detection module further includes a first current limiting resistor, a first end of the first current limiting resistor is connected to the output end of the comparison unit, and a second end of the first current limiting resistor is connected to the input end of the level transmission module.

[0019] Optionally, the level transmission module includes a first transmission unit and a second transmission unit connected in parallel; the input end of the first transmission unit and the input end of the second transmission unit are both connected to the output end of the comparison unit; the output end of the first transmission unit and the output end of the second transmission unit are both connected to the main control circuit;

[0020] Wherein, the first transmission unit is used to detect and indicate the first level signal, and after detecting the first level signal, transmit the first level signal to the main control circuit;

[0021] The second transmission unit is used to detect and indicate the second level signal, and after detecting the second level signal, transmit the second level signal to the main control circuit.

[0022] Optionally, the first transmission unit includes a switch subunit and a second current limiting resistor;

[0023] The control end of the switch subunit is connected to the output end of the comparison unit via the second current limiting resistor; the first end of the switch subunit is grounded; and the second end of the switch subunit is connected to the power supply;

[0024] When the first transmission unit detects the first level signal, the switch subunit is turned on to transmit the first level signal to the main control circuit.

[0025] On the other hand, the utility model also provides an industrial control device, including a main control circuit and the dry-wet contact acquisition circuit described in any one of the first aspects above, wherein the output end of the dry-wet contact acquisition circuit is connected to the input end of the main control circuit.

[0026] The beneficial effects of the dry and wet contact acquisition circuit and industrial control equipment provided by the utility model are:

[0027] The dry-wet contact acquisition circuit includes a dry-wet contact detection module and a level transmission module, wherein the dry-wet contact detection module includes a comparison unit. The output end of the comparison unit is connected to the input end of the level transmission module; the first input end of the comparison unit is used as the input end of the dry-wet contact acquisition circuit, for receiving a dry contact signal or a wet contact signal; the second input end of the comparison unit is connected to a preset signal generator, for receiving a preset signal; the output end of the level transmission module is connected to the main control circuit. The comparison unit is used to compare the voltage amplitude between the dry contact signal or the wet contact signal and the preset signal to obtain a first level signal or a second level signal; the level transmission module is used to transmit the first level signal or the second level signal to the main control circuit. The embodiment of the utility model utilizes a comparison unit to convert different dry-wet contact signals into voltage amplitudes to output different level signals; and utilizes a level transmission module to transmit the level signal to the main control circuit to provide the main control circuit with an accurate output signal that identifies the current working state of the contact. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the technical solutions of the embodiments of the utility model, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the utility model and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without paying creative work.

[0029] Figure 1 It is a structural schematic diagram of the industrial control equipment in the utility model;

[0030] Figure 2 This is one of the structural schematic diagrams of the dry and wet contact acquisition circuit in the utility model;

[0031] Figure 3 This is one of the structural schematic diagrams of the comparison unit in the utility model;

[0032] Figure 4 This is one of the circuit principle diagrams of the comparison unit in the utility model;

[0033] Figure 5 This is the second structural diagram of the comparison unit in the utility model;

[0034] Figure 6 This is the second schematic diagram of the circuit principle of the comparison unit in the utility model;

[0035] Figure 7 It is a structural schematic diagram of the level transmission module in the utility model;

[0036] Figure 8 This is one of the circuit principle schematic diagrams of the first transmission unit in the utility model;

[0037] Fig. 9 This is the second schematic diagram of the circuit principle of the first transmission unit in the utility model;

[0038] Fig.10 This is the second structural diagram of the dry and wet contact acquisition circuit in the utility model;

[0039] Fig.11 This is one of the circuit structure diagrams of the dry and wet contact acquisition circuit in the utility model;

[0040] Fig.12 This is the third structural diagram of the dry and wet contact acquisition circuit in the utility model;

[0041] Fig.13 This is the second circuit structure diagram of the dry and wet contact acquisition circuit in the utility model.

[0042] Icon: 100-industrial control equipment; 200-main control circuit; 300-dry and wet contact acquisition circuit; 400-preset signal generator; 301-dry and wet contact detection module; 101-comparison unit; 1001-first voltage divider unit; 1002-second voltage divider unit; 1003-filter subunit; 102-isolation unit; 302-level transmission module; 2001-first transmission unit; 2002-second transmission unit. DETAILED DESCRIPTION

[0043] In order to make the purpose, technical scheme and advantages of the embodiments of the utility model clearer, the technical scheme in the embodiments of the utility model will be clearly and completely described below in conjunction with the drawings in the embodiments of the utility model. Obviously, the described embodiments are part of the embodiments of the utility model, not all of the embodiments. Generally, the components of the embodiments of the utility model described and shown in the drawings here can be arranged and designed in various different configurations.

[0044] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the present invention to be protected, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0045] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0046] In the description of the present utility model, it should be understood that the terms "center", "up", "down", "left", "right", "vertical", "horizontal", "inside", "outside", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, or are the orientations or positional relationships in which the utility model product is conventionally placed when in use, or are the orientations or positional relationships conventionally understood by those skilled in the art. They are only for the convenience of describing the present utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present utility model.

[0047] Furthermore, the terms “first”, “second”, “third”, etc. are merely used for distinguishing descriptions and are not to be understood as indicating or implying relative importance.

[0048] In the description of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "set", "install", "connect", and "connect" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0049] As described in the background technology, dry contacts and wet contacts have different applications, and the two have coexisted for a long time. In the prior art, the contact type of the current input signal is usually determined by a digital detector before the contact signal is input into the device's total circuit. This process is cumbersome and requires high accuracy of the detection equipment, which will also greatly increase labor costs.

[0050] Based on this, the utility model provides a dry and wet contact acquisition circuit and industrial control equipment, which use a comparison unit to convert different dry and wet contact signals into voltage amplitudes to output different level signals. And use a level transmission module to transmit the level signal to the main control circuit to provide the main control circuit with an accurate output signal that identifies the current working state of the contact. The dry and wet contact acquisition circuit of the utility model has a wide range of applications and can be applied to control circuits with both high voltage and low voltage.

[0051] The technical solution will be described in detail below.

[0052] See also Figure 1 The industrial control device 100 in the utility model includes a main control circuit 200 and a dry-wet contact acquisition circuit 300, wherein the output end of the dry-wet contact acquisition circuit 300 is connected to the input end of the main control circuit 200 to provide the main control circuit 200 with an accurate output signal that identifies the current working state of the contact.

[0053] In the technical solution, the main control circuit 200 can be a central processing unit (CPU), an image processor, a neural network processor (NPU), a microcontroller (MCU), a programmable logic device, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), or one or more integrated circuits. The processor can be used to perform functions related to the technology described in the utility model. In some embodiments, the main control circuit 200 can also include multiple processors integrated into a single logic component.

[0054] It should be noted that, although the above industrial control device 100 only shows the main control circuit 200 and the dry and wet contact acquisition circuit 300, in the specific implementation process, the architecture of the industrial control device 100 may also include other components necessary for normal operation. In addition, those skilled in the art can understand that the architecture of the above industrial control device 100 may also only include components necessary for implementing the solution of the utility model, and does not necessarily include all the components shown in the figure.

[0055] In a technical solution, please refer to Figure 2 The dry-wet contact acquisition circuit 300 of the utility model includes: a dry-wet contact detection module 301 and a level transmission module 302. The dry-wet contact detection module 301 includes a comparison unit 101, and the output end of the comparison unit 101 is connected to the input end of the level transmission module 302; the first input end of the comparison unit 101 is used as the input end of the dry-wet contact acquisition circuit 300 for receiving a dry contact signal or a wet contact signal; the second input end of the comparison unit 101 is connected to the preset signal generator 400 for receiving a preset signal; the output end of the level transmission module 302 is connected to the main control circuit 200.

[0056] Among them, the comparison unit 101 is used to compare the voltage amplitude between the dry contact signal or the wet contact signal and the preset signal to obtain a first level signal or a second level signal; the level transmission module 302 is used to transmit the first level signal or the second level signal to the main control circuit.

[0057] In the technical solution, the first input end of the comparison unit 101 receives a dry contact signal or a wet contact signal, the second input end of the comparison unit 101 receives a preset signal sent by the preset signal generator 400, and then the output end of the comparison unit 101 outputs a first level signal or a second level signal. Specifically, the comparison unit 101 is used to compare the voltage amplitude between the dry contact signal or the wet contact signal and the preset signal, and the comparison result is the above-mentioned first level signal or second level signal. In the embodiment of the utility model, the comparison performed by the comparison unit 101 can be directly based on the basic mode of the comparison unit, that is, comparing the voltage amplitude between the dry contact signal or the wet contact signal and the preset signal. For example, when the voltage amplitude of the dry contact signal is less than the voltage amplitude between the preset signals, the output end of the comparison unit 101 can output a first level signal. The utility model does not limit the signal type of the input end, but directly uses the comparison unit to compare the voltage amplitude of the input signal and the preset signal, quantizes the numerical value of the two, and outputs the first level signal or the second level signal accordingly.

[0058] For example, if the current input signal is a dry contact signal, the comparison unit 101 will compare the voltage amplitude between the current dry contact signal and the preset signal, and output a first level signal or a second level signal, wherein the first level signal and the second level signal are opposite signals. It can be understood that when the first level signal is a high level signal, the second level signal is correspondingly a low level signal.

[0059] Based on this, the utility model uses a simple comparison unit 101 to quantify the voltage amplitude between the dry contact signal or the wet contact signal and the preset signal, and directly converts the dry contact signal or the wet contact signal into a high level signal or a low level signal to automatically be compatible with dry and wet node types, thereby increasing the scope of application and being suitable for control circuits with both high voltage and low voltage; at the same time, it reduces the complexity of the circuit structure.

[0060] It should be noted that no matter whether the input is a dry contact signal or a wet contact signal, the comparison unit 101 is used to compare the voltage amplitude of the dry contact signal or the wet contact signal.

[0061] In an achievable solution, the preset signal generator 400 may be a power supply unit, which is used to output an electrical signal with a known voltage amplitude, and the electrical signal provides a reference signal (an electrical signal with a known voltage amplitude) for the comparison unit 101. Since the preset signal generator 400 may be a power supply unit, for the purpose of distinction, the power supply unit in this embodiment may include a first power supply VDD1 and a second power supply VDD2, wherein the first power supply VDD1 is used to provide an input power supply for the comparison unit 101, and may also provide a preset signal for the comparison unit 101. The second power supply VDD2 is used to power other units except the comparison unit 101.

[0062] See also Figure 3 The comparison unit 101 includes a comparator U1, a first voltage divider unit 1001 and a second voltage divider unit 1002. The output end of the first voltage divider unit 1001 is connected to the first input end of the comparator U1; the input end of the first voltage divider unit 1001 is used as the input end of the dry-wet contact acquisition circuit 300, for receiving a dry contact signal or a wet contact signal; the output end of the second voltage divider unit 1002 is connected to the second input end of the comparator U1, and the input end of the second voltage divider unit 1002 is connected to the preset signal generator 400. The output end of the comparator U1 is used as the output end of the comparison unit 101, and is connected to the input end of the level transmission module 302.

[0063] In the technical solution, the first voltage divider unit 1001 is used to adjust the voltage amplitude of the dry contact signal or the wet contact signal; the second voltage divider unit 1002 is used to adjust the voltage amplitude of the preset signal to adjust the voltage amplitude of the preset signal to a preset threshold. Based on this, the utility model can increase the extensiveness of its contact detection by adjusting the voltage amplitude of the preset signal to meet different preset thresholds.

[0064] In one possible implementation, see Figure 4 The first voltage dividing unit 1001 includes a first resistor R1 and a second resistor R2; the second voltage dividing unit 1002 includes a third resistor R3 and a fourth resistor R4.

[0065] The first end of the first resistor R1 serves as the input end of the dry-wet contact acquisition circuit 300, and is used to receive a dry contact signal or a wet contact signal; the second end of the first resistor R1 is respectively connected to the first end of the second resistor R2 and the first input end of the comparator U1; the second end of the second resistor R2 is grounded.

[0066] The first end of the third resistor R3 is used as an input end of a preset signal for receiving the preset signal; the second end of the third resistor R3 is respectively connected to the first end of the fourth resistor R4 and the second input end of the comparator U1; the second end of the fourth resistor R4 is grounded.

[0067] In this technical solution, please refer to Figure 5 The comparison unit 101 further includes a filter subunit 1003 ; the filter subunit 1003 is connected to the power input terminal of the comparator U1 . The filter subunit 1003 increases the stability of the power input of the comparison unit 101 .

[0068] In a possible implementation method, the filter subunit 1003 includes at least two capacitors arranged in parallel; wherein the first end of the capacitor is connected to the power input end of the comparator U1. Figure 3 The input terminals of the second voltage dividing unit 1002 are both connected to the output terminals of the first power supply VDD1.

[0069] See also Figure 6 , at least two capacitors arranged in parallel in the filter subunit 1003 may be a first capacitor C1 and a second capacitor C2; wherein the first end of the first capacitor C1 and the first end of the second capacitor C2 are respectively connected to the power input end of the comparator U1 and the first power supply VDD1; the second end of the first capacitor C1 and the second end of the second capacitor C2 are both grounded.

[0070] In this technical solution, please refer to Figure 7 The level transmission module 302 includes a first transmission unit 2001 and a second transmission unit 2002 connected in parallel; the input end of the first transmission unit 2001 and the input end of the second transmission unit 2002 are both connected to the output end of the comparison unit 101; the output end of the first transmission unit 2001 and the output end of the second transmission unit 2002 are both connected to the main control circuit 200.

[0071] The first transmission unit 2001 is used to detect and indicate a first level signal, and after detecting the first level signal, transmit the first level signal to the main control circuit. The second transmission unit 2002 is used to detect and indicate a second level signal, and after detecting the second level signal, transmit the second level signal to the main control circuit.

[0072] In this embodiment, the first transmission unit 2001 includes a switch subunit and a second current limiting resistor; the control end of the switch subunit is connected to the output end of the comparison unit 101 via the second current limiting resistor; the first end of the switch subunit is grounded; and the second end of the switch subunit is connected to the power supply.

[0073] When the first transmission unit 2001 detects the first level signal, the switch subunit is turned on to transmit the first level signal to the main control circuit.

[0074] For one possible implementation, see Figure 8 The switch subunit may use a field effect transistor Q1, wherein the control end of the field effect transistor Q1 is connected to the output end of the comparison unit 101 via the second current limiting resistor R5. The second end of the switch subunit, i.e., the drain, is connected to the second power supply VDD2 and the main control circuit 200 respectively. For further information, please refer to Fig. 9 The first transmission unit 2001 further includes a pull-up resistor R6, and the drain of the field effect transistor Q1 is connected to the second power supply VDD2 through the pull-up resistor R6.

[0075] In this embodiment, the threshold voltage Vt of the field effect tube Q1 is a preset value. When the output end of the comparison unit 101 transmits the first level signal or the second level signal, the field effect tube Q1 is turned on or off according to the voltage corresponding to the first level signal or the second level signal. For example, if the field effect tube Q1 can realize low-level signal conduction, that is, when the gate voltage Vg of the field effect tube Q1 (the voltage corresponding to the first level signal or the second level signal transmitted by the output end of the comparison unit 101) is lower than the source voltage Vs, it is low-level conduction and high-level cutoff. Similarly, when the field effect tube Q1 can realize high-level signal conduction, when the gate voltage Vg of the field effect tube Q1 (the voltage corresponding to the first level signal or the second level signal transmitted by the output end of the comparison unit 101) is higher than the source voltage Vs, it is low-level conduction and high-level cutoff.

[0076] The second transmission unit 2002 can be configured similarly, which will not be described in detail here.

[0077] In another possible implementation method, the switch subunit may directly adopt a switch unit module, such as a PMOS-236 chip, wherein the input end of the PMOS-236 chip is connected to the output end of the comparison unit 101, the power supply end of the PMOS-236 chip is connected to the second power supply VDD2; and the output end of the PMOS-236 chip is connected to the main control circuit.

[0078] The second transmission unit 2002 can be configured similarly, which will not be described in detail here.

[0079] In another possible implementation method, the switch subunit in the second transmission unit 2002 may use a field effect transistor Q1, that is, Figure 8 In the embodiment shown, the second transmission unit 2002 can directly adopt a switch unit module.

[0080] In this embodiment, the structures of the second transmission units 2002 and the second transmission units 2002 in the level transmission module 302 can be adjusted according to actual needs.

[0081] In the present technical solution, the dry-wet contact detection module 301 further includes an isolation unit 102 ; a first end of the isolation unit 102 is connected to the output end of the comparison unit 101 ; and a second end of the isolation unit 102 is connected to the input end of the level transmission module 302 .

[0082] In a possible implementation method, the isolation unit 102 can directly adopt a ready-made photoelectric coupling module in the prior art. Fig.10The first end of the isolation unit 102, which is the input end of the photoelectric coupling module (pin 3 in the figure), is connected to the output end of the comparison unit 101; the second end of the isolation unit 102, which is the output end of the photoelectric coupling module (pin 6 in the figure), is connected to the input end of the level transmission module 302.

[0083] In this embodiment, the isolation unit 102 is arranged between the comparison unit 101 and the level transmission module 302, which can isolate the electrical signal at the main control circuit to prevent the electrical signal from interfering with the first level signal or the second level signal of the comparison unit 101; it can also prevent the input signal at the front end of the comparison unit 101 from interfering with the signal of the level transmission module 302, thereby improving the detection accuracy of the dry contact signal or the wet contact signal.

[0084] In order to further reduce the device structure, optimize the circuit structure, and ensure the detection accuracy of the dry contact signal or the wet contact signal, the utility model also provides another embodiment. Fig.11 The first transmission unit 2001 includes a second diode D2, a seventh resistor R7, a pull-up resistor R8 and a first photocoupler PC1, wherein the first diode D1 is the switch subunit in the first transmission unit 2001, and similarly, the seventh resistor R7 is a second current limiting resistor. The second transmission unit 2002 includes a second diode D2, a pull-up resistor R9, a pull-up resistor R10 and a second photocoupler PC2.

[0085] The cathode of the first diode D1 is grounded, and the anode of the first diode D1 is connected to the second pin of the first photocoupler PC1; the first end of the seventh resistor R7 is connected to the output end of the comparison unit 101 as the input end of the first transmission unit 2001; the second end of the seventh resistor R7 is connected to the first pin of the first photocoupler PC1; the fourth pin of the first photocoupler PC1 is connected to the main control circuit as the output end of the first transmission unit 2001; the third pin of the first photocoupler PC1 is grounded. The first transmission unit 2001 also includes a pull-up resistor R8, and the fourth pin of the first photocoupler PC1 is also connected to the second power supply VDD2 through the pull-up resistor R9.

[0086] The cathode of the second diode D2 serves as the input end of the second transmission unit 2002 and is connected to the output end of the comparison unit 101; the anode of the second diode D2 is connected to the second pin of the second photocoupler PC2; the fourth pin of the second photocoupler PC2 serves as the output end of the second transmission unit 2002 and is connected to the main control circuit; the third pin of the second photocoupler PC2 is grounded; the first pin of the second photocoupler PC2 is connected to the first power supply VDD1 through a pull-up resistor R9; and the fourth pin of the second photocoupler PC2 is connected to the second power supply VDD2 through a pull-up resistor R10.

[0087] Based on the above structure, the first transmission unit 2001 can be used to implement low-level detection, and the second transmission unit 2002 can be used to implement high-level detection. The first diode D1 and the second diode D2 can be light-emitting diodes; for example, when the first transmission unit 2001 detects a low-level signal, the first diode D1 can light up to represent a low-level valid input signal; when the second transmission unit 2002 detects a high-level signal, the second diode D2 can light up to represent a high-level valid input signal.

[0088] Since the first transmission unit 2001 and the second transmission unit 2002 are respectively provided with the first photocoupler PC1 and the second photocoupler PC2, they can play an isolation role according to the properties of the photocoupler; that is, they can isolate the electrical signal at the main control circuit and interfere with the signal detected by the comparison unit 101, thereby improving the detection accuracy of the dry contact signal or the wet contact signal.

[0089] See also Fig.12 The dry-wet contact detection module 301 further includes a first current limiting resistor R11 , a first end of the first current limiting resistor R11 is connected to the output end of the comparison unit 101 , and a second end of the first current limiting resistor is connected to the input end of the level transmission module 302 .

[0090] Based on this, see Fig.13 The embodiment of the utility model provides a dry-wet contact acquisition circuit 300, which includes a dry-wet contact detection module 301 and a level transmission module 302, wherein the dry-wet contact detection module 301 includes a comparison unit 101. The comparison unit 101 is used to compare the voltage amplitude between the dry contact signal or the wet contact signal and the preset signal to obtain a first level signal or a second level signal; the level transmission module 302 is used to transmit the first level signal or the second level signal to the main control circuit 200.

[0091] The utility model uses a comparison unit to convert different dry and wet contact signals into voltage amplitudes to output different level signals, and uses a level transmission module to transmit the level signal to the main control circuit to provide the main control circuit with an accurate output signal that identifies the current working state of the contact. It can be applied to control circuits with both high voltage and low voltage.

[0092] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may be subject to various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A dry and wet contact acquisition circuit (300), characterized in that: The dry and wet contact acquisition circuit (300) comprises: a dry and wet contact detection module (301) and a level transmission module (302); The dry-wet contact detection module (301) comprises a comparison unit (101), the output end of the comparison unit (101) is connected to the input end of the level transmission module (302); the first input end of the comparison unit (101) is used as the input end of the dry-wet contact acquisition circuit (300) for receiving a dry contact signal or a wet contact signal; the second input end of the comparison unit (101) is connected to a preset signal generator (400) for receiving a preset signal; the output end of the level transmission module (302) is connected to a main control circuit (200); The comparison unit (101) is used to compare the voltage amplitude between the dry contact signal or the wet contact signal and the preset signal to obtain a first level signal or a second level signal; and the level transmission module (302) is used to transmit the first level signal or the second level signal to the main control circuit (200).

2. The dry and wet contact acquisition circuit (300) according to claim 1, characterized in that: The comparison unit (101) comprises a comparator, a first voltage dividing unit (1001) and a second voltage dividing unit (1002); The output end of the first voltage divider unit (1001) is connected to the first input end of the comparator; the input end of the first voltage divider unit (1001) serves as the input end of the dry-wet contact acquisition circuit (300) and is used to receive the dry contact signal or the wet contact signal; the output end of the second voltage divider unit (1002) is connected to the second input end of the comparator, and the input end of the second voltage divider unit (1002) is connected to the preset signal generator (400); the output end of the comparator serves as the output end of the comparison unit (101) and is connected to the input end of the level transmission module (302).

3. The dry and wet contact acquisition circuit (300) according to claim 2, characterized in that: The first voltage dividing unit (1001) comprises a first resistor and a second resistor; the second voltage dividing unit (1002) comprises a third resistor and a fourth resistor; The first end of the first resistor serves as an input end of the dry-wet contact acquisition circuit (300) and is used to receive the dry contact signal or the wet contact signal; the second end of the first resistor is respectively connected to the first end of the second resistor and the first input end of the comparator; the second end of the second resistor is grounded; The first end of the third resistor serves as the input end of the preset signal and is used to receive the preset signal; the second end of the third resistor is respectively connected to the first end of the fourth resistor and the second input end of the comparator; and the second end of the fourth resistor is grounded.

4. The dry and wet contact acquisition circuit (300) according to claim 2, characterized in that: The comparison unit (101) further comprises a filtering subunit (1003); the filtering subunit (1003) is connected to the power input terminal of the comparator.

5. The dry and wet contact acquisition circuit (300) according to claim 4, characterized in that: The filtering subunit (1003) comprises at least two capacitors arranged in parallel; Wherein, the first end of the capacitor is connected to the power input end of the comparator; and the second end of the capacitor is grounded.

6. The dry and wet contact acquisition circuit (300) according to claim 1, characterized in that: The dry and wet contact detection module (301) further comprises an isolation unit (102); a first end of the isolation unit (102) is connected to the output end of the comparison unit (101); and a second end of the isolation unit (102) is connected to the input end of the level transmission module (302).

7. The dry-wet contact acquisition circuit (300) according to claim 1, characterized in that: The dry-wet contact detection module (301) further comprises a first current limiting resistor, wherein a first end of the first current limiting resistor is connected to an output end of the comparison unit (101), and a second end of the first current limiting resistor is connected to an input end of the level transmission module (302).

8. The dry-wet contact acquisition circuit (300) according to claim 1, characterized in that: The level transmission module (302) comprises a first transmission unit (2001) and a second transmission unit (2002) connected in parallel; the input end of the first transmission unit (2001) and the input end of the second transmission unit (2002) are both connected to the output end of the comparison unit (101); the output end of the first transmission unit (2001) and the output end of the second transmission unit (2002) are both connected to the main control circuit (200); The first transmission unit (2001) is used to detect and indicate the first level signal, and after detecting the first level signal, transmit the first level signal to the main control circuit (200); The second transmission unit (2002) is used to detect and indicate the second level signal, and after detecting the second level signal, transmit the second level signal to the main control circuit (200).

9. The dry and wet contact acquisition circuit (300) according to claim 8, characterized in that: The first transmission unit (2001) comprises a switch subunit and a second current limiting resistor; The control end of the switch subunit is connected to the output end of the comparison unit (101) via the second current limiting resistor; the first end of the switch subunit is grounded; and the second end of the switch subunit is connected to a power supply; When the first transmission unit (2001) detects the first level signal, the switch subunit is turned on to transmit the first level signal to the main control circuit (200).

10. An industrial control device (100), characterized in that: It comprises a main control circuit (200) and a dry-wet contact acquisition circuit (300) according to any one of claims 1 to 9, wherein the output end of the dry-wet contact acquisition circuit (300) is connected to the input end of the main control circuit (200).

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