Detection circuit of dry contact

Abstract

The utility model discloses a detection circuit for a dry contact, which belongs to the field of circuit detection and is characterized in that a microcontroller has six input signals AI1-AI6, and a voltage signal enters an input interface of the microcontroller for logical operation after being sent into the detection circuit for processing through a sampling end. The voltages detected by the AI1-AI5 of the microcontroller and the voltage detected by the AI6 are subtracted respectively, and whether the S1 or S2 or S3 or S4 or S5 of the corresponding dry contact is in an open state or a closed state is judged according to the obtained voltage result value. The dry contact detection circuit disclosed by the utility model is good in compatibility, simple in structure, small in number of components, high in withstand voltage level, small in size, low in cost, suitable for a household energy storage inverter, simple in judgment logic, easy to realize, and capable of accurately and quickly judging the closing condition of each controlled switch.

Description

Technical Field

[0001] The utility model relates to the field of circuit detection, in particular to a detection circuit for a dry contact. Background Art

[0002] Dry contact, also known as DRY CONTACT, is a switch device with two states: closed and open. There is no polarity between the two contacts of the dry contact and they can be interchanged.

[0003] In the field of electrical control of photovoltaic power generation, dry contacts are widely used because the electrical components in the electrical circuit (such as various microprocessors, filters, controllers, switches, etc.) have different characteristics and require different driving voltages / power supplies. Since non-polarity dry contact circuits are widely used, their functions need to be tested.

[0004] The dry contact detection circuits currently on the market are complex, have many components, are costly, and have low sensitivity, which is a technical problem that needs to be solved by those skilled in the art. In addition, the voltage of VCC in the detection circuit is often far lower than 24V. Utility Model Content

[0005] In order to overcome the above problems, the utility model provides a dry contact detection circuit to solve the problems that the existing dry contact detection circuit is complicated, has many components, is high in cost, and has low sensitivity.

[0006] In order to achieve the above object, the technical solution of the utility model is: a dry contact detection circuit, comprising

[0007] The first communication line has a left end connected to the AI1 input interface of the microcontroller and a right end connected to the left end node of the controlled switch S1 of the dry contact;

[0008] A sixth communication line, the left end of which is connected to the AI6 input interface of the microcontroller, and the right end of which is connected to the common node of the controlled switches S1 to S5 of the dry contacts;

[0009] A pull-down resistor R1, the lower end of which is connected to GND, and the upper end of which is connected to the AI6 input interface of the microcontroller;

[0010] A pull-down resistor R6, the lower end of which is connected to GND, and the upper end of which is connected to the AI1 input interface of the microcontroller;

[0011] The middle resistor R7 has its left end connected to the AI6 input interface of the microcontroller, and its right end connected to the pull-up resistor R18 and the anti-reverse diode D1;

[0012] The middle resistor R12 has its left end connected to the AI1 input interface of the microcontroller, and its right end connected to the pull-up resistor R13 and the anti-reverse diode D6;

[0013] The pull-up resistor R18, the lower end is connected to the middle resistor R7, the anti-reverse diode D1, and the upper end is connected to the power supply VCC;

[0014] The pull-up resistor R13, the lower end is connected to the middle resistor R12, the anti-reverse diode D6, and the upper end is connected to the power supply VCC;

[0015] The anti-reverse diode D1, the left end is connected to the middle resistor R7, the pull-up resistor R18, and the right end is connected to the diodes D7 and D8, and the common node of the controlled switches S1 to S5 of the dry contact;

[0016] The anti-reverse diode D6, the left end is connected to the middle resistor R12, the pull-up resistor R13, and the right end is connected to the left end node of the controlled switch S1 of the dry contact;

[0017] The diodes D7 and D8 have their lower ends connected to GND and their upper ends connected to the right end of the anti-reverse diode D1 and the common node of the controlled switches S1 to S5 of the dry contacts.

[0018] Preferably, the second communication line has a left end connected to the AI2 input interface of the microcontroller, and a right end connected to the left end node of the controlled switch S2 of the dry contact;

[0019] A pull-down resistor R5, the lower end of which is connected to GND, and the upper end of which is connected to the AI2 input interface of the microcontroller;

[0020] The middle resistor R11 has its left end connected to the AI2 input interface of the microcontroller, and its right end connected to the pull-up resistor R14 and the anti-reverse diode D5;

[0021] The pull-up resistor R14, the lower end is connected to the middle resistor R11, the anti-reverse diode D5, and the upper end is connected to the power supply VCC;

[0022] The anti-reverse diode D5 has a left end connected to the middle resistor R11 and the pull-up resistor R14, and a right end connected to the left end node of the controlled switch S2 of the dry contact.

[0023] Preferably, the third communication line has a left end connected to the AI3 input interface of the microcontroller, and a right end connected to the left end node of the controlled switch S3 of the dry contact;

[0024] A pull-down resistor R4, the lower end of which is connected to GND, and the upper end of which is connected to the AI3 input interface of the microcontroller;

[0025] The middle resistor R10 has its left end connected to the AI3 input interface of the microcontroller, and its right end connected to the pull-up resistor R15 and the anti-reverse diode D4;

[0026] The pull-up resistor R15, the lower end is connected to the middle resistor R10, the anti-reverse diode D4, and the upper end is connected to the power supply VCC;

[0027] The anti-reverse diode D4 has a left end connected to the middle resistor R10 and the pull-up resistor R15, and a right end connected to the left end node of the controlled switch S3 of the dry contact.

[0028] Preferably, the fourth communication line has a left end connected to the AI4 input interface of the microcontroller, and a right end connected to the left end node of the controlled switch S4 of the dry contact;

[0029] A pull-down resistor R3, the lower end of which is connected to GND, and the upper end of which is connected to the AI4 input interface of the microcontroller;

[0030] The middle resistor R9 has its left end connected to the AI4 input interface of the microcontroller, and its right end connected to the pull-up resistor R16 and the anti-reverse diode D3;

[0031] The pull-up resistor R16, the lower end is connected to the middle resistor R9, the anti-reverse diode D3, and the upper end is connected to the power supply VCC;

[0032] The anti-reverse diode D3 has a left end connected to the middle resistor R9 and the pull-up resistor R16, and a right end connected to the left end node of the controlled switch S4 of the dry contact.

[0033] Preferably, the fifth communication line has a left end connected to the AI5 input interface of the microcontroller, and a right end connected to the left end node of the controlled switch S5 of the dry contact;

[0034] A pull-down resistor R2, the lower end of which is connected to GND, and the upper end of which is connected to the AI5 input interface of the microcontroller;

[0035] The middle resistor R8 has its left end connected to the AI5 input interface of the microcontroller, and its right end connected to the pull-up resistor R17 and the anti-reverse diode D2;

[0036] The pull-up resistor R17, the lower end is connected to the middle resistor R8, the anti-reverse diode D2, and the upper end is connected to the power supply VCC;

[0037] The anti-reverse diode D2 has a left end connected to the middle resistor R8 and the pull-up resistor R17, and a right end connected to the left end node of the controlled switch S5 of the dry contact.

[0038] Preferably, the GND is an analog sampling ground, and the VCC is a voltage source within a +24V or higher safety range.

[0039] Preferably, the anti-reverse diodes D1 to D8 are replaced by solid-state switches, mechanical switches, triodes, field effect transistors, insulated gate bipolar transistors, thyristor semi-controlled or fully-controlled devices.

[0040] Preferably, the A1-A6 input interfaces of the microcontroller are ADC analog-to-digital converter channels inside the microcontroller.

[0041] Compared with the existing solutions, the beneficial effects of the utility model are:

[0042] The utility model discloses a dry contact detection circuit, a VCC voltage +24V or a higher voltage source within a safe range; it meets the standard requirements of the photovoltaic industry, has good compatibility of the detection circuit, a simple structure, a small number of components, a high withstand voltage level, a small size, and a low cost, and is suitable for household energy storage inverters. The judgment logic is simple and easy to implement, and can accurately and quickly judge the closing status of each controlled switch. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, a brief introduction will be given below to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0044] Figure 1 It is an overall principle diagram of an embodiment of the utility model;

[0045] Figure 2 yes Figure 1 The equivalent circuit diagram of the controlled switch S1 of the embodiment of the utility model is closed;

[0046] Figure 3 yes Figure 1 The equivalent circuit diagram of the controlled switch S1 of the embodiment of the utility model is opened; DETAILED DESCRIPTION

[0047] In order to make the purpose, technical solution and advantages of the embodiment of the utility model clearer, the technical solution in the embodiment of the utility model will be clearly and completely described below in conjunction with the drawings in the embodiment of the utility model. Obviously, the described embodiment is a part of the embodiment of the utility model, not all of the embodiments. Based on the embodiment of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0048] like Figure 1-3 As shown, a dry contact detection circuit provided in an embodiment includes:

[0049] A first communication line, the left end of which is connected to the AI1 input interface of the microcontroller (MCU), and the right end of which is connected to the left end node of the controlled switch S1 of the dry contact;

[0050] A second communication line, the left end of which is connected to the AI2 input interface of the microcontroller (MCU), and the right end of which is connected to the left end node of the controlled switch S2 of the dry contact;

[0051] A third communication line, the left end of which is connected to the AI3 input interface of the microcontroller (MCU), and the right end of which is connected to the left end node of the controlled switch S3 of the dry contact;

[0052] A fourth communication line, the left end of which is connected to the AI4 input interface of the microcontroller (MCU), and the right end of which is connected to the left end node of the controlled switch S4 of the dry contact;

[0053] A fifth communication line, the left end of which is connected to the AI5 input interface of the microcontroller (MCU), and the right end of which is connected to the left end node of the controlled switch S5 of the dry contact;

[0054] A sixth communication line, the left end of which is connected to the AI6 input interface of the microcontroller (MCU), and the right end of which is connected to the common node of the controlled switches S1 to S5 of the dry contacts;

[0055] A pull-down resistor R1, the lower end of which is connected to GND, and the upper end of which is connected to the AI6 input interface of the microcontroller (MCU);

[0056] A pull-down resistor R2, the lower end of which is connected to GND, and the upper end of which is connected to the AI5 input interface of the microcontroller (MCU);

[0057] A pull-down resistor R3, the lower end of which is connected to GND, and the upper end of which is connected to the AI4 input interface of the microcontroller (MCU);

[0058] A pull-down resistor R4, the lower end of which is connected to GND, and the upper end of which is connected to the AI3 input interface of the microcontroller (MCU);

[0059] A pull-down resistor R5, the lower end of which is connected to GND, and the upper end of which is connected to the AI2 input interface of the microcontroller (MCU);

[0060] A pull-down resistor R6, the lower end of which is connected to GND, and the upper end of which is connected to the AI1 input interface of the microcontroller (MCU);

[0061] The middle resistor R7 has its left end connected to the AI6 input interface of the microcontroller (MCU), and its right end connected to the pull-up resistor R18 and the anti-reverse diode D1;

[0062] The middle resistor R8 has its left end connected to the AI5 input interface of the microcontroller (MCU), and its right end connected to the pull-up resistor R17 and the anti-reverse diode D2;

[0063] The middle resistor R9 has a left end connected to the AI4 input interface of the microcontroller (MCU), and a right end connected to the pull-up resistor R16 and the anti-reverse diode D3;

[0064] The middle resistor R10 has its left end connected to the AI3 input interface of the microcontroller, and its right end connected to the pull-up resistor R15 and the anti-reverse diode D4;

[0065] The middle resistor R11 has a left end connected to the AI2 input interface of the microcontroller (MCU), and a right end connected to a pull-up resistor R14 and an anti-reverse diode D5;

[0066] The middle resistor R12 has a left end connected to the AI1 input interface of the microcontroller (MCU), and a right end connected to a pull-up resistor R13 and an anti-reverse diode D6;

[0067] The pull-up resistor R18, the lower end is connected to the middle resistor R7, the anti-reverse diode D1, and the upper end is connected to the power supply VCC;

[0068] The pull-up resistor R17, the lower end is connected to the middle resistor R8, the anti-reverse diode D2, and the upper end is connected to the power supply VCC;

[0069] The pull-up resistor R16, the lower end is connected to the middle resistor R9, the anti-reverse diode D3, and the upper end is connected to the power supply VCC;

[0070] The pull-up resistor R15, the lower end is connected to the middle resistor R10, the anti-reverse diode D4, and the upper end is connected to the power supply VCC;

[0071] The pull-up resistor R14, the lower end is connected to the middle resistor R11, the anti-reverse diode D5, and the upper end is connected to the power supply VCC;

[0072] The pull-up resistor R13, the lower end is connected to the middle resistor R12, the anti-reverse diode D6, and the upper end is connected to the power supply VCC;

[0073] The anti-reverse diode D1, the left end is connected to the middle resistor R7, the pull-up resistor R18, and the right end is connected to the diodes D7 and D8, and the common node of the controlled switches S1 to S5 of the dry contact;

[0074] The anti-reverse diode D2, the left end is connected to the middle resistor R8, the pull-up resistor R17, and the right end is connected to the left end node of the controlled switch S5 of the dry contact;

[0075] The anti-reverse diode D3, the left end is connected to the middle resistor R9, the pull-up resistor R16, and the right end is connected to the left end node of the controlled switch S4 of the dry contact;

[0076] The anti-reverse diode D4 has its left end connected to the middle resistor R10 and the pull-up resistor R15, and its right end connected to the left node of the controlled switch S3 of the dry contact;

[0077] The anti-reverse diode D5, the left end is connected to the middle resistor R11, the pull-up resistor R14, and the right end is connected to the left end node of the controlled switch S2 of the dry contact;

[0078] The anti-reverse diode D6, the left end is connected to the middle resistor R12, the pull-up resistor R13, and the right end is connected to the left end node of the controlled switch S1 of the dry contact;

[0079] Diodes D7 and D8, with the lower end connected to GND and the upper end connected to the right end of the anti-reverse diode D1, and the common node of the controlled switches S1 to S5 of the dry contacts;

[0080] GND is the analog sampling ground, and VCC is a voltage source of +24V or higher within the safety range;

[0081] The anti-reverse diodes D1 to D8 are replaced with semi-controlled or fully-controlled devices such as solid-state switches, mechanical switches, triodes, field-effect transistors, insulated gate bipolar transistors, and thyristors;

[0082] The dry contact is a dry contact switch device;

[0083] The A1 to A6 input interfaces of the microcontroller (MCU) are

[0084] Internal analog-to-digital converter channels (ADC);

[0085] When the voltage at the sampling end of the dry contact is greater than VCC, the anti-reverse diodes D1 to D6 will not conduct, thus blocking the voltage at the sampling end of the dry contact from entering the detection circuit, which can protect the detection circuit from being damaged by high voltage. Bias diodes D7 and D8 provide a DC voltage bias of about +0.7V for the sampling ends of all dry contacts. The software makes a difference in the sampling results, and pseudo-differential sampling can prevent the common-mode noise of the power circuit from interfering with the detection voltage value.

[0086] Of course, according to actual needs, the A1-A5 input interface access lines of the microcontroller (MCU) are between 1 and 5, which is also within the protection scope of the present utility model.

[0087] Working principle:

[0088] The voltage signal is sent to the detection circuit through the sampling end for processing, and then enters the microcontroller (MCU) input interface for logic operation. When the voltage detected by AI1~AI5 of the microcontroller (MCU) is subtracted from the voltage detected by AI6, the voltage results are recorded as AI1', AI2', AI3', AI4', and AI5' respectively.

[0089] If any of the values ​​of voltage AI1', AI2', AI3', AI4', AI5'

[0090] <0.5V, the corresponding dry contact S1 or S2 or S3 or S4 or S5 is considered closed.

[0091] If any of the values ​​of voltage AI1', AI2', AI3', AI4', AI5'

[0092] >1V, it is considered that the corresponding dry contact S1 or S2 or S3 or S4 or S5 is disconnected.

[0093] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the utility model, rather than to limit it. Although the utility model has been described in detail with reference to the aforementioned embodiments, ordinary technicians in this field should understand that they can still modify the technical solutions recorded in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not make the essence of the corresponding technical solution deviate from the scope of the technical solution of the embodiments of the utility model.

Claims

1. A dry contact detection circuit, characterized in that: include: The first communication line has a left end connected to the AI1 input interface of the microcontroller and a right end connected to the left end node of the controlled switch S1 of the dry contact; A sixth communication line, the left end of which is connected to the AI6 input interface of the microcontroller, and the right end of which is connected to the common node of the controlled switches S1 to S5 of the dry contacts; A pull-down resistor R1, the lower end of which is connected to GND, and the upper end of which is connected to the AI6 input interface of the microcontroller; A pull-down resistor R6, the lower end of which is connected to GND, and the upper end of which is connected to the AI1 input interface of the microcontroller; The middle resistor R7 has its left end connected to the AI6 input interface of the microcontroller, and its right end connected to the pull-up resistor R18 and the anti-reverse diode D1; The middle resistor R12 has its left end connected to the AI1 input interface of the microcontroller, and its right end connected to the pull-up resistor R13 and the anti-reverse diode D6; The pull-up resistor R18, the lower end is connected to the middle resistor R7, the anti-reverse diode D1, and the upper end is connected to the power supply VCC; The pull-up resistor R13, the lower end is connected to the middle resistor R12, the anti-reverse diode D6, and the upper end is connected to the power supply VCC; The anti-reverse diode D1, the left end is connected to the middle resistor R7, the pull-up resistor R18, and the right end is connected to the diodes D7 and D8, and the common node of the controlled switches S1 to S5 of the dry contact; The anti-reverse diode D6, the left end is connected to the middle resistor R12, the pull-up resistor R13, and the right end is connected to the left end node of the controlled switch S1 of the dry contact; The diodes D7 and D8 have their lower ends connected to GND and their upper ends connected to the right end of the anti-reverse diode D1 and the common node of the controlled switches S1 to S5 of the dry contacts.

2. The dry contact detection circuit according to claim 1, characterized in that: Also includes: A second communication line, the left end of which is connected to the AI2 input interface of the microcontroller, and the right end of which is connected to the left end node of the controlled switch S2 of the dry contact; A pull-down resistor R5, the lower end of which is connected to GND, and the upper end of which is connected to the AI2 input interface of the microcontroller; The middle resistor R11 has its left end connected to the AI2 input interface of the microcontroller, and its right end connected to the pull-up resistor R14 and the anti-reverse diode D5; The pull-up resistor R14, the lower end is connected to the middle resistor R11, the anti-reverse diode D5, and the upper end is connected to the power supply VCC; The anti-reverse diode D5 has a left end connected to the middle resistor R11 and the pull-up resistor R14, and a right end connected to the left end node of the controlled switch S2 of the dry contact.

3. The dry contact detection circuit according to claim 2, characterized in that: Also includes: A third communication line, the left end of which is connected to the AI3 input interface of the microcontroller, and the right end of which is connected to the left end node of the controlled switch S3 of the dry contact; A pull-down resistor R4, the lower end of which is connected to GND, and the upper end of which is connected to the AI3 input interface of the microcontroller; The middle resistor R10 has its left end connected to the AI3 input interface of the microcontroller, and its right end connected to the pull-up resistor R15 and the anti-reverse diode D4; The pull-up resistor R15, the lower end is connected to the middle resistor R10, the anti-reverse diode D4, and the upper end is connected to the power supply VCC; The anti-reverse diode D4 has a left end connected to the middle resistor R10 and the pull-up resistor R15, and a right end connected to the left end node of the controlled switch S3 of the dry contact.

4. The dry contact detection circuit according to claim 3, characterized in that: Also includes: A fourth communication line, the left end of which is connected to the AI4 input interface of the microcontroller, and the right end of which is connected to the left end node of the controlled switch S4 of the dry contact; A pull-down resistor R3, the lower end of which is connected to GND, and the upper end of which is connected to the AI4 input interface of the microcontroller; The middle resistor R9 has its left end connected to the AI4 input interface of the microcontroller, and its right end connected to the pull-up resistor R16 and the anti-reverse diode D3; The pull-up resistor R16, the lower end is connected to the middle resistor R9, the anti-reverse diode D3, and the upper end is connected to the power supply VCC; The anti-reverse diode D3 has a left end connected to the middle resistor R9 and the pull-up resistor R16, and a right end connected to the left end node of the controlled switch S4 of the dry contact.

5. The dry contact detection circuit according to claim 4, characterized in that: Also includes: A fifth communication line, the left end of which is connected to the AI5 input interface of the microcontroller, and the right end of which is connected to the left end node of the controlled switch S5 of the dry contact; A pull-down resistor R2, the lower end of which is connected to GND, and the upper end of which is connected to the AI5 input interface of the microcontroller; The middle resistor R8 has its left end connected to the AI5 input interface of the microcontroller, and its right end connected to the pull-up resistor R17 and the anti-reverse diode D2; The pull-up resistor R17, the lower end is connected to the middle resistor R8, the anti-reverse diode D2, and the upper end is connected to the power supply VCC; The anti-reverse diode D2 has a left end connected to the middle resistor R8 and the pull-up resistor R17, and a right end connected to the left end node of the controlled switch S5 of the dry contact.

6. The dry contact detection circuit according to claim 5, characterized in that: The GND is an analog sampling ground, and the VCC is a voltage source within a +24V or higher safety range.

7. The dry contact detection circuit according to claim 6, characterized in that: The anti-reverse diodes D1-D8 are replaced by solid-state switches, mechanical switches, triodes, field effect transistors, insulated gate bipolar transistors, thyristor semi-controlled or fully controlled devices.

8. The dry contact detection circuit according to claim 7, characterized in that: The A1-A6 input interfaces of the microcontroller are channels of the ADC analog-to-digital converter inside the microcontroller.

Images