Anti-interference interface circuit based on shunt monitoring terminal

Abstract

The utility model relates to the technical field of interface circuits, in particular to an anti-interference interface circuit based on a shunt monitoring terminal, which comprises a photoelectric coupler VLC, one side of the photoelectric coupler VLC is electrically connected with an operational amplifier Q. An anode pin of the operational amplifier Q is electrically connected with a voltage stabilizing diode VD1. The negative electrode pin of the operational amplifier Q is electrically connected with the photoelectric coupler VLC through a resistor R2; the other side of the photoelectric coupler VLC is connected in series with a triode NPN1 and a triode NPN2. According to the utility model, digital or pulse signals transmitted by a detector through a long distance are amplified by the operational amplifier Q and then are isolated by photoelectricity, the operational amplifier Q is connected to form a voltage follower circuit which also has an interference isolation effect, and the electric coupler can also be inhibited under the interference of very high voltage amplitude, so that when the photoelectric coupler VLC is adopted, the interference of the voltage follower circuit can be inhibited. And even forward transmission can also play a role in isolating interference.

Description

Technical Field

[0001] The utility model relates to an anti-interference interface circuit, in particular to an anti-interference interface circuit based on a branch monitoring terminal, belonging to the technical field of interface circuits. Background Art

[0002] In the interface circuit between the controller and the driver, there are inevitably inductive loads that convert weak electricity into strong electricity, as well as contacts used to switch the inductive loads on and off. These are all interference sources that generate strong electrical interference. For this interference, the first thing to do is to absorb it and suppress its generation, and then take isolation measures to block its conduction. This strong electrical interference will also pass through the inductive influence of the conversion interface circuit between the controller and the detector. For this interference, as well as other radiation interference from the space sense, isolation measures are also needed to prevent it from entering the controller through the transmission interface. Utility Model Content

[0003] The purpose of the utility model is to provide an anti-interference interface circuit based on a shunt monitoring terminal. For digital or pulse signals transmitted from a detector over a long distance, they are amplified by an operational amplifier Q and then optically isolated. The operational amplifier Q is connected to a voltage follower circuit and also has the function of isolating interference. The electric coupler can also suppress interference with a very high voltage amplitude. Therefore, when a photoelectric coupler VLC is used, it can also play the role of isolating interference even in forward transmission.

[0004] In order to achieve the above-mentioned object, the main technical solutions adopted by the utility model include: an anti-interference interface circuit based on a shunt monitoring terminal, including a photoelectric coupler VLC, characterized in that one side of the photoelectric coupler VLC is electrically connected to an operational amplifier Q, the positive pin of the operational amplifier Q is electrically connected to a voltage regulator diode VD1, and the negative pin of the operational amplifier Q is electrically connected to the photoelectric coupler VLC through a resistor R2;

[0005] The other side of the photoelectric coupler VLC is provided with a transistor NPN1 and a transistor NPN2 in series. The transistor NPN1 is provided with a capacitor C1 and a resistor R3 in parallel. The transistor NPN2 is provided with a capacitor C2 and a resistor R4 in parallel.

[0006] Preferably, a resistor R1 is electrically connected between the operational amplifier Q and the voltage zener diode VD1 , and one end of the resistor R1 away from the voltage zener diode VD1 is electrically connected to the photoelectric coupler VLC.

[0007] Preferably, one side of the voltage stabilizing diode VD1 is electrically connected to a detector, and the detector includes a voltage detector and a current detector.

[0008] Preferably, a resistor R5 is electrically connected between the photoelectric coupler VLC and the transistor NPN1, and a resistor R6 is electrically connected between the transistor NPN1 and the transistor NPN2.

[0009] Preferably, the resistor R5 is connected in parallel with the capacitor C1, and the resistor R6 is connected in parallel with the capacitor C2.

[0010] Preferably, a relay K and a diode VD2 are connected in parallel to the transistor NPN2.

[0011] Preferably, a resistor R8 is provided in series on the negative pin of the operational amplifier Q, and a resistor R9 is electrically connected to the positive pin of the operational amplifier Q.

[0012] Preferably, the positive pin of the operational amplifier Q is grounded via a resistor R10, and the value of the resistor R10 is 10~100 / 2W.

[0013] The utility model has at least the following beneficial effects:

[0014] 1. For digital or pulse signals transmitted from the detector over a long distance, they are amplified by the operational amplifier Q and then optically isolated. The operational amplifier Q connected to a voltage follower circuit also has the function of isolating interference. The electric coupler can also suppress interference with a very high voltage amplitude. Therefore, when using the photoelectric coupler VLC, it can also play a role in isolating interference even in forward transmission.

[0015] 2. In actual circuits, when the inductive load is disconnected, overvoltage will be generated, resulting in strong electrical interference. If an RC absorption circuit is connected in parallel with the inductor coil, this voltage can be absorbed. In practical applications, the values ​​of R5, R6, C1, and C2 can be selected based on experience. Generally, the values ​​of R5 and R6 are 10-100V2W, and the values ​​of C1 and C2 are 0.1-0.47F / 800V. This absorption circuit can be used for both AC and DC, improving the flexibility and scope of use.

[0016] 3. For the analog signal transmitted by the detector, a differential operational amplifier is usually used to isolate the interference. The output signal of this amplifier is determined by the potential difference between the two input ends. The phase and magnitude of the interference signal are the same for the two input ends, so the interference signal is canceled out. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The drawings described herein are used to provide a further understanding of the present application and constitute a part of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0018] Figure 1 This is the circuit diagram of the utility model;

[0019] Figure 2 This is the circuit diagram of the operational amplifier Q of the utility model. DETAILED DESCRIPTION

[0020] The following will describe the implementation methods of the present application in detail with reference to the accompanying drawings and examples, so that the implementation process of how the present application applies technical means to solve technical problems and achieve technical effects can be fully understood and implemented accordingly.

[0021] like Figure 1-Figure 2 As shown, the anti-interference interface circuit based on the shunt monitoring terminal provided in this embodiment includes a photocoupler VLC, one side of the photocoupler VLC is electrically connected to an operational amplifier Q, the positive pin of the operational amplifier Q is electrically connected to a Zener diode VD1, the negative pin of the operational amplifier Q is electrically connected to the photocoupler VLC via a resistor R2, a resistor R1 is electrically connected between the operational amplifier Q and the Zener diode VD1, and the end of the resistor R1 away from the Zener diode VD1 is electrically connected to the photocoupler VLC;

[0022] For digital or pulse signals transmitted from the detector over a long distance, they are amplified by the operational amplifier Q and then optically isolated. In addition, the operational amplifier Q connected to a voltage follower circuit also has the function of isolating interference. If the detector uses a photoelectric sensor, its output amplitude is too large and the waveform is poor, the voltage regulator diode VD1 and resistor R1 can be used to limit and shape the waveform. If the output waveform is good and the amplitude can be adjusted, these two components can be omitted and the signal can be amplified directly.

[0023] On the other side of the photoelectric coupler VLC, transistors NPN1 and NPN2 are connected in series. Capacitor C1 and resistor R3 are connected in parallel to transistor NPN1. Capacitor C2 and resistor R4 are connected in parallel to transistor NPN2. VLC is a photoelectric coupler. Its input end is a light-emitting diode. The input impedance is very low, generally 100-1K, while the internal resistance of the interference source is generally large, generally 105-106K. According to the voltage divider principle, the interference signal that can enter the light-emitting diode is very small and can only form a very weak current. In addition, the light-emitting diode has a certain current width, so interference with a high voltage amplitude can also be suppressed. Therefore, when using the photoelectric coupler VLC, it can isolate interference even in forward transmission.

[0024] Further, such as Figure 1As shown, one side of the voltage zener diode VD1 is electrically connected to a detector, which includes a voltage detector and a current detector. A resistor R5 is electrically connected between the photocoupler VLC and the transistor NPN1, and a resistor R6 is electrically connected between the transistor NPN1 and the transistor NPN2. The resistor R5 is arranged in parallel with the capacitor C1, and the resistor R6 is arranged in parallel with the capacitor C2. In an actual circuit, when the inductive load is disconnected, an overvoltage will be generated, resulting in strong electrical interference. If an RC absorption circuit is connected in parallel to the inductor coil, this voltage can be absorbed. In actual applications, the values ​​of R5, R6 and C1, C2 can be selected based on experience. Generally, the values ​​of R5 and R6 are 10-100V2W, and the values ​​of C1 and C2 are 0.1-0.47F / 800V. This absorption circuit can be used for both AC and DC, thereby improving the flexibility and scope of use.

[0025] Furthermore, Figure 1 As shown, transistor NPN2 is connected in parallel with relay K and diode VD2. Relay K is an electrical appliance that causes a predetermined step change in the controlled quantity in the electrical output circuit when the change in the input quantity reaches the specified requirement. It has an interactive relationship between the control system and the controlled system and is usually used in automated control circuits. It is actually an "automatic switch" that uses a small current to control the operation of a large current, and plays the role of automatic adjustment, safety protection, and circuit conversion in the circuit.

[0026] Further, if Figure 2 As shown, the negative pin of the operational amplifier Q is connected in series with a resistor R8, the positive pin of the operational amplifier Q is electrically connected to a resistor R9, and the positive pin of the operational amplifier Q is grounded via a resistor R10. The value of resistor R10 is 10~100 / 2W. For the analog signal transmitted by the detector, a differential operational amplifier is usually used to isolate interference. The output signal of this amplifier is determined by the potential difference between the two input terminals. The phase and magnitude of the interference signal are the same for the two input terminals, so the interference signal is canceled out.

[0027] like Figure 1-Figure 2 As shown, the principle of the anti-interference interface circuit based on the branch monitoring terminal provided in this embodiment is as follows:

[0028] For digital or pulse signals transmitted from the detector over a long distance, they are amplified by the operational amplifier Q and then optically isolated. In addition, the operational amplifier Q connected to a voltage follower circuit also has the function of isolating interference. If the detector uses a photoelectric sensor, its output amplitude is too large and the waveform is poor, the voltage regulator diode VD1 and resistor R1 can be used to limit and shape the waveform. If the output waveform is good and the amplitude can be adjusted, these two components can be omitted and the signal can be amplified directly.

[0029] On the other side of the photoelectric coupler VLC, transistors NPN1 and NPN2 are connected in series. Capacitor C1 and resistor R3 are connected in parallel to transistor NPN1, and capacitor C2 and resistor R4 are connected in parallel to transistor NPN2. VLC is a photoelectric coupler, and its input end is a light-emitting diode. The input impedance is very low, generally 100-1K, while the internal resistance of the interference source is generally large, generally 105-106K. According to the voltage divider principle, the interference signal that can enter the light-emitting diode is very small and can only form a very weak current. In addition, the light-emitting diode has a certain current width, so interference with a high voltage amplitude can also be suppressed. Therefore, when using the photoelectric coupler VLC, it can isolate interference even in forward transmission.

[0030] For example, certain words are used in the specification and claims to refer to specific components. Those skilled in the art should understand that hardware manufacturers may use different terms to refer to the same component. This specification and claims do not use differences in names as a way to distinguish components, but use differences in the functions of the components as the criteria for distinction. For example, "including" mentioned throughout the specification and claims is an open term, so it should be interpreted as "including but not limited to". "Approximately" means that within an acceptable error range, those skilled in the art can solve technical problems within a certain error range and basically achieve technical effects.

[0031] It should be noted that the terms "include," "comprises," or any other variations thereof are intended to encompass non-exclusive inclusion, such that a product or system comprising a series of elements includes not only those elements but also other elements not explicitly listed, or elements inherent to such product or system. In the absence of further limitations, an element defined by the phrase "comprising a..." does not exclude the presence of other identical elements in the product or system comprising the element.

[0032] The above description shows and describes several preferred embodiments of the present invention. However, as previously mentioned, it should be understood that the present invention is not limited to the form disclosed herein and should not be construed as excluding other embodiments. Instead, the present invention can be used in various other combinations, modifications, and environments and can be modified within the scope of the present invention as taught herein or through the techniques or knowledge in the relevant field. Modifications and variations made by those skilled in the art that do not depart from the spirit and scope of the present invention are intended to be protected by the claims appended hereto.

Claims

1. An anti-interference interface circuit based on a branch monitoring terminal, including a photoelectric coupler VLC, characterized in that: One side of the photoelectric coupler VLC is electrically connected to an operational amplifier Q, a positive pin of the operational amplifier Q is electrically connected to a voltage stabilizing diode VD1, and a negative pin of the operational amplifier Q is electrically connected to the photoelectric coupler VLC via a resistor R2; The other side of the photoelectric coupler VLC is provided with a transistor NPN1 and a transistor NPN2 in series. The transistor NPN1 is provided with a capacitor C1 and a resistor R3 in parallel. The transistor NPN2 is provided with a capacitor C2 and a resistor R4 in parallel.

2. The anti-interference interface circuit based on the branch monitoring terminal according to claim 1, characterized in that: A resistor R1 is electrically connected between the operational amplifier Q and the Zener diode VD1 . One end of the resistor R1 away from the Zener diode VD1 is electrically connected to the photoelectric coupler VLC.

3. The anti-interference interface circuit based on the branch monitoring terminal according to claim 1, characterized in that: One side of the voltage stabilizing diode VD1 is electrically connected to a detector, which includes a voltage detector and a current detector.

4. The anti-interference interface circuit based on the branch monitoring terminal according to claim 1, characterized in that: A resistor R5 is electrically connected between the photoelectric coupler VLC and the transistor NPN1 , and a resistor R6 is electrically connected between the transistor NPN1 and the transistor NPN2 .

5. The anti-interference interface circuit based on the branch monitoring terminal according to claim 4, characterized in that: The resistor R5 is connected in parallel with the capacitor C1 , and the resistor R6 is connected in parallel with the capacitor C2 .

6. The anti-interference interface circuit based on the branch monitoring terminal according to claim 1, characterized in that: The transistor NPN2 is provided with a relay K and a diode VD2 in parallel.

7. The anti-interference interface circuit based on the branch monitoring terminal according to claim 1, characterized in that: A resistor R8 is connected in series to the negative pin of the operational amplifier Q, and a resistor R9 is electrically connected to the positive pin of the operational amplifier Q.

8. The anti-interference interface circuit based on the branch monitoring terminal according to claim 1, characterized in that: The positive pin of the operational amplifier Q is grounded via a resistor R10 , and the value of the resistor R10 is 10-100 / 2W.

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