Voltage and current signal combination detection circuit

Abstract

The utility model relates to a voltage and current signal combination detection circuit, which comprises a surge absorption unit, a level conversion unit, a current conversion unit, a clamping protection circuit and a filtering absorption loop, the input end of the surge absorption unit is electrically connected with a voltage signal source or a current signal source; the output end of the surge absorption unit is electrically connected with the input end of the level conversion unit and the input end of the current conversion unit; the output end of the level conversion unit and the output end of the current conversion unit are electrically connected with the input end of the clamping protection circuit; and the output end of the clamping protection circuit is electrically connected with the filtering absorption loop. According to the circuit topology mode introduced by the utility model, the two analog signals can be compatibly acquired by a single AD port.

Description

Technical Field

[0001] The utility model belongs to the field of fully automated products and relates to a voltage and current signal merging detection circuit. Background Art

[0002] In the field of industrial control, the control signals between many drivers and controllers are 0-10V and 4-20mA electrical signals. 0-10V voltage signals and 4-20mA current signals are very common control communication signals, widely used in the control of industrial inverters, industrial fans, various pumps, and valves. However, a device often only supports one communication method. When used with a host controller, the inconsistent signaling methods often lead to the replacement of the controller or the addition of an additional notification converter for operation. The use of this circuit can easily solve this problem.

[0003] These two analog signals require the use of two AD ports for analog quantity acquisition. When designing the loop and control board, the circuit topology can be used uniformly for the acquisition of standard industrial communication voltage and current signals. Utility Model Content

[0004] In order to solve the above problems, the technical solution adopted by the present invention is: a voltage and current signal combined detection circuit, including: an electrostatic protection unit, a level conversion unit, a current conversion unit, a clamping protection circuit and a filter absorption circuit;

[0005] The input end of the electrostatic protection unit is electrically connected to a voltage signal source or a current signal source;

[0006] The output end of the electrostatic protection unit is electrically connected to the input end of the level conversion unit and the input end of the current conversion unit;

[0007] The output end of the level conversion unit and the output end of the current conversion unit are electrically connected to the input end of the clamp protection circuit;

[0008] The output end of the clamping protection circuit is electrically connected to the filter absorption loop.

[0009] Furthermore: the electrostatic protection unit includes a surge absorption unit and an anti-reverse protection circuit D1;

[0010] The surge absorption unit includes a bidirectional TVS diode D3, a bidirectional TVS diode D4 and an anti-reverse protection circuit D1;

[0011] The anti-reverse protection circuit D1 is composed of two parallel diodes;

[0012] One end of the bidirectional TVS diode D3 and one end of the bidirectional TVS diode D4 are both connected to the ground of the voltage signal source or the current signal source;

[0013] The other end of the bidirectional TVS diode D3 is connected to one end of the current signal source and the anodes of the two parallel diodes;

[0014] The other end of the bidirectional TVS diode D3 is connected to one end of the voltage signal source and the level conversion circuit.

[0015] Furthermore: the clamping protection circuit includes two series-connected diodes: a first diode and a second diode, the cathode of the first diode is connected to the +5V power supply, the anode of the first diode is connected to the cathode of the second diode, and the anode of the second diode is connected to the ground.

[0016] Furthermore: the filtering and absorbing circuit 7 includes a resistor R1 and a capacitor C1;

[0017] One end of the resistor R1 is connected to the anode and cathode of the first diode, the other end of the resistor R1 is connected to one end of the capacitor C1, and the other end of the capacitor C1 is connected to the anode of the second diode and the ground.

[0018] The utility model provides a voltage and current signal combined detection circuit, which has the following advantages: the circuit topology introduced in the utility model can realize that a single AD port can be compatible with collecting the above two analog signals.

[0019] 1. This circuit is compatible with two types of signal source inputs;

[0020] 2. The two signal sources can use the same AD acquisition port as input;

[0021] 3. When the input resolution is fixed, the two signal sources can obtain the same output amplitude without modifying the conversion ratio of the receiving end, which greatly improves the convenience of use. (For example, under the 5% input condition of 0-10V or the 5% input condition of 0-20mA, the output amplitude obtained by both is the same as the AD conversion value. In this way, the signal source type can be easily switched without modifying the configuration of the receiving end)

[0022] 4. The circuit topology is simple and there are no redundant components. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces 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 present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0024] Figure 1It is a module diagram of a voltage and current signal combined detection circuit;

[0025] Figure 2 The utility model is a circuit diagram of a voltage and current signal combined detection circuit.

[0026] Figure numerals: 3, surge absorption unit, 4, level conversion unit, 5, current conversion voltage unit, 6, clamping protection circuit, 7, filtering absorption circuit. DETAILED DESCRIPTION

[0027] It should be noted that, unless there is any conflict, the embodiments of the present invention and the features in the embodiments may be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0028] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings 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. The following description of at least one exemplary embodiment is actually only illustrative and is in no way intended to limit the present invention and its application or use. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0029] Figure 1 It is a module diagram of a voltage and current signal combined detection circuit;

[0030] A voltage and current signal combined detection circuit, comprising

[0031] The surge absorption unit 3 is used to absorb the high-voltage electrostatic surge signal contained in the 0-10V voltage source or the 4-20mA current source to be detected;

[0032] The level conversion unit 4 is used to perform voltage division level conversion on the voltage signal output by the voltage signal source to be detected;

[0033] The current-to-voltage conversion unit 5 is used to convert the current output by the current signal source to be detected into a voltage;

[0034] A clamping protection circuit 6 is used to perform voltage clamping protection on the voltage output by the level conversion unit or the voltage output by the current conversion voltage unit, so that the voltage range is guaranteed to be between 0-5V;

[0035] The filter absorption circuit 7 is used to filter and absorb the voltage protection signal output by the clamp protection circuit to obtain a stable signal to be measured; the signal to be measured is a voltage signal with an accuracy of generally 0.5V and a current signal with an accuracy of 1mA; the signal to be measured will be transmitted to the analog-to-digital converter.

[0036] Figure 2 The utility model is a circuit diagram of a voltage and current signal combined detection circuit.

[0037] The electrostatic protection unit 3 includes a surge absorption unit and an anti-reverse protection circuit D1;

[0038] The surge absorption unit includes a bidirectional TVS diode D3 and a bidirectional TVS diode D4;

[0039] The anti-reverse protection circuit D1 is composed of two parallel diodes;

[0040] One end of the bidirectional TVS diode D3 and one end of the bidirectional TVS diode D4 are both connected to the ground of the voltage signal source or the current signal source;

[0041] The other end of the bidirectional TVS diode D3 is connected to one end of the current signal source and the anodes of the two parallel diodes;

[0042] The other end of the bidirectional TVS diode D3 is connected to one end of the voltage signal source and the level conversion circuit.

[0043] The clamping protection circuit 6 includes two diodes connected in series: a first diode and a second diode, wherein the cathode of the first diode is connected to the +5V power supply, the anode of the first diode is connected to the cathode of the second diode, and the anode of the second diode is connected to the ground.

[0044] The level conversion unit 4 includes a resistor R2 and a resistor R3; the resistance of the resistor R2 is 300 ohms, and the resistance of the resistor R3 is 200 ohms;

[0045] The anti-reverse protection circuit D1 is composed of two parallel diodes;

[0046] The filtering and absorbing circuit 7 includes a resistor R1 and a capacitor C1;

[0047] One end of the resistor R1 is connected to the anode and cathode of the first diode, the other end of the resistor R1 is connected to one end of the capacitor C1, and the other end of the capacitor C1 is connected to the anode of the second diode and the ground.

[0048] This circuit treats two signal sources, a 0-10 voltage signal source and a 4-20mA current signal source, respectively. After passing through the bidirectional TVS diode D3 and bidirectional TVS diode D4 of the surge absorption unit 3, the voltage signal source enters the level conversion unit 4, and is divided and level-converted by the resistors R2 and R3 of the resistor network. The divided voltage is obtained and input into the next-level clamp protection circuit 6.

[0049] After passing through the anti-reverse protection circuit D1 of the surge absorption unit 3, the current signal source enters the current conversion voltage unit 5 composed of the load resistor R3, obtains the calculated voltage and then enters the next level clamping protection circuit 6. The output voltage signal passes through the RC filter absorption circuit 7 and is sent to the processor's analog-to-digital converter.

[0050] Among them, bidirectional TVS diode D3 and bidirectional TVS diode D4 serve as electrostatic surge absorption devices, which can effectively absorb the high-voltage electrostatic surge signal in the input signal source. The anti-reverse protection circuit D1 is used for anti-reverse control, which can effectively suppress the damage to the subsequent circuit when the current signal is reversely connected to GND.

[0051] Resistors R2 and R3 form a voltage divider network, with R2 / R3 set to 3 / 2. Typically, 300 ohms and 200 ohms are selected based on the downstream circuit. When a voltage signal is input, the input voltage value is 2 / 5 times the input voltage. When a current signal source is input, resistor R3 converts the current into a voltage signal. After conversion, the voltage and current signals pass through clamping protection circuit 6 for voltage clamping protection, ensuring the voltage range is between 0-5V. The signal then passes through the resistor R1 and capacitor C1 filtering circuit to obtain a stable signal to be measured.

[0052] In industrial communications, voltage signal accuracy is generally 0.5V, and current signal accuracy is 1mA. Therefore, the circuit structure designed above can calculate the corresponding analog-to-digital conversion values ​​for voltage and current signals, respectively. See the table below, and the corresponding relationship between voltage and current can be found. It is concluded that at a fixed maximum resolution, the corresponding conversion values ​​for voltage and current are consistent. This means that a single analog-to-digital conversion interface can proportionally acquire voltage and current signals.

[0053]

[0054] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A voltage and current signal combined detection circuit, characterized in that: include: Electrostatic protection unit, level conversion unit, current conversion unit, clamping protection circuit and filter absorption circuit; The input end of the electrostatic protection unit is electrically connected to a voltage signal source or a current signal source; The output end of the electrostatic protection unit is electrically connected to the input end of the level conversion unit and the input end of the current conversion unit; The output end of the level conversion unit and the output end of the current conversion unit are electrically connected to the input end of the clamp protection circuit; The output end of the clamping protection circuit is electrically connected to the filter absorption loop.

2. The voltage and current signal combined detection circuit according to claim 1, characterized in that: The electrostatic protection unit includes a surge absorption unit and an anti-reverse protection circuit D1; The surge absorption unit includes a bidirectional TVS diode D3, a bidirectional TVS diode D4 and an anti-reverse protection circuit D1; The anti-reverse protection circuit D1 is composed of two parallel diodes; One end of the bidirectional TVS diode D3 and one end of the bidirectional TVS diode D4 are both connected to the ground of the voltage signal source or the current signal source; The other end of the bidirectional TVS diode D3 is connected to one end of the current signal source and the anodes of the two parallel diodes; The other end of the bidirectional TVS diode D3 is connected to one end of the voltage signal source and the level conversion circuit.

3. The voltage and current signal combined detection circuit according to claim 1, characterized in that: The clamping protection circuit includes two diodes connected in series: a first diode and a second diode, the cathode of the first diode is connected to a +5V power supply, the anode of the first diode is connected to the cathode of the second diode, and the anode of the second diode is connected to the ground.

4. The voltage and current signal combined detection circuit according to claim 1, characterized in that: The filtering and absorbing circuit includes a resistor R1 and a capacitor C1; One end of the resistor R1 is connected to the anode and cathode of the first diode, the other end of the resistor R1 is connected to one end of the capacitor C1, and the other end of the capacitor C1 is connected to the anode of the second diode and the ground.

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