CN204302420U - A switching value acquisition circuit - Google Patents

Abstract

The utility model discloses a switching value acquisition circuit, which comprises a control power supply module, a rectification threshold module, an isolation module, a filter shaping module and a single-chip microcomputer interface module. The control power supply module provides an external power supply for the switching value acquisition circuit; the rectification threshold module rectifies the control power supply module and provides the threshold for the isolation module to be turned on; The signal output by the isolation module is filtered and decoupled, and the signal is shaped into a stable level signal; the single-chip microcomputer interface module collects the level signal output by the filter and shaper module. The switching value acquisition circuit of the utility model has strong anti-interference ability, simple software processing, high reliability, simple circuit and low cost.

Description

A switching value acquisition circuit

technical field

The utility model relates to the field of electric equipment protection and industrial automation control, in particular to a switching quantity acquisition circuit.

Background technique

At present, with the continuous development of the industrial level, in the field of power equipment protection devices and industrial automation control, the electromagnetic interference on the industrial site is becoming more and more serious, and tens of volts of interference voltage will be generated on the switching value acquisition signal terminal, resulting in inaccurate switching value acquisition. . The traditional switching value acquisition circuit has poor anti-electromagnetic interference ability. Most of the sites use intermediate relays to solve electromagnetic interference. The external control power supply controls the intermediate relay coil, and the contacts of the intermediate relay are connected in series with the switching value signal input circuit. Interference voltage to prevent inaccurate acquisition of switching values caused by interference voltage. However, after the intermediate relay is added, the field wiring is complicated, and the intermediate relay is large in size and high in cost. In addition, when the signal entering the microcontroller is a pulse signal, it will cause complex software processing and low reliability.

Utility model content

Purpose of the utility model: The purpose of the utility model is to provide a switching value acquisition circuit with strong anti-interference ability, simple software processing and high reliability.

The content of the utility model: the switching value acquisition circuit described in the utility model includes a control power supply module, a rectification threshold module, an isolation module, a filter shaping module and a single-chip microcomputer interface module.

The control power supply module is connected to the rectification threshold module, the rectification threshold module is connected to the isolation module, the isolation module is connected to the filter shaping module, and the filter shaping module is connected to the single-chip microcomputer interface module.

Further, the control power supply module includes a control power supply S1 and a switch SB1 connected in series.

Further, the rectification threshold module includes a rectification diode U1, a diode D1 and a resistor R1. The first pin of the rectifier diode U1 is connected to one end of the control power module, the second pin of the rectifier diode U1 is connected to the other end of the control power module, and the third pin of the rectifier diode U1 is connected to the cathode of the diode D1, rectifying The fourth pin of the diode U1 is connected to one end of the resistor R1.

Further, the rectifier diode U1 includes a full-wave bridge rectifier circuit.

Further, the diode D1 includes a unidirectional TVS diode.

Further, the isolation module includes a linear optocoupler U2. The first pin of the input end of the linear optocoupler U2 is connected to one end of the rectification threshold module, the second pin of the input end of the linear optocoupler U2 is connected to the other end of the rectification threshold module, and the first pin of the output end of the linear optocoupler U2, The second pin is connected to the filtering and shaping module.

Further, the filtering and shaping module includes a resistor R2, a capacitor C1, a capacitor C2, a shaping circuit U3 and a power supply VCC. Resistor R2, capacitor C1 and capacitor C2 are connected in parallel, one end of the parallel circuit is grounded, the other end of the parallel circuit is respectively connected to one end of the isolation module and one end of the shaping circuit U3, and the power supply VCC is connected to the other end of the isolation module , the other end of the shaping circuit U3 is connected to the single-chip microcomputer interface module.

Further, the shaping circuit U3 includes a CMOS tri-state buffer.

Further, the single-chip microcomputer interface module includes a single-chip microcomputer I/O port.

The control power supply module provides an external power supply for the switching value acquisition circuit; the rectification threshold module rectifies the control power supply module and provides the threshold for the isolation module to be turned on; The signal output by the isolation module is filtered and decoupled, and the signal is shaped into a stable level signal; the single-chip microcomputer interface module collects the level signal output by the filter and shaper module.

Beneficial effects: the switching value acquisition circuit provided by the utility model can improve the anti-interference ability of the industrial site by reasonably selecting the threshold value of the rectification threshold module; and, no matter whether the voltage of the control power supply is AC voltage or DC voltage, after the filtering and shaping module All can output stable level signals to the single-chip microcomputer interface module, so that the software processing is simple and the reliability is high; in addition, the circuit of the utility model is simple and the cost is low.

Description of drawings

Fig. 1 is a block diagram of the utility model;

Fig. 2 is a kind of specific circuit diagram of the utility model;

Fig. 3 is the input terminal waveform and the output terminal waveform of the shaping circuit when the control power supply voltage of the utility model is a DC voltage;

Fig. 4 is the input terminal waveform and output terminal waveform of the shaping circuit when the control power supply voltage of the present invention is AC voltage.

Detailed ways

The technical solution of the present utility model will be further described below in combination with the accompanying drawings and specific embodiments.

The block diagram of the switching value acquisition circuit of the present invention is shown in Figure 1, including a control power supply module 1, a rectification threshold module 2, an isolation module 3, a filter shaping module 4 and a single-chip microcomputer interface module 5. The control power supply module 1 is connected to the rectification threshold module 2 , the rectification threshold module 2 is connected to the isolation module 3 , the isolation module 3 is connected to the filter shaping module 4 , and the filter shaping module 4 is connected to the single chip microcomputer interface module 5 .

A specific circuit form of the utility model is shown in Fig. 2 . The control power supply module 1 includes a control power supply S1 and a switch SB1, one end of the control power supply S1 is connected to one end of the switch SB1. The rectification threshold module 2 includes a rectification diode U1, a diode D1 and a resistor R1. The first pin of the rectifying diode U1 is connected to the other end of the switch SB1, the second pin of the rectifying diode U1 is connected to the other end of the control power supply S1, the third pin of the rectifying diode U1 is connected to the cathode of the diode D1, and the second pin of the rectifying diode U1 is connected to the cathode of the diode D1. Four pins are connected to one end of resistor R1. The rectifier diode U1 adopts a full-wave bridge rectifier circuit, and the diode D1 adopts a unidirectional TVS diode. The isolation module 3 includes a linear optocoupler U2. The input end of the linear optocoupler includes a diode, and the output end of the linear optocoupler includes a triode. For the convenience of description, the anode of the diode at the input end of the linear optocoupler is called the first pin of the input end of the linear optocoupler. The cathode of the diode at the input end of the optocoupler is called the second pin of the input end of the linear optocoupler, the emitter of the triode at the output end of the linear optocoupler is called the first pin of the output end of the linear optocoupler, and the set of the triode at the output end of the linear optocoupler is called The electrode is called the second pin at the output of the linear optocoupler. The first pin of the input end of the linear optocoupler U2 is connected to the anode of the diode D1, the second pin of the input end of the linear optocoupler U2 is connected to the other end of the resistor R1, the first pin and the second pin of the output end of the linear optocoupler U2 are connected to the filter Shaping module4. The filtering and shaping module 4 includes a resistor R2, a capacitor C1, a capacitor C2, a shaping circuit U3 and a power supply VCC. Wherein, the resistor R2, the capacitor C1 and the capacitor C2 are referred to as a filter decoupling circuit. Resistor R2, capacitor C1 and capacitor C2 are connected in parallel, one end of the parallel circuit is grounded, the other end of the parallel circuit is respectively connected to the first pin of the output terminal of the linear optocoupler U2 and one end of the shaping circuit U3, and the power supply VCC is connected to the linear optocoupler The second pin of the output end of U2 is connected to the interface module 5 of the single-chip microcomputer with the other end of the shaping circuit U3. The shaping circuit U3 uses a CMOS tri-state buffer. The single-chip microcomputer interface module 5 includes a single-chip microcomputer I/O port.

The control power supply module 1 provides an external power supply for the switching value acquisition circuit; the rectification threshold module 2 rectifies the control power supply module 1, and provides the threshold for the isolation module 3 to conduct; the isolation module 3 realizes the isolation of the signal of the switching value input terminal and the acquisition terminal of the single chip microcomputer The filtering and shaping module 4 filters and decouples the signal output by the isolation module 3, and shapes the signal into a stable level signal; the single-chip microcomputer interface module 5 collects the level signal output by the filtering and shaping module 4.

When the control power supply module 1 is turned on, when the voltage of the control power supply S1 exceeds the threshold of the rectification threshold module 2 (that is, the breakdown voltage of the diode D1), the diode D1 reversely breaks down and conducts, and a signal passes through the input terminal of the isolation module 3 , the output end of the isolation module 3 is turned on. Therefore, by reasonably selecting the threshold of the rectification threshold module 2, the anti-interference ability of the industrial site can be improved.

When the voltage of the control power supply S1 is a DC voltage, the rectifier diode U1 can prevent the damage of the isolation module 3 caused by the reverse connection of the positive and negative poles of the control power supply S1, output a level signal after passing through the rectification threshold module 2 and the isolation module 3, and then The filtering and decoupling circuit in the filtering and shaping module 4 outputs a level signal, and sends the level signal to the input end of the shaping circuit U3. As shown in FIG. 3 , the output signal after passing through the shaping circuit U3 is a stable level signal.

When the voltage of the control power supply S1 is an AC voltage, the rectifier diode U1 rectifies the control power supply S1 into a pulsating DC signal, outputs a square wave signal after passing through the isolation module 3, and then outputs a pulsating signal after passing through the filtering and decoupling circuit in the filtering and shaping module 4 level signal, and send this pulsating level signal to the input end of the shaping circuit U3. As shown in FIG. 4 , the output signal after passing through the shaping circuit U3 is a stable level signal.

Therefore, when the control power supply S1 is an AC or DC voltage, the shaping circuit U3 outputs a stable level signal.

The switching value acquisition circuit provided by the utility model can improve the anti-interference ability of the industrial site by reasonably selecting the threshold value of the rectification threshold module 2; It can output a stable level signal to the single-chip microcomputer interface module 5, so that the software processing is simple and the reliability is high; in addition, the circuit of the utility model is simple and the cost is low.

Claims (9)

1. A switch quantity acquisition circuit is characterized in that: comprise control power supply module (1), rectification threshold value module (2), isolation module (3), filter shaping module (4) and single-chip microcomputer interface module (5); The control power supply module (1) is connected to the rectification threshold module (2), the rectification threshold module (2) is connected to the isolation module (3), the isolation module (3) is connected to the filter shaping module (4), and the filter shaping module (4) is connected to the microcontroller interface module (5). 2. The switching value acquisition circuit according to claim 1, characterized in that: the control power supply module (1) comprises a control power supply S1 and a switch SB1 connected in series. 3. The switching value acquisition circuit according to claim 1, characterized in that: the rectification threshold module (2) comprises a rectification diode U1, a diode D1 and a resistor R1; the first pin of the rectification diode U1 is connected to the control power supply One end of the module (1), the second pin of the rectifier diode U1 is connected to the other end of the control power supply module (1), the third pin of the rectifier diode U1 is connected to the cathode of the diode D1, and the fourth pin of the rectifier diode U1 Connect one end of resistor R1. 4. The switching value acquisition circuit according to claim 3, wherein the rectifier diode U1 comprises a full-wave bridge rectifier circuit. 5. The switching value acquisition circuit according to claim 3, wherein the diode D1 comprises a unidirectional TVS diode. 6. The switching value acquisition circuit according to claim 1, characterized in that: the isolation module (3) comprises a linear optocoupler U2; the first pin of the input end of the linear optocoupler U2 is connected to the rectification threshold module (2) One end of the linear optocoupler U2 input end, the second pin connected to the other end of the rectification threshold module (2), the first pin and the second pin of the linear optocoupler U2 output end connected to the filter shaping module (4) . 7. The switching value acquisition circuit according to claim 1, characterized in that: said filter shaping module (4) comprises resistor R2, capacitor C1, capacitor C2, shaping circuit U3 and power supply VCC; resistor R2, capacitor C1 and capacitor The three of C2 are connected in parallel, one end of the parallel circuit is grounded, the other end of the parallel circuit is respectively connected to one end of the isolation module (3) and one end of the shaping circuit U3, and the power supply VCC is connected to the other end of the isolation module (3), The other end of the shaping circuit U3 is connected to the single-chip microcomputer interface module (5). 8. The switching value acquisition circuit according to claim 7, wherein the shaping circuit U3 comprises a CMOS tri-state buffer. 9. The switching value acquisition circuit according to claim 1, characterized in that: the single-chip microcomputer interface module (5) includes a single-chip microcomputer I/O port.