CN110798190A - An electronic switch system for preventing electromagnetic interference - Google Patents

Abstract

The invention provides an electronic switch system for preventing electromagnetic interference. The main controller regularly reads the level signal of the output end of the encoding circuit. When the laser in the off state needs to be turned on, the switch controller provides the level signal for the input end of the encoding circuit. , the encoding circuit encodes the level signal of the input terminal, and the encoded level signal is consistent with the turn-on level signal preset in the main control chip, then the main controller uses the PWM drive module to send the PWM drive signal to the laser to control the The laser is turned on; when the laser in the working state needs to be turned off, the switch controller provides a level signal for the input end of the encoding circuit, and the encoding circuit encodes the level signal at the input end, and the encoded level signal is the same as the preset in the main If the off-level signals in the control chip are consistent, the main controller uses the PWM drive module to send a PWM drive signal to the laser to control the laser to turn off. The present invention improves device sensitivity.

Description

An electronic switch system for preventing electromagnetic interference

technical field

The invention belongs to the technical field of switch circuits, and in particular relates to an electronic switch system for preventing electromagnetic interference.

Background technique

With the advancement of electronic technology and the popularization of computer technology and artificial intelligence, a large number of circuits are controlled by logic chips. The requirements are getting higher and higher, and with the increase of automation, more and more electrical products generate a lot of electromagnetic interference around us. At present, the control and emission switches of carbon dioxide lasers and radio frequency lasers used in medical laser surgery in China mostly use electronic switches. As long as the working power is turned on, the set high-level or low-level signal is input at the control end, and the control system sends out PWM. The signal starts the laser to emit a strong laser to cut human skin or use it for medical beauty. Affected by electromagnetic interference, the probability of laser malfunction caused by traditional electronic switches such as a single high and low level control electronic switch continues to increase, resulting in more cases of human injury. Similar conditions apply to instruments, equipment, and key components controlled by a single electronic switch.

At present, the software and hardware anti-interference method we usually use is: when the software recognizes that the start signal is high or low, add time judgment in the program to avoid the electromagnetic interference signal, for example: when the program judges the switch The signal must be greater than 30ms before it is confirmed as a start signal, and a signal less than 30ms is considered an interference signal. This can reduce the probability of electromagnetic interference misoperation to a certain extent, but the uncertainty of the electromagnetic interference environment will also cause the software anti-shake failure and reduce the sensitivity of the device. Can a method be used to avoid the malfunction of the electronic switch caused by electromagnetic interference, while retaining the sensitivity of the equipment and greatly reducing the probability of electromagnetic interference malfunction. That is to say, in the prior art, in order to avoid electromagnetic interference, most of the single electronic switch ports add anti-shake time to the software, that is, the software finds that a port is in the startup state of 0 or 1 (0V or +5V) and can only be confirmed to be activated after a certain period of time. Signal. But this judgment method reduces the sensitivity of the device.

SUMMARY OF THE INVENTION

Purpose of the invention: In order to solve the problems of low sensitivity in the prior art, the present invention provides an electronic switch system for preventing electromagnetic interference;

Technical scheme: The present invention provides an electronic switch system for preventing electromagnetic interference, which is applied to turning on or off the laser, including: an encoding circuit, a switch controller, a PWM drive module, and a main controller;

The switch controller is used for the operator to input the on/off command, and input the corresponding level signal to the coding circuit according to the input command; the coding circuit is used to encode and output the level signal input by the switch controller, and the main controller Read the level signal in the encoded form output by the encoding circuit, and compare it with the preset on/off level signal. If it is consistent with the preset on/off level signal, use the PWM drive module to send the corresponding signal to the laser. Turn on/off the PWM drive signal to control the laser on/off.

Further, the main controller periodically reads the level signal output by the encoding circuit.

Further, the encoding circuit includes first to fourth transistors and first to fourth resistors; the first and fourth transistors are NPN transistors, and the second and fourth transistors are PNP transistors;

The emitter of the first triode is connected to one end of the first resistor, the other end of the first resistor is grounded, the collector of the first triode is connected to the +5V power supply; the emitter of the second triode is connected to one end of the second resistor , the other end of the second resistor is connected to the +5V power supply, the collector of the second triode is grounded; the emitter of the third triode is connected to one end of the third resistor, the other end of the third resistor is connected to the +5V power supply, and the third The collector of the triode is grounded; the emitter of the fourth triode is grounded, the collector is connected to one end of the fourth resistor, and the other end of the fourth resistor is connected to the +5v power supply; the bases of the first to fourth triodes The poles are the input ends of the encoding circuit, and the emitters of the first to fourth transistors are the output ends of the encoding circuit.

Further, the system also includes a first terminal; the first terminal has 6 ports, one of which is grounded, one is connected to the +5V power supply, and the remaining four ports are respectively connected to the first to fourth transistors. The base; the switch controller provides level signals for the bases of the first to fourth triodes through the first connection terminal.

Further, the system further includes a second connection terminal, the second connection terminal has 4 ports, the four ports are respectively connected to the emitters of the first to fourth triodes, and the main controller is connected through the second connection The terminal reads the level signals of the emitters of the first to fourth transistors.

Further, the main controller adopts STM32F407, and the output end of the encoding circuit and the PWM drive module are all connected to the corresponding i/o ports of the chip.

Further, the system also includes a display, the STM32F407 regularly reads the level signal of the i/o port connected to the output end of the encoding circuit, if all are low level, then the STM32F407 determines that the i/o port is faulty, and sends the signal to the I/O port. The display sends the word "failure"; if the level of the i/o port connected to the output end of the encoding circuit continues to jump, it is determined to be caused by static electricity.

Beneficial effects: the present invention is simple in structure, low in cost, and easy to implement. The present invention uses four-way triodes to form an encoding circuit, which does not require software anti-shake and saves time; and the circuit reduces the probability of false touches due to electromagnetic interference.

Description of drawings

Fig. 1 is the working principle diagram of the present invention;

Fig. 2 is the circuit diagram of the encoding circuit of the present invention;

Figure 3 is a flow chart of the method of the present invention.

Detailed ways

The accompanying drawings constituting a part of the present invention are used to provide further understanding of the present invention, and the exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention.

As shown in Figures 1-2, this embodiment provides an electronic switch system for preventing electromagnetic interference; the system includes an encoding circuit, a switch controller, a PWM drive module, a main controller, a first terminal J1, and a second terminal J2 ; The main controller adopts STM32F407 chip, which includes DSP, FPGA, RAM, FLASH, IO port and bus.

The encoding circuit includes first to fourth transistors and first to fourth resistors; the first and fourth transistors are NPN transistors, and the second and third transistors are PNP transistors.

The emitter of the first triode Q1 is connected to one end of the first resistor R1, the other end of the first resistor is grounded, the collector of the first triode is connected to the +5V power supply; the emitter of the second triode Q2 is connected to the second One end of the resistor R2, the other end of the second resistor is connected to +5V power supply, the collector of the second transistor is grounded; the emitter of the third transistor Q3 is connected to one end of the third resistor R3, and the other end of the third resistor is connected to +5V power supply, the collector of the third transistor is grounded, the emitter of the fourth transistor Q4 is grounded, the collector is connected to one end of the fourth resistor R4, and the other end of the fourth resistor is connected to the +5v power supply; the first The bases of the to fourth triodes are all the input terminals of the encoding circuit, and the emitters of the first to the fourth triodes are all the output terminals of the encoding circuit.

The switch controller is used for the operator to input the on/off command, and input the corresponding level signal to the coding circuit according to the input command; the coding circuit is used to encode and output the level signal input by the switch controller, and the main controller Read the level signal in the encoded form output by the encoding circuit, and compare it with the preset on/off level signal. If it is consistent with the preset on/off level signal, use the PWM drive module to send the corresponding signal to the laser. Turn on/off the PWM drive signal to control the laser on/off.

The first connection terminal has six ports IN-1 to IN-6, one of which is grounded, IN-6 is connected to +5V power supply, and the remaining four ports IN-5 to IN-2 are connected to the first to The base of the fourth triode; the switch controller provides level signals for the bases of the first to fourth triodes through the first connection terminal.

The second connection terminal has four ports OUT-1 to OUT4, and the OUT-1 to OUT4 are respectively connected to the emitters of the first to fourth transistors, and the main controller reads the first to fourth transistors through the second connection terminal. ~The level signal of the emitter of the fourth triode.

As shown in Figure 3, the specific flow when the present invention is applied to the laser generator:

Step 1: Power on the entire circuit, reset the circuit, and initialize the entire circuit to a standby state;

Step 2: The main controller regularly (every 100μs to 200μs) detects the level value of the i/o ports connected to the second terminals OUT1, OUT2, OUT3 and OUT4;

Step 3: If the level of the i/o port is 0, it is determined that the i/o port is faulty, and the word "failure" is sent to the display, and the system is manually turned off for detection; if the level of the i/o port keeps jumping If the system is not affected by static electricity, go to step 4 if the system is not faulty and not affected by static electricity.

Step 4: When the laser in the off state needs to be turned on, the operator provides a level signal to the input end of the encoding circuit through the switch controller, and the encoding circuit encodes the level signal at the input end, and the encoded level signal is the same as the preset signal. The turn-on level signal set in the main controller is consistent, when the level signal read by the main controller is consistent with the preset turn-on level signal, the main controller uses the PWM drive module to send the PWM drive signal to the laser, thereby Control the laser to turn on. When the laser in the working state needs to be turned off, the switch controller provides a level signal to the input end of the encoding circuit. The encoding circuit encodes the level signal of the input end, and the encoded level signal is the same as the preset level. The off-level signals in the master controller are consistent. When the level signal read by the master controller is consistent with the preset off-level signal, the master controller uses the PWM drive module to send the PWM drive signal to the laser, thereby controlling the The laser is off. If the laser is already in working state, but the level signal read by the main controller is consistent with the preset turn-on level signal, the laser is already in the off state but the level signal read by the main controller is consistent with the preset turn-off level signal If the level signal is consistent, the laser keeps the current state unchanged.

In this embodiment, the turn-on level value and the turn-off level value are set as 1011 and 0100 respectively; when the laser needs to be turned on, the switch controller provides a level signal of 1010 for the input end of the encoding circuit; when the laser needs to be turned off, the switch controls The level signal provided by the encoder for the input end of the encoding circuit is 0101;

In addition, it should be noted that each specific technical feature described in the above-mentioned specific implementation manner may be combined in any suitable manner under the circumstance that there is no contradiction. In order to avoid unnecessary repetition, the present invention will not describe various possible combinations.

Claims (7)

1. an electronic switch system of anti-electromagnetic interference, this system is applied to the opening or closing of laser, it is characterized in that, comprise: coding circuit, switch controller, PWM drive module, main controller; The switch controller is used for the operator to input the on/off command, and input the corresponding level signal to the coding circuit according to the input command; the coding circuit is used to encode and output the level signal input by the switch controller, and the main controller Read the level signal in the encoded form output by the encoding circuit, and compare it with the preset on/off level signal. If it is consistent with the preset on/off level signal, use the PWM drive module to send the corresponding signal to the laser. Turn on/off the PWM drive signal to control the laser on/off. 2 . The electronic switch system for preventing electromagnetic interference according to claim 1 , wherein the main controller regularly reads the level signal output by the encoding circuit. 3 . 3 . The electronic switch system for preventing electromagnetic interference according to claim 1 , wherein the encoding circuit comprises first to fourth transistors and first to fourth resistors; The triode is an NPN type triode, and the second and the triode are PNP type triodes; The emitter of the first triode is connected to one end of the first resistor, the other end of the first resistor is grounded, the collector of the first triode is connected to the +5V power supply; the emitter of the second triode is connected to one end of the second resistor , the other end of the second resistor is connected to the +5V power supply, the collector of the second triode is grounded; the emitter of the third triode is connected to one end of the third resistor, the other end of the third resistor is connected to the +5V power supply, and the third The collector of the triode is grounded; the emitter of the fourth triode is grounded, the collector is connected to one end of the fourth resistor, and the other end of the fourth resistor is connected to the +5v power supply; the bases of the first to fourth triodes The poles are the input ends of the encoding circuit, and the emitters of the first to fourth transistors are the output ends of the encoding circuit. 4 . The electronic switch system for preventing electromagnetic interference according to claim 3 , wherein the system further comprises a first connection terminal; the first connection terminal has 6 ports, wherein one port is grounded and one port is grounded. 5 . Connect the +5V power supply, and the other four ports are respectively connected to the bases of the first to fourth triodes; the switch controller provides level signals for the bases of the first to fourth triodes through the first connection terminal. 5 . The electronic switch system for preventing electromagnetic interference according to claim 3 , wherein the system further comprises a second connection terminal, the second connection terminal has four ports, and the four ports are respectively connected to the first connection terminal. 6 . The emitters of the first to fourth triodes, the main controller reads the level signals of the emitters of the first to fourth triodes through the second connection terminal. 6. The electronic switch system for preventing electromagnetic interference according to claim 1, wherein the main controller adopts STM32F407, and the output end of the encoding circuit and the PWM drive module are all corresponding to the i/o port of the chip. connect. 7. The electronic switch system for preventing electromagnetic interference according to claim 6, wherein the system further comprises a display, and the STM32F407 regularly reads the level of the i/o port connected to the output end of the encoding circuit If the signals are all low levels, the STM32F407 determines that the i/o port is faulty and sends the word "failure" to the display; if the level of the i/o port connected to the output end of the encoding circuit continues to jump, then It was determined to be caused by electrostatic influence.

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