CN110032107A - The flogic system and control method of 4 road signal on-off are controlled by 3 relays - Google Patents

Abstract

The invention discloses a logic system for controlling the on-off of 4-channel signals by 3 relays. The main point of the invention is that it includes an MCU control unit, a relay logic control circuit, a USB power supply interface circuit, a USB to TTL level conversion circuit and a signal input and output. interface unit. The MCU control unit is used for access control to the relay logic control circuit. The USB to TTL level conversion circuit is used to convert the USB level received by the USB power interface circuit into a TTL level that can be recognized by the MCU control unit. The signal input and output interface unit is used to connect antennas, filters, AD converters and other instruments and equipment to realize analog signal input and output. The relay logic control circuit includes 3 relays, and the relay contacts are cascaded to realize the expansion of the signal channel, and control the selection of one of the four signals of the signal input and output interface unit.

Description

Logic system and control method for on-off of 4-channel signals controlled by 3 relays

technical field

The invention relates to the field of relay control systems, in particular to a logic system and a control method for controlling the on-off of four-channel signals by three relays.

Background technique

In the industry, it is often necessary to collect analog signals from multiple input devices. However, collecting multiple analog signals through an AD converter has great disadvantages. It needs to constantly plug and unplug the interface connectors to switch, which is obviously troublesome. The interface of the AD converter will also cause wear and tear, reducing its service life.

A single-chip microcomputer, also known as a single-chip microcontroller, is not a chip that completes a certain logic function, but integrates a computer system into a single chip. At present, single-chip microcomputers are widely used in various control fields, such as intelligent instruments, medical equipment, robots, etc. Relays have functions similar to switches. Relays are widely used in various electronic equipment control circuits to isolate control signals from loads. Some special output requirements can only be output when the control signal is sent out in a predetermined logical sequence, and usually, only one signal gating can be controlled by one relay, and four signals are usually required to realize the gating of four signals. The relays are controlled separately. At present, the signal control circuit is generally realized by chip digital circuit, the circuit is more complex, and the technical requirements for designers are relatively high.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a logic system and a control method with simple circuit and convenient implementation, which can control three relays to select four signals based on a single-chip microcomputer.

The basic technical scheme for realizing the purpose of the present invention is: a logic system that controls the on-off of 4-way signals by 3 relays, and its structural characteristics are: including MCU control unit, relay logic control circuit, USB power interface circuit, USB to TTL power Flat conversion circuit and signal input and output interface unit. The MCU control unit is used for access control to the relay logic control circuit. The USB to TTL level conversion circuit is used to convert the USB level received by the USB power interface circuit into a TTL level that can be recognized by the MCU control unit. The signal input and output interface unit is used to connect antennas, filters, AD converters and other equipment to realize analog signal input and output. The relay logic control circuit includes 3 relays. The relay contacts are cascaded to realize the expansion of the signal channel, and control the four-way signal selection of the signal input and output interface unit.

The technical solution based on the above-mentioned basic technical solution is: the MCU control unit is provided with a first crystal oscillator circuit and a reset circuit. The first crystal oscillator circuit is used to provide a clock signal to the MCU control unit. The reset circuit is used to clear the program counter of the MCU control unit to make the MCU control unit work stably.

The technical solution based on the above corresponding technical solutions is: the USB power interface circuit includes a USB socket M1, a tenth capacitor C10, an eleventh polarity capacitor C11 and a ninth light emitting diode D9. The USB socket M1 adopts the Micro USB socket. The eleventh polarity capacitor C11 of the power interface circuit adopts an aluminum electrolytic capacitor, which has the functions of filtering and energy storage, and can make the PC power supply stably. The ninth light-emitting diode D9 is used as a power-on indicator of the power interface circuit, prompting the user that the system is powered on.

The technical solution based on the above-mentioned corresponding technical solutions is: the USB to TTL level conversion circuit includes a level conversion chip G1, which is a USB bus transfer chip, and realizes USB to serial port, USB to IrDA infrared or USB to print port. . The level conversion chip G1 is used to convert the USB level received by the USB power interface circuit into the TTL level that the MCU control unit can recognize.

The technical solution based on the above-mentioned corresponding technical solutions is: the USB to TTL level conversion circuit is provided with a second crystal oscillator circuit, and the second crystal oscillator circuit is used to provide a clock signal to the level conversion chip G1. The level conversion chip G1 adopts the chip of model CH340G. The UD+ pin of CH340G is connected with the D+ pin of MICRO USB, and the UD- pin is connected with the D- pin of MICRO USB. The transmission pin TXD and the reception pin RXD of the CH340G chip are respectively connected with the reception pin RXD and the transmission pin TXD of the MCU control unit. The receiving pin RXD of the MCU control unit is connected with the TXD pin of the CH340G chip with the reverse diode D8. The reverse diode D8 adopts 1N4148 to prevent the current from flowing into the post-stage circuit through this pin and charging the post-stage capacitor. It causes the voltage of the rear stage to have a certain magnitude, which will affect the cold start of the downloaded program of the MCU control unit.

The technical scheme based on the above-mentioned corresponding technical scheme is: the three relays of the relay logic control circuit are divided into a first relay U1, a second relay U2 and a third relay U3. The three relays all use signal relays, and the signal relays control The voltage is 5V, and the contact form is: DPDT. The signal relay has 8 pins, including the positive and negative pins of the relay coil, a pair of normally open contacts, a pair of normally closed contacts and a pair of common terminal contacts, and the isolation effect from the signal is very good.

After the coil of the first relay U1 is connected in series with the first PNP transistor Q1, both ends of the relay coil are connected in parallel with a first freewheeling diode D1, one end of the first PNP transistor Q1 is connected to the power supply +5V, and the first PNP transistor Q1 The gate is connected to the relay control IO port P23 of the MCU control unit, and at the same time, the second resistor R2 is connected in series, and the first resistor R1 is used as a pull-up resistor of the IO port.

After the coil of the second relay U2 is connected in series with the second PNP transistor Q2, both ends of the relay coil are connected in parallel with a second freewheeling diode D2, one end of the second PNP transistor Q2 is connected to the power supply +5V, and the second PNP transistor Q2 The gate is connected to the relay control IO port P22 of the MCU control unit, and at the same time, a fourth resistor R4 is connected in series, and the third resistor R3 is used as a pull-up resistor of the IO port.

After the coil of the third relay U3 is connected in series with the third PNP triode Q3, both ends of the relay coil are connected in parallel with a third freewheeling diode D3, one end of the third PNP triode Q3 is connected to the power supply +5V, and the third PNP triode Q3 The gate is connected to the relay control IO port P21 of the MCU control unit, while the sixth resistor R6 is connected in series, and the fifth resistor R5 is used as a pull-up resistor of the IO port.

The first analog signal channel is input from the normally closed contact of the first relay U1, and is connected to its common terminal contact via the normally closed contact of the third relay U3, and then is contacted from the common terminal of the third relay U3. Point output signal, it is that the P23 port of the MCU control unit sends a high level to the first relay U1, and at the same time, the P21 port sends a high level to the third relay U3.

The second analog signal channel is input from the normally open contact of the first relay U1, and is connected to its common terminal contact via the normally closed contact of the third relay U3, and then is contacted from the common terminal of the third relay U3. Point output signal, the conduction condition is that the P23 port of the MCU control unit sends a low level to the first relay U1, and at the same time, the P21 port sends a high level to the third relay.

The third analog signal channel is input from the normally closed contact of the second relay U2, and is connected to its common terminal contact via the normally open contact of the third relay U3, and then is contacted from the common terminal of the third relay U3. Point output signal, the conduction condition is that the P22 port of the MCU control unit sends a high level to the second relay U2, and at the same time, the P21 port sends a low level to the third relay U3.

The fourth analog signal channel is input from the normally open contact of the second relay, and is connected to its common terminal contact via the normally open contact of the third relay U3, and then from the common terminal contact of the third relay U3. The output signal, the conduction condition is that the P22 port of the MCU control unit sends a low level to the first relay U1, and at the same time, the P21 port sends a low level to the third relay U3.

The technical solution based on the above-mentioned corresponding technical solution is as follows: a signal gating indication circuit is further included. The signal strobe indication circuit consists of four light-emitting diodes and a third load resistor. The four light-emitting diodes are respectively a fourth light-emitting diode D4, a fifth light-emitting diode D5, a sixth light-emitting diode D6 and a seventh light-emitting diode D7. The third load resistor includes an eleventh resistor R11, a twelfth resistor R12, a thirteenth resistor R13 and a fourteenth resistor R14. The fourth light-emitting diode D4 and the eleventh resistor R11 are connected in series between the +5V power supply and the P24 pin of the MCU control unit. The fifth light-emitting diode D5 and the twelfth resistor R12 are connected in series between the +5V power supply and the P25 pin of the MCU control unit. The sixth light-emitting diode D6 and the thirteenth resistor R13 are connected in series between the +5V power supply and the P26 pin of the MCU control unit. The seventh LED D7 and the fourteenth resistor R14 are connected in series between the +5V power supply and the P27 pin of the MCU control unit.

The control method of the logic system in which the on-off of 4 channels of signals is controlled by 3 relays has the following steps:

First, the single-chip C language programming. When selecting a signal channel, use the case selection statement.

2. The sending data unit 0x01 represents the IN1 signal channel. The IO pin P23 of the MCU control unit outputs a high level, which turns off the first PNP transistor Q1. At this time, there is no voltage across the coil of the first relay U1, so the first relay U1 does not work , its normally closed contact and the common end contact are closed, the IN1 branch is turned on, the fourth light-emitting diode D4 is assigned a value of 0, and the light is on to indicate that the IN1 road is strobe. At the same time, the IO pin P21 of the MCU control unit outputs a high level, which turns off the third PNP transistor Q3. At this time, there is no voltage across the coil of the third relay U3, so the third relay U3 does not work, and its normally closed contact is connected to the common terminal. The contact is closed, and the OUT branch is turned on, so that the first analog signal channel is turned on.

3. The sending data unit 0x02 represents the IN2 signal channel. The IO pin P23 of the MCU control unit outputs a low level to turn on the first PNP transistor Q1. At this time, the voltage across the coil of the first relay U1 is 5V, so the first relay U1 When it starts to work, its normally closed contact is disconnected, the normally open contact and the common terminal contact are closed, the IN2 branch is turned on, the fifth light-emitting diode D5 is assigned a value of 0, and the light is on to indicate that the IN2 circuit is gated. At the same time, the IO pin P21 of the MCU control unit outputs a high level, which turns off the third PNP transistor Q3. At this time, there is no voltage across the coil of the third relay U3, so the third relay U3 does not work, and its normally closed contact is connected to the common terminal. The contact is closed, and the OUT branch is turned on, so that the second signal channel is turned on.

4. The sending data unit 0x03 represents the IN3 signal channel. The IO pin P22 of the MCU control unit outputs a high level, so that the second PNP transistor Q2 is turned off. At this time, there is no voltage across the coil of the second relay U2, so the second relay U2 does not work , its normally closed contact and the common end contact are closed, the IN3 branch is turned on, the sixth light-emitting diode D6 is assigned a value of 0, and the light is on to indicate that the IN3 road is strobe. At the same time, the IO pin P21 of the MCU control unit outputs a low level, so that the third PNP transistor Q3 is turned on. At this time, the voltage across the coil of the third relay U3 is 5V, so the third relay U3 starts to work, and the normally closed contact is disconnected. The normally open contact and the common terminal contact are closed, and the OUT branch is turned on, so that the third signal channel is turned on.

5. The sending data unit 0x04 represents the IN4 signal channel. The IO pin P22 of the MCU control unit outputs a low level, which makes the second PNP transistor Q2 conduct. At this time, the voltage across the coil of the second relay U2 is 5V, so the second relay U2 When it starts to work, its normally closed contact is disconnected, the normally open contact and the common terminal contact are closed, the IN4 branch is turned on, the seventh light-emitting diode D7 is assigned a value of 0, and the light is on to indicate that the IN4 is gated. At the same time, the IO pin P21 of the MCU control unit outputs a low level, so that the third PNP transistor Q3 is turned on. At this time, the voltage across the coil of the third relay U3 is 5V, so the third relay U3 starts to work, and the normally closed contact is disconnected. The normally open contact and the common terminal contact are closed, and the OUT branch is turned on, so that the fourth signal channel is turned on.

The present invention has the following beneficial effects: (1) the circuit of the present invention is simple and easy to implement, and the collection and control of four-way signals are realized by using three signal relays based on the single-chip microcomputer, and the communication with the host computer is conveniently completed, and the control of multiple The signal input of the instrument equipment realizes the accurate control of the input signal of the equipment, that is, the analog signal can be collected according to the designated equipment and equipment, and one of the four signals can be selected for control, which greatly improves the control efficiency and accuracy between the equipment.

(2) The present invention can be connected to a computer through a USB data line, and the user can remotely control and precisely control the input and output of the device signal by sending data from the host computer.

(3) The present invention utilizes three signal relays to realize the gating control of four analog signals, which greatly saves the cost.

(4) The present invention selects four-way signals without plugging and unplugging the interface connector to switch, the protection interface is not easy to be damaged, and the use durability of the equipment is greatly improved.

(5) The relay in the present invention selects the signal relay with the model G6J-2P-Y-DC5V, and the isolation effect from the signal is very good. Its control voltage is 5V, and the contact form is: DPDT. The signal relay has 8 pins, including the positive and negative pins of the relay coil, a pair of normally open contacts, a pair of normally closed contacts and a pair of common terminal contacts.

(6) The control method of the logic system based on the single chip microcomputer of the present invention to control 3 relays to select 4 channels of signals realizes the expansion of the signal channel through the cascade connection between the relay contacts. Similarly, it is also possible to use 3N relays to control The logic system of 4N signals on and off, N is a natural number, and has a wide application prospect.

Description of drawings

FIG. 1 is a block diagram of the logic system structure of the present invention in which the on-off of 4-channel signals is controlled by 3 signal relays.

FIG. 2 is a circuit schematic diagram of the present invention.

FIG. 3 is a schematic diagram of the amplification circuit of the MCU control unit in FIG. 2 .

FIG. 4 is a schematic diagram of an amplification circuit of the relay logic control circuit in FIG. 2 .

FIG. 5 is a diagram of the logic method of the present invention for controlling 4 signals by 3 relays.

FIG. 6 is a schematic diagram of an amplification circuit of the USB power interface circuit in FIG. 2 .

FIG. 7 is a schematic diagram of the amplification circuit of the USB-to-TTL level conversion circuit in FIG. 2 .

8 is the truth table of the logic system of the present invention in which 3 signal relays are used to control the on-off of 4-channel signals (0, 1 represent high and low levels, X represents nothing to do with the level of the P2 port of the single-chip microcomputer).

Fig. 9 is a result verification diagram obtained by measuring the gated input and output ports with a multimeter ohm gear according to the present invention under the condition that four-way signals are gated respectively. (Contacts 2 and 7 are normally closed contact pairs, contacts 4 and 5 are normally open contact pairs, / indicates that the relay contacts work in any state).

The numbers in the attached drawings are:

MCU control unit 1,

Relay logic control circuit 2,

USB power interface circuit 3,

USB to TTL level conversion circuit 4,

Signal input and output interface unit 5,

Signal strobe indication circuit 6,

Reset circuit 10, reset button 100.

Detailed ways

It should be noted that like numerals and letters refer to like items in the following figures, so once an item is defined in one figure, it does not require further definition and explanation in subsequent figures. Meanwhile, in the description of the present invention, the terms 'first', 'second', etc. are only used to distinguish the description, and cannot be construed as indicating or implying relative importance.

(Example 1)

Referring to Figures 1 to 7, the logic system of the present invention in which 4-way signals are controlled by 3 relays includes an MCU control unit 1, a relay logic control circuit 2, a USB power interface circuit 3, a USB-to-TTL level conversion circuit 4, Signal input and output interface unit 5 and signal strobe indication circuit 6 .

The MCU control unit 1 adopts a low-power, high-performance CMOS 8-bit microcontroller of the STC company's model STC89C52, with 8K bytes of system programmable Flash memory. The MCU control unit 1 is used for access control to the relay logic control circuit 2. The MCU control unit 1 is provided with a first crystal oscillator circuit and a reset circuit 10 .

The first crystal oscillator circuit includes a second capacitor C2, a third capacitor C3 and a first crystal oscillator Y1. The first crystal oscillator circuit is used to provide the MCU control unit 1 with a clock signal. A 11.0592MHz first crystal oscillator Y2 is connected between the X1 and X2 pins of the MCU control unit 1, the second load capacitor C2 is connected to the X1 pin, and the third load capacitor C3 is connected to the X2 pin. The first crystal oscillator Y1 will Provide the required clock signal.

The reset circuit 10 includes a reset button 100, a first load resistor and a fourth polarity capacitor C4. The reset circuit 10 is used for clearing the program counter of the MCU control unit 1 to make the MCU control unit 1 work stably. The first load resistor includes a seventh resistor R7 and an eighth resistor R8. The reset button 100 is electrically connected between the seventh resistor R7 and the positive electrode of the fourth polarity capacitor C4, and the seventh resistor R7 is electrically connected to the negative electrode of the fourth polarity capacitor C4. One end of the eighth resistor R8 is grounded, and the other end is electrically connected to the negative electrode of the fourth polarity capacitor C4. The positive pole of the fourth polarity capacitor C4 is connected to the +5V power supply.

The USB power interface circuit 3 includes a USB socket M1, a second load resistor, a tenth capacitor C10, an eleventh polarity capacitor C11 and a ninth light emitting diode D9.

The USB female socket M1 adopts the Micro USB female socket. The Micro USB connector is smaller than the standard USB and Mini USB connectors, which saves space and has a plug life and strength of up to 10,000 times. The blind plug structure is designed. The Micro USB standard supports the current USB OTG function, that is, in the absence of a host, data transmission can be directly realized between portable devices, compatible with USB1.1 and USB 2.0, and provides data transmission and charging at the same time. convenient. There are 5 functional pins on the Micro USB plug end, namely: VBUS (power supply positive 5V), D- (data line negative), D+ (data line positive), ID (also divided into connected to the line and not connected to the ground line) two interfaces), GND (signal ground), the ID pin is not needed in this embodiment. The eleventh polarity capacitor C11 of the power interface circuit 3 adopts an aluminum electrolytic capacitor, which has the functions of filtering and energy storage, and can make the PC power supply stably. The ninth light-emitting diode D9 is used as a power-on indicator of the power interface circuit, prompting the user to power on the system. The tenth capacitor C10 and the eleventh polarity capacitor C11 are connected in parallel. VBUS is electrically connected to the positive electrode of the eleventh polarity capacitor C11 and the tenth capacitor C10; the negative electrode of the eleventh polarity capacitor C11 is grounded. The second load resistor includes a ninth resistor R9 and a tenth resistor R10. D- is electrically connected to one end of the tenth resistor R10. D+ is electrically connected to one end of the ninth resistor R9.

The USB to TTL level conversion circuit 4 includes a level conversion chip G1. In this embodiment, the model of the level conversion chip G1 is CH340G, which is a USB bus conversion chip, which can realize USB to serial port, USB to IrDA infrared or USB Turn the print port. If the serial port of the microcontroller (TTL level) wants to communicate with the serial port of the computer (USB level), it is necessary to make the level logic of the two to be the same before they can communicate. In this embodiment, the CH340G chip is used to convert the USB level received by the USB socket M1 into a TTL level that can be recognized by the MCU control unit 1 . The USB to TTL level conversion circuit 4 is provided with a second crystal oscillator circuit, which is used to provide a clock signal to the CH340G chip, and the second crystal oscillator circuit is arranged on the XI and XO pins of the CH340G chip. The second crystal oscillator circuit includes a fifth capacitor C5, a sixth capacitor C6 and a second crystal oscillator Y2.

The UD+ pin of CH340G is connected with the D+ pin of MICRO USB, and the UD- pin is connected with the D- pin of MICRO USB. The transmission pin TXD and the reception pin RXD of the CH340G chip are respectively connected with the reception pin RXD and the transmission pin TXD of the MCU control unit 1. The receiving pin RXD of the MCU control unit 1 is connected with the TXD pin of the CH340G chip with the reverse diode D8. The reverse diode D8 adopts 1N4148 to prevent the current from flowing into the post-stage circuit through this pin and charging the post-stage capacitor. , resulting in a voltage of a certain magnitude in the rear stage, which will affect the cold start of the downloaded program of the MCU control unit 1.

Principle of USB to TTL level conversion circuit 4: CH340G chip has built-in USB bus pull-up resistor and on-chip signal terminal, UD+ and UD- pins should be directly connected to the USB bus. CH340G has built-in power-on reset circuit. During operation, CH340G needs to provide 12MHz clock signal on XI pin. Usually this clock signal is connected by a 12MHz second crystal oscillator Y2 between the XI and XO pins, the fifth load capacitor C5 at the XI pin, and the sixth load capacitor C6 at the XO pin. The built-in second crystal oscillator Y2 will provide the required clock signal. When using an external oscillator to send the clock signal to the XI pin, leave the XO pin floating. CH340G supports 5V operation, when using 5V operation, supply 5V voltage to VCC pin.

The signal gating indication circuit 6 is composed of four light-emitting diodes and a third load resistor. The four light emitting diodes are a fourth light emitting diode D4, a fifth light emitting diode D5, a sixth light emitting diode D6 and a seventh light emitting diode D7. The third load resistor includes an eleventh resistor R11, a twelfth resistor R12, a thirteenth resistor R13 and a fourteenth resistor R14. The fourth light-emitting diode D4 and the eleventh resistor R11 are connected in series between the +5V power supply and the P24 pin of the MCU control unit 1 . The fifth light-emitting diode D5 and the twelfth resistor R12 are connected in series between the +5V power supply and the P25 pin of the MCU control unit 1. The sixth light-emitting diode D6 and the thirteenth resistor R13 are connected in series between the +5V power supply and the P26 pin of the MCU control unit 1 . The seventh LED D7 and the fourteenth resistor R14 are connected in series between the +5V power supply and the P27 pin of the MCU control unit 1. The specific implementation is completed by the program downloaded to the MCU control unit 1, and the user only needs to transmit the data unit on the upper computer and observe it. After a certain signal is gated, the light-emitting diode corresponding to this signal will light up, indicating to the user that the signal is successfully gated: the IN1 signal channel is gated, the fourth LED D4 is on; the IN2 signal channel is gated, the fifth LED D5 ON; IN3 signal channel is gated, the sixth LED D6 is ON; IN4 signal channel is gated, the seventh LED D7 is ON.

The signal input and output interface unit 5 is composed of 6 SMA connector sockets with a 90-degree bend, and the 6 SMA socket sockets are divided into the first SMA socket socket P1, the second SMA socket socket P2, and the third SMA socket socket in turn. P3, the fourth SMA connector female seat P4, the fifth SMA connector female seat P5, and the sixth SMA connector female seat P6. The first SMA connector female seat P1, the second SMA connector female seat P2, the third SMA connector female seat P3, and the fourth SMA connector female seat P4 are used as the input interface of the four-way signal, and the fifth SMA connector female seat P5 is used as the signal input interface. Output interface, the sixth SMA connector female seat P6 is used as a power interface that can be powered independently. The SMA connector socket is used to connect instruments such as antennas, filters, AD converters, etc., to realize analog signal input and output.

The relay logic control circuit 2 includes 3 relays, and the 3 relays are divided into the first relay U1, the second relay U2 and the third relay U3. The three relays all use Omron's signal relay model G6J-2P-Y-DC5V, The signal relay is a small-sized signal relay specially used to process analog signals. Its control voltage is 5V, and the contact form is: DPDT. The signal relay has 8 pins, including the positive and negative pins of the relay coil, a pair of normally open contacts, a pair of normally closed contacts and a pair of common terminal contacts, and the isolation effect from the signal is very good.

After the coil of the first relay U1 is connected in series with the first PNP transistor Q1, both ends of the relay coil are connected in parallel with a first freewheeling diode D1, one end of the first PNP transistor Q1 is connected to the power supply +5V, and the first PNP transistor Q1 The gate is connected to the relay control IO port P23 of the MCU control unit 1, and at the same time, a second resistor R2 is connected in series, and the first resistor R1 is used as a pull-up resistor of the IO port.

After the coil of the second relay U2 is connected in series with the second PNP transistor Q2, both ends of the relay coil are connected in parallel with a second freewheeling diode D2, one end of the second PNP transistor Q2 is connected to the power supply +5V, and the second PNP transistor Q2 The gate is connected to the relay control IO port P22 of the MCU control unit 1, and at the same time, a fourth resistor R4 is connected in series, and the third resistor R3 is used as a pull-up resistor of the IO port.

After the coil of the third relay U3 is connected in series with the third PNP triode Q3, both ends of the relay coil are connected in parallel with a third freewheeling diode D3, one end of the third PNP triode Q3 is connected to the power supply +5V, and the third PNP triode Q3 The gate is connected to the relay control IO port P21 of the MCU control unit 1, and at the same time, a sixth resistor R6 is connected in series, and the fifth resistor R5 is used as a pull-up resistor of the IO port.

The first analog signal channel is input from the normally closed contact of the first relay U1, and is connected to its common terminal contact via the normally closed contact of the third relay U3, and then is contacted from the common terminal of the third relay U3. Point output signal, it is that the P23 port of the MCU control unit 1 sends a high level to the first relay U1, and at the same time, the P21 port sends a high level to the third relay U3.

The second analog signal channel is input from the normally open contact of the first relay U1, and is connected to its common terminal contact via the normally closed contact of the third relay U3, and then is contacted from the common terminal of the third relay U3. Point output signal, the conduction condition is that the P23 port of the MCU control unit 1 sends a low level to the first relay U1, and at the same time, the P21 port sends a high level to the third relay.

The third analog signal channel is input from the normally closed contact of the second relay U2, and is connected to its common terminal contact via the normally open contact of the third relay U3, and then is contacted from the common terminal of the third relay U3. Point output signal, the conduction condition is that the P22 port of the MCU control unit 1 sends a high level to the second relay U2, and at the same time, the P21 port sends a low level to the third relay U3.

The fourth analog signal channel is input from the normally open contact of the second relay, and is connected to its common terminal contact via the normally open contact of the third relay U3, and then from the common terminal contact of the third relay U3. The output signal, the conduction condition is that the P22 port of the MCU control unit 1 sends a low level to the first relay U1, and at the same time, the P21 port sends a low level to the third relay U3.

Referring to Fig. 8 and Fig. 9, the control method of the logic system in which 3 relays control the on-off of 4-way signals of the present invention has the following steps:

First, the single-chip C language programming. When selecting a signal channel, use the case selection statement.

2. The sending data unit 0x01 represents the IN1 signal channel. The IO pin P23 of the MCU control unit 1 outputs a high level, which turns off the first PNP transistor Q1. At this time, there is no voltage across the coil of the first relay U1, so the first relay U1 has no voltage. When it works, its normally closed contact and the common terminal contact are closed, the IN1 branch is turned on, the fourth light-emitting diode D4 is assigned a value of 0, and the light is on to indicate that the IN1 channel is strobe; at the same time, the IO pin P21 of the MCU control unit 1 outputs a high level , so that the third PNP transistor Q3 is turned off. At this time, there is no voltage across the coil of the third relay U3, so the third relay U3 does not work, its normally closed contact and the common terminal contact are closed, and the OUT branch is turned on, thus the first One analog signal channel is turned on.

3. The sending data unit 0x02 represents the IN2 signal channel, and the IO pin P23 of the MCU control unit 1 outputs a low level to turn on the first PNP transistor Q1. At this time, the voltage across the coil of the first relay U1 is 5V, so the first relay U1 starts to work, its normally closed contact is disconnected, the normally open contact and the common terminal contact are closed, the IN2 branch is turned on, the fifth LED D5 is assigned a value of 0, and the light is on to indicate that the IN2 circuit is gated; at the same time, the MCU control unit The IO pin P21 of 1 outputs a high level, which makes the third PNP transistor Q3 cut off. At this time, there is no voltage across the coil of the third relay U3, so the third relay U3 does not work, and its normally closed contact and the common terminal contact are closed. , the OUT branch is turned on, so that the second signal channel is turned on.

4. The sending data unit 0x03 represents the IN3 signal channel. The IO pin P22 of the MCU control unit 1 outputs a high level, so that the second PNP transistor Q2 is turned off. At this time, there is no voltage across the coil of the second relay U2, so the second relay U2 has no voltage. It works, its normally closed contact and the common terminal contact are closed, the IN3 branch is turned on, the sixth light-emitting diode D6 is assigned a value of 0, and the light is on to indicate that the IN3 channel is strobe; at the same time, the output of the IO pin P21 of the MCU control unit 1 is low. level, the third PNP transistor Q3 is turned on. At this time, the voltage across the coil of the third relay U3 is 5V, so the third relay U3 starts to work, the normally closed contact is disconnected, and the normally open contact and the common terminal contact are closed. , the OUT branch is turned on, so that the third signal channel is turned on.

5. The sending data unit 0x04 represents the IN4 signal channel. The IO pin P22 of the MCU control unit 1 outputs a low level to make the second PNP transistor Q2 conduct. At this time, the voltage across the coil of the second relay U2 is 5V, so the second relay U2 starts to work, its normally closed contact is disconnected, the normally open contact and the common terminal contact are closed, the IN4 branch is turned on, the seventh light-emitting diode D7 is assigned a value of 0, and the light is on to indicate that the IN4 channel is gated; at the same time, the MCU The IO pin P21 of the control unit 1 outputs a low level, so that the third PNP transistor Q3 is turned on. At this time, the voltage across the coil of the third relay U3 is 5V, so the third relay U3 starts to work, the normally closed contact is disconnected, and the normally closed contact is disconnected. The open contact and the common terminal are closed, and the OUT branch is turned on, so that the fourth signal channel is turned on.

The invention adopts 5V DC power supply, the user only needs to use a USB data line to complete the power supply and communication of the PC to the invention, and the upper computer only needs to send some simple data characters to control the instrument that the user wants to work. The signal of the device is input to other devices, which saves a lot of unnecessary trouble and greatly improves the efficiency. The invention can realize remote control and accurate control of the transmission signal of the equipment, and also achieve the protection of the precision instruments and equipment, and has practical application value in industry. The present invention realizes the expansion of the signal channel through the cascade connection between the relay contacts. Similarly, the present invention can also realize the logic system of using 3N relays to control the on-off of 4N signals, and N is a natural number.

The specific embodiments described above further describe the purpose, technical solutions and beneficial effects of the present invention in further detail. It should be understood that the above descriptions are only specific embodiments of the present invention, and are not intended to limit the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims (8)

1. a kind of flogic system for controlling 4 road signal on-off by 3 relays, it is characterised in that: including MCU control unit, after Electric appliance logic control circuit, USB power connector circuit, USB turn Transistor-Transistor Logic level conversion circuit and signal input output interface unit； MCU control unit is used for the control that accesses to relay logical control circuit；USB turns Transistor-Transistor Logic level conversion circuit and is used for USB The USB level translation that power interface circuit receives is the Transistor-Transistor Logic level that MCU control unit can identify；Signal input and output connect Mouth unit realizes analog signal input and output for connecing the instrument and equipments such as antenna, filter, converter；Relay logic control Circuit processed includes 3 relays, realizes the extension of signal path between relay contact by cascade, connects to signal input and output Four road signal behaviors of mouth unit are controlled all the way.

2. the flogic system according to claim 1 for controlling 4 road signal on-off by 3 relays, it is characterised in that: MCU Control unit is equipped with the first crystal oscillating circuit and reset circuit；First crystal oscillating circuit is used to provide clock signal to MCU control unit； Reset circuit allows MCU control unit steady operation for resetting the program counter of MCU control unit.

3. the flogic system according to claim 1 for controlling 4 road signal on-off by 3 relays, it is characterised in that: USB Power interface circuit includes USB female seat M1, the tenth capacitor C10, the 11st polar capacitor C11 and the 9th light emitting diode D9；USB Base M1 uses Micro USB female seat；11st polar capacitor C11 of power interface circuit uses alminium electrolytic condenser, has filter The effect of wave and energy storage, can allow PC machine stable power-supplying；9th light emitting diode D9 powers on instruction as power interface circuit Lamp prompts custom system to be powered.

4. the flogic system according to claim 1 for controlling 4 road signal on-off by 3 relays, it is characterised in that: USB Turning Transistor-Transistor Logic level conversion circuit includes electrical level transferring chip G1, it is the switching chip an of usb bus, realize USB turn serial ports, USB turns that IrDA is infrared or USB turns printing port；The USB electricity that electrical level transferring chip G1 is used to receive in USB power connector circuit Flat turn turns to the Transistor-Transistor Logic level that MCU control unit can identify.

5. the flogic system according to claim 4 for controlling 4 road signal on-off by 3 relays, it is characterised in that: USB Turn Transistor-Transistor Logic level conversion circuit equipped with the second crystal oscillating circuit, the second crystal oscillating circuit is used to provide clock letter to electrical level transferring chip G1 Number；Electrical level transferring chip G1 uses the chip of model CH340G；The D+ pin phase of the UD+ pin of CH340G and MICRO USB Connection, UD- pin are connected with the D- pin of MICRO USB；The transmission pin TXD and reception pin RXD of CH340G chip divide It is not connected with the reception pin RXD of MCU control unit and transmission pin TXD；The reception pin RXD of MCU control unit is with instead It is connected to diode D8 with the TXD pin of CH340G chip, backward dioded D8 uses 1N4148, has prevented electric current from can pass through This pin flows into late-class circuit and to the capacitor charging of rear class, and rear class is caused to have the voltage of certain amplitude, causes to influence MCU The cold start-up of control unit downloading program.

6. the flogic system according to claim 4 for controlling 4 road signal on-off by 3 relays, it is characterised in that: relay 3 relays of device logic control circuit are divided into the first relay U1, the second relay U2 and third relay U3；3 relays Device is all made of signal relay, and the signal relay control voltage is 5V, contact form are as follows: DPDT；The signal relay has 8 A pin, the positive and negative anodes pin including relay coil, a pair of of normally opened contact, a pair of of normally-closed contact and a pair of public terminal contacts, It is very good with the isolation effect of signal；

After the coil of first relay U1 is concatenated with the first PNP type triode Q1, relay coil both ends and connect one first it is continuous Diode D1, mono- termination power+5V of the first PNP type triode Q1 are flowed, it is single that the grid of the first PNP type triode Q1 connects MCU control The relay of member controls I/O port P23, while concatenating second resistance R2, pull-up resistor of the first resistor R1 as I/O port；

After the coil of second relay U2 is concatenated with the second PNP type triode Q2, relay coil both ends and connect one second it is continuous Diode D2, mono- termination power+5V of the second PNP type triode Q2 are flowed, it is single that the grid of the second PNP type triode Q2 connects MCU control The relay of member controls I/O port P22, while concatenating the 4th resistance R4, pull-up resistor of the 3rd resistor R3 as I/O port；

After the coil of third relay U3 is concatenated with third PNP type triode Q3, relay coil both ends and to connect a third continuous Diode D3, mono- termination power+5V of third PNP type triode Q3 are flowed, it is single that the grid of third PNP type triode Q3 connects MCU control The relay of member controls I/O port P21, while concatenating the 6th resistance R6, pull-up resistor of the 5th resistance R5 as I/O port；

First via analog signal channel is to input from the normally-closed contact of the first relay U1, and be connected with its public terminal contacts Via the normally-closed contact of third relay U3, then from the public terminal contacts output signal of third relay U3, it is that MCU control is single The P23 mouth of member sends high level to the first relay U1, while P21 mouthfuls send high level to third relay U3；

Second road analog signal channel is to input from the normally opened contact of the first relay U1, and be connected with its public terminal contacts Via the normally-closed contact of third relay U3, then from the public terminal contacts output signal of third relay U3, turn-on condition is MCU The P23 mouth of control unit sends low level to the first relay U1, while P21 mouthfuls send high level to third relay；

Third road analog signal channel is to input from the normally-closed contact of the second relay U2, and be connected with its public terminal contacts Via the normally opened contact of third relay U3, then from the public terminal contacts output signal of third relay U3, turn-on condition is MCU The P22 mouth of control unit sends high level to the second relay U2, while P21 mouthfuls send low level to third relay U3；

4th road analog signal channel be inputted from the normally opened contact of the second relay, and be connected with its public terminal contacts through By the normally opened contact of third relay U3, then from the public terminal contacts output signal of third relay U3, turn-on condition is MCU control The P22 mouth of unit processed sends low level to the first relay U1, while P21 mouthfuls send low level to third relay U3.

7. the flogic system according to one of claims 1 to 6, for controlling 4 road signal on-off by 3 relays, feature exist In: it further include signal gating indicating circuit；Signal gating indicating circuit is made of four light emitting diodes and third load resistance； Four light emitting diodes are respectively the 4th light emitting diode D4, the 5th light emitting diode D5, the 6th Light-Emitting Diode D6 and the 7th Light emitting diode D7；Third load resistance includes eleventh resistor R11, twelfth resistor R12, thirteenth resistor R13 and the tenth Four resistance R14；4th light emitting diode D4 and eleventh resistor R11 be connected on+5V power supply and MCU control unit P24 foot it Between；5th light emitting diode D5 and twelfth resistor R12 is connected between+5V power supply and the P25 foot of MCU control unit；6th Light-Emitting Diode D6 and thirteenth resistor R13 is connected between+5V power supply and the P26 foot of MCU control unit；7th light-emitting diodes Pipe D7 and the 14th resistance R14 are connected between+5V power supply and the P27 foot of MCU control unit.

The control method for the flogic system that 8.3 relays control 4 road signal on-off has follow steps:

One, Single Chip C Language programs, when selection signal channel, using case case statement；

Two, it sends data cell 0x01 and represents IN1 signal path, the IO foot P23 of MCU control unit exports high level, makes first PNP triode Q1 cut-off, the first relay U1 coil both ends do not have voltage at this time, therefore the first relay U1 does not work, it Normally-closed contact and common end contact closure, the conducting of IN1 branch, the 4th light emitting diode D4 are assigned a value of 0, and lamp is bright to represent the choosing of the road IN1 It is logical；The IO foot P21 of MCU control unit exports high level simultaneously, ends third PNP triode Q3, at this time third relay U3 Coil both ends do not have voltage, therefore third relay U3 does not work, its normally-closed contact and common end contact closure, OUT branch Conducting, so that first via analog signal channel is connected；

Three, it sends data cell 0x02 and represents IN2 signal path, the IO foot P23 of MCU control unit exports low level, makes first PNP triode Q1 conducting, the first relay U1 coil both end voltage is 5V at this time, therefore the first relay U1 starts to work, it Normally-closed contact disconnects, normally opened contact and common end contact closure, and IN2 branch conducting, the 5th light emitting diode D5 is assigned a value of 0, lamp It is bright to represent the road IN2 gating；The IO foot P21 of MCU control unit exports high level simultaneously, ends third PNP triode Q3, at this time Third relay U3 coil both ends do not have voltage, therefore third relay U3 does not work, its normally-closed contact and public terminal contacts Closure, OUT branch conducting, thus second road signal channel conductive；

Four, it sends data cell 0x03 and represents IN3 signal path, the IO foot P22 of MCU control unit exports high level, makes second PNP triode Q2 cut-off, the second relay U2 coil both ends do not have voltage at this time, therefore the second relay U2 does not work, it Normally-closed contact and common end contact closure, the conducting of IN3 branch, the 6th Light-Emitting Diode D6 are assigned a value of 0, and lamp is bright to represent the choosing of the road IN3 It is logical；The IO foot P21 of MCU control unit exports low level simultaneously, third PNP triode Q3 is connected, at this time third relay U3 Coil both end voltage is 5V, therefore third relay U3 starts to work, and normally-closed contact disconnects, and normally opened contact is closed with public terminal contacts It closes, the conducting of OUT branch, so that third road signal path is connected；

Five, it sends data cell 0x04 and represents IN4 signal path, the IO foot P22 of MCU control unit exports low level, makes second PNP triode Q2 conducting, the second relay U2 coil both end voltage is 5V at this time, therefore the second relay U2 starts to work, it Normally-closed contact disconnects, normally opened contact and common end contact closure, and IN4 branch conducting, the 7th Light-Emitting Diode D7 is assigned a value of 0, lamp It is bright to represent the road IN4 gating；The IO foot P21 of MCU control unit exports low level simultaneously, third PNP triode Q3 is connected, at this time Third relay U3 coil both end voltage is 5V, therefore third relay U3 starts to work, and normally-closed contact disconnects, normally opened contact and public affairs Terminal contacts closure altogether, OUT branch conducting, so that the 4th tunnel signal path is connected.