Communication signal conversion device, slave system and master-slave communication system

Abstract

The embodiment of the invention provides a communication signal conversion device, a slave system and a master-slave communication system. The communication signal conversion device comprises an input unit, a power supply unit, a code receiving unit and a code sending unit, the input unit is used for converting a control signal sent by the host and an alternating current control signal formed by the power supply into a one-way pulsating direct current signal, and the power supply unit is used for carrying out voltage stabilization processing on the one-way pulsating direct current signal to obtain a power supply voltage. The code receiving unit is used for obtaining a code receiving control signal transmitted to the slave according to the one-way pulsating direct current signal and following voltage processing, and the code sending unit is used for transmitting a feedback signal to the host through the non-polar bus when receiving the feedback signal sent by the slave according to the code receiving control signal. Therefore, the purpose of improving the communication reliability between the host and the slave is achieved.

Description

Technical Field

[0001] The present invention relates to the field of data communication, and in particular to a communication signal conversion device, a slave system and a master-slave communication system. Background Art

[0002] With the rapid development of urban economy and intelligence, urban intelligent networks are constantly being optimized and transformed, covering interconnections from building fire protection to urban electric energy. For example, building fire protection monitoring, urban residents' electricity, water and gas consumption information can be connected to the Internet, and this information can be clearly displayed on the host computer screen, replacing the previous manual meter reading method.

[0003] From the above, it can be seen that the transmission of monitoring information, electricity information, water information and gas information to the host involves the communication between the slave and the host. At present, in order to simplify the power supply and communication wiring operation between the host and the slave, and thus reduce the construction cost, a two-wire non-polarity communication method such as M-BUS bus technology or POWERBUS bus technology is usually used to realize the power supply and communication between the host and the slave.

[0004] However, in the field of power line communication, there is a need for long-distance communication between the host and the slave. In long-distance communication, the host and the slave are usually connected by long wires. Due to the impedance, parasitic capacitance and inductance characteristics of the long wire bus, as well as the bus current when the slave returns the code to the host, there will be a voltage drop and voltage signal fluctuation between the front end and the end of the bus, which will affect the communication reliability between the host and the slave. Summary of the invention

[0005] In view of this, an object of the present invention is to provide a communication signal conversion device, a slave system and a master-slave communication system to improve the communication reliability between a master and a slave.

[0006] In order to achieve the above purpose, the technical solution adopted by the embodiment of the present invention is as follows:

[0007] According to a first aspect of an embodiment of the present invention, there is provided a communication signal conversion device, comprising:

[0008] An input unit, used to connect the host and the power supply through a non-polarity bus, and convert the control signal sent by the host and the AC control signal formed by the power supply into a unidirectional pulsating DC signal;

[0009] A power supply unit, used for performing voltage stabilization processing on the unidirectional pulsating direct current signal to output a power supply voltage;

[0010] a code receiving unit, configured to perform voltage division processing on the unidirectional pulsating direct current signal and the follower voltage respectively to obtain a host control voltage and a first code receiving voltage, and compare the host control voltage with the first code receiving voltage to obtain a code receiving control signal for transmission to the slave; wherein the follower voltage is the power supply voltage; and

[0011] The code sending unit is used to access the signal output terminal of the slave machine, and when receiving the feedback signal sent by the slave machine according to the code receiving control signal, transmit the feedback signal to the host machine through the non-polarity bus.

[0012] The embodiment of the present invention converts the AC control signal into a unidirectional pulsating DC signal through an input unit, which can not only retain the control signal characteristics issued by the host, but also retain the signal characteristics of the power supply, so that the unidirectional pulsating DC signal can not only be processed by the power supply unit to obtain the power supply voltage, but also can be processed by the code receiving unit to obtain the code receiving control signal. It is worth noting that, since the code receiving control signal processed by the code receiving unit is based on the comparison result of the host control voltage and the first code receiving voltage, and the host control voltage is obtained by dividing the unidirectional pulsating DC signal, and the first code receiving voltage is obtained by dividing the following voltage, and the following voltage is a power supply voltage obtained by stabilizing the unidirectional pulsating DC signal, therefore, the first code receiving voltage of the code receiving unit has the function of following the unidirectional pulsating DC signal, that is, following the control signal sent by the host and the AC control signal formed by the power supply. In this way, when there is a voltage drop and voltage signal fluctuation between the front end and the end of the bus, the slave can follow the voltage drop and voltage signal fluctuation through the communication signal conversion device, so that the first code receiving voltage can be dynamically adjusted with the voltage drop and voltage signal fluctuation, thereby effectively solving the problems caused by the impedance, parasitic capacitance and inductance characteristics of the long wire of the bus, and the bus current when the slave returns the code to the host, etc., which is conducive to improving the communication reliability between the host and the slave.

[0013] In an optional embodiment, the input unit includes a full-bridge rectifier circuit; the two input ends of the full-bridge rectifier circuit form two non-polarity input pins, which are used to connect the host and the power supply through the non-polarity bus, and the output end of the full-bridge rectifier circuit is connected to the power supply unit.

[0014] Therefore, by using a full-bridge rectifier circuit as an input unit, not only can the circuit structure be simplified, but also the AC control signal can be converted into a unidirectional pulsating DC signal, thereby ensuring the reliability and efficiency of signal conversion.

[0015] In an optional implementation, the input unit further includes a low-pass filter circuit; the low-pass filter circuit is connected between the output end of the full-bridge rectifier circuit and the power supply unit.

[0016] Therefore, by configuring a low-pass filter circuit in the input unit, high-frequency noise or fluctuations in the unidirectional pulsating DC signal can be removed, which is beneficial to improving the stability of the signal output to the power supply unit, thereby ensuring the stability of the power supply voltage provided by the power supply unit.

[0017] In an optional implementation, the input unit further includes an anti-backflow circuit; the anti-backflow circuit is connected between the low-pass filter circuit and the power supply unit.

[0018] Therefore, by configuring an anti-backflow circuit in the input unit, charge backflow can be effectively prevented, further improving the stability of the power supply voltage provided by the power supply unit.

[0019] In an optional embodiment, the low-pass filter circuit includes a filter resistor and a filter capacitor; the anti-backflow circuit includes a diode; the filter resistor and the diode are connected in series in sequence between the output end of the full-bridge rectifier circuit and the input end of the power supply unit; one end of the filter capacitor is connected to the cathode of the diode, and the other end is grounded.

[0020] Therefore, by using filter resistors and filter capacitors to form a low-pass filter circuit and using a diode as an anti-backflow circuit, the circuit structure can be effectively simplified and the circuit manufacturing difficulty and manufacturing cost can be reduced while ensuring the original circuit function.

[0021] In an optional implementation, the power supply unit includes:

[0022] A first voltage stabilizing circuit, the input end of which is connected to the unidirectional pulsating direct current signal, and the output end of which is used to output a first power supply voltage and is grounded through a first filter capacitor; and

[0023] A second voltage stabilizing circuit, wherein the input end is connected to the first power supply voltage, the output end is used to output a second power supply voltage and is grounded through a second filter capacitor; the second power supply voltage is less than the first power supply voltage, and the follower voltage is the first power supply voltage or the second power supply voltage.

[0024] Therefore, by configuring two voltage stabilizing circuits in the power supply unit and making the supply voltages output by the two voltage stabilizing circuits different from each other, the different power supply requirements of the power supply unit for the various components of the slave machine can be better met. Among them, by configuring the first voltage stabilizing circuit to be powered by a unidirectional pulsating direct current signal, and configuring the second voltage stabilizing circuit to be powered by the first supply voltage output by the first voltage stabilizing circuit, such a structural configuration can effectively reduce the heat generated by the power supply unit and further improve the stability of the power supply unit. In addition, by configuring a filter capacitor in each voltage stabilizing circuit, the stability and reliability of the supply voltage finally output by the power supply unit can be further improved.

[0025] In an optional implementation, both the first voltage stabilizing circuit and the second voltage stabilizing circuit are low voltage dropout linear regulators.

[0026] Therefore, by using a low voltage difference linear regulator as a voltage stabilization circuit, it is beneficial to further simplify the circuit structure and reduce the difficulty and cost of circuit manufacturing while ensuring that the circuit has functionality.

[0027] In an optional embodiment, the device further comprises:

[0028] An automatic threshold circuit, comprising a third voltage-dividing resistor, a fourth voltage-dividing resistor and a voltage follower; one end of the third voltage-dividing resistor is connected to the unidirectional pulsating direct current signal, and the other end is grounded through the fourth voltage-dividing resistor; the input end of the voltage follower is connected between the third voltage-dividing resistor and the fourth voltage-dividing resistor, and the output end is used to output a target following voltage;

[0029] Correspondingly, the following voltage is adjusted to the target following voltage.

[0030] Therefore, by adding an automatic threshold circuit, the target following voltage output by the automatic threshold circuit is used as the following voltage for voltage division processing in the code receiving unit, so that the first code receiving voltage obtained based on this can be isolated from the power supply voltage, so as to avoid the voltage drop caused by the power supply voltage supplying power to the slave, thereby affecting the accurate following of the first code receiving voltage to the AC control signal input by the non-polarity bus, which is beneficial to further improve the voltage following accuracy and reliability, and thus make the code receiving control signal output by the code receiving unit more accurate and reliable.

[0031] In an optional implementation, the code receiving unit includes:

[0032] A voltage-dividing circuit comprises a first voltage-dividing resistor and a second voltage-dividing resistor, wherein one end of the first voltage-dividing resistor is connected to the unidirectional pulsating direct current signal, and the other end of the first voltage-dividing resistor is grounded through the second voltage-dividing resistor, and a connection point between the first voltage-dividing resistor and the second voltage-dividing resistor is used to output the host control voltage; and

[0033] A comparison circuit comprises a first threshold control resistor, a second threshold control resistor and a first comparator; one end of the first threshold control resistor is connected to the follower voltage, the other end is grounded through the second threshold control resistor, and the connection between the first threshold control resistor and the second threshold control resistor is used to output the first code receiving voltage; the non-phase input end of the first comparator is connected to the host control voltage, the inverting input end is connected to the first code receiving voltage, and the output end outputs a first code receiving control signal; the code receiving control signal comprises the first code receiving control signal.

[0034] Therefore, by configuring the code receiving unit as above, not only can the circuit function of the code receiving unit be guaranteed, but also the circuit structure can be simplified, the difficulty and cost of circuit manufacturing can be reduced, and the circuit reliability can be improved. In addition, the magnitude of the first code receiving voltage can be adjusted by the first threshold regulating resistor and the second threshold regulating resistor, so that the communication signal conversion device provided by the embodiment of the present invention can be applicable to communication scenarios of different buses, for example, so that the magnitude of the first code receiving voltage meets the magnitude of the host code sending voltage specified in the M-BUS bus protocol, or so that the magnitude of the first code receiving voltage meets the magnitude of the host code sending voltage specified in the POWERBUS bus protocol, thereby improving the versatility and practicality of the communication signal conversion device.

[0035] In an optional embodiment, the comparison circuit further includes a third threshold control resistor, a fourth threshold control resistor and a second comparator; one end of the third threshold control resistor is connected to the follower voltage, and the other end is grounded through the fourth threshold control resistor, and the connection between the third threshold control resistor and the fourth threshold control resistor is used to output a second code receiving voltage less than the first code receiving voltage; the non-phase input end of the comparator is connected to the host control voltage, the inverting input end is connected to the second code receiving voltage, and the output end outputs a second code receiving control signal; and

[0036] The communication signal conversion device also includes:

[0037] The automatic discharge unit comprises a release control circuit and a discharge regulating resistor; the input end of the release control circuit is connected to the unidirectional pulsating direct current signal, the output end is grounded through the discharge regulating resistor, and the discharge trigger end is used to connect the second receiving code control signal; the discharge regulating resistor is used to control the discharge rate of the release control circuit.

[0038] Therefore, by further configuring the above structure in the comparison circuit and adding an automatic discharge unit in the communication signal conversion device, it is possible to use the second code receiving control signal to trigger the automatic discharge unit to discharge, so that the level of the unidirectional pulsating DC signal drops faster, better offset the influence of the parasitic capacitance, and thus improve the communication speed between the host and the slave. In addition, through the third threshold control resistor and the fourth threshold control resistor, the size of the second code receiving voltage can be adaptively controlled according to different scenarios, so that the discharge control of the automatic discharge unit can be more adaptable to the required application scenario. Moreover, by controlling the discharge rate of the release control circuit through the discharge control resistor, the communication speed between the host and the slave can be adaptively adjusted according to different application scenarios. For example, when the amount of communication data between the host and the slave is large, the discharge speed can be accelerated by reducing the resistance of the discharge control resistor, so that the level of the unidirectional pulsating DC signal drops faster, so as to complete the transmission of the communication data faster; and when the number of communications between the host and the slave is small, the resistance of the discharge control resistor can be maintained, or the resistance of the control resistor can be increased to maintain or slow down the transmission speed of the communication data.

[0039] In an optional implementation, the first threshold control resistor, the second threshold control resistor, the third threshold control resistor, the fourth threshold control resistor and the discharge control resistor are detachable resistors or variable resistors.

[0040] Therefore, by setting each regulating resistor as a detachable resistor or a variable resistor, it is convenient to replace regulating resistors with different resistance values ​​according to different usage requirements, or the resistance value of the regulating resistor can be changed without disassembly, thereby reducing the regulation difficulty and regulation cost of each regulating resistor.

[0041] In an optional implementation, the non-polarity bus is an M-BUS bus, and the code receiving control signal is the first code receiving control signal; or, the non-polarity bus is a POWERBUS bus, and the code receiving control signal includes the first code receiving control signal and the second code receiving control signal.

[0042] Therefore, through the above configuration, the communication signal conversion device provided in the embodiment of the present invention can be applicable to power line communication scenarios of different protocols and has stronger versatility.

[0043] In an optional implementation, the release control circuit includes a fifth voltage-dividing resistor, a sixth voltage-dividing resistor, a timer, a time-controlled switch, a first operational amplifier, and a first field effect transistor;

[0044] One end of the fifth voltage-dividing resistor is connected to the supply voltage, and the other end is grounded through the sixth voltage-dividing resistor, and the connection between the fifth voltage-dividing resistor and the sixth voltage-dividing resistor forms a trigger voltage output terminal;

[0045] The trigger input end of the timer is the discharge trigger end, and the output end is connected to the control end of the time-controlled switch, and is used to output a time-controlled signal to the time-controlled switch;

[0046] The normally closed end of the time-controlled switch is connected to the non-inverting input end of the first operational amplifier, and the normally open end is used to be connected to the trigger voltage output terminal when the time-controlled signal indicates that the discharge is triggered, and is grounded when the time-controlled signal indicates that the discharge is not triggered;

[0047] The inverting input terminal of the first operational amplifier is connected to the source of the first field effect transistor;

[0048] The gate of the first field effect transistor is connected to the output end of the first operational amplifier, the drain is connected to the unidirectional pulsating direct current signal, and the source is connected in series with the discharge regulating resistor.

[0049] Therefore, by configuring the release control circuit with the above structure, not only can the stability and reliability of the discharge control be guaranteed, but also the circuit structure can be simplified, and the difficulty and cost of circuit manufacturing can be reduced.

[0050] In an optional implementation, the code sending unit includes a seventh voltage-dividing resistor, an eighth voltage-dividing resistor, a second operational amplifier, a code sending control switch, a second field effect transistor and a code sending regulating resistor;

[0051] One end of the seventh voltage-dividing resistor is connected to the supply voltage, and the other end is grounded through the eighth voltage-dividing resistor;

[0052] The non-inverting input terminal of the second operational amplifier is connected between the seventh voltage-dividing resistor and the eighth voltage-dividing resistor, the inverting input terminal is connected to the source of the second field effect transistor, and the output terminal is connected to the gate of the second field effect transistor through the code control switch;

[0053] The code control switch is used to turn on or off the connection between the second operational amplifier and the second field effect transistor;

[0054] The drain and source of the second field effect transistor are connected to form a code output terminal for connecting to the non-polarity bus;

[0055] The coding regulating resistor is used to adjust the coding current, one end of which is connected to the coding output terminal, and the other end is grounded.

[0056] Therefore, by configuring the coding unit with the above structure, not only can the stability and reliability of the coding control be guaranteed, but also the circuit structure can be simplified, and the difficulty and cost of circuit manufacturing can be reduced. In addition, by adjusting the coding current through the coding control resistor, the coding unit can be adapted to the coding current requirements of different communication protocols, for example, the coding current can meet the slave return code current specified in the M-BUS bus protocol, or the coding current can meet the slave return code current specified in the POWERBUS bus protocol, thereby improving the versatility and practicality of the communication signal conversion device.

[0057] In an optional implementation, the coding regulating resistor is a detachable resistor or a variable resistor.

[0058] Therefore, by setting the coding control resistor as a detachable resistor or a variable resistor, it is convenient to replace the coding control resistor with different resistance values ​​according to different usage requirements, or the resistance value of the coding control resistor can be changed without disassembly, thereby reducing the control difficulty and control cost of the coding control resistor.

[0059] According to a second aspect of the embodiments of the present invention, a slave system is provided, comprising slaves and a communication signal conversion device connected to each other; the communication signal conversion device is the communication signal conversion device in any of the above-mentioned embodiments.

[0060] According to a third aspect of an embodiment of the present invention, a master-slave communication system is provided, comprising a host and a slave system; the host is connected to the slave system via a non-polarity bus, and the slave system is the slave system provided in the second aspect above.

[0061] Since the slave system and the master-slave communication system provided by the present invention both include the communication signal conversion device provided by the first aspect of the embodiment of the present invention, the slave system and the master-slave communication system provided by the present invention also have the beneficial technical effects produced by the communication signal conversion device provided by the first aspect above, which will not be repeated here.

[0062] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, preferred embodiments are given below and described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0063] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0064] Figure 1A schematic diagram of a communication framework between a host and multiple slave systems in a related art is shown;

[0065] Figure 2 A structural block diagram of a communication signal conversion device provided by an embodiment of the present invention is shown;

[0066] Figure 3 A schematic diagram of an application scenario of a communication signal conversion device provided by an embodiment of the present invention is shown;

[0067] Figure 4 A schematic diagram showing voltage characteristics and current characteristics at an output end of a unidirectional pulsating direct current signal provided by an embodiment of the present invention is shown;

[0068] Figure 5 A circuit structure block diagram of an input unit provided by an embodiment of the present invention is shown;

[0069] Figure 6 A circuit diagram of a communication signal conversion device provided by an embodiment of the present invention is shown;

[0070] Figure 7 A schematic diagram comparing two communication waveforms provided in an embodiment of the present invention is shown;

[0071] Figure 8 A schematic diagram of the circuit structure of an automatic discharge unit proposed in an embodiment of the present invention is shown;

[0072] Fig. 9 A schematic diagram showing another application scenario of the communication signal conversion device provided by an embodiment of the present invention is shown;

[0073] Fig.10 A structural block diagram of a slave system provided by an embodiment of the present invention is shown;

[0074] Fig.11 A structural block diagram of a master-slave communication system provided by an embodiment of the present invention is shown.

[0075] Icon: 100-communication signal conversion device, 110-input unit, 120-power supply unit, 130-receiving unit, 140-sending unit, 111-full-bridge rectifier circuit, 112-low-pass filter circuit, 113-anti-backflow circuit, R2-filter resistor, C1-filter capacitor, D1-full-bridge rectifier circuit, C2-first filter capacitor, LDO1-first voltage stabilizing circuit, LDO2-second voltage stabilizing circuit, C3-second filter capacitor, R7-third voltage divider resistor, R6-fourth voltage divider resistor, BUFF-voltage follower, R4-first voltage divider resistor, R5-second voltage divider resistor, R10-first threshold control circuit Resistance, R11-second threshold control resistor, COMP0-first comparator, R9-third threshold control resistor, R13-fourth threshold control resistor, COMP2-second comparator, DC-release control circuit, R1-discharge control resistor, R14-fifth voltage-dividing resistor, R15-sixth voltage-dividing resistor, S1-time control switch, OPA1-first operational amplifier, M2-first field effect transistor, R8-seventh voltage-dividing resistor, R12-eighth voltage-dividing resistor, OPA2-second operational amplifier, SW1-coding control switch, M1-second field effect transistor, R3-coding control resistor, 10-slave system, 11-slave. DETAILED DESCRIPTION

[0076] The following will be combined with the accompanying drawings in the embodiments of the present invention to clearly and completely describe the technical solutions 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. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0077] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without making creative work are within the scope of protection of the present invention.

[0078] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0079] In the description of the present invention, it should be noted that if terms such as orientation are mentioned, for example, "center", "up", "down", "left", "right", "vertical", "horizontal", "inside", "outside", etc., the orientation or position relationship indicated by these terms is based on the orientation or position relationship shown in the corresponding drawings, or the orientation or position relationship in which the product of the invention is usually placed when in use. It is only for the convenience of describing the present invention and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. In addition, the terms "first", "second", "third", etc. are only used to distinguish the description, and cannot be understood as indicating or implying relative importance.

[0080] In addition, terms such as "horizontal" and "vertical" do not mean that the components are required to be absolutely horizontal or suspended, but can be slightly tilted. For example, "horizontal" may simply mean that its direction is more horizontal than "vertical", and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0081] In the embodiments of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "set", "install", "connect", "connection", etc. should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, or an electrical connection; it can be directly connected, or connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0082] In the field of power line communication, there is a need for long-distance communication between the host and the slave, so the host and the slave are connected by a long wire bus. As a result, due to the impedance, parasitic capacitance and inductance characteristics of the long wire bus, as well as the bus current when the slave returns the code to the host, there will be a voltage drop and voltage signal fluctuation between the front end and the end of the bus, such as Figure 1 As shown, Figure 1 It is a schematic diagram of the communication framework between a host and multiple slave systems in the related technology. It can be seen that the voltage signal received by each slave system is different. The longer the distance between the slave system and the host, the greater the voltage drop of the voltage signal it receives. In the M-BUS bus protocol and the POWERBUS protocol, whether the slave system can perform the code return operation depends on the relevant judgment of the voltage signal. However, in the judgment of the voltage signal, the voltage drop and fluctuation of the voltage signal are not taken into account, which will cause the slave system to be unable to accurately perform the code return operation, thereby causing communication errors and affecting the communication reliability between the host and the slave.

[0083] Therefore, in order to solve the technical problem in the related art that the communication reliability between the host and the slave is low due to the failure to consider the voltage drop and voltage signal fluctuation between the front end and the end of the bus between the host and the slave, an embodiment of the present invention first provides a communication signal conversion device to convert the AC control signal into a unidirectional pulsating DC signal through an input unit, which can not only retain the control signal characteristics issued by the host, but also retain the signal characteristics of the power supply, so that the unidirectional pulsating DC signal can not only be processed by the power supply unit to obtain the power supply voltage, but also can be processed by the code receiving unit to obtain the code receiving control signal. It is worth noting that the code receiving control signal processed by the code receiving unit is based on the comparison result of the host control voltage and the first code receiving voltage, and the host control voltage is obtained by dividing the unidirectional pulsating DC signal, and the first code receiving voltage is obtained by dividing the following voltage, and the following voltage is a power supply voltage obtained by stabilizing the unidirectional pulsating DC signal. Therefore, the first code receiving voltage of the code receiving unit has the function of following the unidirectional pulsating DC signal, that is, following the control signal sent by the host and the AC control signal formed by the power supply. In this way, when there is a voltage drop and voltage signal fluctuation between the front end and the end of the bus, the slave can follow the voltage drop and voltage signal fluctuation through the communication signal conversion device, so that the first code receiving voltage can be dynamically adjusted with the voltage drop and voltage signal fluctuation, thereby effectively solving the problems caused by the impedance, parasitic capacitance and inductance characteristics of the long wire of the bus, and the bus current when the slave returns the code to the host, which is conducive to improving the communication reliability between the host and the slave.

[0084] The following, combined Figure 2 For a description of the communication signal conversion device provided by the embodiment of the present invention, please refer to Figure 2 , Figure 2 1 is a structural block diagram of a communication signal conversion device provided by an embodiment of the present invention; the communication signal conversion device 100 includes:

[0085] The input unit 110 is used to connect the host and the power supply through a non-polarity bus, and convert the control signal sent by the host and the AC control signal formed by the power supply into a unidirectional pulsating DC signal;

[0086] A power supply unit 120, used for performing voltage stabilization processing on the unidirectional pulsating direct current signal to output a power supply voltage;

[0087] The code receiving unit 130 is used to perform voltage division processing on the unidirectional pulsating direct current signal and the following voltage supply voltage respectively to obtain a host control voltage and a first code receiving voltage, and compare the host control voltage with the first code receiving voltage to obtain a code receiving control signal for transmission to the slave; wherein the following voltage is the supply voltage; and

[0088] The code sending unit 140 is used to access the signal output terminal of the slave device, and when receiving the feedback signal sent by the slave device according to the code receiving control signal, transmit the feedback signal to the host through the non-polarity bus.

[0089] In the above, the input unit 110 can be implemented by using any circuit in the related art that can convert the AC control signal into a unidirectional pulsating DC signal, and the technical principle of fusing the control signal sent by the host and the power supply signal of the power supply into the AC control signal can be found in the related art and will not be described in detail here. Similarly, the power supply unit 120 can be implemented by using any voltage stabilizing circuit that can perform voltage stabilization processing on the unidirectional pulsating DC signal.

[0090] In addition, based on the above description of the code receiving unit 130 and the code sending unit 140, various implementation methods of implementing the code receiving unit 130 and the code sending unit 140 can also be obtained from the relevant technology. It is worth noting that the description here does not mean that the code receiving unit 130 and the code sending unit 140 are structures that have been disclosed in the relevant technology, but means that under the premise of the inventive concept of the code receiving unit 130 and the code sending unit 140 proposed in the embodiment of the present invention, those skilled in the art can obtain from the relevant technology a variety of circuit schemes that can realize the functions of the code receiving unit 130 and the code sending unit 140 recorded in the embodiment of the present invention. Therefore, it should not be considered that the code receiving unit 130 and the code sending unit 140 provided in the embodiment of the present invention have only the implementation methods described below. Similarly, it should not be considered that the input unit 110 and the power supply unit 120 provided in the embodiment of the present invention have only the implementation methods described below. The implementation methods described below are some improved schemes proposed to achieve better technical effects.

[0091] The communication signal conversion device 100 provided in the embodiment of the present invention can be used as an independent circuit module product, assembled in a slave system and connected to a slave (such as a slave controller) of the slave system; it can also be used as a part of the slave system, which is assembled in the slave system at the factory and sold together with the slave system.

[0092] When the communication signal conversion device provided by the embodiment of the present invention needs to be applied to the communication between the host and the slave system, for example, in the communication signal processing of the host and the slave system in the field of power line communication, the communication signal conversion device can be connected between the host and the slave, such as Figure 3 As shown, Figure 3It is a schematic diagram of an application scenario of a communication signal conversion device provided by an embodiment of the present invention. It can be seen that the two terminals of the input unit of the communication signal conversion device 100 are connected to a two-wire non-polarity bus, wherein the two-wire non-polarity bus can be an M-BUS bus or a POWERBUS bus, and the output end of the code receiving unit of the communication signal conversion device 100 is connected to the slave, the signal input end of the code sending unit is connected to the signal output end of the slave, and the code sending output end of the code sending unit is connected to one of the two-wire non-polarity buses. The connection between the communication signal conversion device and the slave is a wiring description for when the communication signal conversion device is an independent circuit module product. If the communication signal conversion device and the slave are integrated to form a slave system, the above-mentioned related wiring operations can be omitted in actual applications.

[0093] After the connection between the host and the slave system is completed, the communication signal conversion device 100 can be used to realize that the slave receives the control signal sent by the host and the slave returns the code to the host. The relevant working principle is as follows:

[0094] When the input unit 110 receives the AC control signal including the control signal sent by the host through the bus, the AC control signal is converted into a unidirectional pulsating DC signal and transmitted to the power supply unit 120 and the code receiving unit 130 respectively. In either the M-BUS bus protocol or the POWERBUS bus protocol, the host transmits data to the slave by controlling the bus voltage, and the slave transmits data to the host by controlling the bus current. Taking the M-BUS bus as an example, Figure 4 As shown, Figure 4 It is a schematic diagram of voltage characteristics and current characteristics at the output end of a unidirectional pulsating direct current signal provided by an embodiment of the present invention. In the communication protocol of the M-BUS bus, the host transmits data to the slave by adjusting the voltage of the bus level. When the level at the output end of the unidirectional pulsating direct current signal (equivalent to the bus level) is 36V, the corresponding digital signal is 1, and when the level at the output end of the unidirectional pulsating direct current signal is 24V, the corresponding digital signal is 0. The digital signal can be understood as a code receiving control signal obtained by the code receiving unit, and the acquisition of the code receiving control signal can refer to the relevant records below.

[0095] When the power supply unit 120 receives a unidirectional pulsating DC signal, it stabilizes the unidirectional pulsating DC signal to obtain a stable power supply voltage. The power supply voltage can be used to power the slave, such as the controller of the slave, or to power other circuit components of the communication signal conversion device, such as the code receiving unit 130 and the code sending unit 140.

[0096] When the code receiving unit 130 receives the unidirectional pulsating DC signal, it also receives the supply voltage output by the power supply unit, namely, the following voltage. Then, the unidirectional pulsating DC signal and the following voltage are divided to obtain a host control voltage and a first code receiving voltage suitable for comparison. It can be seen that the first code receiving voltage obtained can follow the voltage of the AC control signal received by the slave system to avoid the influence of voltage drop and signal fluctuation. Then, the host control voltage and the first code receiving voltage are compared to convert the voltage signal into a digital signal. The digital signal obtained is the code receiving control signal. Specifically, when the host control voltage is greater than the first code receiving voltage, the code receiving control signal output by the code receiving unit 130 is 1, and when the host control voltage is less than or equal to the first code receiving voltage, the code receiving control signal output by the code receiving unit 130 is 0. When the code receiving control signal is 1, it indicates that the slave can trigger the code sending unit 140 to perform a code return operation, so as to transmit the data to be sent to the host through the code sending unit 140. When the code receiving control signal is 0, it indicates that the slave cannot perform a code return operation through the code sending unit 140, and the slave does not transmit data to the host.

[0097] The slave transmits data to the host by controlling the current output from the code output terminal of the code sending unit. Figure 4 It can be seen that the slave sends data to the host only when the level at the output end of the unidirectional pulsating DC signal is 36V (equivalent to when the receiving code control signal is 1), and in the process of the slave sending data to the host, when the current at the output end of the unidirectional pulsating DC signal (equivalent to the bus current) is 1.5mA+15mA, the corresponding digital signal is 1, and when the current at the output end of the unidirectional pulsating DC signal is less than 1.5mA+15mA, the corresponding digital signal is 0.

[0098] It should be understood that the data transmission principle between the host and the slave is only briefly described above, and the detailed technical principles can be found in the provisions of the relevant bus protocol.

[0099] In some embodiments, in order to simplify the circuit structure of the input unit and ensure the reliability and efficiency of signal conversion, an embodiment of the present invention provides an implementation scheme of the input unit, that is, the input unit includes a full-bridge rectifier circuit; the two input ends of the full-bridge rectifier circuit form two non-polarity input pins, which are used to connect the host and the power supply through the non-polarity bus, and the output end of the full-bridge rectifier circuit is connected to the power supply unit. Based on this, after the AC control signal is converted and processed by the full-bridge rectifier circuit, a unidirectional pulsating DC signal can be obtained. Therefore, in the above text, the output end of the unidirectional pulsating DC signal is the output end of the full-bridge rectifier circuit.

[0100] Based on the previous embodiment, in some embodiments, in order to remove high-frequency noise or fluctuations in the unidirectional pulsating DC signal, so as to improve the stability of the signal output to the power supply unit, and thus ensure the stability of the power supply voltage provided by the power supply unit, the input unit may further include a low-pass filter circuit; the low-pass filter circuit is connected between the output end of the full-bridge rectifier circuit and the power supply unit. Based on this, the unidirectional pulsating DC signal input into the power supply unit is an electrical signal processed by the low-pass filter circuit.

[0101] Based on the above embodiment, in some embodiments, in order to effectively prevent the charge from flowing back and further improve the stability of the power supply voltage provided by the power supply unit, please refer to Figure 5 , Figure 5 1 is a circuit structure block diagram of an input unit provided in an embodiment of the present invention. The input unit 110 may further include an anti-backflow circuit 113; the anti-backflow circuit 113 is connected between the low-pass filter circuit 112 and the power supply unit 120. Based on this, the unidirectional pulsating direct current signal input into the power supply unit 120 is an electrical signal processed by the full-bridge rectifier circuit 111, the low-pass filter circuit 112 and the anti-backflow circuit 113.

[0102] In some embodiments, in order to effectively simplify the circuit structure of the input unit and reduce the difficulty and cost of circuit manufacturing, an embodiment of the present invention provides an implementation scheme of the input unit, please refer to Figure 6 , Figure 6 It is a circuit diagram of a communication signal conversion device provided by an embodiment of the present invention, wherein the low-pass filter circuit includes a filter resistor R2 and a filter capacitor C1; the anti-backflow circuit includes a diode D1; the filter resistor R2 and the diode D1 are connected in series between the output end of the full-bridge rectifier circuit D1 and the input end of the power supply unit; one end of the filter capacitor C1 is connected to the negative electrode of the diode D1, and the other end is grounded. Based on this, VREG in the figure is an electrical signal processed by the low-pass filter circuit formed by the full-bridge rectifier circuit D1, the filter resistor R2 and the filter capacitor C1, and the anti-backflow circuit formed by the diode D1. Among them, the two input pins VBL1 and VBL2 of the full-bridge rectifier circuit D1 are the two non-polar input pins recorded above. In some embodiments, in order to further improve the stability of the electrical signal VREG input to the power supply unit, and further improve the stability of the power supply voltage output by the power supply unit, the capacitance value of the filter capacitor C1 can be configured to be 220μF.

[0103] In some embodiments, in order to improve the stability and applicability of the power supply unit, an embodiment of the present invention provides an implementation scheme of the power supply unit, that is, please continue to refer to Figure 6 , the power supply unit may include:

[0104] A first voltage stabilizing circuit LDO1, whose input end is connected to the unidirectional pulsating DC signal, and whose output end is used to output a first supply voltage V5 and is grounded through a first filter capacitor C2; and

[0105] The second voltage stabilizing circuit LDO2 has an input terminal connected to the first power supply voltage V5, and an output terminal for outputting a second power supply voltage V33 and grounded through a second filter capacitor C3; the second power supply voltage V33 is less than the first power supply voltage V5. Based on this, in the code receiving unit, the follower voltage used is the first power supply voltage V5 or the second power supply voltage V33.

[0106] Therefore, by configuring two voltage stabilizing circuits in the power supply unit and making the supply voltages output by the two voltage stabilizing circuits different from each other, the different power supply requirements of the power supply unit for the various components of the slave can be better met. Among them, by configuring the first voltage stabilizing circuit LDO1 to be powered by a unidirectional pulsating direct current signal, and configuring the second voltage stabilizing circuit LDO2 to be powered by the first supply voltage output by the first voltage stabilizing circuit LDO1, such a structural configuration can effectively reduce the heat generated by the power supply unit and further improve the stability of the power supply unit. In addition, by configuring filter capacitors in each voltage stabilizing circuit, the stability and reliability of the supply voltage finally output by the power supply unit can be further improved.

[0107] It should be noted that, based on the embodiment in which the input unit includes a full-bridge rectifier circuit, a low-pass filter circuit and an anti-backflow circuit, for example, Figure 6 On the basis of the embodiment shown, the unidirectional pulsating direct current signal connected to the first voltage stabilizing circuit LDO1 will be adaptively adjusted to the electrical signal VREG.

[0108] In some embodiments, the first power supply voltage may be 5V, and the second power supply voltage may be 3.3V, but is not limited thereto, and may be adaptively adjusted according to the operating voltage of the components to be powered in the slave. In addition, in addition to the two voltage stabilizing circuits, a corresponding number of voltage stabilizing circuits may be added according to the power supply voltage required in the actual application scenario, thereby providing more power supply voltages with different voltage values.

[0109] In some embodiments, in order to further simplify the structure of the voltage stabilizing circuit and reduce the difficulty and cost of circuit manufacturing, the first voltage stabilizing circuit LDO1 and the second voltage stabilizing circuit LDO2 are both low dropout linear regulators (Low Dropout Regulator, LDO).

[0110] In some embodiments, the capacitance values ​​of the first filter capacitor C2 and the second filter capacitor C3 may be the same or different. To simplify circuit design, the capacitance values ​​of the first filter capacitor C2 and the second filter capacitor C3 are the same, for example, both are 10 μF.

[0111] In some embodiments, in order to improve the accuracy and reliability of the code receiving control signal output by the code receiving unit, the communication signal conversion device provided in the embodiment of the present invention may also include an automatic threshold circuit. Please continue to refer to Figure 6 , the automatic threshold circuit may include a third voltage-dividing resistor R7, a fourth voltage-dividing resistor R6 and a voltage follower BUFF; one end of the third voltage-dividing resistor R7 is connected to the unidirectional pulsating DC signal, and the other end is grounded through the fourth voltage-dividing resistor R6; the input end of the voltage follower BUFF is connected between the third voltage-dividing resistor R7 and the fourth voltage-dividing resistor R6, and the output end is used to output the target following voltage VREGD. Correspondingly, the following voltage used in the code receiving unit is adjusted to the target following voltage VREGD, and the first power supply voltage or the second power supply voltage is no longer used.

[0112] In the above, the unidirectional pulsating DC signal connected to the third voltage-dividing resistor R7 refers to the electrical signal output by the input unit. For example, if the circuit structure of the input unit adopts Figure 6 The structure shown in FIG. 1 shows, the unidirectional pulsating DC signal connected to the third voltage-dividing resistor R7 is Figure 6 If the input unit only includes a full-bridge rectifier circuit and a low-pass filter circuit, the unidirectional pulsating DC signal connected to the third voltage-dividing resistor R7 refers to the electrical signal obtained by processing the full-bridge rectifier circuit and the low-pass filter circuit. If the input unit only includes a full-bridge rectifier circuit and an anti-backflow circuit, the unidirectional pulsating DC signal connected to the third voltage-dividing resistor R7 refers to the electrical signal obtained by processing the full-bridge rectifier circuit and the anti-backflow circuit. If the input unit only includes a full-bridge rectifier circuit, the unidirectional pulsating DC signal connected to the third voltage-dividing resistor R7 refers to the electrical signal obtained by processing the full-bridge rectifier circuit.

[0113] The following describes the working principle of the automatic threshold circuit:

[0114] by Figure 6Taking the communication signal conversion device shown in the figure as an example, the third voltage-dividing resistor R7 and the fourth voltage-dividing resistor R6 in the automatic threshold circuit will feed back the voltage of the VREG electrical signal to the voltage follower BUFF, and then the voltage follower BUFF will perform voltage isolation on the VREG electrical signal and output the target follower voltage VREGD. In the subsequent process, the target follower voltage VREGD will be transmitted to the code receiving unit to control the magnitude of the first code receiving voltage of the code receiving unit, and can also power the components performing voltage division processing in the code receiving unit. Therefore, when the AC control signal connected to the input unit changes, the electrical signal VREG and the target follower voltage VREGD will change accordingly, so the first code receiving voltage as the comparison threshold of the host control voltage will also change accordingly, thereby realizing the dynamic adjustment of the comparison threshold of the host control voltage, thereby enhancing the communication reliability between the host and the slave.

[0115] Therefore, by adding an automatic threshold circuit, the target following voltage output by the automatic threshold circuit is used as the following voltage for voltage division processing in the code receiving unit, so that the first code receiving voltage obtained based on this can be isolated from the power supply voltage, so as to avoid the voltage drop caused by the power supply voltage supplying power to the slave, thereby affecting the accurate following of the first code receiving voltage to the AC control signal input by the non-polarity bus, which is beneficial to further improve the voltage following accuracy and reliability, thereby making the code receiving control signal output by the code receiving unit more accurate and reliable, thereby enhancing the communication reliability between the host and the slave.

[0116] In some embodiments, the resistance value of the third voltage-dividing resistor R7 may be 5.6 MΩ, and the resistance value of the fourth voltage-dividing resistor R6 may be 400 KΩ, but is not limited thereto.

[0117] In some embodiments, in order to reduce the manufacturing difficulty and manufacturing cost of the code receiving unit and improve the applicability of the code receiving unit, thereby improving the versatility of the communication signal conversion device provided by the embodiment of the present invention, the embodiment of the present invention also provides an implementation scheme of the code receiving unit, please continue to refer to Figure 6 , the code receiving unit may include:

[0118] A voltage-dividing circuit includes a first voltage-dividing resistor R4 and a second voltage-dividing resistor R5, wherein one end of the first voltage-dividing resistor R4 is connected to the unidirectional pulsating DC signal, and the other end of the first voltage-dividing resistor R4 is grounded through the second voltage-dividing resistor R5, and a connection point between the first voltage-dividing resistor R4 and the second voltage-dividing resistor R5 is used to output the host control voltage Vt; and

[0119] The comparison circuit includes a first threshold control resistor R10, a second threshold control resistor R11 and a first comparator COMP0; one end of the first threshold control resistor R10 is connected to the follower voltage, and the other end is grounded through the second threshold control resistor R11, and the connection between the first threshold control resistor R10 and the second threshold control resistor R11 is used to output the first receiving code voltage V C0DA The first comparator COMP0 has a positive input terminal connected to the host control voltage, and a negative input terminal can form a pin CODA and be connected to the first receiving code voltage V C0DA , the output end outputs a first code receiving control signal RX0; the code receiving control signal includes the first code receiving control signal RX0.

[0120] In the above description, the unidirectional pulsating direct current signal connected to the first voltage-dividing resistor R4 refers to the electrical signal output by the full-bridge rectifier circuit of the input unit.

[0121] The following describes the working principle of the code receiving unit:

[0122] by Figure 6 Taking the communication signal conversion device shown in the figure as an example, after the full-bridge rectifier circuit in the input unit processes the AC control signal to obtain a unidirectional pulsating DC signal, the unidirectional pulsating DC signal is divided by the first voltage-dividing resistor R4 and the second voltage-dividing resistor R5 to obtain the host control voltage Vt. Subsequently, the host control voltage Vt is sent to the first comparator COMP0, and the first comparator COMP0 compares the host control voltage Vt with the first receiving code voltage V C0DA The comparison is performed to convert the voltage signal into a digital signal of 0 or 1. For example, when the host control voltage Vt is greater than the first receiving code voltage V C0DA When the value of the output first code receiving control signal RX0 is 1, it means that the bus level is high, for example, 36V or close to 36V; and when the host control voltage Vt is less than or equal to the first code receiving voltage V C0DA When the value of the output first code receiving control signal RX0 is 0, it means that the bus level at this time is a low level, for example, 24 V or close to 24 V. Subsequently, the first code receiving control signal will be transmitted to the controller of the slave.

[0123] In addition, in the above, the first receiving code voltage V can be controlled by configuring the ratio of the first threshold control resistor R10 and the second threshold control resistor R11. C0DAFor example, when the non-polarity bus is an M-BUS bus, the ratio of the first threshold control resistor R10 to the second threshold control resistor R11 can be configured to make the first receiving code voltage meet the host sending code voltage specified in the M-BUS bus protocol. For another example, when the non-polarity bus is a POWERBUS bus, the ratio of the first threshold control resistor R10 to the second threshold control resistor R11 can be configured to make the first receiving code voltage meet the host sending code voltage specified in the POWERBUS bus protocol.

[0124] As an example of calculating the ratio of the first threshold control resistor R10 and the second threshold control resistor R11, in the M-BUS bus protocol, the specified receiving code voltage has two level signals. For the convenience of description, the voltages corresponding to the two level signals are described as VH (for example, the 36V mentioned above) and VL (for example, the 24V mentioned above), VH>VL, then the first threshold control resistor R10 and the second threshold control resistor R11 will satisfy the following relationship: (R10+R11) / R11=VH / VL, wherein, since VH and VL are known, the value of (R10+R11) / R11 is also known. Based on this, the values ​​of R10 and R11 can be configured so that the configured values ​​of R10 and R11 satisfy (R10+R11) / R11=VH / VL.

[0125] In the POWERBUS bus protocol, the specified receiving code voltage has three level signals. For the convenience of description, the voltages corresponding to the three level signals are described as VH1, VM1 and VL1 respectively. VH1>VM1>VL1, then the first threshold control resistor R10 and the second threshold control resistor R11 will satisfy the following relationship: (R10+R11) / R11=VM1 / VL1. Similarly, since VM1 and VL1 are known, the value of (R10+R11) / R11 is also known. Based on this, the values ​​of R10 and R11 can be configured so that the configured values ​​of R10 and R11 satisfy (R10+R11) / R11=VM1 / VL1.

[0126] As can be seen from the above, the embodiment of the present invention can not only realize the circuit function of the code receiving unit by configuring the code receiving unit as above, but also simplify the circuit structure, reduce the difficulty and cost of circuit manufacturing, and improve the circuit reliability. In addition, the magnitude of the first code receiving voltage can be adjusted by the first threshold regulating resistor and the second threshold regulating resistor, so that the communication signal conversion device provided by the embodiment of the present invention can be applicable to communication scenarios of different buses, thereby improving the versatility and practicality of the communication signal conversion device.

[0127] Although the above-described scheme can be used to obtain the configuration values ​​of R10 and R11 to obtain the corresponding first receiving code voltage V C0DA However, in the communication signal conversion device, in order to offset the influence of parasitic capacitance in the bus and maintain the life of each device in the communication signal, the control signal sent by the host will be processed by voltage division, that is, the received code voltage will be processed by voltage division before being transmitted to the first comparator COMP0, such as Figure 6 Therefore, directly using VH / VL or VM1 / VL1 to calculate the relationship between R10 and R11 will obviously make the first receiving code voltage V C0DA There is a certain error. Therefore, in order to solve this technical problem, the embodiment of the present invention also provides another solution for configuring the values ​​of R10 and R11, for example, Figure 6 Taking the communication signal conversion device shown as an example, the values ​​of R4, R5, R7 and R6 can be configured according to the working voltage safety requirements of each device in the communication signal conversion device and the parasitic capacitance elimination requirements. After these values ​​are configured, according to the calculation principle of the circuit, the relationship between the value of the host control voltage Vt obtained by the voltage division of R4 and R5 and the value of the VTRX value, as well as the value of the target follower voltage VREGD obtained by the voltage division of R7 and R6 can be known. Taking the M-BUS bus protocol as an example, it is assumed that the configuration of R4 and R5 makes the host control voltage Vt satisfy: Vt = VTRX / 15, where VTRX is the voltage of a unidirectional pulsating DC signal. Since VTRX is the voltage of the signal obtained by the rectification of the AC control signal by the full-bridge rectifier circuit D1, the rectification process generally does not change the voltage of the original signal, or the voltage changes little. Therefore, VTRX is essentially equal to or close to the voltage of the AC control signal, that is, equal to or close to the bus voltage. According to the regulations of the code receiving voltage and the working principle of the code receiving unit, when the host control voltage Vt satisfies Vt>VH / 15, the first code receiving control signal is 1. Therefore, the first code receiving voltage V C0DA The value can be set to VH / 15, since V C0DA = VREGD × (R11 / (R11+R10)), where V C0DA The values ​​of R11 and VREGD are known, so the value of R11 / (R11+R10) can be calculated based on this, and then the values ​​of R11 and R10 can be configured based on this. The configuration principle of the POWERBUS bus protocol is similar, so it will not be repeated here.

[0128] In some embodiments, to further improve the communication reliability between the host and the slave, the first receiving code voltage V C0DA The value of can be set to be smaller than VH / 15. As an example, the first receiving code voltage V C0DAAn intermediate value between VH / 15 and VL / 15 can be used, which can avoid the loss of the bus level input into the communication signal conversion device, thereby affecting the accurate determination of the host control voltage by the code receiving unit.

[0129] In the communication between the host and the slave, in addition to communication reliability, it is best to also take into account communication efficiency. However, in the related art, the parasitic capacitance of the long wire bus is not considered to easily cause the host's control signal to fall slowly from VH to VL, thereby causing the communication speed between the host and the slave to be unable to be improved. In order to solve this technical problem, in some embodiments, please continue to refer to Figure 6 The communication signal conversion device provided in the embodiment of the present invention is also provided with an automatic discharge unit, and accordingly, another comparison branch is added to the comparison circuit, namely:

[0130] The comparison circuit also includes a third threshold control resistor R9, a fourth threshold control resistor R13 and a second comparator COMP2; one end of the third threshold control resistor R9 is connected to the follower voltage, and the other end is grounded through the fourth threshold control resistor R13, and the connection between the third threshold control resistor R9 and the fourth threshold control resistor R13 is used to output a voltage less than the first receiving code voltage V C0DA The second receiving code voltage V C1DA The non-inverting input terminal of the second comparator COMP2 is connected to the host control voltage Vt, and the inverting input terminal is connected to the second receiving code voltage V C1DA , the output end outputs a second receiving code control signal RX1.

[0131] Correspondingly, the communication signal conversion device also includes:

[0132] The automatic discharge unit includes a release control circuit DC and a discharge regulating resistor R1; the input end of the release control circuit DC is connected to the unidirectional pulsating direct current signal, the output end is grounded through the discharge regulating resistor R1, and the discharge trigger end is used to connect the second code receiving control signal; the discharge regulating resistor R1 is used to control the discharge rate of the release control circuit DC. The smaller the resistance value of the discharge regulating resistor R1, the greater the discharge rate of the release control circuit DC, and vice versa, the greater the resistance value of the discharge regulating resistor R1, the smaller the discharge rate of the release control circuit DC.

[0133] In the above, the second comparison branch formed by the third threshold control resistor R9, the fourth threshold control resistor R13 and the second comparator COMP2 is mainly used to determine whether the host control voltage is less than the voltage of the low-level code receiving signal in the relevant bus protocol, and use the judgment result-the second code receiving control signal to trigger the automatic discharge unit, so that the release control circuit in the automatic discharge unit is triggered by the falling edge of the AC signal, so that the host control voltage can quickly drop from a high level to a low level, thereby accelerating the falling speed of the falling edge of the communication waveform, improving the signal integrity of the communication waveform, and achieving the purpose of improving communication efficiency, such as Figure 7 As shown, Figure 7 1 is a schematic diagram comparing two communication waveforms provided by an embodiment of the present invention. In the figure, curve A represents a communication waveform curve when the communication signal conversion device is not equipped with an automatic discharge unit and a second comparison branch, and curve B represents a communication waveform curve when the communication signal conversion device is equipped with an automatic discharge unit and a second comparison branch. It can be seen that the falling edge of curve B is from V H (or V C0DA ) drops to V C1DA It takes time T0, and the falling edge of curve A starts from V H (or V C0DA ) drops to V C1DA It takes time T0+T1, and it is obvious that curve B has a faster discharge capability. Since in the bus protocol (M-BUS bus protocol or POWERBUS bus protocol) mentioned in the embodiment of the present invention, the host transmits data to the slave by alternating high and low levels. Therefore, curve B with a faster falling edge falling speed has a faster speed of changing from high level to low level, thereby improving the communication speed.

[0134] In addition, due to the existence of the discharge regulating resistor R1, the resistance value of the discharge regulating resistor R1 can be adjusted according to actual needs, thereby changing the discharge speed of the automatic discharge unit, so that the communication speed can also change at any time. For example, when the amount of communication data between the host and the slave is large, the discharge speed can be accelerated by reducing the resistance value of the discharge regulating resistor, thereby accelerating the level drop rate of the unidirectional pulsating DC signal to complete the transmission of the communication data faster; when the number of communications between the host and the slave is small, the resistance value of the discharge regulating resistor can be maintained, or the resistance value of the regulating resistor can be increased to maintain or slow down the transmission speed of the communication data.

[0135] The working principle of the second comparison branch and the automatic discharge unit is described below:

[0136] From the circuit structure of the second comparison branch, it can be seen that when the host control voltage Vt is greater than the second receiving code voltage V C1DAWhen the value of the second code receiving control signal RX1 is 1, and the host control voltage Vt is less than or equal to the second code receiving voltage V C1DA When the second code receiving control signal RX1 is 0, the value of the second code receiving voltage V C1DA The corresponding is the low-level receiving code voltage specified by the M-BUS or POWERBUS bus protocol, so as to sense whether the receiving code voltage drops from a high level to a low level, thereby realizing timely transmission of the data sent by the host to the slave. Therefore, when the second receiving code control signal RX1 received by the controller of the slave changes from 1 to 0, it means that the receiving code voltage drops from a high level to a low level. Therefore, in order to make the receiving code voltage drop from a high level to a low level faster, so as to complete the data transmission faster, it is necessary to enable the automatic discharge unit so that the automatic discharge unit can quickly reduce the host control voltage Vt. The magnitude of the host control voltage Vt is determined by the voltage VTRX of the unidirectional pulsating DC signal. Therefore, after part of the unidirectional pulsating DC signal is discharged through the automatic discharge unit, the purpose of reducing the host control voltage Vt can be achieved.

[0137] That is to say, when the second code receiving control signal RX1 changes from 1 to 0, the slave controller will enable the release control circuit. In other words, the release control circuit is triggered by the falling edge of the second code receiving control signal RX1, and the triggered release control circuit will discharge to the ground through the discharge control resistor R1. The discharge current of the release control circuit is determined by the discharge control resistor R1. As an example, the relationship between the discharge current IEDC and the discharge control resistor R1 can be expressed as: IEDC = VEDC / R1, where VEDC is Figure 6 The voltage at the EDC pin is shown. In some examples, to facilitate the calculation of the discharge current, the release control circuit can be configured so that VEDC=1V. Based on this, the relationship between the discharge current IEDC and the discharge control resistor R1 can be simplified to IEDC=1 / R1. It is worth noting that when the EDC pin is suspended, the discharge function of the release control circuit fails.

[0138] In some examples, in order to ensure the discharge effect and the communication speed, the release control circuit will discharge for a set time after being triggered, and the set time range can be [4μs, 6μs]. As an example of a value, the set time can be configured to 5μs.

[0139] In addition, the resistance values ​​of the third threshold regulating resistor and the fourth threshold regulating resistor can be adjusted so that the second receiving code voltage can adapt to different scenarios, thereby making the discharge control of the automatic discharge unit more adaptable to the required application scenario, and making the communication signal conversion device not only applicable to the M-BUS bus protocol, but also applicable to the POWERBUS bus protocol. From the above description of the M-BUS bus protocol and the POWERBUS bus protocol, it can be seen that the M-BUS bus communication scenario is a dual-level communication scenario, through the branch where the first comparator COMP0 is located and the corresponding first receiving code voltage V configured C0DA Data transmission between the host and the slave can be realized. In this scenario, the slave only needs to determine whether to perform the return code operation based on the first code receiving control signal RX0, that is, to send a code to the host. The POWERBUS bus communication scenario is a three-level communication scenario. The POWERBUS bus protocol stipulates that the slave can only send a code to the host when the code receiving voltage is the intermediate voltage VM1. Therefore, in addition to using the branch where the first comparator COMP0 is located and configuring the corresponding first code receiving voltage V C0DA In addition, it is also necessary to use the branch where the second comparator COMP1 is located and configure the corresponding second receiving code voltage V C1DA , in order to achieve data transmission between the host and the slave, in this scenario, the slave needs to determine whether to send a code to the host based on the first code receiving control signal RX0 and the second code receiving control signal RX1. For example, when RX0=0 and RX1=1, the slave can perform the operation of sending a code to the host, but it is not limited to this. The RX0 value and RX1 value that trigger the slave to send a code to the host can be configured according to actual needs.

[0140] It can be seen that when the non-polarity bus is an M-BUS bus, the code receiving control signal is the first code receiving control signal RX0; when the non-polarity bus is a POWERBUS bus, the code receiving control signal includes the first code receiving control signal RX0 and the second code receiving control signal RX1.

[0141] The following describes the second receiving code voltage V for the above two communication scenarios. C1DA Configuration scheme:

[0142] For the M-BUS bus communication scenario, the communication signal conversion device provided in the embodiment of the present invention may be configured with the branch where the second comparator COMP1 is located, or may not be configured. In the case where the branch where the second comparator COMP1 is located is configured, the branch where the second comparator COMP1 is located is mainly used to control whether the automatic discharge unit performs a discharge operation. It can be seen from the above related records that the second received code voltage V C1DA is related to the receiving code level, and the second receiving code voltage V C1DAThe third threshold control resistor R9 and the fourth threshold control resistor R13 are related. Therefore, the appropriate second receiving code voltage V can be obtained by configuring the values ​​of the third threshold control resistor R9 and the fourth threshold control resistor R13. C1DA . In one example, the third threshold control resistor R9 and the fourth threshold control resistor R13 satisfy the following relationship: (R9+R13) / R13=VH / (VH-(VH-VL) / 8), wherein the meanings of VH and VL can be found in the relevant records above and will not be elaborated here. Since VH and VL are known, the value of (R9+R13) / R13 can be obtained by the above relationship. Based on this, the values ​​of R9 and R13 can be configured so that the configured values ​​of R9 and R13 satisfy (R9+R13) / R13=VH / (VH-(VH-VL) / 8), and a suitable second receiving code voltage V can be obtained. C1DA .

[0143] For the POWERBUS bus communication scenario, the communication signal conversion device provided in the embodiment of the present invention needs to configure the branch where the second comparator COMP1 is located. Similarly, the value of the third threshold control resistor R9 and the fourth threshold control resistor R13 can be configured to achieve the acquisition of a suitable second receiving code voltage V C1DA . In one example, the third threshold control resistor R9 and the fourth threshold control resistor R13 satisfy the following relationship: (R9+R13) / R13=VH1 / VM1, wherein the meanings of VH1 and VM1 can be found in the above related records and will not be repeated here. Since VH1 and VM1 are known, the value of (R9+R13) / R13 can be obtained by the above relationship. Based on this, the values ​​of R9 and R13 can be configured so that the configured values ​​of R9 and R13 satisfy (R9+R13) / R13=VH1 / VM1, and a suitable second receiving code voltage V can be obtained. C1DA .

[0144] Although the above scheme can be used to find the configuration values ​​of R9 and R13 to obtain the corresponding second receiving code voltage V C1DA However, in the communication signal conversion device, in order to offset the influence of parasitic capacitance in the bus and maintain the life of each device in the communication signal, the control signal sent by the host will be processed by voltage division, that is, the received code voltage will be processed by voltage division before being transmitted to the second comparator COMP1, such as Figure 6 Therefore, directly using VH / (VH-(VH-VL) / 8) or VH1 / VM1 to calculate the relationship between R9 and R13 will obviously make the second receiving code voltage V C1DA There is a certain error. Therefore, in order to solve this technical problem, the embodiment of the present invention also provides another solution for configuring the values ​​of R9 and R13, for example, Figure 6Taking the communication signal conversion device shown as an example, the values ​​of R4, R5, R7 and R6 can be configured according to the working voltage safety requirements of each device in the communication signal conversion device and the parasitic capacitance elimination requirements. After these values ​​are configured, according to the calculation principle of the circuit, the relationship between the value of the host control voltage Vt obtained by the voltage division of R4 and R5 and the value of the VTRX value, as well as the value of the target follower voltage VREGD obtained by the voltage division of R7 and R6 can be known. Taking the M-BUS bus protocol as an example, it is assumed that the configuration of R4 and R5 makes the host control voltage Vt satisfy: Vt = VTRX / 15, where VTRX is the voltage of a unidirectional pulsating DC signal. Since VTRX is the voltage of the signal obtained by the rectification of the AC control signal by the full-bridge rectifier circuit D1, the rectification process generally does not change the voltage of the original signal, or the voltage changes little. Therefore, VTRX is essentially equal to or close to the voltage of the AC control signal, that is, equal to or close to the bus voltage. According to the regulation of the code receiving voltage and the working principle of the code receiving unit, when the host control voltage Vt satisfies Vt>VL / 15, the second code receiving control signal RX1 is 1. Therefore, the second code receiving voltage V C1DA The value can be set to VL / 15, since V C1DA = VREGD × (R13 / (R13+R9)), where V C1DA The values ​​of R13 and VREGD are known, so the value of R13 / (R13+R9) can be calculated based on this, and then the values ​​of R13 and R9 can be configured based on this. The configuration principle of the POWERBUS bus protocol is similar, so it will not be repeated here.

[0145] As can be seen from the above, as long as the communication scenario in which the communication signal conversion device is located has not changed, the pre-configured values ​​of the threshold control resistors can be used all the time, and there is no need to adjust the resistance of each threshold control resistor in the application. However, if the communication scenario in which the communication signal conversion device is located changes, then before the communication signal conversion device is applied to the new communication scenario, it is necessary to reconfigure the resistance of each threshold control resistor according to the relevant regulations of the new communication scenario. Among them, the reconfiguration of the resistance of the threshold control resistor can be achieved by replacing the resistor, or the threshold control resistor can be set as a variable resistor to achieve the reconfiguration of the resistance.

[0146] Based on this, in some embodiments, in order to facilitate the adjustment of the resistance value of the regulating resistor, the first threshold regulating resistor R10, the second threshold regulating resistor R11, the third threshold regulating resistor R9, the fourth threshold regulating resistor R13 and the discharge regulating resistor R1 are detachable resistors or variable resistors. As an example of a detachable resistor, please continue to refer to Figure 6, these regulating resistors can be placed outside the integrated circuit board C of the communication signal conversion device. In this way, when the resistance value of one or more regulating resistors needs to be changed, there is no need to disassemble the internal circuit structure of the communication signal conversion device, that is, the circuit structure on the integrated circuit board, and the regulating resistors can be disassembled and replaced.

[0147] Therefore, by setting each regulating resistor as a detachable resistor or a variable resistor, it is convenient to replace regulating resistors with different resistance values ​​according to different usage requirements, or the resistance value of the regulating resistor can be changed without disassembly, thereby reducing the regulation difficulty and regulation cost of each regulating resistor.

[0148] In addition, the above-mentioned release control circuit can be implemented by using the discharge circuit in the related art. However, in order to ensure the compatibility of the release control circuit with other circuits in the communication signal conversion device provided in the embodiment of the present invention, as well as the stability and reliability of the discharge control, and to simplify the circuit structure to a certain extent to reduce the difficulty and cost of circuit manufacturing, in some embodiments, the embodiment of the present invention also provides an implementation scheme of the release control circuit, please refer to Figure 8 , Figure 8 1 is a schematic diagram of the circuit structure of an automatic discharge unit proposed in an embodiment of the present invention. The release control circuit includes a fifth voltage-dividing resistor R14, a sixth voltage-dividing resistor R15, a timer, a time-controlled switch S1, a first operational amplifier OPA1 and a first field effect transistor M2.

[0149] One end of the fifth voltage-dividing resistor R14 is connected to the power supply voltage, and the other end is grounded through the sixth voltage-dividing resistor R15, and the connection between the fifth voltage-dividing resistor R14 and the sixth voltage-dividing resistor R15 forms a trigger voltage output terminal. As an example, the voltage at the trigger voltage output terminal may be 1V, the power supply voltage connected to the fifth voltage-dividing resistor R14 is 3.3V, the resistance value of the fifth voltage-dividing resistor R14 may be 23KΩ, and the resistance value of the sixth voltage-dividing resistor R15 may be 10KΩ.

[0150] The trigger input terminal EN of the timer is the discharge trigger terminal, which is connected to the second code receiving control signal RX1. The output terminal of the timer is connected to the control terminal of the time control switch S1, and is used to output a time control signal to the time control switch S1.

[0151] The normally closed end of the timing switch S1 is connected to the non-inverting input end of the first operational amplifier OPA1, and the normally open end is used to be connected to the trigger voltage output terminal when the timing signal indicates that the discharge is triggered, and is grounded when the timing signal indicates that the discharge is not triggered.

[0152] The inverting input terminal of the first operational amplifier OPA1 is connected to the source of the first field effect transistor M2.

[0153] The gate of the first field effect transistor M2 is connected to the output end of the first operational amplifier OPA1, the drain is connected to the unidirectional pulsating direct current signal, the source is led out to form an EDC pin and is connected in series with the discharge regulating resistor R1.

[0154] The following description Figure 8 The working principle of the automatic discharge unit shown:

[0155] When the trigger input terminal EN of the timer is triggered by the falling edge of the second code receiving control signal RX1, the timer will output a timing signal for indicating the connection of the discharge circuit to the timing switch S1, so that the timing switch S1 is connected to the trigger voltage output terminal. At this time, the positive input terminal of the first operational amplifier OPA1 is connected to a voltage of 1V, thereby turning on the first field effect transistor M2. After the first field effect transistor M2 is turned on, the path between the TRX terminal and the discharge regulating resistor R1 is turned on, so the unidirectional pulsating DC signal can be input into the automatic discharge unit through the TRX terminal and discharged to the ground through the discharge regulating resistor R1.

[0156] In some embodiments, in order to ensure the stability and reliability of the code transmission control, the structure of the code transmission circuit can be simplified, and the difficulty and cost of circuit manufacturing can be reduced. The embodiment of the present invention also proposes an implementation scheme of the code transmission unit. Please continue to refer to Figure 6 The code sending unit includes a seventh voltage-dividing resistor R8, an eighth voltage-dividing resistor R12, a second operational amplifier OPA2, a code sending control switch SW1, a second field effect transistor M1 and a code sending regulating resistor R3.

[0157] One end of the seventh voltage-dividing resistor R8 is connected to the power supply voltage, and the other end is grounded through the eighth voltage-dividing resistor R12; in some examples, the power supply voltage connected to the seventh voltage-dividing resistor R8 is the second power supply voltage V33.

[0158] The non-inverting input terminal of the second operational amplifier OPA2 is connected between the seventh voltage-dividing resistor R8 and the eighth voltage-dividing resistor R12, the inverting input terminal is connected to the source of the second field effect transistor OPA2, and the output terminal is connected to the gate of the second field effect transistor OPA2 through the coding control switch SW1.

[0159] The coding control switch SW1 is used to turn on or off the connection between the second operational amplifier OPA2 and the second field effect transistor M1. The on-off control terminal TX of the coding control switch SW1 is connected to the slave controller. When the slave controller inputs a digital signal 1 to the on-off control terminal TX, the coding control switch SW1 turns on the connection between the second operational amplifier OPA2 and the second field effect transistor M1. When the slave controller inputs a digital signal 0 to the on-off control terminal TX, the coding control switch SW1 turns off the connection between the second operational amplifier OPA2 and the second field effect transistor M1.

[0160] The drain and source of the second field effect transistor M1 are connected to form a code output terminal IS for connecting to the non-polarity bus.

[0161] The coding regulating resistor R3 is used to adjust the coding current, one end of which is connected to the coding output terminal IS, and the other end is grounded.

[0162] Below, explain Figure 6 The working principle of the coding unit shown:

[0163] When the slave controller determines that the code return operation can be performed to the host according to the first code receiving control signal RX0, or the first code receiving control signal RX0 and the second code receiving control signal RX1, the signal to be sent to the host will be transmitted to the on / off control terminal TX of the code sending control switch SW1. When the on / off control terminal TX receives the signal 1, the code sending control switch SW1 will turn on the connection between the second operational amplifier OPA2 and the second field effect transistor M1, so that the second field effect transistor M1 is turned on and outputs the code sending current through the code sending output terminal IS, thereby increasing the bus current. When the on / off control terminal TX receives the signal 0, the code sending control switch SW1 will disconnect the connection between the second operational amplifier OPA2 and the second field effect transistor M1. At this time, the gate of the second field effect transistor M1 is grounded, the second field effect transistor M1 is turned off, and the code sending output terminal IS has no code sending current output or the code sending current is reduced, thereby restoring the bus current to its original size.

[0164] Therefore, the coding unit can convert the digital signal input by the slave controller into a current signal, thereby sending the slave data to the host.

[0165] In addition, since the code transmission output terminal IS is also connected to the grounded code transmission control resistor R3, the size of the code transmission current can be changed by adjusting the size of the code transmission control resistor R3, thereby meeting the code transmission current size specified in different bus protocols and realizing slave data transmission applicable to different bus protocols. The larger the code transmission control resistor R3, the smaller the code transmission current; and the smaller the code transmission control resistor R3, the larger the code transmission current.

[0166] In some embodiments, in order to facilitate the replacement of coding control resistors with different resistance values ​​according to different usage requirements, or to change the resistance value of the coding control resistor without disassembly, thereby reducing the control difficulty and control cost of the coding control resistor, the coding control resistor is also a detachable resistor or a variable resistor.

[0167] As an example of a detachable resistor, Figure 6 For example, when the communication signal conversion device is applied to a communication scenario, such as a POWERBUS bus communication scenario, please refer to Fig. 9 , Fig. 9 is another application scenario schematic diagram of the communication signal conversion device provided by an embodiment of the present invention, which can be Figure 6 The regulating resistors R1 and R3 shown in the figure are externally arranged outside the integrated circuit board C of the communication signal conversion device. In this way, when the resistance value of the regulating resistor needs to be changed, it is not necessary to disassemble the internal circuit structure of the communication signal conversion device, that is, the circuit structure on the integrated circuit board, and the regulating resistor can be disassembled and replaced. Fig. 9 In the figure, the MCU chip represents the slave controller, which can communicate with the host through the TX and RX0 ends of the communication signal conversion device.

[0168] In addition, Fig. 9 In the application scenario shown, the resistance of each regulating resistor can be configured as follows: R1 is 2KΩ, R3 is 5Ω, R10 is 201KΩ, R11 is 51KΩ, R9 is 51KΩ, and R13 is 201KΩ. In addition, capacitors C1 to C3 can be externally placed, and the capacitance of each external capacitor can be configured as follows: C1 is 220μF, C2 is 10μF, and C3 is 10μF. Among them, the resistance of R1 is configured as 2KΩ to improve the discharge capacity of the automatic discharge unit and enhance the waveform integrity; the capacitance of C1 is configured as 220μF to improve the power supply stability of the power supply unit; the resistance of R3 is configured as 5Ω to control the code current at 200mA.

[0169] Corresponding to the embodiment of the communication signal conversion device, the embodiment of the present invention further provides a slave system, see Fig.10 , Fig.10 1 is a structural block diagram of a slave system provided by an embodiment of the present invention. The slave system 10 includes slaves 11 connected to each other and a communication signal conversion device 100 in any of the above embodiments of the present invention.

[0170] Corresponding to the embodiment of the slave system, the embodiment of the present invention also provides a master-slave communication system, see Fig.11 , Fig.11It is a structural block diagram of a master-slave communication system provided by an embodiment of the present invention. The master-slave communication system 1 comprises a host and a slave system in any of the above embodiments of the present invention; the host is connected to the slave system via a non-polarity bus.

[0171] In the above, the working principles of the slave system and the master-slave communication system can refer to the relevant records of the communication signal conversion device in any embodiment of the present invention, and will not be repeated here.

[0172] It is worth noting that the technical features or technical solutions in any of the above embodiments of the present invention can be combined or combined with each other as long as there is no contradiction in the combination or combination.

[0173] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A communication signal conversion device, characterized in that: include: An input unit, used to connect the host and the power supply through a non-polarity bus, and convert the control signal sent by the host and the AC control signal formed by the power supply into a unidirectional pulsating DC signal; A power supply unit, used for performing voltage stabilization processing on the unidirectional pulsating direct current signal to output a power supply voltage; A code receiving unit, configured to perform voltage division processing on the unidirectional pulsating direct current signal and the follower voltage respectively to obtain a host control voltage and a first code receiving voltage, and compare the host control voltage with the first code receiving voltage to obtain a code receiving control signal for transmission to the slave; wherein the follower voltage is the power supply voltage; as well as The code sending unit is used to access the signal output terminal of the slave machine, and when receiving the feedback signal sent by the slave machine according to the code receiving control signal, transmit the feedback signal to the host machine through the non-polarity bus.

2. The communication signal conversion device according to claim 1, characterized in that: The input unit includes a full-bridge rectifier circuit; the two input ends of the full-bridge rectifier circuit form two non-polarity input pins for connecting the host and the power supply through the non-polarity bus, and the output end of the full-bridge rectifier circuit is connected to the power supply unit.

3. The communication signal conversion device according to claim 2, characterized in that: The input unit further includes a low-pass filter circuit; the low-pass filter circuit is connected between the output end of the full-bridge rectifier circuit and the power supply unit.

4. The communication signal conversion device according to claim 3, characterized in that: The input unit further includes an anti-backflow circuit; the anti-backflow circuit is connected between the low-pass filter circuit and the power supply unit.

5. The communication signal conversion device according to claim 4, characterized in that: The low-pass filter circuit includes a filter resistor and a filter capacitor; the anti-backflow circuit includes a diode; The filter resistor and the diode are connected in series between the output end of the full-bridge rectifier circuit and the input end of the power supply unit in sequence; one end of the filter capacitor is connected to the cathode of the diode, and the other end is grounded.

6. The communication signal conversion device according to claim 1, characterized in that: The power supply unit comprises: A first voltage stabilizing circuit, the input end of which is connected to the unidirectional pulsating direct current signal, and the output end of which is used to output a first power supply voltage and is grounded through a first filter capacitor; and A second voltage stabilizing circuit, wherein the input end is connected to the first power supply voltage, the output end is used to output a second power supply voltage and is grounded through a second filter capacitor; the second power supply voltage is less than the first power supply voltage, and the follower voltage is the first power supply voltage or the second power supply voltage.

7. The communication signal conversion device according to claim 6, characterized in that: The first voltage stabilizing circuit and the second voltage stabilizing circuit are both low voltage dropout linear regulators.

8. The communication signal conversion device according to claim 1, characterized in that: The device also includes: An automatic threshold circuit, comprising a third voltage-dividing resistor, a fourth voltage-dividing resistor and a voltage follower; one end of the third voltage-dividing resistor is connected to the unidirectional pulsating direct current signal, and the other end is grounded through the fourth voltage-dividing resistor; the input end of the voltage follower is connected between the third voltage-dividing resistor and the fourth voltage-dividing resistor, and the output end is used to output a target following voltage; The following voltage is adjusted to the target following voltage.

9. The communication signal conversion device according to any one of claims 1 to 8, characterized in that: The code receiving unit comprises: A voltage-dividing circuit comprises a first voltage-dividing resistor and a second voltage-dividing resistor, wherein one end of the first voltage-dividing resistor is connected to the unidirectional pulsating direct current signal, and the other end of the first voltage-dividing resistor is grounded through the second voltage-dividing resistor, and a connection point between the first voltage-dividing resistor and the second voltage-dividing resistor is used to output the host control voltage; and A comparison circuit comprises a first threshold control resistor, a second threshold control resistor and a first comparator; one end of the first threshold control resistor is connected to the follower voltage, the other end is grounded through the second threshold control resistor, and the connection between the first threshold control resistor and the second threshold control resistor is used to output the first code receiving voltage; the non-phase input end of the first comparator is connected to the host control voltage, the inverting input end is connected to the first code receiving voltage, and the output end outputs a first code receiving control signal; the code receiving control signal comprises the first code receiving control signal.

10. The communication signal conversion device according to claim 9, characterized in that: The comparison circuit further includes a third threshold control resistor, a fourth threshold control resistor and a second comparator; one end of the third threshold control resistor is connected to the follower voltage, and the other end is grounded through the fourth threshold control resistor, and the connection between the third threshold control resistor and the fourth threshold control resistor is used to output a second code receiving voltage less than the first code receiving voltage; the non-phase input end of the second comparator is connected to the host control voltage, the inverting input end is connected to the second code receiving voltage, and the output end outputs a second code receiving control signal; as well as The communication signal conversion device also includes: The automatic discharge unit comprises a release control circuit and a discharge regulating resistor; the input end of the release control circuit is connected to the unidirectional pulsating direct current signal, the output end is grounded through the discharge regulating resistor, and the discharge trigger end is used to connect the second receiving code control signal; the discharge regulating resistor is used to control the discharge rate of the release control circuit.

11. The communication signal conversion device according to claim 10, characterized in that: The first threshold regulating resistor, the second threshold regulating resistor, the third threshold regulating resistor, the fourth threshold regulating resistor and the discharge regulating resistor are detachable resistors or variable resistors.

12. The communication signal conversion device according to claim 10 or 11, characterized in that: The non-polarity bus is an M-BUS bus, and the code receiving control signal is the first code receiving control signal; or the non-polarity bus is a POWERBUS bus, and the code receiving control signal includes the first code receiving control signal and the second code receiving control signal.

13. The communication signal conversion device according to claim 10 or 11, characterized in that: The release control circuit includes a fifth voltage-dividing resistor, a sixth voltage-dividing resistor, a timer, a time-controlled switch, a first operational amplifier and a first field effect transistor; One end of the fifth voltage-dividing resistor is connected to the supply voltage, and the other end is grounded through the sixth voltage-dividing resistor, and the connection between the fifth voltage-dividing resistor and the sixth voltage-dividing resistor forms a trigger voltage output terminal; The trigger input terminal of the timer is the discharge trigger terminal, and the output terminal is connected to the control terminal of the time-controlled switch, and is used to output a time-controlled signal to the time-controlled switch; The normally closed end of the time-controlled switch is connected to the non-inverting input end of the first operational amplifier, and the normally open end is used to be connected to the trigger voltage output terminal when the time-controlled signal indicates that the discharge is triggered, and is grounded when the time-controlled signal indicates that the discharge is not triggered; The inverting input terminal of the first operational amplifier is connected to the source of the first field effect transistor; The gate of the first field effect transistor is connected to the output end of the first operational amplifier, the drain is connected to the unidirectional pulsating direct current signal, and the source is connected in series with the discharge regulating resistor.

14. The communication signal conversion device according to claim 1, characterized in that: The code sending unit includes a seventh voltage-dividing resistor, an eighth voltage-dividing resistor, a second operational amplifier, a code sending control switch, a second field effect transistor and a code sending regulating resistor; One end of the seventh voltage-dividing resistor is connected to the supply voltage, and the other end is grounded through the eighth voltage-dividing resistor; The non-inverting input terminal of the second operational amplifier is connected between the seventh voltage-dividing resistor and the eighth voltage-dividing resistor, the inverting input terminal is connected to the source of the second field effect transistor, and the output terminal is connected to the gate of the second field effect transistor through the code control switch; The code control switch is used to turn on or off the connection between the second operational amplifier and the second field effect transistor; The drain and source of the second field effect transistor are connected to form a code output terminal for connecting to the non-polarity bus; The coding regulating resistor is used to adjust the coding current, one end of which is connected to the coding output terminal, and the other end is grounded.

15. The communication signal conversion device according to claim 14, characterized in that: The coding regulating resistor is a detachable resistor or a variable resistor.

16. A slave system, characterized in that: It comprises a slave machine and a communication signal conversion device connected to each other; the communication signal conversion device is the communication signal conversion device according to any one of claims 1 to 15.

17. A master-slave communication system, characterized in that: It comprises a host and a slave system; the host is connected to the slave system via a non-polarity bus, and the slave system is the slave system according to claim 16.

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