Redundant rs485 transceiver digital isolation repeater circuit and isolation repeater

Abstract

The application provides a redundant RS485 transceiving digital isolation repeater circuit and an isolation repeater, and belongs to the technical field of industrial automation control. The circuit comprises: a first RS485 communication module, which is used for sending a signal on a first RS485 bus to a digital isolation module and sending a low-level signal to a first signal transceiving module; the first signal transceiving module is used for triggering an enable signal to be in a sending state based on the low-level signal and sending the enable signal to the digital isolation module; the digital isolation module is used for sending the enable signal and the signal on the first RS485 bus to a second RS485 communication module and performing electrical isolation; and the second RS485 communication module is used for transmitting the signal on the first RS485 bus to a second RS485 bus based on the enable signal. The application scheme can improve the reliability and EMC performance of the RS485 isolation repeater.

Description

Technical Field

[0001] This application relates to the field of industrial automation control technology, specifically to a redundant RS485 transceiver conversion digital isolation relay circuit and isolation repeater. Background Technology

[0002] RS485 bus systems offer advantages such as simple hardware design, convenient control, low cost, and long transmission distance, making them widely used in industrial control and monitoring systems. Traditional RS485 isolation repeaters employ opto-isolation and magnetic isolation methods.

[0003] The circuit structure of an RS485 isolation repeater using opto-isolation involves two high-speed optocoupler chips in addition to the RS485 communication chip, and employs numerous discrete components. The optocouplers achieve isolation through the conversion of current to light. Compared to traditional optocouplers, magnetic couplings based on magnetic isolation technology solve the problems associated with optocouplers.

[0004] However, opto-isolation technology has poor reliability, and magnetic isolation technology has poor EMC (electromagnetic compatibility) performance. Therefore, how to improve the reliability and EMC performance of RS485 isolation repeaters remains an unsolved problem. Utility Model Content

[0005] The purpose of this application is to provide a redundant RS485 transceiver conversion digital isolation repeater circuit and isolation repeater, which can solve the problems of poor reliability and EMC performance of existing RS485 isolation repeaters.

[0006] In a first aspect, embodiments of this application provide a redundant RS485 transceiver conversion digital isolation relay circuit, the circuit comprising: a first RS485 communication module, a first signal transceiver conversion module, a digital isolation module, and a second RS485 communication module;

[0007] The first RS485 communication module is connected to the first RS485 bus. The receiving end of the first RS485 communication module is connected to the first end of the first signal transceiver conversion module and the transmitting end of the digital isolation module. The first RS485 communication module is used to send signals on the first RS485 bus to the digital isolation module and to send low-level signals to the first signal transceiver conversion module.

[0008] The second terminal of the first signal transceiver conversion module is connected to the transceiver enable terminal of the digital isolation module. The first signal transceiver conversion module is used to trigger the enable signal to be in the transmission state based on the low level signal and send the enable signal to the digital isolation module.

[0009] The transmit / receive enable terminal of the digital isolation module is connected to the transmit / receive enable terminal of the second RS485 communication module, and the transmit terminal of the digital isolation module is connected to the transmit terminal of the second RS485 communication module. The digital isolation module is used to send enable signals and signals on the first RS485 bus to the second RS485 communication module and to perform electrical isolation.

[0010] The second RS485 communication module is connected to the second RS485 bus and is used to transmit signals from the first RS485 bus to the second RS485 bus based on an enable signal.

[0011] In one possible implementation of the first aspect, the circuit further includes: a second signal transceiver conversion module;

[0012] The receiving end of the second RS485 communication module is connected to the receiving end of the digital isolation module. The second RS485 communication module is used to send signals on the second RS485 bus to the digital isolation module.

[0013] The receiving end of the digital isolation module is also connected to the transmitting end of the first RS485 communication module and the second end of the second signal transceiver conversion module. The digital isolation module is also used to send signals on the second RS485 bus to the first RS485 communication module and to send low-level signals to the second signal transceiver conversion module.

[0014] The first end of the second signal transceiver conversion module is connected to the transceiver enable end of the first RS485 communication module. The second signal transceiver conversion module is also used to trigger the enable signal to be in the transmission state based on the low level signal and send the enable signal to the first RS485 communication module.

[0015] The first RS485 communication module is also used to transmit signals on the second RS485 bus to the first RS485 bus based on an enable signal.

[0016] In one possible implementation of the first aspect, the first signal transceiver module includes: a first charging / discharging unit, a first charge discharging unit, and a first inverter;

[0017] The first end of the first charging and discharging unit is connected to the receiving end of the first RS485 communication module, and the second end of the first charging and discharging unit is connected to the input end of the first inverter. The first charging and discharging unit is used to charge based on the high-level signal of the receiving end of the first RS485 communication module and to discharge based on the low-level signal of the receiving end of the first RS485 communication module.

[0018] The first end of the first charge discharge unit is connected to the first end of the first charge discharge unit, and the second end of the first charge discharge unit is connected to the second end of the first charge discharge unit. The first charge discharge unit is used to provide a channel for discharging charge for the first charge discharge unit.

[0019] The output of the first inverter is connected to the transmit / receive enable terminal of the digital isolation module. The first inverter is used to reverse the phase of the low-level signal or high-level signal of the receiving end of the first RS485 communication module by 180°.

[0020] In one possible implementation of the first aspect, the first charging and discharging unit includes: a first resistor and a first capacitor, and the first charge discharging unit includes a first diode;

[0021] The first end of the first resistor is connected to the receiver of the first RS485 communication module and the cathode of the first diode. The second end of the first resistor is connected to the first end of the first capacitor, the anode of the first diode, and the input of the first inverter. The second end of the first capacitor is grounded. The output of the first inverter is connected to the transmit / receive enable terminal of the digital isolation module.

[0022] Wherein, the first end of the first resistor is the first end of the first signal transceiver conversion module, and the output end of the first inverter is the second end of the first signal transceiver conversion module.

[0023] In one possible implementation of the first aspect, the second signal transceiver module includes: a second charging / discharging unit, a second charge discharging unit, and a second inverter;

[0024] The first end of the second charging and discharging unit is connected to the receiving end of the digital isolation module, and the second end of the second charging and discharging unit is connected to the input end of the second inverter. The second charging and discharging unit is used to charge based on the high-level signal of the receiving end of the digital isolation module and to discharge based on the low-level signal of the receiving end of the digital isolation module.

[0025] The first end of the second charge discharge unit is connected to the first end of the second charge discharge unit, and the second end of the second charge discharge unit is connected to the second end of the second charge discharge unit. The second charge discharge unit is used to provide a channel for discharging charge for the second charge discharge unit.

[0026] The output of the second inverter is connected to the transmit / receive enable terminal of the first RS485 communication module. The second inverter is used to reverse the phase of the low-level signal or high-level signal received by the digital isolation module by 180°.

[0027] In one possible implementation of the first aspect, the second charging / discharging unit includes: a second resistor and a second capacitor, and the second charge discharging unit includes a second diode;

[0028] The first end of the second resistor is connected to the receiving end of the digital isolation module and the cathode of the second diode. The second end of the second resistor is connected to the first end of the second capacitor, the anode of the second diode, and the input end of the second inverter. The second end of the second capacitor is grounded. The output end of the second inverter is connected to the transmit / receive enable end of the first RS485 communication module.

[0029] The output of the second inverter is the first terminal of the second signal transceiver module, and the first terminal of the second resistor is the second terminal of the second signal transceiver module.

[0030] In one possible implementation of the first aspect, the first RS485 bus and the second RS485 bus are multiplexed, and there are multiple first RS485 communication modules, first signal transceiver conversion modules, second signal transceiver conversion modules, digital isolation modules, and second RS485 communication modules.

[0031] A first DC / DC module is connected between every two first RS485 communication modules, and a second DC / DC module is connected between every two second RS485 communication modules. The first DC / DC module is used to provide operating power to the first RS485 communication modules, and the second DC / DC module is used to provide operating power to the second RS485 communication modules.

[0032] In one possible implementation of the first aspect, the second RS485 bus includes: a first signal line and a second signal line; the circuit also includes a third resistor, the first end of which is connected to a first power supply voltage input terminal, and the second end of which is connected to either the first signal line or the second signal line.

[0033] In one possible implementation of the first aspect, the circuit further includes a bus voltage regulation module;

[0034] The first terminal of the bus voltage regulation module is connected to the second power supply voltage input terminal, the second terminal of the bus voltage regulation module is grounded, the bus voltage regulation module is connected to the second RS485 bus, and the bus voltage regulation module is used to regulate the voltage of the second RS485 bus between the first signal line and the second signal line when the second RS485 bus is idle based on the resistance value.

[0035] In one possible implementation of the first aspect, the bus voltage regulation module includes: a pull-up resistor, a pull-down resistor, and a fourth resistor;

[0036] The series connection node of the pull-up resistor and the fourth resistor is connected to the first signal line of the second RS485 bus, and the series connection node of the pull-down resistor and the fourth resistor is connected to the second signal line of the second RS485 bus. The pull-up resistor is also connected to the second power supply voltage input terminal, and the pull-down resistor is also grounded.

[0037] Secondly, embodiments of this application provide a redundant RS485 transceiver conversion digital isolation repeater, which includes a redundant RS485 transceiver conversion digital isolation repeater circuit as described in any of the first aspects.

[0038] In this application, the first RS485 communication module sends signals on the first RS485 bus to the digital isolation module and sends a low-level signal to the first signal transceiver conversion module. The first signal transceiver conversion module triggers an enable signal to be in a transmitting state based on the low-level signal and sends the enable signal to the digital isolation module. The digital isolation module sends an enable signal and signals on the first RS485 bus to the second RS485 communication module and performs electrical isolation. The second RS485 communication module enables the transmitting end based on the enable signal and transmits the signals on the first RS485 bus to the second RS485 bus.

[0039] This application solution includes a signal transceiver conversion module and a digital isolation module. Compared with opto-isolation, it has a lower failure rate and higher reliability. Compared with magnetic isolation, it generates less electromagnetic interference, has better EMC performance, and is highly easy to use and practical.

[0040] Other features and advantages of the embodiments of this application will be described in detail in the following detailed description section. Attached Figure Description

[0041] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0042] Figure 1 This is a schematic block diagram of the redundant RS485 transceiver conversion digital isolation relay circuit provided in the embodiments of this application;

[0043] Figure 2 This is a schematic block diagram of the redundant RS485 transceiver conversion digital isolation relay circuit provided in the embodiments of this application;

[0044] Figure 3 This is a schematic circuit diagram of the first signal transceiver conversion module provided in an embodiment of this application;

[0045] Figure 4 This is a schematic circuit diagram of the second signal transceiver conversion module provided in an embodiment of this application;

[0046] Figure 5This is a schematic block diagram of the redundant RS485 transceiver conversion digital isolation relay circuit provided in the embodiments of this application;

[0047] Figure 6 This is a schematic block diagram of a redundant RS485 transceiver conversion digital isolation repeater provided in an embodiment of this application. Detailed Implementation

[0048] In the following description, specific details such as particular system architectures and techniques are set forth for illustrative purposes and not for limitation, in order to provide a thorough understanding of the embodiments of this application. However, those skilled in the art will understand that this application can also be implemented in other embodiments without these specific details. In other instances, detailed descriptions of well-known systems, apparatuses, circuits, and methods have been omitted so as not to obscure the description of this application with unnecessary detail.

[0049] It should be understood that, when used in this specification and the appended claims, the term "comprising" indicates the presence of the described features, integrals, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or collections thereof.

[0050] It should also be understood that the terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the scope of the application. As used in this specification and the appended claims, the singular forms “a,” “an,” and “the” are intended to include the plural forms unless the context clearly indicates otherwise.

[0051] It should also be further understood that the term “and / or” as used in this application specification and the appended claims means any combination of one or more of the associated listed items and all possible combinations, and includes such combinations.

[0052] As used in this specification and the appended claims, the term "if" may be interpreted, depending on the context, as "when," "once," "in response to determination," or "in response to detection." Similarly, the phrase "if determined" or "if [the described condition or event] is detected" may be interpreted, depending on the context, as "once determined," "in response to determination," "once [the described condition or event] is detected," or "in response to detection of [the described condition or event]."

[0053] Furthermore, in the description of this application, the terms "first," "second," "third," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0054] References to "one embodiment" or "some embodiments" as described in this specification mean that one or more embodiments of this application include a specific feature, structure, or characteristic described in connection with that embodiment. Therefore, the phrases "in one embodiment," "in some embodiments," "in some other embodiments," "in other embodiments," etc., appearing in different parts of this specification do not necessarily refer to the same embodiment, but rather mean "one or more, but not all, embodiments," unless otherwise specifically emphasized. The terms "comprising," "including," "having," and variations thereof mean "including but not limited to," unless otherwise specifically emphasized.

[0055] In this application specification, unless otherwise stated, directional terms such as "up," "down," "left," and "right" generally refer to the orientation or positional relationship based on the accompanying drawings, or the orientation or positional relationship in which the product of the invention is usually placed when in use.

[0056] In this application specification, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0057] RS485 bus systems offer advantages such as simple hardware design, convenient control, low cost, and long transmission distance, making them widely used in industrial control and monitoring systems. Traditional RS485 isolation repeaters employ opto-isolation and magnetic isolation methods, and are implemented using non-domestic chips.

[0058] The circuit structure of an RS485 isolation repeater using opto-isolation involves two high-speed optocoupler chips in addition to the RS485 communication chip, and the use of numerous discrete components increases circuit complexity and circuit board size. In opto-isolation, the optocoupler achieves isolation through the conversion of current and light, consuming significant power itself and thus increasing system power consumption. Furthermore, it suffers from long latency, poor temperature characteristics, and short lifespan, making it prone to failure and affecting system stability.

[0059] Another implementation technology is magnetic isolation technology. Compared with traditional optocouplers, magnetic couplers based on magnetic isolation technology solve the problems of optocouplers and have advantages such as high reliability, long life, high performance, low power consumption, small package, and ease of use. However, it has inherent disadvantages, such as complex process, high cost, poor EMC performance, and frequent problems of radiation exceeding the standard.

[0060] Furthermore, the aforementioned implementation methods mostly use foreign chips, which cannot be independently controlled.

[0061] To address the aforementioned deficiencies, this application provides a redundant RS485 transceiver conversion digital isolation relay circuit. A first RS485 communication module sends signals from the first RS485 bus to a digital isolation module and a low-level signal to a first signal transceiver conversion module. The first signal transceiver conversion module triggers an enable signal to transmit based on the low-level signal and sends this enable signal to the digital isolation module. The digital isolation module sends an enable signal and signals from the first RS485 bus to a second RS485 communication module, performing electrical isolation. The second RS485 communication module enables the transmitting end based on the enable signal, transmitting signals from the first RS485 bus to the second RS485 bus.

[0062] This application solution includes a signal transceiver conversion module and a digital isolation module. Compared with opto-isolation, it has a lower failure rate and higher reliability. Compared with magnetic isolation, it generates less electromagnetic interference, has better EMC performance, and is highly easy to use and practical.

[0063] The overall structure of the redundant RS485 transceiver conversion digital isolation relay circuit provided in this application is described below through specific embodiments.

[0064] Please see Figure 1 , Figure 1 This is a schematic block diagram of the redundant RS485 transceiver conversion digital isolation relay circuit 100 provided in an embodiment of this application. Figure 1 As shown, the circuit 100 includes: a first RS485 communication module 110, a first signal transceiver conversion module 120, a digital isolation module 130, and a second RS485 communication module 140.

[0065] According to one embodiment of this application, taking the transmission of signals from a first RS485 bus to a second RS485 bus (from left to right) as an example, a redundant RS485 transceiver conversion digital isolation relay circuit 100 is described.

[0066] According to one embodiment of this application, a first RS485 communication module 110 is connected to a first RS485 bus. The receiving end RXD1 of the first RS485 communication module 110 is connected to the first terminal of the first signal transceiver conversion module 120 and the transmitting end TXD2 of the digital isolation module 130. The first RS485 communication module 110 is used to send signals (A signal and B signal) on the first RS485 bus to the digital isolation module 130, and to send low-level signals to the first signal transceiver conversion module 120.

[0067] According to one embodiment of this application, the second terminal of the first signal transceiver conversion module 120 (automatic transceiver control circuit) is connected to the (T / R) transceiver enable terminal E2 of the digital isolation module 130. The first signal transceiver conversion module 120 is used to trigger the enable signal to be in the transmission state based on the low level signal and send the enable signal to the digital isolation module 130.

[0068] According to one embodiment of this application, the transmit / receive enable terminal E2 of the digital isolation module 130 is connected to the transmit / receive enable terminal E3 of the second RS485 communication module 140, and the transmit terminal TXD2 of the digital isolation module 130 is connected to the transmit terminal TXD3 of the second RS485 communication module 140. The digital isolation module 130 is used to send an enable signal and signals on the first RS485 bus to the second RS485 communication module 140, and to perform electrical isolation, so that the signal transmission is safe and stable.

[0069] In one embodiment, the digital isolation module 130 is a 4-channel digital isolation chip, such as the π142M31. This chip employs digital isolation and tolerance technology, offering the following advantages: ultra-low power consumption, with each channel consuming only 0.58mA; high-speed transmission, with a maximum data transmission rate of up to 10Mbps, meeting the demands of high-speed data transmission; an isolation voltage of 3000Vrms, ensuring safety and stability under high-voltage environments; and low transmission latency, typically 9ns, ensuring rapid signal response. These advantages make it widely applicable in industrial control fields.

[0070] According to one embodiment of this application, the second RS485 communication module 140 is connected to a second RS485 bus. The second RS485 communication module 140 is used to enable the transmitting end TXD3 based on an enable signal, and transmit the signal on the first RS485 bus to the second RS485 bus.

[0071] In one embodiment, the first RS485 communication module 110 and the second RS485 communication module 140 are non-isolated RS485 chips, such as the SIT65HVD75DR. These chips have a wide power supply range of 3~5.5V, suitable for various power environments; their electrostatic discharge (ESD) protection (HBM, Human Body Model) reaches over 15KV, effectively resisting ESD interference.

[0072] In one embodiment, the RS485 chip has an input voltage of ±15V (+15V for low input voltage; -15V for high input voltage), ensuring stable operation under high voltage conditions; it has strong noise immunity, making it suitable for use in electrical noise environments; and its data transmission rate can reach up to 20Mbps, meeting the needs of high-speed data transmission.

[0073] In addition, the RS485 chip features driver short-circuit output protection, receiver open-circuit failure protection, and integrated transient voltage suppression, ensuring stable operation under various working conditions.

[0074] This embodiment uses digital isolation, which has a lower failure rate and higher reliability compared to opto-isolation; compared to magnetic isolation, it generates less electromagnetic interference, has better EMC performance, and is more easy to use and practical.

[0075] Please refer to Figure 2. Figure 2 This is a schematic block diagram of the redundant RS485 transceiver conversion digital isolation relay circuit 100 provided in an embodiment of this application. Figure 2 As shown, the circuit 100 also includes a second signal transceiver conversion module 150.

[0076] According to one embodiment of this application, taking the transmission of signals from the second RS485 bus to the first RS485 bus (from right to left) as an example, the redundant RS485 transceiver conversion digital isolation relay circuit 100 is described.

[0077] According to one embodiment of this application, the receiving end RXD3 of the second RS485 communication module 140 is connected to the receiving end RXD2 of the digital isolation module 130. The second RS485 communication module 140 is used to send signals (A signal and B signal) on the second RS485 bus to the digital isolation module 130.

[0078] According to one embodiment of this application, the receiving end RXD2 of the digital isolation module 130 is also connected to the transmitting end TXD1 of the first RS485 communication module 110 and the second end of the second signal transceiver conversion module 150. The digital isolation module 130 is also used to send signals on the second RS485 bus to the first RS485 communication module 110 and to send low-level signals to the second signal transceiver conversion module 150.

[0079] According to one embodiment of this application, the first terminal of the second signal transceiver module 150 is connected to the transceiver enable terminal E1 of the first RS485 communication module 110. The second signal transceiver module 150 is also used to trigger an enable signal to a transmit state based on a low-level signal and send an enable signal to the first RS485 communication module 110.

[0080] According to one embodiment of this application, the first RS485 communication module 110 is further configured to enable the transmitting end TXD1 based on an enable signal, and transmit the signal on the second RS485 bus to the first RS485 bus.

[0081] The specific structure of the redundant RS485 transceiver conversion digital isolation relay circuit 100 provided in this application embodiment is described below through specific embodiments.

[0082] Please refer to Figure 3. Figure 3 This is a schematic circuit diagram of the first signal transceiver conversion module 120 provided in an embodiment of this application. Figure 3 As shown, the first signal transceiver conversion module 120 includes: a first charging and discharging unit 122, a first charge discharge unit 124, and a first inverter f1.

[0083] In one embodiment, the first inverter f1 can be an AiP74HC14SA14.

[0084] Combination Figure 1 and Figure 3 According to one embodiment of this application, the first terminal of the first charging / discharging unit 122 is connected to the receiving terminal RXD1 (receiving unit R1) of the first RS485 communication module 110, and the second terminal of the first charging / discharging unit 122 is connected to the input terminal of the first inverter f1. The first charging / discharging unit 122 is used to charge based on the high-level signal of the receiving terminal RXD1 of the first RS485 communication module 110, and to discharge based on the low-level signal of the receiving terminal RXD1 of the first RS485 communication module 110.

[0085] Combination Figure 1 and Figure 3 According to one embodiment of this application, a first terminal of the first charge discharge unit 124 is connected to a first terminal of the first charge discharge unit 122, and a second terminal of the first charge discharge unit 124 is connected to a second terminal of the first charge discharge unit 122. The first charge discharge unit 124 is used to provide a channel for discharging charge for the first charge discharge unit 122. The output terminal of the first inverter f1 is connected to the transmit / receive enable terminal E2 of the digital isolation module 130. The first inverter f1 is used to reverse the phase of the low-level signal or high-level signal of the receiver RXD1 of the first RS485 communication module 110 by 180°.

[0086] Combination Figure 1 and Figure 3 According to one embodiment of this application, point F (transmit / receive enable terminal E3 of the second RS485 communication module 140) is connected to the transmit / receive enable terminal E2 of the digital isolation module 130, the receiving unit R3 (receiving terminal RXD3) and the transmitting unit T3 (transmitting terminal TXD3) of the second RS485 communication module 140. The receiving unit R3 and the transmitting unit T3 of the second RS485 communication module 140 are connected to the second RS485 bus.

[0087] Please continue reading Figure 3According to one embodiment of this application, the first charging and discharging unit 122 includes a first resistor Rd1 and a first capacitor C1, and the first charge discharging unit 124 includes a first diode D1.

[0088] Combination Figure 1 and Figure 3 According to one embodiment of this application, the first end of the first resistor Rd1 is connected to the receiving end RXD1 (receiving unit R1) of the first RS485 communication module 110 and the cathode of the first diode D1. The second end of the first resistor Rd1 is connected to the first end of the first capacitor C1, the anode of the first diode D1, and the input end of the first inverter f1. The second end of the first capacitor C1 is grounded (digital ground), and the output end of the first inverter f1 is connected to the transmit / receive enable terminal E2 of the digital isolation module 130.

[0089] Wherein, the first end of the first resistor Rd1 is the first end of the first signal transceiver conversion module 120, and the output end of the first inverter f1 is the second end of the first signal transceiver conversion module 120.

[0090] Combination Figure 1 and Figure 3 In one embodiment, since the right-side RS485 bus is connected to pull-up resistor Rup, fourth resistor Rt, and pull-down resistor Rdown, the differential voltage between the left and right RS485 buses when idle is greater than 200mV. Point E is normally at a high level when idle, the first capacitor C1 is fully charged, and due to the action of the first inverter f1, the potential at point F is low. The second RS485 communication module 140 is in receive mode by default.

[0091] When the receiving unit R1 of the first RS485 communication module 110 receives a 1-bit low-level signal, the potential of point E becomes low, the first capacitor C1 begins to discharge, the potential of point F becomes high, and the transmitting unit T3 of the second RS485 communication module 140 starts to transmit the signal from the receiving unit R1 of the first RS485 communication module 110, thereby realizing the automatic transmission and reception of signals.

[0092] In one embodiment, a set of values ​​for a first resistor Rd1 and a first capacitor C1 can be determined based on the threshold of the first inverter f1 and the data transmission rate of the RS485 bus to meet the requirements of RS485 bus communication.

[0093] Please refer to Figure 4. Figure 4 This is a schematic circuit diagram of the second signal transceiver conversion module 150 provided in an embodiment of this application. Figure 4As shown, the second signal transceiver conversion module 150 includes: a second charging / discharging unit 152, a second charge discharging unit 154, and a second inverter f2. In one embodiment, the second inverter f2 can be an AiP74HC14SA14.

[0094] Combination Figure 2 and Figure 4 According to one embodiment of this application, the first terminal of the second charging / discharging unit 152 is connected to the receiving terminal RXD2 (receiving unit R2) of the digital isolation module 130, the second terminal of the second charging / discharging unit 152 is connected to the input terminal of the second inverter f2, and the receiving unit R2 of the digital isolation module 130 is connected to the receiving unit R3 (receiving terminal RXD3) of the second RS485 communication module 140. The second charging / discharging unit 152 is used to charge based on the high-level signal of the receiving terminal RXD2 of the digital isolation module 130 and to discharge based on the low-level signal of the receiving terminal RXD2 of the digital isolation module 130.

[0095] Combination Figure 2 and Figure 4 According to one embodiment of this application, the first terminal of the second charge discharge unit 154 is connected to the first terminal of the second charge discharge unit 152, and the second terminal of the second charge discharge unit 154 is connected to the second terminal of the second charge discharge unit 152. The second charge discharge unit 154 is used to provide a channel for discharging charge for the second charge discharge unit 152. The output terminal of the second inverter f2 is connected to the transmit / receive enable terminal E1 of the first RS485 communication module 110, and the second inverter f2 is used to reverse the phase of the enable signal of the receiver RXD2 of the digital isolation module 130 by 180°.

[0096] Combination Figure 2 and Figure 4 According to one embodiment of this application, point K (transmit / receive enable terminal E1 of the first RS485 communication module 110) is connected to the receiving unit R1 (receiving end RXD1) and the transmitting unit T1 (transmitting end TXD1) of the first RS485 communication module 110. The receiving unit R1 and the transmitting unit T1 of the first RS485 communication module 110 are connected to the first RS485 bus.

[0097] Please continue reading Figure 4 According to one embodiment of this application, the second charging and discharging unit 152 includes a second resistor Rd2 and a second capacitor C2, and the second charge discharging unit 154 includes a second diode D2.

[0098] Combination Figure 2 and Figure 4According to one embodiment of this application, the first end of the second resistor Rd2 is connected to the receiving terminal RXD2 of the digital isolation module 130 and the cathode of the second diode D2. The second end of the second resistor Rd2 is connected to the first end of the second capacitor C2, the anode of the second diode D2, and the input terminal of the second inverter f2. The second end of the second capacitor C2 is grounded (digital ground), and the output terminal of the second inverter f2 is connected to the transmit / receive enable terminal E1 of the first RS485 communication module 110.

[0099] The output of the second inverter f2 is the first terminal of the second signal transceiver module 150, and the first terminal of the second resistor Rd2 is the second terminal of the second signal transceiver module 150.

[0100] Combination Figure 2 and Figure 4 In one embodiment, the potential of point J in idle normal state is high level, the second capacitor C2 is fully charged, and due to the action of the second inverter f2, the potential of point K is low level, and the first RS485 communication module 110 is in receive state by default.

[0101] When the receiving unit R3 of the second RS485 communication module 140 receives a 1-bit low-level signal, the potential of point J becomes low, the second capacitor C2 starts to discharge, the potential of point K becomes high, and the transmitting unit T1 of the first RS485 communication module 110 starts to transmit the signal of the receiving unit R3 of the second RS485 communication module 140, thereby realizing the automatic transmission and reception of signals.

[0102] In one embodiment, a set of values ​​for a second resistor Rd2 and a second capacitor C2 can be determined based on the threshold of the second inverter f2 and the data transmission rate of the RS485 bus to meet the requirements of RS485 bus communication.

[0103] Combination Figure 1 and Figure 2 In one embodiment, when a signal is transmitted on the left RS485 bus, the receiving end RXD1 of the first RS485 communication module 110 receives the signal and, through the automatic transceiver conversion and digital isolation module 130, drives the second RS485 communication module 140 into transmit mode, which then transmits the signal to the right RS485 bus. Similarly, when a signal is transmitted on the right RS485 bus, the receiving end RXD3 of the second RS485 communication module 140 receives the signal and, through the digital isolation module 130 and automatic transceiver conversion, drives the first RS485 communication module 110 into transmit mode, which then transmits the signal to the left RS485 bus.

[0104] Please see Figure 5 , Figure 5This is a schematic block diagram of the redundant RS485 transceiver conversion digital isolation relay circuit 100 provided in an embodiment of this application. Figure 5 As shown, the circuit 100 includes multiple isolated channels, each with the same operating mode. The first RS485 bus and the second RS485 bus are multiple, and there are multiple first RS485 communication modules 110, first signal transceiver conversion modules 120, second signal transceiver conversion modules 150, digital isolation modules 130, and second RS485 communication modules 140.

[0105] In one embodiment, the circuit 100 includes two isolated channels, with the first RS485 bus and the second RS485 bus being two channels.

[0106] According to one embodiment of this application, a first DC / DC module 160 (DC-to-DC regulated power supply module) is connected between every two first RS485 communication modules 110, and a second DC / DC module 170 is connected between every two second RS485 communication modules 140. The first DC / DC module 160 provides 5V / 24V operating power to the first RS485 communication modules 110, and the second DC / DC module 170 provides 5V / 24V operating power to the second RS485 communication modules 140.

[0107] Combination Figure 1 and Figure 3 According to one embodiment of this application, the second RS485 bus includes a first signal line RS485_A and a second signal line RS485_B. The circuit 100 also includes a third resistor Rpu. A first terminal of the third resistor Rpu is connected to a first power supply voltage input terminal VCC1, and a second terminal of the third resistor Rpu is connected to either the first signal line RS485_A or the second signal line RS485_B. The third resistor Rpu is used for voltage division.

[0108] Combination Figure 1 and Figure 3 According to one embodiment of this application, the circuit 100 further includes a bus voltage adjustment module 180. A first terminal of the bus voltage adjustment module 180 is connected to a second power supply voltage input terminal VCC2, a second terminal of the bus voltage adjustment module 180 is grounded, and the bus voltage adjustment module 180 is connected to a second RS485 bus. The bus voltage adjustment module 180 is used to adjust the voltage between the first signal line RS485_A and the second signal line RS485_B when the second RS485 bus is idle, based on the resistance value.

[0109] Please continue reading Figure 3According to one embodiment of this application, the bus voltage regulation module 180 includes: a pull-up resistor Rup, a pull-down resistor Rdown, and a fourth resistor Rt. The series connection of the pull-up resistor Rup and the fourth resistor Rt is connected to the first signal line RS485_A of the second RS485 bus, and the series connection of the pull-down resistor Rdown and the fourth resistor Rt is connected to the second signal line RS485_B of the second RS485 bus. The pull-up resistor Rup is also connected to the second power supply voltage input terminal VCC2, which can increase the pull-up level of the first signal line RS485_A. The pull-down resistor Rdown is also grounded, which can provide a pull-down level for the second signal line RS485_B.

[0110] In one embodiment, the voltage between the first signal line RS485_A and the second signal line RS485_B can be adjusted by changing the resistance values ​​of the pull-up resistor Rup, the pull-down resistor Rdown, and the fourth resistor Rt.

[0111] This application proposes a dual-channel RS485 isolator based on domestically produced chips, capable of automatic transmit / receive switching. This isolator is a digital isolator that uses ductile isolation technology, solving the problems associated with optocouplers. It has a simple manufacturing process and, compared to magnetic isolation, requires no additional MCU (Microcontroller Unit) control circuitry, resulting in lower cost, higher reliability, higher data transmission rate, and better EMC performance.

[0112] The key aspects of this application are: redundant RS485 bus communication; automatic transmit / receive switching circuit, which matches the RS485 bus communication rate by setting reasonable resistor and capacitor values; and the use of digital isolation technology, resulting in high reliability and low cost. The ideas and technologies protected by this application include: a dual-channel redundant RS485 communication bus, the design of the automatic transmit / receive switching circuit, the circuit design of the digital isolator, and the use of entirely domestically produced chips.

[0113] This application also provides a redundant RS485 transceiver conversion digital isolation repeater; please refer to [link to relevant documentation]. Figure 6 , Figure 6 This is a schematic block diagram of the redundant RS485 transceiver conversion digital isolation repeater 200 provided in an embodiment of this application. Figure 6 As shown, the redundant RS485 transceiver digital isolation repeater 200 includes a redundant RS485 transceiver digital isolation repeater circuit 100.

[0114] According to one embodiment of this application, the redundant RS485 transceiver conversion digital isolation repeater 200 further includes a battery module 210. The battery module 210 is connected to the redundant RS485 transceiver conversion digital isolation repeater circuit 100.

[0115] In the above embodiments, the descriptions of each embodiment have different focuses. For parts that are not described in detail or recorded in a certain embodiment, please refer to the relevant descriptions of other embodiments.

[0116] The above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application, and should all be included within the protection scope of this application.

Claims

1. A redundant RS485 transceiver conversion digital isolation relay circuit, characterized in that, The circuit includes: a first RS485 communication module, a first signal transceiver conversion module, a digital isolation module, and a second RS485 communication module; The first RS485 communication module is connected to the first RS485 bus. The receiving end of the first RS485 communication module is connected to the first end of the first signal transceiver conversion module and the transmitting end of the digital isolation module. The first RS485 communication module is used to send signals on the first RS485 bus to the digital isolation module and to send low-level signals to the first signal transceiver conversion module. The second terminal of the first signal transceiver conversion module is connected to the transceiver enable terminal of the digital isolation module. The first signal transceiver conversion module is used to trigger the enable signal to be in the transmission state based on the low level signal and send the enable signal to the digital isolation module. The transmit / receive enable terminal of the digital isolation module is connected to the transmit / receive enable terminal of the second RS485 communication module, and the transmit terminal of the digital isolation module is connected to the transmit terminal of the second RS485 communication module. The digital isolation module is used to send an enable signal and signals on the first RS485 bus to the second RS485 communication module and to perform electrical isolation. The second RS485 communication module is connected to the second RS485 bus and is used to transmit signals on the first RS485 bus to the second RS485 bus based on an enable signal.

2. The redundant RS485 transceiver conversion digital isolation relay circuit according to claim 1, characterized in that, The circuit also includes: a second signal transceiver conversion module; The receiving end of the second RS485 communication module is connected to the receiving end of the digital isolation module, and the second RS485 communication module is used to send signals on the second RS485 bus to the digital isolation module; The receiving end of the digital isolation module is also connected to the transmitting end of the first RS485 communication module and the second end of the second signal transceiver conversion module. The digital isolation module is also used to send signals on the second RS485 bus to the first RS485 communication module and to send low-level signals to the second signal transceiver conversion module. The first end of the second signal transceiver conversion module is connected to the transceiver enable end of the first RS485 communication module. The second signal transceiver conversion module is also used to trigger the enable signal to be in the transmission state based on the low level signal and send the enable signal to the first RS485 communication module. The first RS485 communication module is also used to transmit signals on the second RS485 bus to the first RS485 bus based on an enable signal.

3. The redundant RS485 transceiver conversion digital isolation relay circuit according to claim 1, characterized in that, The first signal transceiver conversion module includes: a first charging and discharging unit, a first charge discharging unit, and a first inverter; The first end of the first charging and discharging unit is connected to the receiving end of the first RS485 communication module, and the second end of the first charging and discharging unit is connected to the input end of the first inverter. The first charging and discharging unit is used to charge based on the high-level signal of the receiving end of the first RS485 communication module and to discharge based on the low-level signal of the receiving end of the first RS485 communication module. The first end of the first charge discharge unit is connected to the first end of the first charge discharge unit, and the second end of the first charge discharge unit is connected to the second end of the first charge discharge unit. The first charge discharge unit is used to provide a channel for the first charge discharge unit to discharge charge. The output of the first inverter is connected to the transmit / receive enable terminal of the digital isolation module. The first inverter is used to reverse the phase of the low-level signal or high-level signal of the receiving end of the first RS485 communication module by 180°.

4. The redundant RS485 transceiver conversion digital isolation relay circuit according to claim 3, characterized in that, The first charging and discharging unit includes a first resistor and a first capacitor, and the first charge discharging unit includes a first diode; The first end of the first resistor is connected to the receiving end of the first RS485 communication module and the cathode of the first diode. The second end of the first resistor is connected to the first end of the first capacitor, the anode of the first diode, and the input end of the first inverter. The second end of the first capacitor is grounded. The output end of the first inverter is connected to the transmit / receive enable end of the digital isolation module. Wherein, the first end of the first resistor is the first end of the first signal transceiver conversion module, and the output end of the first inverter is the second end of the first signal transceiver conversion module.

5. The redundant RS485 transceiver conversion digital isolation relay circuit according to claim 2, characterized in that, The second signal transceiver conversion module includes: a second charging and discharging unit, a second charge discharging unit, and a second inverter; The first end of the second charging and discharging unit is connected to the receiving end of the digital isolation module, and the second end of the second charging and discharging unit is connected to the input end of the second inverter. The second charging and discharging unit is used to charge based on the high-level signal of the receiving end of the digital isolation module and to discharge based on the low-level signal of the receiving end of the digital isolation module. The first end of the second charge discharge unit is connected to the first end of the second charge discharge unit, and the second end of the second charge discharge unit is connected to the second end of the second charge discharge unit. The second charge discharge unit is used to provide a channel for the second charge discharge unit to discharge charge. The output of the second inverter is connected to the transmit / receive enable terminal of the first RS485 communication module. The second inverter is used to reverse the phase of the low-level signal or high-level signal received by the digital isolation module by 180°.

6. The redundant RS485 transceiver conversion digital isolation relay circuit according to claim 5, characterized in that, The second charging and discharging unit includes a second resistor and a second capacitor, and the second charge discharging unit includes a second diode; The first end of the second resistor is connected to the receiving end of the digital isolation module and the cathode of the second diode. The second end of the second resistor is connected to the first end of the second capacitor, the anode of the second diode, and the input end of the second inverter. The second end of the second capacitor is grounded. The output end of the second inverter is connected to the transmit / receive enable end of the first RS485 communication module. Wherein, the output terminal of the second inverter is the first terminal of the second signal transceiver conversion module, and the first terminal of the second resistor is the second terminal of the second signal transceiver conversion module.

7. The redundant RS485 transceiver conversion digital isolation relay circuit according to claim 2, characterized in that, The first RS485 bus and the second RS485 bus are multiple, and there are multiple first RS485 communication modules, first signal transceiver conversion modules, second signal transceiver conversion modules, digital isolation modules, and second RS485 communication modules. A first DC / DC module is connected between every two first RS485 communication modules, and a second DC / DC module is connected between every two second RS485 communication modules. The first DC / DC module is used to provide operating power to the first RS485 communication modules, and the second DC / DC module is used to provide operating power to the second RS485 communication modules.

8. The redundant RS485 transceiver conversion digital isolation relay circuit according to claim 1, characterized in that, The second RS485 bus includes: a first signal line and a second signal line; the circuit also includes a third resistor, the first end of which is connected to the first power supply voltage input terminal, and the second end of which is connected to the first signal line or the second signal line.

9. The redundant RS485 transceiver conversion digital isolation relay circuit according to claim 8, characterized in that, The circuit also includes a bus voltage regulation module; The first terminal of the bus voltage adjustment module is connected to the second power supply voltage input terminal, the second terminal of the bus voltage adjustment module is grounded, the bus voltage adjustment module is connected to the second RS485 bus, and the bus voltage adjustment module is used to adjust the voltage between the first signal line and the second signal line when the second RS485 bus is idle based on the resistance value.

10. The redundant RS485 transceiver conversion digital isolation relay circuit according to claim 9, characterized in that, The bus voltage regulation module includes: a pull-up resistor, a pull-down resistor, and a fourth resistor; The series connection node of the pull-up resistor and the fourth resistor is connected to the first signal line of the second RS485 bus, the series connection node of the pull-down resistor and the fourth resistor is connected to the second signal line of the second RS485 bus, the pull-up resistor is also connected to the second power supply voltage input terminal, and the pull-down resistor is also grounded.

11. A redundant RS485 transceiver conversion digital isolation repeater, characterized in that, Includes a redundant RS485 transceiver conversion digital isolation relay circuit as described in any one of claims 1 to 10.

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