A multi-protocol communication interface multiplexing circuit and a data acquisition device

Abstract

This invention discloses a multi-protocol communication interface multiplexing circuit and a data acquisition device, belonging to the field of communication interface multiplexing technology. The circuit includes a microcontroller, a first communication transceiver with integrated isolation power supply, a second communication transceiver, a multiplexed communication interface, and a protection module. This invention achieves time-division multiplexing of multiple protocols on the same physical interface without adding external analog switching chips, by enabling the isolation power supply of the first communication transceiver to directly power the second communication transceiver and connecting their differential signal terminals in parallel. Combined with the microcontroller's precise mutual exclusion high-impedance control logic, this invention perfectly realizes time-division multiplexing of multiple protocols on the same physical interface, greatly saving internal board space and external terminal resources.

Description

Technical Field

[0001] This invention relates to the field of communication interface multiplexing technology, specifically to a multi-protocol communication interface multiplexing circuit and a data acquisition device. Background Technology

[0002] In power systems, industrial automation, and smart grids, RS485 bus and Controller Area Network (CAN bus) are the two most widely used fieldbus communication methods. Typically, microcontrollers are equipped with independent universal asynchronous transceivers (UAVs) and CAN controller peripherals. These peripherals achieve physical layer signal conversion through independent RS485 transceivers and CAN transceivers, respectively. Furthermore, the device housing needs to have independent RS485 interface terminals and CAN interface terminals. In addition, to ensure system safety and interference immunity, a strict electrical isolation mechanism must be implemented between the microcontroller-side circuitry and the bus communication-side circuitry to meet high AC withstand voltage standards.

[0003] However, existing conventional designs generally suffer from significant drawbacks such as high hardware redundancy and wasted interface resources. In practical applications, customers often only choose one of the independently configured RS485 and Controller Area Network (CAN) interfaces. The physical presence of dual interfaces not only occupies limited terminal block space but also reduces the sealing of the product casing, hindering the improvement of the overall protection level. In traditional isolated communication architectures, RS485 isolation circuits and CAN isolation circuits typically require independent optocouplers or digital isolation chips, as well as independent DC-DC isolated power supply modules. These isolation devices, especially power isolation modules using transformer solutions, are bulky and have complex wiring, severely restricting the development of products towards miniaturization and high density. Furthermore, the complex isolators, power modules, and redundant connector terminals result in high hardware bill of materials costs and, to some extent, increase the system failure rate. Existing optimization solutions sometimes introduce external analog switches to achieve interface multiplexing, but this still cannot fundamentally eliminate the space occupation and cost pressure caused by additional components. Therefore, how to eliminate independent discrete power isolation devices to reduce the printed circuit board area, how to allow two circuits to share a set of external interfaces to reduce the number of enclosure slots and improve the physical protection level, and how to achieve flexible time-division multiplexing of multiple buses without adding additional analog switching devices have become the core technical problems that urgently need to be solved. Summary of the Invention

[0004] In view of the above-mentioned problems, the present invention provides a multi-protocol communication interface multiplexing circuit and a data acquisition device.

[0005] Therefore, the technical problem solved by this invention is that existing RS485 and CAN dual communication solutions are usually configured with independent external interfaces and independent power isolation modules, resulting in high hardware redundancy, many terminals, large size of isolation devices and high cost, which seriously restricts the miniaturization and high protection design of equipment.

[0006] To solve the above-mentioned technical problems, the present invention provides the following technical solution: a multi-protocol communication interface multiplexing circuit, including a microcontroller; The first communication transceiver integrates an isolated power supply; Second communication transceiver; Reuse communication interfaces; The isolation power output terminal of the first communication transceiver is connected to the power pin of the second communication transceiver; The differential signal terminals of the first and second communication transceivers are connected in parallel to the multiplexed communication interface. The microcontroller is connected to the first control terminal of the first communication transceiver and the second control terminal of the second communication transceiver, respectively, and is used to control the first control terminal and the second control terminal to enable one of the first communication transceiver and the second communication transceiver and put the other communication transceiver in a high impedance state.

[0007] As a preferred embodiment of the multi-protocol communication interface multiplexing circuit described in this invention, the first communication transceiver is an RS485 transceiver with an isolated power supply. The second communication transceiver is a CAN transceiver.

[0008] As a preferred embodiment of the multi-protocol communication interface multiplexing circuit described in this invention, the first data terminal of the microcontroller is connected to the data terminal of the first communication transceiver. The second data terminal of the microcontroller is connected to the data terminal of the second communication transceiver; The first control terminal is the enable terminal of the first communication transceiver, and the second control terminal is the control terminal used to control the working state of the second communication transceiver.

[0009] As a preferred embodiment of the multi-protocol communication interface multiplexing circuit described in this invention, in response to the RS485 communication mode control signal received by the microcontroller, the microcontroller controls the second control terminal to cause the second communication transceiver to enter a high-impedance state. The microcontroller also controls the first control terminal to enable the first communication transceiver.

[0010] As a preferred embodiment of the multi-protocol communication interface multiplexing circuit described in this invention, in response to the CAN communication mode control signal received by the microcontroller, the microcontroller controls the first control terminal to put the first communication transceiver in a high-impedance state. The microcontroller also controls the second control terminal to enable the second communication transceiver.

[0011] In a preferred embodiment of the multi-protocol communication interface multiplexing circuit described in this invention, the logic-side power input pin of the first communication transceiver shares the local system power supply with the microcontroller.

[0012] As a preferred embodiment of the multi-protocol communication interface multiplexing circuit described in this invention, a protection module is provided, which is connected to the multiplexing communication interface.

[0013] In a preferred embodiment of the multi-protocol communication interface multiplexing circuit described in this invention, the protection module includes a transient voltage suppression diode, which is connected in parallel between the differential signal lines of the multiplexed communication interface.

[0014] In a preferred embodiment of the multi-protocol communication interface multiplexing circuit described in this invention, the protection module includes a transient voltage suppression diode, which is connected across the differential signal terminal of the multiplexed communication interface and ground.

[0015] To solve the above-mentioned technical problems, the present invention also provides the following technical solution: a data acquisition device, which is provided with the aforementioned multi-protocol communication interface multiplexing circuit.

[0016] The beneficial effects of this invention are as follows: First, it utilizes a communication transceiver with integrated isolated power supply for cross-connection power supply, eliminating the need for separate discrete power isolation devices, significantly reducing PCB area and achieving miniaturization; second, two circuits share a single external interface, reducing casing slots and significantly improving the physical protection level and environmental adaptability of the equipment; third, it eliminates redundant terminals and expensive isolation components, and achieves multi-bus multiplexing without the need for additional analog switches, effectively reducing material costs; fourth, it allows for flexible switching of communication protocols through microcontroller software configuration, improving system scalability. Attached Figure Description

[0017] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a topology diagram of a multi-protocol communication interface multiplexing circuit provided in one embodiment of the present invention.

[0019] Figure 2 This is a diagram of a dual communication isolation circuit scheme in the prior art.

[0020] Figure 3 This is a structural block diagram of an optional embodiment of the present invention.

[0021] Figure 4 This is a circuit diagram showing the interface pin mapping of a first communication transceiver provided in one embodiment of the present invention.

[0022] Figure 5 The main isolation and protection circuit diagram of a first communication transceiver provided in one embodiment of the present invention is shown.

[0023] Figure 6 An electromagnetic compatibility grounding protection circuit diagram is provided for one embodiment of the present invention.

[0024] Figure 7 The main communication circuit diagram of the second communication transceiver provided in one embodiment of the present invention is shown.

[0025] Figure 8 This is a transistor driving circuit diagram provided for one embodiment of the present invention.

[0026] Figure 9 This is a circuit diagram of an optocoupler isolation circuit provided in one embodiment of the present invention.

[0027] Figure 10 This is a diagram of an external port and a filter circuit provided for one embodiment of the present invention. Detailed Implementation

[0028] To enable those skilled in the art to better understand the present invention, specific embodiments of the present invention are described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without inventive effort should fall within the protection scope of the present invention.

[0029] refer to Figures 1 to 10 This paper provides a multi-protocol communication interface multiplexing circuit.

[0030] refer to Figure 2 It is understandable that in the existing technology, the RS485 circuit and the CAN circuit are not interconnected and are each configured with multiple independent power isolators under the main power supply, resulting in hardware redundancy and occupying a lot of interface resources.

[0031] refer to Figure 1 and Figure 3 The present invention provides a multi-protocol communication interface multiplexing circuit, including: a microcontroller 100, a first communication transceiver 200, a second communication transceiver 300, a multiplexed communication interface 400, and a protection module 500.

[0032] The isolated power output terminal of the first communication transceiver 200 is connected to the power pin of the second communication transceiver 300, so as to output the isolated power of the RS485 chip with integrated power isolation function to the CAN chip.

[0033] The differential signal terminals of the first transceiver 200 and the second transceiver 300 are connected in parallel to the multiplexed communication interface 400, thereby sharing the same set of external physical interfaces.

[0034] The microcontroller 100 is connected to the first communication transceiver 200 and the second communication transceiver 300 respectively to achieve mutual exclusion control, and a protection module 500 is connected in series between the parallel node and the multiplexed communication interface 400.

[0035] In one alternative implementation, the first communication transceiver 200 is specifically an RS485 transceiver with isolated power supply; the second communication transceiver 300 is specifically a CAN transceiver, and the logic-side power input pin of the first communication transceiver 200 shares the local system power supply with the microcontroller 100.

[0036] refer to Figure 4 This represents the pin mapping relationship of the interface at the front end of the first communication transceiver.

[0037] Each network label corresponds to the power supply, ground, receiver, transmitter, and control terminals of the microcontroller. These labels are used to indicate the physical path of the connections to the subsequent main chip and clarify the underlying interaction channel between the microcontroller and the isolation communication module.

[0038] refer to Figure 5 This is the main isolation and protection circuit structure of the first communication transceiver.

[0039] The first communication transceiver 200 preferably uses the CA-IS3092W chip. The data and control pins of the microcontroller 100 are connected to the logic side of this chip through the aforementioned mapping relationship. The chip integrates a high-efficiency isolated power supply and outputs a stable isolated voltage through its pin 16; the network designation of this isolated voltage is VISO, and this VISO network is directly connected to and powers the subsequent second communication transceiver.

[0040] A protection module 500, consisting of multiple transient voltage suppression diodes, is installed on the path from the differential signal pins A and B to the multiplexed communication interface 400.

[0041] The transient voltage suppressor diode TSS2 is directly connected in parallel between the two differential signal lines to suppress differential mode overvoltage, while the transient voltage suppressor diodes TSS1 and TSS3 are respectively connected across a single differential signal line and the isolation ground network to discharge common mode surge energy to the ground network.

[0042] refer to Figure 6 To further enhance the system's electromagnetic compatibility (EMC) performance in complex industrial environments, an EMC grounding protection circuit is added to the circuit. This part includes a safety Y capacitor CY1, which is connected between the isolation ground GND485 and the system ground, providing a fast discharge path for high-frequency interference signals, thereby forming a highly reliable communication link with an isolated physical layer.

[0043] In some other embodiments, reference is made to... Figure 7 This section details the main communication circuit of the second communication transceiver. The second communication transceiver 300 uses a CAN bus communication chip, and its core operating power is directly taken from the attached chip. Figure 5 The VISO network label output by the first communication transceiver eliminates the need for a separate power isolation component. The differential output of this CAN communication chip is ultimately connected in parallel with the differential signal of the first communication transceiver on the physical circuit, leading to the external multiplexed communication interface.

[0044] refer to Figure 8 This is the transistor drive circuit for the second communication transceiver.

[0045] This circuit utilizes the switching characteristics of a transistor to receive the operating status control signals issued by the microcontroller 100, thereby achieving control level conversion and signal amplification and driving.

[0046] refer to Figure 9 This is the optocoupler isolation circuit before the second communication transceiver.

[0047] This section isolates the microcontroller's logic control signals from the bus-side circuitry using optocouplers and their peripheral inductor and resistor-capacitor matching networks. This ensures that signals can be transmitted without distortion even under high-voltage interference and enables precise switching logic for high-impedance bus states.

[0048] refer to Figure 10 , which is the external port and filter circuit.

[0049] This section includes connector sockets and a parallel array of filter capacitors, which are used to securely extract underlying communication signals and effectively filter out high-frequency noise on the power and ground networks, ensuring the stability of overall signal transmission.

[0050] To achieve precise control, the first data terminal of the microcontroller 100 is connected to the data terminal of the first communication transceiver 200, and the second data terminal of the microcontroller 100 is connected to the data terminal of the second communication transceiver 300.

[0051] The microcontroller 100 is connected to the first control terminal of the first communication transceiver 200 and the second control terminal of the second communication transceiver 300. The first control terminal is the enable terminal of the first communication transceiver 200, and the second control terminal is the control terminal used to control the working state of the second communication transceiver 300.

[0052] In response to the RS485 communication mode control signal received by the microcontroller 100, the microcontroller 100 controls the second control terminal to put the second communication transceiver 300 into a high-impedance state, and at the same time, the microcontroller 100 also controls the first control terminal to put the first communication transceiver 200 into an enabled state.

[0053] In response to the CAN communication mode control signal received by the microcontroller 100, the microcontroller 100 controls the first control terminal to put the first communication transceiver 200 into a high-impedance state, and at the same time, the microcontroller 100 also controls the second control terminal to put the second communication transceiver 300 into an enabled state.

[0054] In another alternative embodiment, the present invention also provides a data acquisition device, which is provided with a multi-protocol communication interface multiplexing circuit as described in any of the foregoing embodiments.

[0055] In complex industrial control or power monitoring applications, data acquisition devices often need to be compatible with different communication networks. Thanks to the integrated multi-protocol communication interface multiplexing circuit, the data acquisition device only needs to reserve one set of multiplexed communication interfaces 400 for external connection in its shell structure design, which greatly reduces the number of physical openings and thus effectively improves the overall dustproof and waterproof physical protection level of the device.

[0056] To address the problem that redundant hardware structures and excessive interface resources in existing technologies make it difficult to achieve miniaturization and high protection design of devices, this invention, through the above configuration, enables the first communication transceiver with isolated power supply to directly power the second communication transceiver, and physically connects the differential communication lines of the two to the same set of external communication interfaces.

[0057] By using a microcontroller to keep the native state terminals of idle transceivers in a high-impedance state, the time-division multiplexing problem of multiple communication protocols on a single physical port can be solved without the need for additional analog switches or multiplexing chips. Eliminating bulky independent discrete power supplies and using isolation devices effectively reduces the internal circuit board area. Furthermore, by sharing external communication terminals, the number of openings in the device casing is reduced, thereby improving the device's structural compactness and physical protection level. This reduces hardware manufacturing costs while providing the underlying hardware interface with extremely high software configuration flexibility.

[0058] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A multi-protocol communication interface multiplexing circuit, characterized in that, include: Microcontroller (100); The first communication transceiver (200) integrates an isolated power supply; Second communication transceiver (300); Multiplex the communication interface (400); The isolated power output terminal of the first communication transceiver (200) is connected to the power supply pin of the second communication transceiver (300); The differential signal terminal of the first communication transceiver (200) and the differential signal terminal of the second communication transceiver (300) are connected in parallel to the multiplexed communication interface (400). The microcontroller (100) is connected to the first control terminal of the first communication transceiver (200) and the second control terminal of the second communication transceiver (300) respectively, and is used to control the first control terminal and the second control terminal to enable one of the first communication transceiver (200) and the second communication transceiver (300) and put the other communication transceiver in a high impedance state.

2. The multi-protocol communication interface multiplexing circuit as described in claim 1, characterized in that: The first communication transceiver (200) is an RS485 transceiver with an isolated power supply; The second communication transceiver (300) is a CAN transceiver.

3. The multi-protocol communication interface multiplexing circuit as described in claim 2, characterized in that: The first data terminal of the microcontroller (100) is connected to the data terminal of the first communication transceiver (200); The second data terminal of the microcontroller (100) is connected to the data terminal of the second communication transceiver (300); The first control terminal is the enable terminal of the first communication transceiver (200), and the second control terminal is the control terminal used to control the working state of the second communication transceiver (300).

4. The multi-protocol communication interface multiplexing circuit as described in claim 3, characterized in that: In response to the RS485 communication mode control signal received by the microcontroller (100), the microcontroller (100) controls the second control terminal to cause the second communication transceiver (300) to enter a high impedance state; The microcontroller (100) also controls the first control terminal to enable the first communication transceiver (200).

5. The multi-protocol communication interface multiplexing circuit as described in claim 3, characterized in that: In response to the CAN communication mode control signal received by the microcontroller (100), the microcontroller (100) controls the first control terminal to put the first communication transceiver (200) into a high impedance state; The microcontroller (100) also controls the second control terminal to enable the second communication transceiver (300).

6. The multi-protocol communication interface multiplexing circuit as described in claim 1, characterized in that: The logic-side power input pin of the first communication transceiver (200) shares the local system power supply with the microcontroller (100).

7. The multi-protocol communication interface multiplexing circuit as described in claim 1, characterized in that, Also includes: A protection module (500) is connected to the multiplexed communication interface (400).

8. The multi-protocol communication interface multiplexing circuit as described in claim 7, characterized in that: The protection module (500) includes a transient voltage suppression diode connected in parallel between the differential signal lines of the multiplexed communication interface (400).

9. The multi-protocol communication interface multiplexing circuit as described in claim 7, characterized in that: The protection module (500) includes a transient voltage suppression diode connected across the differential signal terminal of the multiplexed communication interface (400) and ground.

10. A data acquisition device, characterized in that: The data acquisition device is provided with a multi-protocol communication interface multiplexing circuit as described in any one of claims 1 to 9.

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