RS485 line distribution conversion device and method with fault diagnosis function

Abstract

The present invention relates to the technical field of communication systems, and discloses an RS485 line distribution conversion device with a fault diagnosis function and a fault diagnosis method, comprising a power interface system, a single-chip processing system, an RS485 host, N RS485 slaves, N+1 RS485 communication circuits, and a data storage circuit; the N+1 RS485 communication circuits are electrically connected to each other; the power interface system is electrically connected to the single-chip processing system and the N+1 RS485 communication circuits respectively; the data storage circuit is electrically connected to the single-chip processing system; the single-chip processing system is electrically connected to the N+1 RS485 communication circuits respectively; the data storage circuit is electrically connected to the power interface system and the single-chip processing system respectively. The present invention solves the problem that the prior art cannot support sending data from multiple nodes at the same time and cannot support different communication parameters.

Description

Technical Field

[0001] The present invention relates to the technical field of communication systems, and more specifically to an RS485 line distribution conversion device with a fault diagnosis function and a fault diagnosis method. Background Art

[0002] In the industrial control and petrochemical industries, instrument data acquisition and communication are extremely important. The most common communication method is the RS485 bus mode. This bus adopts half-duplex working mode, supports multi-point connection, and uses a bus to connect each node in series.

[0003] The disadvantages of the RS485 bus are: ① When a node on the network fails, it will cause the entire system to fail or partially fail, and it is difficult to determine the location of the failure; ② Because it is a half-duplex mode, when there are multiple slave nodes in the communication network sending data at the same time, it will cause the entire network to fail or the data received by the host to be confused; ③ The parameters of the entire network must be consistent, and it is impossible to support different communication parameters for different slaves in the same network.

[0004] The solution to the above problems is to add an RS485 line distribution conversion device. The slave interfaces of the RS485 line distribution conversion devices commonly found on the market are hardware-based, so they mainly solve the above problem ① and cannot solve the remaining problems.

[0005] An RS485 automatic transceiver isolation circuit is currently available, comprising an isolation power supply circuit that provides isolated power for an internal communication circuit, thereby realizing complete isolation of the power supply of internal and external transceivers from the ground; an RS485 communication isolation circuit that realizes internal and external RS485 bus data conversion and isolation; an RS485 data flow direction control circuit that realizes automatic conversion of communication link data flow direction when there is no CPU control; and an RS485 interface lightning protection circuit that is used to suppress transient differential common mode high voltage, thereby effectively protecting RS485 communication protocol chips U2 and U3.

[0006] Since the existing technology cannot support sending data from multiple nodes at the same time and cannot support different communication parameters, how to invent an RS485 line distribution conversion device that supports sending data from nodes at the same time and supports different communication parameters is a technical problem that urgently needs to be solved in this technical field. Summary of the invention

[0007] In order to solve the problem that the prior art cannot support sending data from multiple nodes simultaneously and cannot support different communication parameters, the present invention provides an RS485 line distribution conversion device with a fault diagnosis function, which is reliable, stable and efficient.

[0008] In order to achieve the above-mentioned purpose of the present invention, the technical scheme adopted is as follows:

[0009] A RS485 line distribution conversion device with a fault diagnosis function comprises a power interface system, a single-chip microcomputer processing system, an RS485 host, N RS485 slaves, N+1 RS485 communication circuits, and a data storage circuit; the N+1 RS485 communication circuits are electrically connected to each other; the power interface system is electrically connected to the single-chip microcomputer processing system and the N+1 RS485 communication circuits respectively; the data storage circuit is electrically connected to the single-chip microcomputer processing system; the single-chip microcomputer processing system is electrically connected to the N+1 RS485 communication circuits respectively; the data storage circuit is electrically connected to the power interface system and the single-chip microcomputer processing system respectively.

[0010] Preferably, it also includes N+1 interface protection circuits, the RS485 host is electrically connected to one RS485 communication circuit via one interface protection circuit; the N RS485 slaves are electrically connected to the interface protection circuits of N RS485s respectively via the interface protection circuits.

[0011] Further, specifically, it includes 4 RS485 slaves and 5 RS485 communication circuits.

[0012] Furthermore, the power interface system includes an external power supply, a power protection circuit, and a step-down circuit; the external power supply, the power protection circuit, and the step-down circuit are connected in series in sequence; the step-down circuit is electrically connected to the single-chip microcomputer processing system, N+1 RS485 communication circuits, and the data storage circuit respectively.

[0013] Furthermore, the power protection circuit includes a resettable fuse BX1, a diode D4, and a varistor RM1; one end of the resettable fuse BX1 is electrically connected to an external power supply; the cathode of the diode D4 is electrically connected to the other end of the resettable fuse BX1 and one end of the varistor RM1, respectively, and the anode of the diode D4 is grounded; the other end of the resistor RM1 is grounded.

[0014] Furthermore, the step-down circuit includes a first step-down circuit; the first step-down circuit uses a TPS4530 chip for step-down; and the first step-down circuit is electrically connected to the single-chip processing system and the data storage circuit respectively.

[0015] Furthermore, the step-down circuit also includes a second step-down circuit; the second step-down circuit uses an AMS1117-3.3 chip for step-down; and the second step-down circuit is electrically connected to N+1 RS485 communication circuits respectively.

[0016] Furthermore, the single-chip microcomputer processing system includes an STM32F103 main control chip; the data storage circuit adopts a W25Q128 chip; and the RS485 communication circuit adopts a MAX13487 chip.

[0017] Furthermore, the interface protection circuit is used to protect the differential mode and common mode interference on the communication line; the interface protection circuit includes a first electrostatic ESD protection diode PSM712.1, a second electrostatic ESD protection diode PSM712.2, and a TVS diode SMBJ6.5CA; the positive pole of SMBJ6.5CA is electrically connected to the A port of the MAX13487 chip and one end of PSM712.1 respectively; the negative pole of SMBJ6.5CA is electrically connected to the B port of the MAX13487 chip and one end of PSM712.2 respectively; the other end of PSM712.1 and the other end of PSM712.2 are both grounded.

[0018] A fault diagnosis method for RS485 line distribution conversion with fault diagnosis function:

[0019] S1. Connect the power interface system to the power supply; after the RS485 host is powered on, it enters the configuration mode; if a configuration command is received in the configuration mode, it enters the configuration mode until restarted, otherwise it enters the working mode;

[0020] S2.N RS485 slaves communicate with the RS485 master through the MCU processing system in mobus mode; configure the communication parameters between the main RS485 master and N RS485 slaves; restart after the configuration is completed, and the RS485 master enters the working mode;

[0021] S3. In working mode, after receiving the data, the RS485 host forwards the data to N RS485 slaves through the single-chip microcomputer processing system through N+1 RS485 communication circuits; when multiple RS485 slaves receive data at the same time, multiple groups of data are forwarded to the RS485 host through the single-chip microcomputer processing system;

[0022] S4. During data transmission and reception, the data storage circuit saves data loss data and data interference data during data transmission and reception through the single-chip processing system with each power-on and power-off as one cycle, and the data loss data and data interference data saved during data transmission and reception are called fault judgment data;

[0023] S5. Re-enter the configuration mode of the RS485 host, read the fault judgment data in different time periods by setting different modbus addresses, and perform fault diagnosis based on the fault judgment data.

[0024] The beneficial effects of the present invention are as follows:

[0025] The present invention discloses a RS485 line distribution conversion device with fault diagnosis function, including a power interface system, a single-chip processing system, an RS485 host, N RS485 slaves, N+1 RS485 communication circuits, and a data storage circuit; the N+1 RS485 communication circuits are electrically connected to each other; the power interface system is electrically connected to the single-chip processing system and the N+1 RS485 communication circuits respectively; the data storage circuit is electrically connected to the single-chip processing system; the single-chip processing system is electrically connected to the N+1 RS485 communication circuits respectively; the data storage circuit is electrically connected to the power interface system and the single-chip processing system respectively. Thus, when a certain node on the network fails, the present invention can prevent the system from being paralyzed as a whole or partially, and it is easy to determine the fault location, thereby improving the reliability and stability of the RS485 communication system; the present invention also supports multiple slave nodes to send data at the same time, supports different communication parameters of different slaves in the same network, improves the troubleshooting efficiency of solving on-site faults, and improves the implementation efficiency of new projects. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 The present invention discloses a system topology diagram of an RS485 line distribution conversion device with a fault diagnosis function.

[0027] Figure 2 The present invention is a schematic diagram of a power protection circuit of an RS485 line distribution conversion device with a fault diagnosis function.

[0028] Figure 3 The present invention is a schematic diagram of the first step-down circuit of an RS485 line distribution conversion device with a fault diagnosis function.

[0029] Figure 4 The present invention is a schematic diagram of the second step-down circuit of an RS485 line distribution conversion device with a fault diagnosis function.

[0030] Figure 5 The present invention is a schematic diagram of a single-chip computer system circuit chip of an RS485 line collection and distribution conversion device with a fault diagnosis function.

[0031] Figure 6 The present invention is a schematic diagram of a single-chip computer system circuit interface circuit of an RS485 line distribution conversion device with a fault diagnosis function.

[0032] Figure 7 The present invention discloses a schematic diagram of a storage circuit of an RS485 line distribution conversion device with a fault diagnosis function.

[0033] Figure 8The present invention discloses a communication and interface protection circuit diagram of an RS485 line distribution conversion device with a fault diagnosis function.

[0034] Fig. 9 The present invention is a flow chart of an RS485 line distribution conversion method with a fault diagnosis function. DETAILED DESCRIPTION

[0035] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0036] Example 1

[0037] like Figure 1 As shown, an RS485 line distribution conversion device with fault diagnosis function includes a power interface system, a single-chip processing system, an RS485 host, N RS485 slaves, N+1 RS485 communication circuits, and a data storage circuit; the N+1 RS485 communication circuits are electrically connected to each other; the power interface system is electrically connected to the single-chip processing system and the N+1 RS485 communication circuits respectively; the data storage circuit is electrically connected to the single-chip processing system; the single-chip processing system is electrically connected to the N+1 RS485 communication circuits respectively; the data storage circuit is electrically connected to the power interface system and the single-chip processing system respectively. .

[0038] Example 2

[0039] like Figure 1 As shown, it includes a power interface system, a single-chip processing system, an RS485 host, N RS485 slaves, N+1 RS485 communication circuits, and a data storage circuit; the N+1 RS485 communication circuits are electrically connected to each other; the power interface system is electrically connected to the single-chip processing system and the N+1 RS485 communication circuits; the data storage circuit is electrically connected to the single-chip processing system; the single-chip processing system is electrically connected to the N+1 RS485 communication circuits; the data storage circuit is electrically connected to the power interface system and the single-chip processing system. .

[0040] In a specific embodiment, it also includes N+1 interface protection circuits, the RS485 host is electrically connected to one RS485 communication circuit through one interface protection circuit; the N RS485 slaves are electrically connected to the N RS485 interface protection circuits through the interface protection circuits respectively.

[0041] In a specific embodiment, specifically, it includes 4 RS485 slaves and 5 RS485 communication circuits.

[0042] like Figure 2As shown, in a specific embodiment, the power interface system includes an external power supply, a power protection circuit, and a step-down circuit; the external power supply, the power protection circuit, and the step-down circuit are connected in series in sequence; the step-down circuit is electrically connected to the single-chip microcomputer processing system, N+1 RS485 communication circuits, and the data storage circuit respectively.

[0043] In this embodiment, the device is powered by a 9-36VDC external power supply, which is connected to a step-down circuit after passing through a power protection circuit. The step-down circuit reduces the input 9-36VDC voltage to 5V and 3.3V voltages. 5V is used to power the RS485 circuit, and 3.3V is used to power the microcontroller system and the data storage system.

[0044] like Figure 3 As shown, in a specific embodiment, the power protection circuit includes a resettable fuse BX1, a diode D4, and a varistor RM1; one end of the resettable fuse BX1 is electrically connected to an external power supply; the cathode of the diode D4 is electrically connected to the other end of the resettable fuse BX1 and one end of the varistor RM1, respectively, and the anode of the diode D4 is grounded; the other end of the resistor RM1 is grounded.

[0045] In this embodiment, the power protection circuit further includes a capacitor C1, a capacitor C2, and a capacitor C3; two ends of the capacitor C1, the capacitor C2, and the capacitor C3 are electrically connected to two ends of the resistor RM1 respectively.

[0046] In this embodiment, the capacitors C1 , C2 , and C3 are all 1000μ / 50V.

[0047] like Figure 4 As shown, in a specific embodiment, the step-down circuit includes a first step-down circuit and a second step-down circuit; the first step-down circuit uses a TPS4530 chip for step-down; the second step-down circuit uses an AMS1117-3.3 chip for step-down; the first step-down circuit is electrically connected to a single-chip processing system and a data storage circuit respectively; the second step-down circuit is electrically connected to N+1 RS485 communication circuits respectively;

[0048] In this embodiment, the TPS4530 chip is a DCDC step-down chip of TI, with an input voltage range of 9-36V and a driving current of 3A. It reduces the DC voltage rectified by the protection circuit to 5V and is the ultimate source of power for the entire board.

[0049] In this embodiment, the 3.3V step-down circuit of the chip AMS1117-3.3 adopts an LDO step-down solution, and the output current can reach up to 1.1A, which can provide a clean, low-ripple system power supply for the single-chip system and the communication system circuit.

[0050] like Figure 5, Figure 6 As shown, in a specific embodiment, the single-chip microcomputer processing system includes an STM32F103 main control chip.

[0051] In this embodiment, the parameters of the STM32F103 main control chip are: CPU bit number: 32-Bit, FLASH capacity: 256kB, RAM capacity: 48K, CPU core: ARM Cortex-M3, main frequency (MAX): 72MHz.

[0052] like Figure 7 As shown, in a specific embodiment, the data storage circuit adopts the W25Q128 chip.

[0053] In this embodiment, the W25Q128 chip has a storage space of 16MB, which has a redundancy of more than 40% for the maximum storage capacity of the system.

[0054] like Figure 8 As shown, in a specific embodiment, the RS485 communication circuit adopts the MAX13487 chip.

[0055] In this embodiment, the MAX13487 chip has an automatic direction control function, and the maximum communication rate can reach 500Kbsp. The TVS diode SMBJ6.5CA and PSM712 can protect the differential mode and common mode interference on the communication line.

[0056] In a specific embodiment, an interface protection circuit is used to protect differential mode and common mode interference on a communication line; the interface protection circuit includes a first electrostatic ESD protection diode PSM712.1, a second electrostatic ESD protection diode PSM712.2, and a TVS diode SMBJ6.5CA; the positive electrode of SMBJ6.5CA is electrically connected to the A port of the MAX13487 chip and one end of PSM712.1 respectively; the negative electrode of SMBJ6.5CA is electrically connected to the B port of the MAX13487 chip and one end of PSM712.2 respectively; the other end of PSM712.1 and the other end of PSM712.2 are both grounded.

[0057] The invention discloses an RS485 line distribution conversion device with a fault diagnosis function, comprising a power interface system, a single-chip processing system, a data storage circuit, an RS485 host, N RS485 slaves, and N+1 RS485 communication circuits; the N+1 RS485 communication circuits are electrically connected to each other; the RS485 communication circuit includes an interface protection circuit; the power interface system is electrically connected to the single-chip processing system, the N+1 RS485 communication circuits, and the data storage circuit respectively; the data storage circuit is electrically connected to the single-chip processing system; the RS485 host is electrically connected to one RS485 The interface protection circuit of the communication circuit is electrically connected; the N RS485 slaves are electrically connected to the N RS485 interface protection circuits respectively; the single-chip microcomputer processing system is electrically connected to N+1 RS485 communication circuits respectively; therefore, when a node on the network fails, the system will not be paralyzed as a whole or partially, and the fault location is easy to determine, thereby improving the reliability and stability of the RS485 communication system; the present invention also supports multiple slave nodes to send data at the same time, supports different communication parameters of different slaves in the same network, improves the troubleshooting efficiency of solving on-site faults, and improves the implementation efficiency of new projects.

[0058] Example 3

[0059] like Fig. 9 As shown, a fault diagnosis method for RS485 line distribution conversion with fault diagnosis function:

[0060] S1. Connect the power interface system to the power supply; after the RS485 host is powered on, it enters the configuration mode; if a configuration command is received in the configuration mode, it enters the configuration mode until restarted, otherwise it enters the working mode;

[0061] In this embodiment, within 3 seconds after the device is powered on, the host sends 0x78, 0x78, 0x01, 0x0d, a four-byte configuration instruction to the main RS485 interface with a communication parameter of 9600 baud rate, no parity, and one stop bit, and then the device enters the configuration mode.

[0062] S2.N RS485 slaves communicate with the RS485 master through the MCU processing system in mobus mode; configure the communication parameters between the main RS485 master and N RS485 slaves; restart after the configuration is completed, and the RS485 master enters the working mode;

[0063] In this embodiment, the modbus slave address is 1, and the communication parameters (column-to-frame interval, baud rate, parity check, stop bit, etc.) of the master RS485 interface and the four slave RS485 interfaces are configured through the configuration register. After the configuration is completed, the power is turned on again. If there is no configuration instruction within 3 seconds, it enters the working mode.

[0064] S3. In working mode, after receiving the data, the RS485 host forwards the data to N RS485 slaves through the single-chip microcomputer processing system through N+1 RS485 communication circuits; when multiple RS485 slaves receive data at the same time, multiple groups of data are forwarded to the RS485 host through the single-chip microcomputer processing system;

[0065] In this embodiment, the four slave RS485 interfaces send the received data through the master RS485 interface. When multiple slave RS485 interfaces receive data at the same time, multiple groups of data are forwarded to the master RS485 interface in pairs, and the pair frame interval is 10-100ms, which is subject to the configuration parameters;

[0066] S4. During data transmission and reception, the data storage circuit saves data loss data and data interference data during data transmission and reception through the single-chip processing system with each power-on and power-off as one cycle, and the data loss data and data interference data saved during data transmission and reception are called fault judgment data;

[0067] In this embodiment, the communication parameters are stored during the data forwarding process, with each power-on and power-off as a cycle, and a total of 10 fault judgment data are stored. The fault judgment data is stored in the storage circuit, and the communication is carried out in the modbus slave mode. The modbus slave address is the number of communications, the most recent address is 2, and the previous address is 10. The fault judgment data is the number of frames sent and received from each RS485 interface, which is used to determine the data loss situation. The slave interface combination with frame column pairs and the number of column pairs are used to determine the address conflict and data interference.

[0068] S5. Re-enter the configuration mode of the RS485 host, read the fault judgment data in different time periods by setting different modbus addresses, and perform fault diagnosis based on the fault judgment data.

[0069] Obviously, the above embodiments of the present invention are only examples for clearly explaining the present invention, and are not intended to limit the implementation methods of the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention shall be included in the protection scope of the claims of the present invention.

Claims

1. A fault diagnosis method for RS485 line distribution conversion with fault diagnosis function, characterized in that: S1. Connect the power interface system to the power supply; after the RS485 host is powered on, it enters the configuration mode; if a configuration command is received in the configuration mode, it enters the configuration mode until restarted, otherwise it enters the working mode; S2.N RS485 slaves communicate with the RS485 master through the MCU processing system in mobus mode; configure the communication parameters between the main RS485 master and N RS485 slaves; restart after the configuration is completed, and the RS485 master enters the working mode; S3. In the working mode, after receiving the data, the RS485 host forwards the data to N RS485 slaves through the single-chip processing system through N+1 RS485 communication circuits; when multiple RS485 slaves receive data at the same time, multiple groups of data are forwarded to the RS485 host through the single-chip processing system; S4. During data transmission and reception, the data storage circuit stores data loss data and data interference data during data transmission and reception by means of the microcontroller processing system with each power-on and power-off as one cycle. The data loss data and data interference data stored during data transmission and reception are called fault judgment data; S5. Re-enter the configuration mode of the RS485 host, read the fault judgment data in different time periods by setting different modbus addresses, and perform fault diagnosis based on the fault judgment data.

2. An RS485 line distribution conversion device with fault diagnosis function, characterized in that: Used to implement the fault diagnosis method as described in claim 1, comprising a power interface system, a single-chip microcomputer processing system, an RS485 host, N RS485 slaves, N+1 RS485 communication circuits, and a data storage circuit; the N+1 RS485 communication circuits are electrically connected to each other; the power interface system is electrically connected to the single-chip microcomputer processing system and the N+1 RS485 communication circuits respectively; the data storage circuit is electrically connected to the single-chip microcomputer processing system; the single-chip microcomputer processing system is electrically connected to the N+1 RS485 communication circuits respectively; the data storage circuit is electrically connected to the power interface system and the single-chip microcomputer processing system respectively.

3. The RS485 line distribution conversion device with fault diagnosis function according to claim 2 is characterized in that: It also includes N+1 interface protection circuits, the RS485 host is electrically connected to one RS485 communication circuit through one interface protection circuit; the N RS485 slaves are electrically connected to the N RS485 interface protection circuits through the interface protection circuits respectively.

4. The RS485 line distribution conversion device with fault diagnosis function according to claim 2 is characterized in that: Specifically, it includes 4 RS485 slaves and 5 RS485 communication circuits.

5. The RS485 line distribution conversion device with fault diagnosis function according to claim 2 is characterized in that: The power interface system includes an external power supply, a power protection circuit, and a step-down circuit; the external power supply, the power protection circuit, and the step-down circuit are connected in series in sequence; the step-down circuit is electrically connected to the single-chip microcomputer processing system, N+1 RS485 communication circuits, and the data storage circuit respectively.

6. The RS485 line distribution conversion device with fault diagnosis function according to claim 5, characterized in that: The power protection circuit includes a resettable fuse BX1, a diode D4, and a varistor RM1; one end of the resettable fuse BX1 is electrically connected to an external power supply; the cathode of the diode D4 is electrically connected to the other end of the resettable fuse BX1 and one end of the varistor RM1, respectively, and the anode of the diode D4 is grounded; the other end of the resistor RM1 is grounded.

7. The RS485 line distribution conversion device with fault diagnosis function according to claim 6 is characterized in that: The step-down circuit includes a first step-down circuit; the first step-down circuit uses a TPS4530 chip to step down the voltage; the first step-down circuit is electrically connected to the single-chip processing system and the data storage circuit respectively.

8. The RS485 line distribution conversion device with fault diagnosis function according to claim 7, characterized in that: The step-down circuit also includes a second step-down circuit; the second step-down circuit uses an AMS1117-3.3 chip for step-down; and the second step-down circuit is electrically connected to N+1 RS485 communication circuits respectively.

9. The RS485 line distribution conversion device with fault diagnosis function according to claim 2, characterized in that: The single-chip processing system comprises an STM32F103 main control chip; the data storage circuit adopts a W25Q128 chip; and the RS485 communication circuit adopts a MAX13487 chip.

10. The RS485 line distribution conversion device with fault diagnosis function according to claim 4, characterized in that: The interface protection circuit is used to protect the differential mode and common mode interference on the communication line; the interface protection circuit includes a first electrostatic ESD protection diode PSM712.1, a second electrostatic ESD protection diode PSM712.2, and a TVS diode SMBJ6.5CA; the positive electrode of SMBJ6.5CA is electrically connected to the A port of the MAX13487 chip and one end of PSM712.1 respectively; the negative electrode of SMBJ6.5CA is electrically connected to the B port of the MAX13487 chip and one end of PSM712.2 respectively; the other end of PSM712.1 and the other end of PSM712.2 are both grounded.

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