Isolated RS485 serial port expansion module

By using the optocoupler of the isolated RS485 serial port expansion module in conjunction with the high-performance isolation circuit of the RS485 transceiver chip, the problems of electrical interference and damage between devices in RS485 serial communication are solved, thereby improving the stability and reliability of the system, supporting multiple signal outputs and fault alarms, and reducing wiring complexity and cost.

CN223552101UActive Publication Date: 2025-11-14WUXI BRIGHTSKY ELECTRONICS
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Patent Information

Application Number
CN202423220097.5
Authority / Receiving Office
CN · China
Patent Type
Utility models(China)
Current Assignee / Owner
Filing Date
2024-12-26
Publication Date
2025-11-14
Estimated Expiration
2034-12-26

AI Technical Summary

Technical Problem

In industrial automation, intelligent equipment control, and fire alarm systems, RS485 serial communication is susceptible to electrical interference and damage between devices, affecting the stability and reliability of the system.

Method used

An isolated RS485 serial port expansion module is adopted, which utilizes optocouplers and a high-performance isolation circuit of a 485 transceiver chip to achieve safe and reliable transmission of serial signals between different devices, and prevents electrical interference and damage between devices through electrical isolation technology.

Benefits of technology

It improves the stability and reliability of the system, prevents electrical interference and damage between devices, enhances the reliability and durability of the modules, supports fault alarms and multi-channel signal output, reduces system wiring complexity and saves costs.

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Abstract

The utility model relates to the technical field of fire alarm communication, in particular to an isolation type RS485 serial port expansion module, which not only has the basic function of serial port communication, but also effectively prevents electrical interference and damage among equipment through an electrical isolation technology, improves the stability and reliability of a system, and improves the reliability of the system. The device comprises a CPU main control unit, a power supply unit and an expansion serial port unit, the CPU main control unit comprises a W77C58 single-chip microcomputer U1, the single-chip microcomputer U1 is connected with an expansion main serial port module, a storage unit and an external interface J1, the expansion serial port unit comprises four identical expansion serial port circuits, and one expansion serial port circuit comprises a triode Q1, an optocoupler G101, an optocoupler G102 and an optocoupler G103.
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Description

Technical Field

[0001] This utility model relates to the field of fire alarm communication technology, specifically to an isolated RS485 serial port expansion module. Background Technology

[0002] Serial communication is a common technology in fields such as industrial automation, intelligent equipment control, security monitoring, and fire alarms. For example, in a fire alarm system, multiple area alarm controllers and a centralized alarm controller need to communicate via RS485 serial ports. However, this can easily lead to electrical interference and damage between devices, affecting the stability and reliability of the system. Summary of the Invention

[0003] To address the aforementioned technical issues, this utility model provides an isolated RS485 serial port expansion module, which not only possesses the basic functions of serial communication but also effectively prevents electrical interference and damage between devices through electrical isolation technology, thereby improving the stability and reliability of the system.

[0004] The technical solution is as follows: An isolated RS485 serial port expansion module, characterized in that it includes a CPU main control unit, a power supply unit, and an expansion serial port unit. The CPU main control unit includes a single-chip microcomputer U1 of model W77C58. The single-chip microcomputer U1 is connected to the expansion main serial port module, a storage unit, and an external interface J1. The expansion serial port unit includes four identical expansion serial port circuits, one of which includes a transistor Q1, optocoupler G101, optocoupler G102, and optocoupler G103. Pin 6 of optocoupler G101 is connected to VCC, pin 4 is grounded, and pin 5 is connected to one end of resistor R301 and pin 11 of the single-chip microcomputer U1. Pin 1 of G101 is connected to a 5V power supply, and pin 3 is connected to one end of resistor R501. The other end of resistor R501 is connected to pin 1 of the 485 transceiver chip U6. Pin 1 of optocoupler G102 is connected to VCC, pin 3 is connected to one end of resistor R502, pin 4 is grounded, pin 5 is connected to one end of resistor R302 and one end of resistor R303, and pin 6 is connected to a 5V power supply and the other end of resistor R302. The other end of resistor R502 is connected to pin 3 of the microcontroller U1, and the other end of resistor R303 is connected to the base of transistor Q1. The emitter of transistor Q1 is connected to the 5V power supply, and the base of transistor Q1 is connected to one end of resistor R304 and the 485 transceiver chip U6. Pins 2 and 3 of the device are connected to the device. The other end of resistor R304 is grounded. Pin 1 of optocoupler G103 is connected to VCC, pin 3 is connected to one end of resistor R503, pin 4 is grounded, pin 5 is connected to one end of resistor R305 and pin 4 of the 485 transceiver chip U6, the other end of resistor R503 is connected to pin 13 of the microcontroller U1, the other end of resistor R305 is connected to a 5V power supply, pin 5 of the 485 transceiver chip U6 is connected to one end of resistor R210 and ground, pin 6 is connected to one end of resistor R104, pin 7 is connected to one end of resistor R103, pin 8 is connected to one end of resistor R209 and a 5V power supply, the other end of resistor R104 and the other end of resistor R210 are connected to the anode of diode D202, and the other end of resistor R209 and the other end of resistor R103 are connected to the cathode of diode D202.

[0005] A further feature is that the extended main serial port module includes a 485 transceiver chip U5. Pin 1 of the 485 transceiver chip U5 is connected to pins 4, 2, and 3 of the microcontroller U1, and is also connected to pin 2 of the microcontroller U1. Pin 4 is connected to pin 5 of the microcontroller U1. Pin 5 is connected to one end of resistor R208 and ground. Pin 6 is connected to one end of resistor R102. Pin 7 is connected to one end of resistor R101. Pin 8 is connected to one end of resistor R207 and VCC. The other end of resistor R102 and the other end of resistor R208 are connected to the anode of diode D201, the cathode of diode D103, and one end of fuse F102. The anode of diode D103 is grounded. The other end of fuse F102 is connected to the external interface J1. Pins 17 and 18 of the external interface J1 are connected to the cathodes of diodes D201 and D102, and one end of fuse F101. The anode of diode D102 is grounded, and the other end of fuse F101 is connected to pins 19 and 20 of the external interface J1.

[0006] The storage unit includes storage chip U3 and storage chip U4;

[0007] The power supply unit includes a voltage regulator U10. Pin 1 of the voltage regulator U10 is connected to a 24V power supply, one end of capacitor C3, one end of capacitor C101, one end of capacitor C102, and one end of fuse F1. Pin 2 of the voltage regulator U10 is connected to one end of inductor L1 and the cathode of diode D2. Pin 4 of the voltage regulator U10 is connected to the other end of inductor L1, the cathode of diode D101, one end of capacitor C4, one end of capacitor C103, one end of capacitor C104, one end of capacitor C105, one end of capacitor C106, one end of capacitor C107, and one end of capacitor C108, and outputs VCC. Diode D1... The anode, the other end of capacitor C3, the other end of capacitor C101, the other end of capacitor C102, the anode of diode D2, pins 3 and 5 of voltage regulator U10, the anode of diode D101, the other end of capacitor C4, the other end of capacitor C103, the other end of capacitor C104, one end of capacitor C105, the other end of capacitor C106, the other end of capacitor C107, and the other end of capacitor C108 are connected and grounded. The other end of fuse F1 is connected to pins 22, 24, and 26 of external interface J1. The cathode of diode D1 is connected to pins 21, 23, and 25 of external interface J1.

[0008] The extended serial port unit also includes an extended serial port protection circuit, an extended serial port power supply circuit, and an extended serial port indicator circuit. The extended serial port protection circuit includes fuses F103-F110 and diodes D104-D111. One end of fuses F103-F110 is connected to pins 15 and 16, 13 and 14, 11 and 12, 9 and 10, 7 and 8, 5 and 6, 3 and 4, and 1 and 2 of the external interface J1, respectively. The cathode of diode D202 is connected to the cathode of diode D104 and the other end of fuse F103, and the anode and cathode of diode D202 are connected to diode D104 and the other end of fuse F103, respectively. The cathode of 5 and the other end of the fuse F104; the extended serial port power supply circuit includes an isolation power chip U11, pin 2 of the isolation power chip U11 is connected to one end of capacitor C5, one end of capacitor C109 and VCC, pin 1 of the isolation power chip U11 is connected to the other end of capacitor C5, the other end of capacitor C109 and ground, pin 3 of the isolation power chip U11 is connected to one end of capacitor C6, one end of capacitor C114 and ground, and pin 4 of the isolation power chip U11 is connected to the other end of capacitor C6, the other end of capacitor C114 and outputs 5V power; the extended serial port indicator circuit includes four indicator lights V1-V4 corresponding to the extended serial port circuit.

[0009] By adopting this utility model, an optocoupler is used in conjunction with a 485 transceiver chip. Through the high-performance isolation circuit of the optocoupler and the 485 transceiver chip, safe and reliable transmission of serial signals between different devices is achieved. It not only has the basic functions of serial communication, but also effectively prevents electrical interference and damage between devices through electrical isolation technology, thereby improving the stability and reliability of the system. Attached Figure Description

[0010] Figure 1 This is the schematic diagram of the CPU main control unit circuit.

[0011] Figure 2 This is the schematic diagram of the power supply unit circuit.

[0012] Figure 3 Schematic diagram of the extended serial port unit circuit;

[0013] Figure 4 Schematic diagram of one of the extended serial port circuits;

[0014] Figure 5 This is a circuit diagram for expanding the serial port protection circuit, the serial port power supply circuit, and the serial port indicator light circuit. Detailed Implementation

[0015] See Figures 1 to 5As shown, an isolated RS485 serial port expansion module includes a CPU main control unit, a power supply unit, and an expansion serial port unit. The CPU main control unit includes a W77C58 microcontroller U1, which is connected to the expansion main serial port module, a storage unit, and an external interface J1. The expansion serial port unit includes four identical expansion serial port circuits, one of which includes a transistor Q1, optocouplers G101, G102, and G103. Pin 6 of optocoupler G101 is connected to VCC, pin 4 is grounded, and pin 5 is connected to one end of resistor R301 and pin 11 of microcontroller U1. Pin 1 connects to the 5V power supply; pin 3 connects to one end of resistor R501; the other end of resistor R501 connects to pin 1 of the 485 transceiver chip U6; pin 1 of optocoupler G102 connects to VCC; pin 3 connects to one end of resistor R502; pin 4 is grounded; pin 5 connects to one end of resistor R302 and one end of resistor R303; pin 6 connects to the 5V power supply and the other end of resistor R302; the other end of resistor R502 connects to pin 3 of microcontroller U1; the other end of resistor R303 connects to the base of transistor Q1; the emitter of transistor Q1 connects to the 5V power supply; the base of transistor Q1 connects to one end of resistor R304 and the 485 transceiver chip U6. Pins 2 and 3 of the connector are connected to the ground via the other end of resistor R304. Pin 1 of optocoupler G103 is connected to VCC, pin 3 is connected to one end of resistor R503, pin 4 is grounded, pin 5 is connected to one end of resistor R305 and pin 4 of 485 transceiver chip U6, the other end of resistor R503 is connected to pin 13 of microcontroller U1, the other end of resistor R305 is connected to 5V power supply, pin 5 of 485 transceiver chip U6 is connected to one end of resistor R210 and ground, pin 6 is connected to one end of resistor R104, pin 7 is connected to one end of resistor R103, pin 8 is connected to one end of resistor R209 and 5V power supply, the other end of resistor R104 and the other end of resistor R210 are connected to the anode of diode D202, and the other end of resistor R209 and the other end of resistor R103 are connected to the cathode of diode D202.

[0016] The extended main serial port module includes a 485 transceiver chip U5. Pin 1 of the 485 transceiver chip U5 is connected to pins 4, 2, and 3 of the microcontroller U1, which are also connected to pin 2 of the microcontroller U1. Pin 4 is connected to pin 5 of the microcontroller U1. Pin 5 is connected to one end of resistor R208 and ground. Pin 6 is connected to one end of resistor R102. Pin 7 is connected to one end of resistor R101. Pin 8 is connected to one end of resistor R207 and VCC. The other end of resistor R102 is connected to the other end of resistor R208 and is also connected to the anode of diode D201, the cathode of diode D103, and one end of fuse F102. The anode of diode D103 is grounded, and the other end of fuse F102 is connected to external interface J1. Pins 17 and 18 of the circuit are connected to the other end of resistor R101 and resistor R207, and are connected to the cathodes of diode D201 and D102, one end of fuse F101, the anode of diode D102 is grounded, and the other end of fuse F101 is connected to pins 19 and 20 of external interface J1.

[0017] The storage unit includes storage chip U3 and storage chip U4;

[0018] The power supply unit includes a voltage regulator U10. Pin 1 of voltage regulator U10 is connected to a 24V power supply, one end of capacitor C3, one end of capacitor C101, one end of capacitor C102, and one end of fuse F1. Pin 2 of voltage regulator U10 is connected to one end of inductor L1 and the cathode of diode D2. Pin 4 of voltage regulator U10 is connected to the other end of inductor L1, the cathode of diode D101, one end of capacitor C4, one end of capacitor C103, one end of capacitor C104, one end of capacitor C105, one end of capacitor C106, one end of capacitor C107, and one end of capacitor C108, and outputs VCC. Diode D1... The anode, the other end of capacitor C3, the other end of capacitor C101, the other end of capacitor C102, the anode of diode D2, pins 3 and 5 of voltage regulator U10, the anode of diode D101, the other end of capacitor C4, the other end of capacitor C103, the other end of capacitor C104, one end of capacitor C105, the other end of capacitor C106, the other end of capacitor C107, and the other end of capacitor C108 are connected and grounded. The other end of fuse F1 is connected to pins 22, 24, and 26 of external interface J1. The cathode of diode D1 is connected to pins 21, 23, and 25 of external interface J1.

[0019] The extended serial port unit also includes an extended serial port protection circuit, an extended serial port power supply circuit, and an extended serial port indicator circuit. The extended serial port protection circuit includes fuses F103-F110 and diodes D104-D111. One end of fuses F103-F110 is connected to pins 15 and 16, 13 and 14, 11 and 12, 9 and 10, 7 and 8, 5 and 6, 3 and 4, and 1 and 2 of external interface J1, respectively. The cathode of diode D202 is connected to the cathode of diode D104 and the other end of fuse F103, and the anode and cathode of diode D202 are connected to diode D104 and D111, respectively. The cathode of D105 is connected to the other end of fuse F104; the extended serial port power supply circuit includes an isolation power chip U11. Pin 2 of the isolation power chip U11 is connected to one end of capacitor C5, one end of capacitor C109, and VCC. Pin 1 of the isolation power chip U11 is connected to the other end of capacitor C5, the other end of capacitor C109, and ground. Pin 3 of the isolation power chip U11 is connected to one end of capacitor C6, one end of capacitor C114, and ground. Pin 4 of the isolation power chip U11 is connected to the other end of capacitor C6 and the other end of capacitor C114 and outputs 5V power; the extended serial port indicator circuit includes four indicator lights V1-V4 corresponding to the extended serial port circuit.

[0020] This application utilizes an internal high-performance isolation circuit to achieve electrical isolation of RS485 serial port signals between different devices, effectively preventing electrical interference and damage between devices. The isolated RS485 serial port expansion module integrates multiple protection functions, such as overcurrent protection, lightning protection, and short-circuit protection. These protection functions effectively prevent damage to the module under abnormal conditions, improving its reliability and durability. Simultaneously, the module also supports a fault alarm function; when a fault occurs, it will promptly issue an alarm signal to remind the user to handle the situation.

[0021] It supports multiple signal outputs, allowing simultaneous connection and communication with multiple devices. This multi-output capability not only improves system flexibility but also reduces wiring complexity and saves costs. Furthermore, the module supports hot-swapping, enabling users to easily add or remove devices at any time.

[0022] To ensure stable operation of the module under various environmental conditions, multiple measures are employed in its circuit design. For example, high-quality components and processes are used to reduce circuit temperature drift and noise; a stable power supply circuit design is adopted to ensure normal operation even under large voltage fluctuations; and internal interference is reduced through optimized circuit layout and wiring.

[0023] Optocouplers utilize the property of light signals transmitting through an insulating medium to achieve signal isolation. An optocoupler consists of a light-emitting diode (LED) and a photosensitive element (such as a photoresistor or phototransistor). When an input signal is applied to the LED, the light signal emitted by the LED is received by the photosensitive element and converted into an electrical signal for output. Because the input and output of the optocoupler are transmitted via optical signals, electrical isolation is achieved between them. In isolated RS485 serial port expansion modules, optocouplers are commonly used for signal isolation and level conversion.

Claims

1. An isolated RS485 serial port expansion module, characterized in that, It includes a CPU main control unit, a power supply unit, and an extended serial port unit. The CPU main control unit includes a W77C58 microcontroller U1, which is connected to an extended main serial port module, a storage unit, and an external interface J1. The extended serial port unit includes four identical extended serial port circuits. One of these circuits includes a transistor Q1, optocouplers G101, G102, and G103. Pin 6 of optocoupler G101 is connected to VCC, pin 4 is grounded, pin 5 is connected to one end of resistor R301 and pin 11 of the microcontroller U1, and pin 1 of optocoupler G101 is connected to a 5V power supply and pin 3 is connected to... One end of resistor R501 is connected to the other end of resistor R501, which is connected to pin 1 of the 485 transceiver chip U6. Pin 1 of optocoupler G102 is connected to VCC, pin 3 is connected to one end of resistor R502, pin 4 is grounded, pin 5 is connected to one end of resistor R302 and one end of resistor R303, and pin 6 is connected to a 5V power supply and the other end of resistor R302. The other end of resistor R502 is connected to pin 3 of the microcontroller U1, and the other end of resistor R303 is connected to the base of transistor Q1. The emitter of transistor Q1 is connected to the 5V power supply, and the base of transistor Q1 is connected to one end of resistor R304 and the 485 transceiver chip U6. Pins 2 and 3 of the device are connected to the device. The other end of resistor R304 is grounded. Pin 1 of optocoupler G103 is connected to VCC, pin 3 is connected to one end of resistor R503, pin 4 is grounded, pin 5 is connected to one end of resistor R305 and pin 4 of the 485 transceiver chip U6, the other end of resistor R503 is connected to pin 13 of the microcontroller U1, the other end of resistor R305 is connected to a 5V power supply, pin 5 of the 485 transceiver chip U6 is connected to one end of resistor R210 and ground, pin 6 is connected to one end of resistor R104, pin 7 is connected to one end of resistor R103, pin 8 is connected to one end of resistor R209 and a 5V power supply, the other end of resistor R104 and the other end of resistor R210 are connected to the anode of diode D202, and the other end of resistor R209 and the other end of resistor R103 are connected to the cathode of diode D202.

2. The isolated RS485 serial port expansion module according to claim 1, characterized in that, The extended main serial port module includes a 485 transceiver chip U5. Pin 1 of the 485 transceiver chip U5 is connected to pins 4, 2, and 3 of the microcontroller U1, and is also connected to pin 2 of the microcontroller U1. Pin 4 is connected to pin 5 of the microcontroller U1. Pin 5 is connected to one end of resistor R208 and ground. Pin 6 is connected to one end of resistor R102. Pin 7 is connected to one end of resistor R101. Pin 8 is connected to one end of resistor R207 and VCC. The other end of resistor R102 and the other end of resistor R208 are connected to the anode of diode D201, the cathode of diode D103, and one end of fuse F102. The anode of diode D103 is grounded. The other end of fuse F102 is connected to the external interface J1. Pins 17 and 18 of the external interface J1 are connected to the cathodes of diodes D201 and D102, and one end of fuse F101. The anode of diode D102 is grounded, and the other end of fuse F101 is connected to pins 19 and 20 of the external interface J1.

3. The isolated RS485 serial port expansion module according to claim 1, characterized in that, The storage unit includes storage chip U3 and storage chip U4.

4. The isolated RS485 serial port expansion module according to claim 1, characterized in that, The power supply unit includes a voltage regulator U10. Pin 1 of the voltage regulator U10 is connected to a 24V power supply, one end of capacitor C3, one end of capacitor C101, one end of capacitor C102, and one end of fuse F1. Pin 2 of the voltage regulator U10 is connected to one end of inductor L1 and the cathode of diode D2. Pin 4 of the voltage regulator U10 is connected to the other end of inductor L1, the cathode of diode D101, one end of capacitor C4, one end of capacitor C103, one end of capacitor C104, one end of capacitor C105, one end of capacitor C106, one end of capacitor C107, and one end of capacitor C108, and outputs VCC. Diode D1... The anode, the other end of capacitor C3, the other end of capacitor C101, the other end of capacitor C102, the anode of diode D2, pins 3 and 5 of voltage regulator U10, the anode of diode D101, the other end of capacitor C4, the other end of capacitor C103, the other end of capacitor C104, one end of capacitor C105, the other end of capacitor C106, the other end of capacitor C107, and the other end of capacitor C108 are connected and grounded. The other end of fuse F1 is connected to pins 22, 24, and 26 of external interface J1. The cathode of diode D1 is connected to pins 21, 23, and 25 of external interface J1.

5. An isolated RS485 serial port expansion module according to claim 1, characterized in that, The extended serial port unit also includes an extended serial port protection circuit, an extended serial port power supply circuit, and an extended serial port indicator circuit. The extended serial port protection circuit includes fuses F103-F110 and diodes D104-D111. One end of fuses F103-F110 is connected to pins 15 and 16, 13 and 14, 11 and 12, 9 and 10, 7 and 8, 5 and 6, 3 and 4, and 1 and 2 of the external interface J1, respectively. The cathode of diode D202 is connected to the cathode of diode D104 and the other end of fuse F103, and the anode and cathode of diode D202 are connected to diode D104 and the other end of fuse F103, respectively. The cathode of 5 and the other end of the fuse F104; the extended serial port power supply circuit includes an isolation power chip U11, pin 2 of the isolation power chip U11 is connected to one end of capacitor C5, one end of capacitor C109 and VCC, pin 1 of the isolation power chip U11 is connected to the other end of capacitor C5, the other end of capacitor C109 and ground, pin 3 of the isolation power chip U11 is connected to one end of capacitor C6, one end of capacitor C114 and ground, and pin 4 of the isolation power chip U11 is connected to the other end of capacitor C6, the other end of capacitor C114 and outputs 5V power; the extended serial port indicator circuit includes four indicator lights V1-V4 corresponding to the extended serial port circuit.