**Abstract:**
In response to the limitations of unstable performance and low integration in domestic dental treatment chair control systems, a control system based on STM32 master-slave communication mode has been designed. The main controller uses the STM32F105VCT6 as the central processing unit, responsible for managing actuators and sensor modules. The slave module is composed of an STC89C52 microcontroller and a set of physical buttons, allowing for user interaction. The system implements a multi-machine communication protocol via RS-485 bus, enabling real-time data exchange and status monitoring through an LCD display. Experimental results confirm that the system is stable, highly automated, and offers strong human-computer interaction capabilities, making it a promising solution for future dental equipment development.
**Keywords:** STM32F105VCT6; dental comprehensive treatment chair; STC89C52; master-slave; multi-machine communication; RS-485
**CLC number:** TN919; TP273
**Document identification code:** A
**DOI:** 10.16157/j.issn.0258-7998.170268
**Chinese citation format:** Xu Xinjian, Wen Guojun, Wang Yudan, et al. Design of dental comprehensive treatment chair control system based on STM32[J]. Application of Electronic Technique, 2017, 43(9): 50-52, 56.
**English citation format:** Xu Xinjian, Wen Guojun, Wang Yudan, et al. Design of control system of dental treatment based on STM32 [J]. Application of Electronic Technique, 2017, 43 (9): 50-52, 56.
**0 Introduction**
Dental comprehensive treatment chairs are essential equipment in oral disease diagnosis and treatment [1], playing a critical role in modern dental care. As living standards improve, people's demands for dental health have increased, leading to a surge in patients and driving up the demand for advanced dental chairs [2]. However, the domestic market remains dominated by foreign products due to issues like unstable control systems, poor user interface, and low integration [3]. This situation highlights the urgent need for a more reliable and efficient control system. A well-designed control system with high automation and strong user interaction can significantly enhance the competitiveness of domestic dental equipment in the global market.
This paper presents a control system based on STM32, using a master-slave communication architecture. The high-performance STM32F105VCT6 chip manages various functions, while the RS-485 bus ensures smooth communication between the master and slave units. The system also features an LCD screen for real-time status updates, improving usability and system integration.
**1 System Overview and Working Principle**
The control system comprises a main control unit, a main control panel, a sub-control panel, and a power module. The main control unit includes the STM32F105VCT6 microcontroller, relay control circuits, detection circuits, and an LCD display. The main and sub-control panels are built around the STC89C52 microcontroller, matrix keyboard, and RS-485 communication interface. The power module provides 24V, 5V, and 3.3V DC power after rectification and voltage regulation.
Actuators include functions such as suction, water supply, backrest adjustment, and lamp control. Sensors monitor actuator status and provide feedback to the STM32 for real-time analysis. When the system is running, users can control functions and adjust parameters through the control panels. Commands are sent via the RS-485 bus, processed by the main controller, and executed accordingly, ensuring accurate and responsive operation.
**2 Hardware Design**
**2.1 Control Chip Selection**
The main control unit uses the STM32F105VCT6, which offers 100 I/O ports, two 12-bit ADCs, and multiple communication interfaces. This makes it ideal for complex control tasks. The sub-control panels use the STC89C52, which is sufficient for basic input and communication functions.
**2.2 Power Module Design**
The power module converts 24V AC to 24V, 5V, and 3.3V DC using regulators like LM7824, LM2576s-5.0, and AMS1117-3.3. Filtering capacitors and Y capacitors are added to reduce interference and ensure stable power delivery.
**2.3 Relay Control Circuit**
Relays are used to control actuators such as motors and solenoid valves. The STM32 controls the relays via GPIO signals, with ULN2003D drivers for high-current applications. Each relay is connected to a corresponding actuator, enabling precise control.
**2.4 Actuator and Sensor Selection**
Actuators include 24V DC motors, solenoid valves, and lamps. Sensors such as position switches, temperature sensors, and flow meters monitor system status and provide feedback to the STM32 for real-time adjustments.
**3 Software Design**
**3.1 Master-Slave Communication Protocol**
The system uses a 9-bit asynchronous communication protocol over RS-485. The 9th bit indicates whether the data is an address or command. The master controls the communication, ensuring no bus conflicts. Handshake and response mechanisms guarantee reliable data exchange.
**3.2 Parameter Setting Program**
Users can set parameters such as water volume, heating temperature, and movement limits. The system enters a setting mode when the SET button is pressed, allowing adjustments through a parameter adjustment button. Changes are saved upon pressing SET again, and the system reverts to previous settings if interrupted.
**3.3 Function Control Program**
The function control program manages actuator operations based on sensor data and user inputs. It displays real-time status on the LCD and triggers alarms if errors occur, helping users monitor and respond to system conditions effectively.
**4 System Testing**
**4.1 Boot Self-Test**
Upon startup, the system checks all modules and actuators. If any component fails, an error code is displayed. This helps identify and resolve issues quickly.
**4.2 Communication Test**
Testing confirmed that the master-slave communication protocol works reliably. The system accurately processes key presses and executes commands, proving its stability and practicality.
**5 Conclusion**
This paper introduces a STM32-based control system for dental treatment chairs, utilizing a master-slave architecture and RS-485 communication. The system improves hardware integration, reliability, and user experience. Practical tests show that it is stable, efficient, and suitable for widespread application in dental equipment.
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