Abstract: This paper integrates single-chip microcomputer technology with embedded automation procedure control and speech synthesis technology to independently control small and medium-sized boilers in industrial settings. It can provide prompts and alarms in Chinese. It can receive sensor signals from the industrial site and output control parameters for conventional industrial physical quantities. The automation control program and speech synthesis program can be rewritten and modified according to the user's industrial needs, achieving direct control of small and medium- sized boilers in industrial settings. Keywords: Single-chip microcomputer; Speech synthesis; Boiler automatic control Keywords: SCM; Speech synthesis technique; Automatic boiler control 1. Introduction At present, most industrial boilers are still in a state of high energy consumption, large waste and serious environmental pollution. Therefore, it is of great significance to develop and research new measurement and control devices with high automation, great energy-saving potential, improved safety factor, reduced environmental pollution, reduced labor intensity and low price. A microcontroller integrates the CPU, memory, input and output components required by a microcomputer on a chip. Since its inception, the performance of microcontrollers has been continuously improved and perfected. Its small size, high speed and low power consumption make its application field increasingly wide. The working environment of industrial control systems is harsh and the interference is strong. Therefore, the control system is required to be stable and have strong anti-interference ability [1]. Microcontrollers can meet these requirements. Therefore, microcontrollers have been widely used in the control field. Using microcontrollers to control boilers is a good choice [2]. 2. System Hardware Design 2.1 System Overall Design [align=center] Fig.2-1 The Diagram of Boiler Control System[/align] As shown in Fig.2-1, the boiler is equipped with temperature, pressure, and liquid level sensors. These signals reflecting the boiler's operating status are sent to the instrument layer. The instrument layer includes temperature instruments, pressure instruments, and liquid level instruments. We can set upper and lower limits on these instruments. If the signal sent by the sensor is higher than the set upper limit or lower than the set lower limit, the relay switch inside the instrument will close, and the output signal representing the upper or lower limit will output a high level. These signals serve as the switch signal inputs of the system's main control board. The output control signal of the system's main control board is connected to the system's actuator after passing through the relay. A relay is a physical component that can drive a large current with a small current. The signal voltage output by our system is relatively low and cannot directly drive high-power electrical appliances [3-4]. Therefore, a relay is needed in the middle. The other output of the main control board is connected to the system display board, so that the boiler's operating status can be displayed intuitively to the user. 2.2 Main Control Board Circuit Design As shown in Figure 2-2, the alarm signal from the system enters the control board and is connected to an opto-isolator to prevent interference and system malfunction. It is then connected to a 74LS244, an eight-in-one tri-state buffer, which is connected to an 80C31. The memory is connected to the 80C31 via a 74LS373. The 80C31 outputs a voice alarm signal through the UM5100 voice chip. After passing through the 74LS373, the 80C31 outputs a display signal. After passing through the 74LS273, the 80C31 is connected to the opto-isolator, and then through a transistor to output a control execution signal. [align=center] Figure 2-2 Control board diagram of the System[/align] 3. Software Design The software of this control system mainly consists of a main program, interrupt service routines, various fault handling and alarm subroutines, and delay subroutines. The main program is mainly responsible for system initialization, interrupt setting, manual and automatic switching, etc.; the interrupt program is mainly responsible for judging the limit signal and then transferring to the corresponding processing program; the detection module is mainly responsible for the input of the signal and judging and transferring to the interrupt program or detection module; the voice module is mainly responsible for voice prompts and alarms[5]. After the system starts and initializes, it will then announce via voice that the boiler is on. The system will begin detecting signals. If the signals do not exceed the set limits, the system will continue detecting; otherwise, it will enter an interrupt handling program. In the interrupt handling program, it will first check for low liquid level and high pressure limits. If any are found, it will issue a voice alarm and stop the boiler's automatic operation, switching to manual operation. Otherwise, it will check the liquid level, temperature, and pressure to see if they are above the upper limit or below the lower limit. If there are high temperature or high pressure signals, it will stop the blower and delay for 15 seconds before interrupting and returning to continue detecting; otherwise, it will continue detecting. If there are low temperature or low pressure signals, it will start the blower and grate and delay for 30 seconds before interrupting and returning to continue detecting; otherwise, it will continue detecting. If there are high liquid level signals, it will stop the water pump and delay for 10 seconds before interrupting and returning to continue detecting; otherwise, it will continue detecting. If there are low liquid level signals, it will start the water pump and delay for 15 seconds before interrupting and returning to continue detecting. [align=center]Fig.3-1 System Flowchart[/align] 4. Conclusion This system achieves a coal-saving efficiency of over 10%; the boiler control is automated, greatly reducing the labor intensity of personnel; the boiler can operate safely, reducing accidents and ensuring personal safety; it can realize voice alarms and intuitively reflect the operating status of the boiler. It can convert the boiler's sensor signals into upper and lower limit signals through instruments and send them to the control board; after receiving the signals, the control board will execute the program written in our EPROM. If it is a limit signal, it will immediately stop automatic control and switch to manual control; otherwise, it will determine which over-limit signal it is, output a control signal, output a voice alarm and display, and return to the program to continue detection. In this way, the boiler can operate according to our requirements. References [1] Lai Shouhong, ed. Microcomputer Control Technology. Beijing: Machinery Industry Press, 2004 [2] Zhang Liangyi et al., ed. Microcomputer Control of Industrial Boilers. Shanghai: Shanghai Jiaotong University Press, 1999 [3] Gao Wenhuan et al., ed. Analysis and Design of Analog Circuits. Beijing: Tsinghua University Press, 2002 [4] Fang Jianchun, ed. Speech Synthesis Technology and Single-Chip Microcomputer Integrated System. Beijing: Beijing University of Aeronautics and Astronautics Press, 1994 [5] Yu Fashan, ed. Principles and Application Technology of Single-Chip Microcomputers. Xuzhou: China University of Mining and Technology Press, 2003