The Development Of Multi-channel Temperature Control Heat Needle Instrument

Among all the treatment of soft tissue pain, silver needle moxibustion treatment is a main method. However, it's complicated to operate, and due to temperature fluctuations, it is easy to burn the skin. With the development of electronic technology, the traditional silver needle therapy is geared to instrumentation and intellectualization. The heating method has developed into electronic heating, using electronic technology to heat the silver needle and control its temperature.Through the analysis of the trend and present situation of electronic heat silver needle therapeutic apparatus, this paper raised an idea of researching and developing a new therapeutic apparatus for soft tissue pain—multi-channel temperature control heat needle instrument. It includes two parts: the inner heat needle and control system. This paper focuses on the control system, which takes the AVR microcontroller as frame, combined with thermocouple temperature acquisition circuits, PWM low-frequency heating control circuits, RS-232 communication circuits, keyboard input and display circuits and other peripheral circuits. With modular design, the control system is divided into various functional modules, each module is individually designed and debugged, and then debugged together.The premise of hardware circuit design is low-cost and scalable. On the one hand, the chip to choose should be the universal selection of the market, the circuit interface should be simple, with pin space reserved for future extensions. On the other hand, from the perspective of the circuit structure, for the signal processing circuit of 48- channel inner heat needles, a multi-channel analog switch to time-sharing process the multi-channel signal so that multiple signals share a signal processing circuit.That helps simplify the circuit structure, and reduces the difficulty of debugging, and significantly reduces design costs. Software circuit design adopts the design philosophy of functional subroutinization, the main program is responsible for calling based on the timing. In addition, function module unused is set to sleep mode, reducing power consumption and increasing life expectancy. As the core of the control system is composed by a number of MCU, if they cannot work in parallel, the system will result in errors or lost data or even system crashes. So a communication protocol have been formulated to provide data exchange rules between the MCU so that each MCU maximizes the individual efficiency and collaborative work efficiency, and temporal logic is clear to avoid disruption which causes bus line conflict. In the preparation of temperature control algorithm program, based on the PID temperature control algorithm, and through experimental methods to adjust the parameters. Finally, realizes temperature control function, and meets the scheduled requirements.Multi-channel temperature control heat needle instrument is versatile with a good man-machine interface, easy operation and stable temperature control performance to meet the design requirements.