The Research Of The Temperature Control Device Base On Ultrasonic Grating Effect

Diffraction grating of the application has been developed as a relatively maturetechnology, the theory developed ultrasonic grating temperature control device can bea demonstration of ultrasound in the different liquids at different temperatures spreadof the diffraction phenomenon. Ultrasonic grating experimental instrument digitaldisplay composed of liquid pool of high-frequency power source and built-inpiezoelectric crystal. The core of this paper is the development of grating temperatureexperimental apparatus to use microcontroller to control the temperature of the liquidin the sump, the piezoelectric crystal in the excitation of the power oscillator frequencyultrasound in the mercury lamp light source through the liquid pool to placepiezoelectric ceramics, spectrophotometer meter eyepiece (or eyepiece micrometer) onthe stable and clearly observed to about6-8diffraction fringes.The temperature control experiment instrument is divided into six parts by the maincontrol section, the temperature acquisition, frequency acquisition part, the part of thepower output, USB communication part and the host computer software processing ofseveral components.The main control part of the chip using the Microchip PIC18F2550microcontroller, itsstrong anti-jamming capability, reduced instruction set running time of program, andon-chip integrated USB communications module to facilitate data transmission.The temperature acquisition by a platinum resistance sensor, and temperature datathrough the microcontroller A/D converter module, and calculated the actualmeasured temperature value. According to the measured temperature and settemperature value, the PID algorithm to calculate the required output power.Part of the power output by controlling the number of half-wave of the full currentconduction of the thruster control cycle power control of the heating resistance wire,and the past control the conduction of the thruster current rate, the control method cansignificantly reduce the electromagnetic interference.The process temperature control device, the chip USB communication modules andhost computer communication, with do not have to worry about hot-swapping may bethe damage to the computer, and no additional power advantages of reducing the cost of hardware development. PC software features three main aspects, including the USBdata communication, data processing and image processing and display. In actual use,the PC is not only the need for temperature control device of the control algorithmparameters settings also need to deal with the data acquisition hardware, storage, youneed to host computer program to save the collected data.The temperature control device was designed with scientific modular design, and isconducive to program development, expansion and maintenance, allows the instrumentto meet a variety of different measurement or control requirements. Reasonable layoutand advanced SCR control method, it has good electrical properties, to minimize theimpact of other external equipment.