Based On TMS320F2812, The Development Of Electronic Universal Testing Machines

Electronic universal testing machines is equipped with the digital measurement system of the new type of machine. It can provide some tests of mechanical properties ,such as tensile and peel,and is used for Rubber, plastic, paper, leather, metal wire, metal foils, fabric, strings, tape, binder ,and so on. It is applicable to industrial and mining enterprises quality inspection, colleges and universities teaching and scientific research units of materials research equipment.Domestic electronic universal testing-machines is controlled mostly by the mcu of 51 series, whose control accuracy, data processing ability is poor ; some testing-machines is controlled by the computer-platform , which is equipped with large, complex system ; Currently, foreign electronic universal testing machines occupied the high-end market, who is usually expensive.This thesis will design a high cost performance of electronic universal testing-machines, using TMS320F2812, a DSP chip, with high performance.This thesis mainly studies the measurement and control system of electronic universal testing-machines. The system's main modules are: A/D transform, digital signal processing, PWM control, the keyboard and display control, clock, and printer.Realization of the three aspects of ADC values measured: force measurement, displacement measurement ,and current measurement .The force measurement, in Electronic universal testing machines, is the essential one of the tasks; displacement measurement, this used for extension project of small displacement, the precise measurements; current measurement, as the feedback of the motor control of electric circuit.Digital signal processing, mainly refers to the pulse signal when encoder being used to measure displacements. Encoder uses the interrupt INT1, can be further define the displacement direction accoding to the phase.Pulse width modulation (PWM) signal ,used for dc motor, controlled by the current & speed closed-loop, with the PID control theory, and get more smoothly speed control effect. The keyboard provides the encoding of 32 buttons, using inversion method, supported by the interface function of GPIO.Mcu can communicate with printer ,who has data buffer, through SCI-interface.It is only responsible for writing data of the result to the buffer, and then continue the next job, don't wait for the printing-process, and improve the efficiency of test.This thesis make full use of strong computing capability and rich internal peripheral resources of the digital signal processor (DSP), the overall design scheme of the electronic universal testing machines is given,base on the dsp. The paper introduced the hardware interface circuit and the software design, analyzed the characteristics and existing problems , and given the improving and expanding method.