Introduction In the study of the temperature characteristics of thermal convection acceleration sensors, the sensor system needs to be placed on a rotating table that can be rotated 360 degrees in the longitudinal direction, and the rotating table should be placed in a constant temperature test chamber. When the rotary table rotates, the phenomenon that the acceleration of gravity felt by the direction of the sensor’s sensitive surface changes, detects the change in the sensitivity of the sensor. In order to make the measurement data reliable, the control system uses a stepping motor as the drive. By controlling the number of rotation steps (angle), the turntable is rotated through an angle. After the output data of the sensor is stable, the relevant data can be recorded. To achieve this function, a stepper motor turntable controlled by a single chip microcomputer is developed. Second, the overall design of the system The stepping motor requires an excitation signal from the coil of the stepper motor, and a power amplifier is required to generate a driving current based on the signal. A ring distributor and power driver specifically designed for stepper motors can achieve this function.输入 Enter control information through the keyboard, including the steering and rotation angle of the motor. The single-chip microcomputer receives these information and generates corresponding control signals to transmit to the motor controller; at the same time, the single-chip microcomputer also controls the multi-bit digital tube to display the information input by the keyboard and the actual rotation. According to actual needs, human-computer interaction is realized through 4 *; 4 deterministic keyboards and a pair of 4 LED digital tubes; key input and LED display are controlled by the control chip HD7279A; the microcontroller uses AT89C51 Flash microcontroller; because the measurement range is not required The gradient of the tilt angle change is very fine. The low-cost two-phase stepping motor 42BYG121 is used. Its step angle is 1.8 degrees. It can be subdivided by a half-step driving method to obtain a step angle of 0.9 degrees.
Instructions can be implemented using the following routines: void write7279 (unsigned char cmd, unsigned char dta) {send_byte (cmd); send_byte (dta); 的 The routine to read data from HD7279A is as follows: unsigned char read7279 (unsigned char command ) {Send_byte (command); return (receive_byte ());｝ define the relevant command words as follows: Blower motor define.
The ring distributor and The motor driver uses L297 and L298N chips. L297 converts the continuous pulses given by the microcontroller into the phase winding pulse sequence required by the stepper motor. The phase pulse signal is amplified by L298N to drive the stepper motor to rotate. The system’s working process is as follows: the system uses the keyboard to input numerical values, and the input key values are transmitted to the microcontroller through the HD7279A chip, and the microcontroller recognizes whether the key values represent data or function keys, or the transmitted data is displayed by the HD7279A driving LED digital tube, The rotation angle of the stepping motor is determined according to the input value, and a certain pulse signal is output. The phase pulses of each phase of the stepping motor are converted from L297. The stepping motor is driven by L298N amplification. The stepping motor drives the mechanical part to rotate. Third, the main interface and programming to achieve data input and display interface chip adopts HD7279A, it is a smart display driver chip with a serial interface that can simultaneously drive 8-bit common female LED digital tube, the chip can also connect up to With a 64-key keyboard matrix, a single chip can complete all functions of LED display and keyboard interface.
Tags: Blower motor
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