DSP and CAN bus applications in DC motor test systems
With the rapid development of the electronics industry, the demand for small DC motors is increasing. This type of DC motor often needs to test its current and speed before leaving the factory. The specific way is to provide the motor with a variety of duty cycle PWM control signals, respectively test the motor current and speed under different duty cycles.
The traditional test method requires the use of multiple general-purpose instruments: the signal generator is used to provide the PWM signal required by the motor, the current of the motor is sampled through the resistor, and the voltage meter is displayed, the speed is measured by the photoelectric induction method, and the waveform is observed through the oscilloscope. At present, most of the methods used in China are traditional test methods. The traditional method requires multiple test points on each production line of the workshop. Each test point can only measure the motor current and speed controlled by the PWM signal under a duty cycle. Therefore, it is costly to have a tester and a complete tester at each test point.
Moreover, in the test process, to complete a motor test must pass through a number of test points, each test point must be tested by the tester plugging and unplugging the motor, making the test efficiency very low. Therefore, the traditional test methods seriously restrict the efficiency of DC motor manufacturers. In response to this situation, the author designed a new DC motor automatic test system based on DSP controller TMS320F2810. The system provides PWM control signals of various duty cycles to the motor, samples the current signal and output pulse signal of the motor through the DSP, calculates the current and speed of the motor, and sends it to the display for display, and also sends the data through the CAN bus. It is sent to the host computer for saving and analysis, and can send commands and data to each control node through the host computer. This system can test multiple motors at the same time, and can test the current and speed under all duty cycles at one test point, which greatly improves the test efficiency.
