This paper designs a peristaltic pump control system of coater based on STM32. The 57 type stepper motor is subdivided by 4.3 inch touch screen control signal. When the system runs, the operation mode of the stepper motor can be changed at any time, including rotation direction, rotation rate and torque number, so as to achieve the purpose of precise real-time control of the peristaltic pump stepper motor. 。 At present, the automatic coating instrument is widely used, thermostatic element and the peristaltic pump control technology in the coating instrument has been developed accordingly. This project developed a peristaltic pump controller based on STM32. Its main function is to achieve accurate and efficient measurement and control of fluids in coating experiments. An electronic peristaltic pump system for precise liquid delivery is developed, which is specially designed for precise measurement and assembly of various reagent solutions (culture medium, buffer, diluent, etc.
) in microbial laboratories. It can be widely used in professional microbiological laboratories of various biological, chemical enterprises, government testing institutions and scientific research units. The peristaltic pump in the automatic coating instrument can realize the device of precise control of liquid delivery, which is convenient for driving liquid flow. STM32 Minimum System Control Stepper Motor Driver Drive Peristaltic Pump. This method is reliable, stable and low cost.
This design adopts STM32 Control System Stepper Motor Driver Serial Port Touch Screen, and precisely controls Peristaltic Pump through circuit design and software development.
The system takes the stepper motor controller as the core and uses touch screen to realize visual operation. Pulse generated by STM32 internal timer is used as control signal to change the frequency of control signal and then control the speed of stepper motor.
Pulse signal determines the start, stop and steering of stepper motor. The system structure is shown in Figure 1.
The control system can realize touch screen control. The hardware circuit of the system is composed of control and drive parts. The control part mainly completes the input of the control signal, the output of the pulse and the display of the state; the driving part mainly drives the stepper motor by increasing the driving power of the circuit.
As can be seen from Figure 1, the hardware of the system includes four parts: STM32 minimal system, THB6128 chip driver circuit, serial touch screen and two-phase hybrid stepping motor. The peripheral components of the hardware circuit are few and the integration is high.
The control circuit design includes STM32 minimal system and related peripheral circuit, which completes input signal processing and output of control pulse and LCD control signal. The selected STM32 chip has the following advantages: high performance, low cost, low power consumption, using ARM Cortex-M3 core. The essence of driving circuit is the application of electronic technology, which mainly completes the amplification from weak to strong current. The essence of stepping motor drive is to convert logic level into current signal with certain power needed by motor winding. The driver chip chooses THB6128, a high-subdivision two-phase hybrid stepper motor driver chip produced by Toshiba Company, which can realize subdivision setting. STM32 outputs control signals to drive 57 series stepper motors.
The hardware circuit is shown in Figure 2. The human-machine interface part uses the touch screen of Guangzhou Dacai Company. Its configuration software is easy to use and it is very convenient for users to design friendly human-machine interface. In this system, STM32 circuit is communicated with touch screen by serial port protocol. The design of man-machine interface is shown in Figure 3.
The overall structure of the system software is modular, each functional module is relatively independent, which is convenient for programming, debugging and functional expansion.
According to the functional requirements, the software is composed of initialization module, speed regulation module and touch screen display module. The core software of the system is the stepper motor control program. After initialization, the control system enters the main cycle inquiry instruction queue program. Touch screen signal triggers the function module of the main program as trigger condition, and calls the corresponding function subroutine. The software main program flow is shown in Figure 4. This project drives creeping pump in coating instrument by stepper motor. Touch screen interface can operate the start and stop of stepper motor and control the speed and direction of stepper motor. The 57 stepper motor is driven by subdividing the driving chip and adopting the pulse width modulation technology to improve the stability of the stepper motor. This paper is devoted to the research and application of peristaltic pump technology in the process of separating liquid controlled by coating apparatus. The peristaltic pump device with STM32 as the core accomplishes accurate control of separating liquid volume, and the electronic control system with motion controller and touch screen constructs overall coordinated control. A fully automatic peristaltic coating facing the application of coating experiment has been successfully developed. The prototype realizes friendly man-machine interface operation and timely communication effect of motion controller. The control method of the whole system is simple and feasible, the structure of the controller is simple and reliable, and the performance-price ratio is high, so it has good practical popularization value.