MCU in the application of electromagnetic vibrating feeder
Electromagnetic vibrating dosing machine is a new type of feeding equipment, used to massive, granular and powdered materials from hopper uniformly continuous or quantitatively to go to the affected device. In industrial production, the dosing equipment is widely used in coal, metallurgy, chemical industry, food industry
. With the development of increasingly high precision ingredients, so research and development weighfeeder automatic control system to improve dosing accuracy and level of automation equipment, has important practical significance.
1 system, the basic structure and working principle
Work, electromagnetic vibrating feeder according to the quantitative control of the material inside the hopper gave solids flowmeters, flow meter will actually feeding amount detected, feedback to the control system. If the actual value and the system does not match a given value, regulating the electromagnetic vibrating feeder, the feeding amount to achieve automated sorting machine
Value system. From out of the chute-type materials are solids flowmeters horizontal vibration conveyor, vertical screw conveyor feeder reservoir in the back to form a loop system. If the actual value matches the value of a given system, material conveying to the output port. The use of controlled amplitude of the feeder
Dosing to achieve, as a control target amplitude of the electromagnetic vibrating feeder, the thyristor controlled voltage.
Is divided into eight parts of the system design, namely the power system, the monitor program design, the design of the memory, A / D converter interface design D / A converter interface design, the keyboard display interface design, the strong electric drive I / O port design and serial port expansion design.
Throughout the MCU system design, power supply design is to first consider, for the 8031 ??power supply is DC +5 V, ADC574 and DAC1210 power supply required +5 V and a set of + /-12V power supply, control high voltage relay +12 V power supply is required. By entering, buck, rectifier, filter, regulator,
Required output voltage. hot water heat exchanger
Since the microcontroller's own anti-interference ability is poor, especially in some of the conditions are relatively poor, noisy situations, problems often arise due to outside interference caused microcontroller crash phenomenon, causing the system is not working properly, set the program to effectively monitor MAX692 interference and
Protect data, allowing the system work reliably.
System uses 8031 ??to develop, expand a program memory and a 6264 27256 data memory. Chosen as the 74LS138 decoder chip selection, system input and output analog analog each way, regardless of the system accuracy requirements, were selected 12 of the
ADC574 and 12 DAC1210 as the system A / D and D / A extension, A / D and D / A and the CPU bus isolation between the use of technology, from solids flowmeters measure flow through the resistance strain force sensor, conversion into a voltage by the ADC574 converted into digital by microcontroller PID control,
Control DAC1210 output voltage control thyristor, then adjust the amplitude of the feeder. System has two vertical screw conveyor vibration motor, two horizontal conveyor vibration motor and a need to control the electric vibrator starts and stops, the microcontroller through the control signals to optical isolation
These strong electrical control equipment. 8155 Expansion 8 keyboard, eight seven-segment digital display interface. Using the PC as a PC, SCM as the next crew distributed structure, using MAX485 chip serial port on the 8031 ??expansion, the hosts on the cluster machine remote site control
System control block diagram: the amount of feedback after A / D conversion of the analog to digital, and then computing the difference with the set amount for by the PID controller operation, the output result by D / A becomes analog, adjust the corresponding parameters, control of the actuator, to achieve the purpose of regulation.
(2) Software Design
The system program is divided into five main modules that the main program module, display module, keyboard module, serial port communication module, timer TO interrupt processing module and PID control module.
The main program module initialize the system. Display module is the on-chip RAM memory information to the 8155 output. Keyboard module function is to set parameters, calibration and system start and stop control. Serial port communication module is set to 3 serial ports work, in fact,
Now multi-machine communication, as the next crew of real-time high, which generally use the serial interrupt way communication, timer TO interrupt processing module is to achieve counting, in order to start the device, delay shutdown. PID control module is based on incremental PID control algorithm to calculate △ u (n)
, According to u (n) = u (n-1) + △ u (n) is calculated control quantity u (n), and converted to an integer, to a D / A converter.
Electromagnetic vibrating feeder due to the use of the mechanical vibration to learn the theory of resonance, consume less power. Control of single electromagnetic vibrating feeder uniform feeding, adjust the amplitude of the feeder, the rated amplitude range, automatic control via input signal can directly regulate the amplitude can be adjusted
Section feeder feeding amount. Has a simple structure, easy to adjust, stable and remote computer control and other characteristics, the production process can achieve centralized control and automatic control.