Control Strategy and Process of Automatic Batching System in the New Materials Industry

In the new material production industry, ingredients are usually uniformly mixed with raw materials in a certain proportion to form new materials. Therefore, the automatic batching system is an important component of the industry's production. During the production process, various raw materials must be strictly mixed evenly according to the proportion in the formula, and completed by the automatic batching system. Currently, factories generally adopt two methods. One method is to manually weigh and then mix various raw materials in a proportioning machine at the same time. Another method is automatic weighing and automatic mixing. Due to the fact that many raw materials are in powder or granular form, the human body is prone to inhaling dust and other debris during manual batching, resulting in occupational diseases, increased production risks, and labor costs. At the same time, there are many types and quantities of ingredients, making on-site management of manual ingredients difficult and prone to mismatches. This not only makes it difficult to ensure quality, but also increases management costs. In order to ensure product quality and improve production efficiency, an accurate and reliable automatic batching system is required.
Through the analysis of the characteristics of the batching process, the results indicate that the automatic batching process has the following characteristics:
(1) The controlled object is a unidirectional irreversible system. Raw materials cannot be returned to the conveyor belt from the automatic batching system;
(2) Has significant time delay. When the ingredient reaches the set value, the PLC controls the motor to stop conveying the raw material. At this point, some of the raw materials on the conveyor belt cannot be recycled, so the automatic batching system has a significant time delay;
(3) The control feature is switching. The start and stop control of the automatic batching system is a switching value;
(4) The automatic batching system is linear in the normal working area, therefore, we consider using control strategies such as fast, slow, and issuing stop feed commands, as well as using PLC interlocking technology to ensure the smooth progress of batching.
After the automatic batching system is started, the industrial computer sends a signal to the PLC to start feeding, and the signal is successfully received. The PLC controls the frequency converter to drive the motor to quickly feed. At the same time, the industrial control host continuously reads the weighing data of the weighing instrument through the serial port. When the weight value approaches the set value, the industrial control host sends a control command to the PLC to stop feeding. At this point, the PLC controls the frequency converter to slowly feed, estimating the residual amount of raw materials on the conveying mechanism in advance. When the difference between the set value and the actual feeding amount is equal to the residual amount of raw materials on the conveying mechanism, the PLC truly sends a stop command, which is executed by the frequency converter to control the motor shutdown. After the shutdown, there is no residual raw material on the conveying mechanism, and the batching accuracy meets the requirements.
The main tasks completed by the industrial computer are as follows:
(1) Provide animated display of the batching process of the automatic batching system;
(2) Send control commands to the PLC and read the operating status of the PLC;
(3) Read the weighing signal on the weighing instrument, display the weighing value on the display, and send instructions to the PLC based on the weighing data;
(4) Database and reports, saving ingredient data, printing reports;
(5) Add and modify formulas;
(6) Auxiliary alarm and other functions for ingredient failure.