The constant flow control of the feeding system is regulated by PID, and the flow metering control is a combination of metering deviation and variable frequency speed control. According to the system process flow introduces the flow control mode of the Batching system and the system control process, details the selection of PLC and PLC batching system frequency control in the hardware settings, parameter settings and software design process.

Weighing and Dosage system is a very important process in the production process of fine chemical plant, and the quality of dosage process is very important to the quality of the whole product. Automatic batching control process is a multi-input, multi-output system, each batching and conveying production line is strictly coordinated control, timely and accurate monitoring and adjustment of material level and flow. The system consists of programmable controllers and electronic belt scales to form a two-level computer control network, connecting field instrumentation, control computers, PLCs, frequency converters and other equipment with high intelligence and fast processing speed through the field bus. In the automatic dosage production process, the main material and auxiliary materials in a certain proportion with the electronic belt scale to complete the belt conveyor conveying materials for measurement. PLC is mainly responsible for conveying equipment, weighing the process of real-time control, and complete the system failure detection, display and alarm, while the frequency converter output signals to regulate the speed of the belt conveyor role.

Software composition of dosage system: the software part of conventional dosage system is a visualized computer operating system designed and developed for monitoring and automatic dosage of dosage section. It has the features of simple and convenient operation, strong reliability, friendly man-machine interface, complete functions, etc. It can be widely used in feed, grain, pharmacy, metallurgy, chemical and other industries which need computerized automatic dosage, and has high level of intelligent informatization: the upper computer has the function of management of formula library; the intelligent report software provides a large amount of data information for the production management such as the list of dosage results, the list of raw material consumption, the list of production quantity, the record of formula usage results, etc. It can provide production shift report by time, formula and other production reports. The intelligent report software provides a large amount of data information for production management, such as the list of batching results, the list of raw material consumption, the list of production quantity, the record of formula usage results, etc. The statistics and printing function can be performed according to the time and formula, such as the production of shift report, daily report, monthly report and annual report. Meanwhile, it provides two kinds of user-defined report components, one is to adopt crystal report for secondary design; the other is to embed the data seamlessly into EXCEL report. In addition, the system can interact with other management systems to meet the requirements of deep-level data analysis. The upper part stores the parameters such as cumulative quantity, proportion, running start and stop time of each road for each run for querying. The software part of the system can automatically complete the system dosage process, the computer screen real-time display of the dosage system (workflow, the software is simple to operate, the screen is realistic. Meanwhile, it has the following characteristics: the upper computer software sets the running password and important parameter password modification protection, and the user realizes the hierarchical management, which can define the personnel's authority arbitrarily.