The dosage system uses a Siemens S7-200 programmable controller with dual CPUs to form a redundant system, and the STEP7MicroWin V4.0SP6 programming software provided by Siemens as a human-machine interface to write programs, debug programs, download programs, etc. The PC and PLC experimental machine are connected with a PC/PPI cable to communicate and set up the corresponding parameters. Setting. Use RS-485 bus to connect the PC with PL. It consists of a water heating unit, a weighing module, a digital temperature sensor, a kettle weighing, a data acquisition card and a PC. The digital temperature sensor converts the measured temperature of the liquid into a digital quantity and transmits it to the PC through the data acquisition card, and converts the real-time volume of the mixed liquid into a digital quantity and transmits it to the PC through the data acquisition card. The monitoring system based on LabVIEW software displays the liquid mixing process in real time.

The water heating device applies different temperature signals to the digital temperature sensor by changing the temperature of the liquid. The data acquisition card collects the temperature signals to the PC and analyzes and calculates the collected data with LabVIEW software, and the final measurement results are displayed on the interface of the dosage system. The weighing control system monitors the liquid mixing process in real time, and collects the measured data to PC through the data acquisition card, and displays them on the interface of the weighing system as the mixing container curve and the product container curve.

The weighing system contains functions such as data acquisition, storage, processing and analysis, display and historical data, etc. The front panel is a graphical user interface, which provides three modules such as liquid mixing, temperature acquisition and system operation module, etc. The liquid mixing module has a mixing container curve and a product container curve, which show the mixing of the two liquids and the weight of the product respectively, and the speed of liquid mixing can be changed through the adjusting valves and pumps, and there is a digital display on the liquid mixing container. The speed of liquid mixing can be changed by adjusting the valve and pump, and there is a digital display on the liquid mixing container. The temperature acquisition module can set the liquid heating temperature and display the collected temperature data on the mixing temperature curve in real time. The system operation module allows stopping, automatic and manual operation of the liquid mixing and temperature acquisition, and provides help information for the operation of this monitoring system.