Boil Sugar Machine Plc Based Control System

In candy manufacturing process, cooking and whipping are two key procedures , because they have decided the quantity of moisture, sugar, fat and other additives of the candy, thus decided the candy's quality. What's more, these procedures are the key to promote productivity due to its long processing time. As a result ,it is very important to develop a good control system for the cooker and whipping vessel.In this thesis, a PLC-based control system with high automation, high productivity and guaranteed syrup quality is designed for a candy manufacturing machine (thermosyphon cooker and whipping vessel). The main contents of this thesis include: 1. the introduction of the arise, progress, present status and trend of development of PLC, and the aim of this work——to improve the production efficiency and operation reliability of the sugar manufacturing machine; 2. the planning of the overall function and structure of the control system, and the functional partition of system hardware and software; 3. the designing of the hardware function modules of the control system, namely power supply module, module of main circuit for motor, module of liquid level control, module of flow rate measurement, module of pressure and temperature measurements, module of gas pressure control, I/O address assignment of PLC; 4. the development of the software of the control system, i.e. PLC control program; 5. the designing of the human-machine interface.Through the design procedure of the control system, the adopted general design methodology is as follows: first, planning the overall structure of the control system, and then designing the function and structure of each module, respectively. In this way, on the one hand, the design logic is clear; on the other hand, it is convenient for the designing and debugging of each module. The practical application of the control system indicates that although the system still needs further improvement, the expected overall function of the control system, i.e. to improve the production efficiency and operation reliability of the machine, is basically accomplished.