The successful research and development of disposable environmental tableware equipment control system mainly depends on the following aspects:
1. The demand analysis is relatively clear. Requirement analysis is the basis of system development, and explicit requirement analysis is the key to clarify business process and system function.
2. The simple operation, convenient maintenance and reliability requirements are fully considered in the design. The control panel design is simple and clear, PLC selection is reasonable, and resource allocation design is reasonable.
3. Fully consider the internal structure and functional requirements of the injection molding machine, and adopt simple and clear hardware wiring design.
4. In the design of control software, the program structure is selected reasonably, and the problem of too long scanning time is solved by using the instruction step + high order instruction program structure.
Now let's have a detailed understanding of the components of the tableware equipment control system:
I.e. control panel:
1. The design of the control panel of disposable tableware equipment mainly considers the convenience of system control operation to avoid misoperation; in addition, the convenience of system hardware wiring, system circuit maintenance and the overall aesthetics of the panel need to be considered.
2. Resource allocation design
Resource allocation mainly includes the determination of input and output points, corresponding function buttons, function descriptions, etc. See Table 1 for details. In order to describe resource allocation more clearly, the table also lists some resource allocation within PLC, including time relay and intermediate relay.
3. Hardware circuit and software design
The design of hardware circuit is relatively simple, and the external wiring of PLC can be designed according to the resource table. The software design is relatively complex, so it is necessary to draw software program flow chart. As can be seen from the figure, the control program mainly has three branches: inching, automatic and single step execution.
The control program of disposable environmental protection tableware equipment system is developed by pfsoft development tool of the supplier. Pfsoft software is installed in PC, PC and PLC are connected, pfsoft development interface is opened, LC control ladder program is compiled and downloaded to PLC ladder program, which can simulate debugging in PLC. The debugging platform adopts "electrical control and PLC experimental platform start to use traditional programming control instructions, Although there is no problem in function, but the function is complex and the program is long, which makes PLC scan the program too long and does not meet the requirements of molding machine control. The traditional control instruction structure is abandoned, and the program structure of step instruction + higher-order instruction is adopted to make the program structure clearer, the program length greatly shortened, and the scanning time of the program meets the control requirements.