Automatic control system is the soul of automatic production line and automatic equipment. Whether it is a high-precision, fast-responding steel rolling production line with complex process flow, or a street automatic juicer with simple start-stop control, the application of automated control systems is ubiquitous. For engineering and technical personnel, especially automation system engineers, it is not without benefit to understand and master some basic knowledge of system design. The expression form of the system design, there are two kinds of drawings and documents, mainly in the form of drawings.
Basic automation system design drawings mainly serve equipment debuggers, electronic control equipment manufacturers, production line maintenance and overhaul personnel, and on-site operators. The basic requirements of design drawings are: First, the drawing surface is clean and refreshing. Second, the design content is correct and the national norms and standards are strictly implemented. Third, the system configuration is optimal, safest and most economical. We have an overview of the automation system design through the following aspects.
1. Design software
With the popularization of computers, engineers and technicians have completely bid farewell to the era of drawing with pencil and ink pen. Application design software has completely replaced drawing with a pen, and the functions developed are becoming more and more powerful. The current electrical design software is mainly CAD, Eplan, SeeElectircal, EB, etc. Most of the design software is a customized enterprise database, dedicated symbols, equipment models, drawing frames, etc., can customize standardized design processes, automatically generate terminal diagrams, wiring diagrams, various reports, and can be seamlessly integrated with mechanical 3D software for quick completion The production of digital prototypes realizes mechatronics design.
2. Design specifications
The design must follow the international and domestic design specifications, including the use of standard design atlases, domestic and international standard technical specifications. among them
Design atlases: including standard atlases such as national standard and European standard. Commonly used design software libraries usually already contain commonly used standard component graphics, which can be selected from the library when making drawings. Non-standard graphics need to be designed by yourself.
Technical specifications include: selection of high and low voltage electrical system components, voltage levels, short circuit protection, overvoltage protection, etc.
3. Design basis
The main involved basis of the automation system is the process and equipment professional data, that is, the requirements of the process flow, the requirements of the control accuracy, what is the control object and so on. These contents are withdrawn from the technical function requirements book, motor and component equipment table data.
4. Design content
The complete design drawings include: drawing catalog, manual, power distribution diagram, network architecture diagram, control schematic diagram, process schematic diagram (including the location of main equipment and electronic control equipment), schematic diagram of cabinets, components and equipment tables, cables table.
5. Matters needing attention (from a control perspective)
a) Uninterruptible power supply:
The PLC controller and HMI system of the basic automation system usually need UPS power supply to prevent the automation system data from being lost in the event of a sudden power failure in the factory or equipment.
b) Grounding protection:
The grounding protection of the control system is essential to the stable operation of the system. The grounding method will not be repeated here.
c) Emergency stop system
The emergency stop system is the ultimate protection method for people and equipment, and is an indispensable and important link in the design of automation systems.
6. Development trend
With the gradual popularization of BIM and other three-dimensional design software, the boundaries of professional design will become more and more blurred. The design of the whole process and the integrated life cycle will gradually replace the single professional design, as will the design of automation systems. Therefore, it is the inevitable choice of every engineering designer to fully grasp the knowledge of various disciplines and use advanced application design software proficiently.