What Are the Different Types of Desktop Computer Cases?

A computer is a modern intelligent electronic device that can automatically and quickly perform a large number of numerical calculations and various information processing according to a program stored in advance. Consists of hardware and software, both of which are inseparable. People call computers without any software installed as bare metal. With the development of science and technology, some new types of computers are now emerging: biological computers, photonic computers, quantum computers, and so on.

Computer type

It is a general term for a computer system that uses a bus structure to detect and control the production process, its electromechanical equipment, and process equipment. Referred to as industrial computer. It consists of a computer and process input / output (I / O) through two major parts. A computer is composed of a host computer, input / output devices, external disk drives, and tape drives. A part of the process input / output channel is added outside the computer to send the detection data of the industrial production process to the computer for processing; on the other hand, the computer must use the commands and information to control the production process into industrial control object control variables The signal is sent to the controller of the industrial control object. The controller exercises control over the operation of the production equipment. The main categories of industrial control computers are: IPC (PC bus industrial computer), PLC (programmable control system), DCS (distributed control system), FCS (field bus system) and CNC (numerical control system).

IPC

That is, an industrial computer based on the PC bus. According to IDC statistics in 2000, PCs accounted for more than 95% of general-purpose computers. Because of their low price, high quality, large output, and rich software / hardware resources, they have been familiar and recognized by a large number of technical personnel. Annoying foundation. Its main components are an industrial chassis, a passive backplane, and various boards that can be inserted on it, such as CPU cards, I / O cards, and so on. It also adopts the design of all-steel chassis, machine clamp strip filter, double positive pressure fan and EMC (Electro Magnetic Compatibility) technology to solve the problems of electromagnetic interference, vibration, dust, high / low temperature in industrial sites.

IPC has the following characteristics:

Reliability: Industrial PC has fast diagnosis and maintainability in dust, smoke, high / low temperature, humidity, vibration, corrosion, and its MTTR (Mean Time to Repair) is generally more than 100,000 hours.

Real-time, industrial PC performs real-time online detection and control of the industrial production process, responds quickly to changes in working conditions, performs timely collection and output adjustment (watchdog function is not available on ordinary PCs), and resets itself in distress Ensure the normal operation of the system.

Expansibility. Because the industrial PC uses a baseboard + CPU card structure, it has strong input and output functions. It can expand up to 20 boards, which can be used with various peripherals, boards such as controllers, and video surveillance in the industrial field The system, vehicle detector, etc. are connected to complete various tasks.

Compatibility, can use ISA, PCI and PICMG resources at the same time, and support various operating systems, multi-language assembly, multi-tasking operating system.

Programmable Logic Controller (PLC)

The English name of PLC is ProgrammableLogicController, and the Chinese name is Programmable Logic Controller. It is defined as: an electronic system for digital operation, which is designed for applications in industrial environments. It uses a type of programmable memory for its internal stored programs, performs logical operations, sequence control, timing, counting and arithmetic operations, and other user-oriented instructions, and controls various types of machinery through digital or analog input / output Or production process. Programmable logic controller (ProgrammableLogicController) is a kind of digital arithmetic operation electronic system specially designed for application in industrial environment. It uses a programmable memory that stores instructions for performing logical operations, sequence control, timing, counting, and arithmetic operations within it. It controls various types of mechanical equipment or production through digital or analog input and output. process.

Programmable controller is a new type of general-purpose automatic control device developed for the industrial environment by the combination of computer technology and automation control technology. It appears as a replacement product of traditional relays. With the rapid development of microelectronic technology and computer technology, programmable controllers have more computer functions, not only can realize logic control, but also have data processing, communication, network and other functions. Because it can change the control process through software, and has the characteristics of small size, convenient assembly and maintenance, simple programming, high reliability, strong anti-interference ability, etc., it has been widely used in various fields of industrial control, greatly promoting the mechatronics. process.

Distributed Control System (DCS)

It is a series of high-performance, high-quality, low-cost, flexible configuration distributed control system products, which can form various independent control systems, distributed control systems DCS, monitoring and data acquisition systems (SCADA), and can meet various industrial fields The need for process control and information management. The system's modular design, reasonable software and hardware function configuration, and easy-to-expand capabilities can be widely used in decentralized control of various large, medium and small power stations, transformation of power plant automation systems, steel, petrochemical, papermaking, cement, etc. Industrial production process control.

Fieldbus system (FCS)

It is an all-digital serial, two-way communication system. Measurement and control equipment such as probes, exciters and controllers in the system can be interconnected, monitored and controlled. In the classification of the factory network, it not only serves as a local network for process control (such as PLC, LC, etc.) and application of intelligent instruments (such as inverters, valves, bar code readers, etc.), but also has embedded control applications distributed on the network Features. Due to its broad application prospects, many powerful foreign manufacturers compete to invest in product development. There are more than forty types of fieldbuses known internationally. The typical fieldbuses are: FF, Profibus, LONworks, CAN, HART, CC-LINK, etc.

Numerical control system (CNC)

The modern numerical control system is a numerical control system using a microprocessor or a special microcomputer. The system program (software) stored in the memory in advance implements the control logic, implements some or all of the numerical control functions, and connects with peripheral devices through interfaces. Numerical control, referred to as CNC system.

NC machine tools are mechatronics products formed by the penetration of new technologies represented by numerical control systems into the traditional machinery manufacturing industry; their technical scope covers many areas: (1) mechanical manufacturing technology; (2) information processing, processing, and transmission technology; (3) automatic control technology; (4) servo drive technology; (5) sensor technology; (6) software technology.

Desktop

It is also called a desktop computer. It is an independent computer that is completely separated from other components. Compared with laptops and netbooks, it is relatively large. The host, monitor, and other devices are generally relatively independent and generally need to be placed on a computer desk. Or on a dedicated workbench. Hence the name desktop. For very popular microcomputers, most people's homes and companies use desktop computers. Desktops are relatively better than laptops. The desktop has the following characteristics:

Heat dissipation. Desktop computers have advantages unmatched by notebook computers. Desktop chassis has been widely used because of its large space and good ventilation.

Scalability. Desktop chassis is convenient for users to upgrade hardware, such as optical drive, hard drive. Optical drive such as desktop chassis

Embedded system is an application-centric, microprocessor-based, software and hardware that can be tailored to meet the comprehensive and strict requirements of the application system on functions, reliability, cost, volume, and power consumption. Dedicated computer system. It generally consists of four parts: embedded microprocessor, peripheral hardware equipment, embedded operating system and user's application program. It is the fastest growing field in the computer market, and it is also a wide variety of computer systems. Embedded systems include almost all electrical appliances in life, such as handheld pda, calculator, TV set-top box, mobile phone, digital TV, multimedia player, car, microwave oven, digital camera, home automation system, elevator, air conditioner, security system, Vending machines, cellular phones, consumer electronics, industrial automation instruments, and medical instruments.

The core components of an embedded system are embedded processors, which are divided into 4 categories: embedded microcontrollers (Micro Contrller Unit, MCU, commonly known as single-chip microcomputer), embedded microprocessors (Micro Processor Unit, MPU), and embedded DSP processor ( Digital Signal Processor (DSP) and Embedded System on Chip (SOC). Embedded microprocessors generally have four characteristics:

1. Has strong support for real-time and multi-tasking, can complete multi-tasking and has a short interrupt response time, thereby reducing the execution time of internal code and real-time operating system to a minimum;

2. It has a very powerful storage area protection function. This is because the software structure of the embedded system has been modularized. In order to avoid wrong cross effects between software modules, it is necessary to design a powerful storage area protection function. Conducive to software diagnosis;

3. Scalable processor structure to quickly expand the high-performance embedded microprocessor that meets the application;

4. The power consumption of the embedded microprocessor must be very low, especially for battery-powered embedded systems used in portable wireless and mobile computing and communication equipment. The power consumption can only be mw or even w.