Shared by: Zheng Chuhong
I still remember that when I joined UniMAT, the company's first training course was about the definition, characteristics and classification of PLC, and I have benefited a lot so far. Some people may think that as a graphic designer, there is not much actual contact with products and customers, and it does not matter if you do not understand products, but UniMAT does not think so. The automation industry is a very specialized industry. No matter what position it is, the basic knowledge of products must be necessary, and mastering it is more helpful to the work. Below, I will share some of the training content at that time with all friends who have transferred to the automation industry from other industries.
A PLC is an electronic system that operates digitally and is designed for use in an industrial environment. It uses programmable memory to store instructions for performing operations such as logic operations, sequential control, timing, counting, and arithmetic operations, and controls various operations through digital and analog inputs and outputs. Type of machinery or production process. PLC and its related equipment should be designed according to the principle of easy to form a whole with the industrial control system and easy to expand its functions.
1. Features of PLC:
1. High reliability and long service life
2. Strong environmental adaptability
3. Flexible and universal
4. Easy to use and easy to maintain
5. The entire connection process only needs a screwdriver to complete.
Second, the classification of PLC
PLC is produced by the needs of modern mass production, and the classification of PLC must also meet the needs of modern production. Generally speaking, programmable controllers can be classified from three aspects. One is to classify from the size of PLC control, the other is to classify from the performance level of PLC, and the third is to classify from the structural characteristics of PLC.
1. Classification according to the control scale: it can be divided into mainframes, medium-sized computers and minicomputers.
(1) Small computer: The control point of a small computer is generally within 256 points, which is suitable for the control of a single computer or a small system.
(1) Japan Omron Corporation CQM1
Processing speed: 0.5~10ms/1k words
Memory: 3.2~7.2k
Digital 192 points, analog 44 channels
(2) Germany SIEMENS S7-200
Processing speed: 0.8~1.2ms
RAM: 2k
Digital: 248 points, 35 points analog
(2) Medium-sized machine: The control point of the medium-sized machine generally does not exceed 2048 points, which can directly control the equipment, and can also monitor multiple next-level PLCs. Suitable for control of medium or large control systems.
(1) Japan OMRON company C200HG
Processing speed 0.15~ 0.6 ms/ 1k words
Memory 15.2~31.2k
Quantity 1184 points
(2) Germany SIEMENS S7-300
Processing speed: 0.8~1.2ms
RAM: 2k
Digital 1024 points, analog 128 channels
Network: PROFIBUS, Industrial Ethernet, MPI
(3) The control points of the host are generally greater than 2048 points, which can not only complete complex arithmetic operations, but also perform complex matrix operations. Not only can the equipment be directly controlled, but also multiple next-level programmable controllers can be monitored.
(1) Japan Fuji F200
Processing speed: 2.5ms/1k words
RAM: 32k
Input and output points: 3200
(2) Japan Omron CV2000
Processing speed 0.125ms / 1k words
Memory 62k I/O points 2048
(3) Germany SIEMENS S7-400
Processing speed: 0.3ms/1k words
RAM: 512k
Number of input and output points: 12672
(4) Germany AEG A500
Processing speed: 1.3ms/1k words
RAM: 62k 64k
Input and output points: 5088
2. Classification according to control performance: it can be divided into high-end machines, mid-end machines and low-end machines.
(1) Low-end machine
This type of PLC has basic control functions and general computing power. The working speed is relatively low, and the number of input and output modules in the energy band is relatively small. For example, the S7-200 produced by the German SIEMENS company belongs to this category.
(2) Mid-range machine
The PLC has powerful control functions and powerful computing power. It can not only complete general logic operations, but also more complex trigonometric, exponential and PID operations. The working speed is relatively fast, the number of input and output modules that can be brought is also relatively large, and the types of input and output modules are also relatively large. For example, the S7-300 produced by the German SIEMENS company belongs to this category.
(3) High-end machine
This type of PLC
