5 stages of PLC technology learning
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A logical stage
The so-called logic phase is to realize the general logic design in the relay system. Since it is a relay system, the knowledge of power drag is the basis of this stage. My personal conclusion is that the root of the relay system lies in a word "grab". The reason why the relay system can achieve logic control is in this word. In the relay system, there are mainly three Dongdong A normally open; B normally closed; C coil. This corresponds to the basic elements of the PLC, but the method of reading is not the same.
So can you copy the original relay system? No! The way they work is different. All the hard elements in the relay system start to compete in the same tense, and all the soft elements in the PLC are scanned and calculated by the CPU of the PLC. Finally, the result of the temporal state is calculated, which is the working mode of the PLC scanning cycle. . (Just find a PLC book is introduced)
Focus:
1. This stage is to learn the electric drag, corresponding to the normally open, normally closed, coil in the PLC ladder diagram.
2. Can complete simple system design
two. Sequence control phase
Sequential control is widely used in industry, such as a general automatic machine tool, which is a sequential control process. There are two ways to realize the sequence control in the PLC design: a sequence control instruction in a PLC such as Mitsubishi STL; and a second stop control mode. No matter which kind of control method we want to complete at the beginning of the design is the process, it is the thread of the system consists of three main aspects: one "step" two "active step" three "conversion conditions".
Focus:
1. Master the system context design system flow
2. Master the "start and stop" control mode and convert the flowchart into a ladder diagram
Can complete general system design
three. Assembly phase
This phase is essentially different from the relay control system, which cannot be realized by the relay control system, and is also the root of improving the function of the PLC control system! I call it the assembly stage because it is very similar to the assembly language programming of the microcontroller, such as the transfer instruction MOV in the microcontroller, which is the same function in the advanced instructions in the PLC. This stage is more difficult, the first is to learn the computer foundation; the second is to fully understand the internal functions and resources of the PLC; the third is familiar with all the functions of advanced instructions (without rote memorization). If you don't understand the computer basics, you can't understand the advanced instructions and the resources in the PLC. The design ideas and the relay system are very different. For example, the first one of I0.0 and IB0 is "bit". The "point" of the logic design, the second is "bytes" not covered in the logic design.
Focus:
Computer foundation
2. PLC resources
3. Command function
4. Adapting to the programming thinking of single chip microcomputer
Can complete complex system design
four. Special stage
Special phases are for special-function systems such as motion control, PID temperature control, network connectivity, and more. Different PLCs can achieve different functions. Some functions are integrated in the PLC and some need to be extended. Therefore, it is necessary to select according to different control objects. Mastering this stage can greatly improve the PLC program, but you need to master other automation knowledge other than PLC, such as servo, inverter and so on.
Focus:
1. Understand the system configuration needs
2. Reasonable choice of expansion unit
3. Learning how to use extension units
Can complete special system design
The learning at this stage requires certain practical conditions to be completed.
Fives. Network stage
With the development of automation technology, the application of PLC to the lower position machine is also very common. This stage group should learn the communication protocol of different PLCs and some communication instructions. For example, PLC controls the inverter through the programming port, such as Siemens' USS protocol and inverter to exchange information. There are also industrial Ethernet and fieldbus such as PROFIBUS of the West; AS-i; and so on.
The five stages of PLC control system learning have been introduced. Now everyone has already understood the process of PLC learning. Xiaobian here reminds everyone to take a step by step when learning, do not want to learn, to follow the above 5 Learn from the stages.