1. Safety is paramount throughout the entire process.
The most important aspect of safety is the importance placed on it in people's minds; then, it must be supplemented by technological guarantees. Although it is said to be "supplemented," it should not be underestimated, and the weight of the word "guarantee" must be understood; this is said in order to highlight the importance of "putting it in mind."
Based on a thorough and comprehensive understanding of the controlled object and control process, and considering operational safety, we will make every effort to resolve accidental and unsafe factors in the operation or action process, and develop a control program that conforms to the process, is safe and reliable, easy to operate, and convenient to maintain.
Of course, improving the system is also an important aspect of safety.
2. Preliminary preparations are a prerequisite.
Many of you are probably aware of the importance of preliminary preparations, including understanding control requirements and the overall design approach, as well as mastering relevant and fundamental knowledge. Please refer to the two previous summaries for more details.
Similarly, many people know that the first step is to prepare in advance, and the second is to master the PLC hardware wiring and software operation.
In a broader sense, learning PLC is also a gradual process that can be summarized as "preparatory work." This is called being prepared for a rainy day; opportunity favors the prepared.
3. The program structure must be arranged reasonably.
A good program should have a clear and reasonable structure, making it easy to read and debug. When the program is large or the control is complex, attention should be paid to the application of design methods and programming techniques.
"Program architecture is very important." This means that the application of subroutines not only reduces program size but also increases readability and facilitates program debugging and modification.
When practicing programming or creating small programs, if you have time, you can do this kind of training, such as comparing different solutions and approaches to broaden your thinking and gain experience.
4. Program debugging is a component.
The developed program must be debugged to find errors and improve functionality. Debugging is divided into simulation debugging (mimicking the actual situation) and field debugging; only programs that have passed field debugging and are approved are usable programs.
In addition, the considerations during debugging must be comprehensive, listing as many possible scenarios as possible, including misoperation, component failure, and sudden power outage, and attention should be paid to the coordination between the PLC and the peripheral circuits.
A PLC is a component of a control system, so it must be considered within the context of the entire system.
5. Through regular learning and accumulation
Some knowledge and experience require accumulation over time, as many people have experienced. However, PLC programming itself, especially the basic applications of small PLCs, is generally not considered difficult.
Some people who have used Mitsubishi FX2N, Siemens 200, and Panasonic FP0 find the basic instructions easy to learn; for function instructions, they can handle most programming needs by consulting the manual and conducting simple experiments. However, medium-sized PLCs require more knowledge.
Some experienced individuals also emphasized the necessity of hands-on learning, stating that "learning by doing and doing by learning repeatedly yields excellent results"; and that "practical experience is the fastest way to learn; you forget what you've learned if you don't do it." They also stressed the importance of utilizing existing resources for learning.
In fact, you can gain a lot of experience in the repair process, such as the good methods and shortcomings of others, including the function of the program and the design of the circuit, all of which can be used in future designs.
6. Conclusion
This article discusses a general direction. Once you grasp this general direction, beginners can start to familiarize themselves with the instructions and conduct programming experiments.
