1, hardware is fundamental, don't expect other electricians to connect all the wires for you, design the hardware circuit diagram, and then let you learn programming, so it is difficult for you to understand the essence of PLC. You need to know what contactors and relays are, how they are wired in practice, what is the self-locking circuit, and how the interlocking circuit realizes the time-related control of several relays. There are also basic functions such as time relay and thermal protection. After all, these things are used to isolate and control many industrial control equipment. Only by thoroughly understanding their performance and application logic can you understand what industrial electrical automation is. When you are just learning relay circuit, you can install a motor forward and backward rotation circuit, a star triangle starting circuit, a heating and cooling temperature control circuit and so on. These objects can make you deeply understand the basic concept of "circuit" in electrical control, which is not necessary for single chip microcomputer and high-level language programmers, but must be mastered as PLC programmers.
2.PLC and peripheral circuits also need to be explored by themselves, because the basic thing is to connect external control circuits through input and output I/O. You can tell what is the * * * terminal of COM, why there are inputs such as NPN and PNP, and what are the outputs of transistors and relays. You can simply find a button, wire it according to the instructions to form a single circuit, and then press the button. The I/O LED light corresponding to the input of PLC must be on. Release the button, and this light should be off, so that the input circuit will be normal, and you will understand the relationship between the input circuit and PLC smoothly. As for the output circuit, you can play with the relay output at first, which is the contact anyway. You can connect a relay outside, find a short wire to temporarily short the internal contact of PLC, and the external relay will work, then disconnect the short wire and the external relay will be reset. Through such physical operation, you will understand that the essence of PLC is just a complex multi-group relay.
3. Prepare the laptop and download line, find the PLC supplier to get the corresponding editing software, install the editing software, read the instructions in the programming manual or video, and connect the download line with the download port of PLC. Generally, when the PLC is powered on, after it is connected, the editing software will remind you that it has been connected. At this time, you can find some simple cases of this PLC, import it directly, or try to input and compile it manually. Then download it to PLC and let it run. Although these small details sound simple, for a novice, you must experiment step by step, until you fully master them, you will be considered as a foot in the door of PLC.