Let's take a look at the basic composition of PLC

Simple understanding, PLC is like a small computer, CPU is responsible for processing data, including logical operations, timing, counting, arithmetic operations and transmission, communication networking, compiling the compiled program, executing commands, and transmitting the results to the output terminal . The PLC's memory (memory) consists of two parts. One is the ROM that stores the system program. The content in this read-only memory is solidified by the PLC before leaving the factory and cannot be changed by the user. The other is the readable storage for the user program and working status data. Write RAM memory.
Then there are input and output units and I/O expansion interfaces, which are responsible for connecting with external devices. Finally, there is a power supply module, which converts the external input power into the DC power required by the PLC's CPU, memory, input and output interfaces and other internal circuits, such as 24V, after processing.

Compared with other control equipment, the biggest feature of PLC is that it is sturdy, simple, reliable, and durable. Therefore, PLC must be used in the selection of processor and memory, PCB board circuit layout, power supply unit and communication loop design, and structural design. Follow these characteristics. It can be said that whether a PLC can run stably and reliably for a long time determines its quality. Therefore, we mainly look at how the reliability of PLC is designed.
First, we turn over the M262, we can see that there are 4 screws at the bottom, but they are hexagon sockets, and the common flat-head and Phillips screwdrivers cannot be unscrewed. This can also prevent some people from opening the PLC at will. We easily unscrewed 4 screws with a special Allen screwdriver.

However, although the 4 screws have been unscrewed, the bottom cover and the upper cover of the M262 are still tightly fixed together with a ring of buckles. You can only use a flat-blade screwdriver to push in one by one and then forcefully open the bottom cover.

After the buckles are loosened one by one, the bottom cover and the top cover are separated smoothly.