The use of clock register in Siemens 300

1. When looking at the program of Siemens PLC300, sometimes you will encounter such a situation, and you still can't find the meaning of this register, but don't panic, you must first understand that it represents a 1-second clock, so you can Find in the time register

2. You can right-click the CPU in the hardware, view the properties, and this picture will appear

, This is the time register you are looking for, pay attention to its memory byte, it corresponds to what you see in the program,

3. But you may be wondering, the program is M99.5, this byte is 99, don’t panic, if you look at this picture again, you will understand why the program is M99.5, and M99.5 stands for 1 second clock In addition, it means to close once a second in the program.