What does it mean that the data in Siemens S7-2 has bytes, words and double words? What does it mean that the data types are string, integer and real floating-point number?
1 double word =2 words =4 bytes =32 bits
You need to have a good look at the basic computer applications.
The string "You need to study hard"
The integer number is 1 2 3
The floating-point type is 1.5 2.45
You need to lay a good foundation, otherwise it will be difficult to learn.