Firstly, according to byte, each character is converted into a number of 10. For example, the character' 3 '(ascii code value 3 is actually stored in PLC) is converted into the number 3 of 10, and then multiplied by the proportion according to the number of digits, and then added, in the form of 10 * A+B+0. 1 * C+0.

As for how to convert ascii code into binary data of 10, in fact, there is no need for special explanation in this case, because it is 0-9 ascii code, and the corresponding ascii code range is 48-57. You just need to subtract 48 directly from the address of DB 12. DBB7 obtains 10 binary data (of course, there is no arithmetic operation of byte data in step7).