1. First created 2 blocks, one FB block, and one FC block.
2. After the FB block is created, when it is called in the MAIN main program, it will let you add a DB block. Among the DB blocks, the default is to keep the data. However, when the FC is called, the DB block is not called.
3. The difference between the interface call of FB and FC block
4. In the main program, when the fb block is used, the data is saved, but after the fc block is called, the data is cleared, as shown in the figure
