ISPSoft User Manual The system assigns a 4096-word memory block to the function block instance declared in a POU of the program type in a project for an AH5X0 series CPU module. The function block instance declared in the POU of the program type and the inferior function blocks are assigned the same memory block. Besides, the system assigns another 4096-word memory block to a function block instance declared in the global symbol table. In the example above, the system assigns three 4096-word memory blocks. The memory blocks that an AH5X0 series CPU module reserves for function block instances are stored in the internal memory.
The memory blocks assigned to the function blocks in a project for an AH5X0 series CPU module are not devices available to users. No matter what the size of the memory that a function block instance occupies is, the size of the memory block assigned to the function block instance is 4096 words. As a result, users have to be careful when they program a CPU module. The calculation of the size of a function block instance is as follows. The size of the memory that a function block instance occupies is 2 words. size which is less than one word is calculated as one word.
The size of the memory that a symbol whose data The size of the memory that a local symbol in a function block instance occupies is calculated by the word. The type is a function block (inferior function block instance) occupies is calculated by means of (1). Please refer to the following example. The local symbols declared in the function block definitions are listed in the table below. 7-26 Function block Number of local symbols definition Function block A Two symbols whose data types are DWORD. One symbol whose data type is LREAL. One inferior function block instance.