Technical data

8.3.2
Block Address Lists in Data
Block DB 0
Data block DB 0 contains a list with the start addresses of all blocks
in the memory submodule or in the DB RAM of the CPU. The system
program generates this list after POWER UP and updates it
automatically when you enter or change blocks at the programmer.
Address list start addresses A 256 words long address list is reserved in DB 0 for each block type
i.e. one word is reserved for each block. Blocks that are not loaded or
have been deleted have the start address "0".
The start addresses of the block address lists are also entered in the
system data RS 32 to RS 38.
RS 32:Start address of the DX address list
RS 33:Start address of the FX address list
RS 34:Start address of the DB address list
RS 35:Start address of the SB address list
RS 36:Start address of the PB address list
RS 37:Start address of the FB address list
RS 38:Start address of the OB address list (only 48 words long)
Block start addresses The start addresses always refer to the first word after the block
header:
•• this is DW 0 of data blocks
•• this is the first STEP 5 operation of a logic block
(in FBs, this is the "JU" operation before the name and the
parameter list)
8
User Memory Organization in the CPU 928B
CPU 928B Programming Guide
C79000-B8576-C898-01
8 - 11