In the I/O Manager, you select the signals to be acquired. There are 3 ways of selecting measured values:

• Selection using the absolute address of the S7 operands, see Selection via the absolute address of the operands

• Selection using the S7 symbol addresses (symbol table and symbols from DBs) using a symbol browser, see Selection via the symbolic operand addresses

• Selection using the CFC connectors (when programming the CPU with SIMATIC CFC), see Selection of CFC connectors

SIMATIC CPU	Access using absolute address	Access using symbol	Access using CFC connectors1
S7-300	X	X	X
S7-400	X	X	X
WinAC	X	X	X
S7-1500	X	X	-

Supported operand ranges:

Operand range	SIMATIC CPUs S7-300/400	SIMATIC CPUs S7-1500
Inputs (I)	X	X
Peripheral inputs (PI)	X	-
Outputs (O)	X	X
Markers (M)	X	X
Data blocks (DB)	X	X

For S7-1500 you can use optimized data blocks. Signals within these data blocks can only be accessed using their symbolic names and not using the address or the operand. To access these data ranges, you must use the Request blocks from the ibaREQsym family, see ibaREQsym iba block family .