Siemens S7-300 appendix Technical data, Data areas and their retentivity, Address areas I/O

Technical data of CPU 31xC 6.2 CPU 312C

Technical data

IEC Timers		Yes
•	Type	SFB
•	Number	unlimited (limited only by RAM size)
Data areas and their retentivity
Flag bits		128 bytes
•	Retentive memory	Configurable
•	Default retentivity	MB0 to MB15
Clock flag bits		8 (1 byte per flag bit)
Data blocks		Max. 511
		(DB 1 to DB 511)
•	Length	max. 16 KB
Local data per priority class		max. 256 bytes
Blocks
Total		1024 (DBs, FCs, FBs)
		The maximum number of blocks that can be
		loaded may be reduced if you are using another
		MMC.
OBs		see the Instruction List
•	Length	max. 16 KB
Nesting depth
•	Per priority class	8
• additional within an error OB		4
FBs		Max. 512
		(FB 0 to FB 511)
•	Length	max. 16 KB
FCs		Max. 512
		(FC 0 to FC 511)
•	Length	max. 16 KB
Address areas (I/O)
Total I/O address area		max. 1024 bytes/1024 bytes
		(can be freely addressed)
I/O process image		128 bytes/128 bytes
Digital channels		Max. 256
•	of those local	Max. 256
•	Integrated channels	10 DI / 6 DO
Analog channels		Max. 64
•	of those local	Max. 64
•	Integrated channels	None

6-4	CPU 31xC and CPU 31x, Technical data
	Manual, Edition 08/2004, A5E00105475-05