Siemens Simatic S7-300 CPU 31xC and CPU 31x S7-300 - Manual (Page 186)

Technical data of CPU 31x
7.5 CPU 315-2 PN/DP
CPU 31xC and CPU 31x, Technical data
7-20
Manual, Edition 08/2004, A5E00105475-05
Technical data
IEC Timers
Yes
• Type SFB
• Number Unlimited
(limited only by RAM size)
Data areas and their retentivity
Flag bits
2048 bytes
• Retentive memory Configurable
• Default retentivity From MB0 to MB15
Clock flag bits 8 (1 byte per flag bit)
Data blocks
•
Number 1023
(DB 1 to DB 1023)
• Length 16 KB
• Non-Retain support (configured retention) Yes
Local data per priority class Max. 1024 bytes per run level / 510 bytes per
block
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 16 KB
Nesting depth
• Per priority class 8
• additional within an error OB 4
FBs See the Instruction List
• Number 2048
(FB 0 to FB 2047)
• Length 16 KB
FCs See the Instruction List
• Number 2048
(FC 0 to FC 2047)
• Length 16 KB
Address areas (I/O)
Total I/O address area
max. 2048 bytes/2048 bytes
(can be freely addressed)
Distributed max. 2000 bytes
I/O process image 128/128
Digital channels 16384/16384
of those local Max. 1024
Analog channels 1024/1024
of those local Max. 256