Siemens S7-300 appendix Diagnostic buffer Yes Number of entries not configurable Max

Technical data of CPU 31x 7.4 CPU 315-2 DP

Technical data

Diagnostic buffer			Yes
• Number of entries (not configurable)			Max. 100
Communication functions
PG/OP communication			Yes
Global data communication			Yes
• Number of GD circuits			8
• Number of GD packets			Max. 8
	–	Sending stations	Max. 8
	–	Receiving stations	Max. 8
• Length of GD packets			max. 22 bytes
	–	Consistent data	22 bytes
S7 basic communication			Yes
• User data per request			max. 76 bytes
	–	Consistent data	76 bytes (for X_SEND or X_RCV)
			64 bytes (for X_PUT or X_GET as the server)
S7 communication			Yes
•	As server		Yes
•	as client		Yes (via CP and loadable FBs)
• User data per request			Max. 180 bytes (with PUT/GET)
	–	Consistent data	64 byte (as the server)
S5-compatible communication			Yes (via CP and loadable FCs)
Number of connections			16
can be used for
•	PG communication		Max. 15
	–	Reserved (default)	1
	–	Configurable	1 to 15
•	OP communication		Max. 15
	–	Reserved (default)	1
	–	Configurable	1 to 15
•	S7-based communication		Max. 12
	–	Reserved (default)	12
	–	Configurable	0 to 12
Routing			Yes (max. 4)
Interfaces
1st interface
Type of interface			Integrated RS485 interface
Physics			RS 485
electrically isolated			No
Interface power supply			max. 200 mA
(15 to 30 VDC)

7-16	CPU 31xC and CPU 31x, Technical data
	Manual, Edition 08/2004, A5E00105475-05