Siemens S7-300 appendix Technical data Communication functions, Interfaces 1st interface

Technical data of CPU 31x 7.2 CPU 312

Technical data

Communication functions

PG/OP communication			Yes
Global data communication			Yes
• Number of GD circuits			4
• Number of GD packets			Max. 4
	–	Sending stations	Max. 4
	–	Receiving stations	Max. 4
• 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
•	As server		Yes
• User data per request			Max. 180 bytes (with PUT/GET)
	–	Consistent data	64 bytes
S5-compatible communication			Yes (via CP and loadable FCs)
Number of connections			Max. 6
can be used for
•	PG communication		Max. 5
	–	Reserved (default)	1
	–	Configurable	from 1 to 5
•	OP communication		Max. 5
	–	Reserved (default)	1
	–	Configurable	from 1 to 5
•	S7-based communication		Max. 2
	–	Reserved (default)	2
	–	Configurable	from 0 to 2
Routing			No
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)
Functionality
•	MPI		Yes
•	PROFIBUS DP		No
•	Point-to-point communication		No

7-6	CPU 31xC and CPU 31x, Technical data
	Manual, Edition 08/2004, A5E00105475-05