Siemens S7-300 appendix Communication functions

Technical data of CPU 31x 7.7 CPU 317-2 PN/DP

Technical data

•	Number of variables		30
	– Of those as status variable		Max. 30
	– Of those as control variable		Max. 14
Forcing
•	Variables		Inputs/Outputs
•	Number of variables		Max. 10
Block status			Yes
Single step			Yes
Breakpoints			2
Diagnostic buffer			Yes
• Number of entries (not configurable)			Max. 100
Communication functions
Open IE communication via TCP/IP			Yes (via integrated PROFINET interface and
			loadable FBs, max. 8 connections)
PG/OP communication
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
S7 communication			Yes
•	As server		Yes
•	as client		Yes (via integrated PN interface and loadable
			FBs, or even via CP and loadable FBs)
• User data per request			See the STEP 7 Online Help, Common
	–	Consistent data	parameters of SFBs/FBs and SFC/FC of the S7
			communication)
S5-compatible communication			Yes (via CP and loadable FCs)
Number of connections			32
can be used for
•	PG communication		Max. 31
	–	Reserved (default)	1
	–	Configurable	1 to 31
•	OP communication		Max. 31
	–	Reserved (default)	1
	–	Configurable	1 to 31
•	S7-based communication		Max. 30
	–	Reserved (default)	0
	–	Configurable	0 to 30

7-36	CPU 31xC and CPU 31x, Technical data
	Manual, Edition 08/2004, A5E00105475-05