Siemens SIMATIC NET S7-300 User Manual

7 Programming FCs (Functions) and FBs for S7 Ethernet CPs
A-190
S7-CPs for Industrial Ethernet Configuring and Commissioning
Release 01/2007
C79000-G8976-C182-07
Specifying the Data Area on the CPU
When you call an FC, you transfer the address and length of the data area in the
CPU. Remember, that the maximum length of the data area depends on the block
type and block version being used.
 AG_SEND and AG_RECV
Up to version V3.0 of these blocks, a maximum of 240 bytes could be sent or
received. The current block versions allow a data area of up to 8192 bytes for
an S7-300. With an S7-400, the FCs AG_LSEND / AG_LRECV must still be
used for larger data areas.
 AG_LSEND / AG_LRECV
Using the CPs of the S7-400 and with earlier versions of the S7-300, larger
data areas can only be transferred with the FCs AG_LSEND or AG_LRECV.
Please check the length of the data area in the product information.
The following table shows the limit values of the various connection types.
Table 7-1
FC
ISO Transport ISO-on-TCP TCP UDP
AG_LSEND
(S7-400)
AG_SEND
(S7-300)
8192 bytes 8192 bytes 8192 bytes 2048 bytes
AG_SEND
(S7-400)
240 bytes 240 bytes 240 bytes 240 bytes
AG_LRECV
(S7-400)
AG_RECV
(S7-300)
8192 bytes 8192 bytes 8192 bytes 2048 bytes
AG_RECV
(S7-400)
240 bytes 240 bytes 240 bytes 240 bytes
Note
For information on the length of the data area you can transfer with older versions
of the Ethernet CPs, refer to the product information bulletin / manual of the
Ethernet CP you are using /2/.
Working without the Job Header
On specified connections, the address and job parameters are specified by the
connection configuration. The user program only provides the user data in the UDP
data area when sending with AG_SEND / AG_LSEND or receives the data with
AG_RECV / AG_LRECV.

Siemens SIMATIC NET S7-300 Specifications

General

Product Type Designation	SIMATIC NET S7-300
Mounting	DIN rail mounting
Protection Class	IP20
CPU Models	Various models available (e.g., CPU 312, CPU 314)
Communication Interfaces	MPI, PROFIBUS DP
Power Supply	24 V DC power supply required. Different power supply modules available.
I/O Modules	Digital input modules, digital output modules, analog input modules, analog output modules
Programming	STEP 7 software
Supply Voltage	24V DC or 120/230V AC (depending on model)
Digital Inputs	Available via digital input modules
Digital Outputs	Available via digital output modules
Analog Inputs	Available via analog input modules
Analog Outputs	Available via analog output modules
Communication Functions	MPI, PROFIBUS DP, Ethernet (depending on model)
Protocols	MPI, PROFIBUS DP, TCP/IP (depending on model)
Operating Temperature	0°C to 60°C
Storage Temperature	70 °C
Memory	Depends on CPU model (e.g., 32 KB to 1.5 MB)