Siemens SIMATIC NET S7-300 User Manual

4 SEND/RECEIVE Interface in the User Program
A-96
S7-CPs for Industrial Ethernet Configuring and Commissioning
Release 01/2007
C79000-G8976-C182-07
FC Calls Slower than the Transmission Time
If a block is called again before the data were completely transferred or received,
the procedure is as follows on the interface of the FC blocks:
 AG_SEND/AG_LSEND:
The job is positively acknowledged. The Ethernet CP is ready to receive a new
send job (at the earliest however with the next call).
 AG_RECV/AG_LRECV:
The job is acknowledged with “New Data Received” when the data have been
transferred to the user program. Following this, the FC call can be repeated.
Notice
Remember that resource shortages can occur if the processing speeds on the
sender and receiver are not the same (sender faster than receiver).
The sender receives a message from the FCs if problems occur (“No resources on
the destination station”).

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)