Properties and functions
1.4 Configuration limits and performance data
SIMATIC CP 4163-1
14
Operating Instructions, 12/2022, C79000-G8976-C588-01
1.4.3
Characteristic data Open User Communication
Open User Communication (OUC) provides access to communication over TCP, ISO-on-TCP
and UDP connections.
Characteristic
Explanation / values
Number of connections
•
Max. number of connections via T blocks:
(ISO-on-TCP + TCP + UDP)
≤
63
of which:
–
TCP connections: 0 ... 63
1)
–
ISO-on-TCP connections: 0 ... 63
–
UDP connections: 0 ... 63
Notes:
•
1)
Avoid overload at receiving end
The flow control on TCP connections cannot control permanent
overload of the recipient. You should therefore make sure that the
processing capabilities of a receiving CP are not permanently exceeded
by the sender (approximately 150 200 messages per second).
Maximum data length for program blocks
Program blocks allow the transfer of user data in the following lengths:
•
ISO-on-TCP, TCP: 1 to 32 kbytes
•
UDP: 1 to 1472 bytes
LAN interface max. data field length generated
by CP per protocol data unit (TPDU = transport
protocol data unit)
•
For sending and receiving
–
ISO-on-TCP, TCP: 1452 bytes / TPDU
Restrictions for UDP
•
Restrictions UDP broadcast / multicast
To avoid overloading the CP due to high broadcast / multicast frame traffic, the receipt of
UDP broadcast / multicast on the CP is limited.
•
UDP frame buffering
Length of the frame buffer: At least 7360 bytes
Following a buffer overflow, newly arriving frames that are not fetched by the user
program are discarded.
