Performance data
2.3 SEND/RECEIVE interface
CP 443-1 (EX30)
22 Manual, 03/2019, C79000-G8976-C255-05
Maximum data length for the AG_SSEND and
AG_SRECV program blocks
AG_SSEND and AG_SRECV allow the transfer of user data with the
following lengths:
• 1. ISO-on-TCP, TCP, ISO transport: 1 to 1452 bytes
• 2. UDP: 1 to 1452 bytes
LAN interface max. data field length generat-
ed by CP per protocol data unit
• For sending
ISO transport, ISOonTCP, TCP:
– 400 bytes / TPDU with AG_SEND / AG_LSEND
– 1452 bytes / TPDU with AG_SSEND
• For receiving
– ISO transport: 512 bytes / TPDU
– ISO-on-TCP: 1452 bytes / TPDU
– TCP: 1452 bytes / TPDU
● Transfer is not confirmed
The transmission of UDP frames is unconfirmed, in other words the loss of messages is
not detected or displayed by the send blocks (AG_SEND or AG_LSEND).
● No receipt of UDP broadcast
To avoid overload due to high broadcast load, the CP does not allow reception of UDP
broadcasts. As an alternative, use the multicast function via a UDP connection. This
gives you the option of registering the CP as a node in a multicast group.
● UDP packet buffering
Length of the frame buffer with buffering enabled: 2 KB
Note: Following a buffer overflow, newly arriving frames are discarded.
Number of simultaneous SEND/RECEIVE calls
The number of SEND/RECEIVE calls that can be used at the same time is limited both by
the CPU and by the CP.
If the maximum number of simultaneous SEND/RECEIVE calls is exceeded, the value
8302H (no receive resources) is indicated in the STATUS of the surplus SEND functions.
This can, for example, happen when too many SEND/RECEIVE calls are sent at the same
time in OB1.
In productive operation, the number of SEND/RECEIVE calls that can be used at one time
depends on the CPU resources being used. Note the information on the available CPU
resources in section System environment (Page 27).
To Next Page
Loading...
Need help?
General
