Technical data

Table Of Contents
Open Communication via Industrial Ethernet
System Software for S7-300/400 System and Standard Functions - Volume 2/2
A5E00739858-01
23-29
23.10 Receiving Data via TCP native and ISO on TCP with
FB 64 "TRCV"
Description
FB 64 "TRCV" receives data over an existing communication connection.
The are two variants available for receiving and processing the data:
Variant 1: Received data block is processed immediately.
Variant 2: Received data block is stored in a receive buffer and is only
processed when the buffer is full.
The following table shows the relationships between the connection type is shown
in the following table:
Connection Type Variant
B#16#01 and
B#16#11
The user can specify the variant.
B#16#12 Variant 2 (fixed)
The following table describes both variants in detail.
Received data ... Range (of Values)
for LEN
Range (of
Values) for
RCVD_LEN
Description
are available
immediately
0 1 to x The data go into a buffer whose length x is
specified in the ANY pointer of the receive
buffer (DATA parameter).
After being received, a data block is
immediately available in the receive buffer.
The amount of data received (RCVD_LEN
parameter) can be no greater than the size
specified in the DATA parameter. Receiving
is indicated by NDR = 1.
are stored in the
receive buffer. The
data are available as
soon as the
configured length is
reached.
11 to 1460, if the
connection type
= B#16#01
1 to 8192, if the
connection type
= B#16#11
1 to 1452, if the
connection type
= B#16#12 and a
CP is being used
1 to 8192, if the
connection type
= B#16#12 and
no CP is being
used
Same value
as in the LEN
parameter
The data go into a buffer whose length is
specified by the LEN parameter. If this
specified length is reached, the received
data are made available in the DATA
parameter (NDR = 1).