Siemens SIMATIC S7-1200 System Manual page 844

Communication
11.2 PROFINET
TRCV_C is reset when the COM_RST parameter is set. If data is being received when it
executes again, this can lead to a loss of data. The following scenarios are possible
depending on the CONT parameter:
● CONT = "0":
An existing communications connection is established.
● CONT = "1" and a communications connection was established:
An existing communications connection is reset and established again.
● CONT = "1" and no communications connection was established:
No communications connection is established.
The COM_RST parameter is reset following evaluation by the instruction TRCV_".
TRCV_C handles the same receive modes as the TRCV instruction. The following table
shows how data is entered in the receive area:
Protocol variant Availability of data in the receive
area
TCP The data is immediately availa-
ble.
(Ad hoc mode)
TCP (data receipt The data is available as soon as
with specified the data length specified at the
length) LEN parameter has been fully
received.
ISO on TCP (pro- The data is available as soon as
tocol-controlled the data length specified at the
data transfer) LEN parameter has been fully
received.
Note
Ad hoc mode
The "ad hoc mode" is only available with the TCP protocol variant. To configure the TRCV_C
instruction for ad hoc mode, set the ADHOC instruction input parameter. The length of the
receive area is defined by the pointer at the DATA parameter. The data length actually
received is output at the RCVD_LEN parameter. A maximum of 1460 bytes can be received.
Note
Importing of S7-300/400 STEP 7 projects containing "ad hoc mode" into the S7-1200
In S7-300/400 STEP 7 projects, "ad hoc mode" is selected by assigning "0" to the LEN
parameter. In the S7-1200, you configure the TRCV_C instruction for ad hoc mode by setting
the ADHOC instruction input parameter..
If you import an S7-300/400 STEP 7 project containing "ad hoc mode" into the S7-1200, you
must change the LEN parameter to "65535".
844
Connection_type parameter of
the connection description
B#16#11
B#16#11
B#16#12
System Manual, V4.2, 09/2016, A5E02486680-AK
LEN RCVD_LEN
parameter parameter
Selected with 1 to 1472
the TRCV_C
instruction
ADHOC input
1 to 8192 Identical to the
value at the
LEN parameter
1 to 8192 Identical to the
value at the
LEN parameter
S7-1200 Programmable controller