Siemens SIMATIC S7-1200 - Page 844

Communication
11.2 PROFINET
S7-1200 Programmable controller
844 System Manual, V4.2, 09/2016, A5E02486680-AK
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
Connection_type parameter of
the connection description
LEN
parameter
RCVD_LEN
parameter
TCP
(Ad hoc mode)
The data is immediately availa-
ble.
B#16#11 Selected with
the TRCV_C
instruction
ADHOC input
1 to 1472
TCP (data receipt
with specified
length)
The data is available as soon as
the data length specified at the
LEN parameter has been fully
received.
B#16#11 1 to 8192 Identical to the
value at the
LEN parameter
ISO on TCP (pro-
tocol-controlled
data transfer)
The data is available as soon as
the data length specified at the
LEN parameter has been fully
received.
B#16#12 1 to 8192 Identical to the
value at the
LEN parameter
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 instructi
on 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 param
eter..
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".