Siemens SIMATIC S7 System Manual page 403

Table 10- 3 TSEND_C and TRCV_C data types for the parameters
Parameter and type
REQ IN
(TSEND_C)
EN_R IN
(TRCV_C)
CONT IN
LEN IN
CONNECT IN_OUT
DATA IN_OUT
COM_RST IN_OUT
DONE OUT
BUSY OUT
ERROR OUT
STATUS OUT
RCVD_LEN OUT
(TRCV_C)
Note
The TSEND_C instruction requires a low-to-high transition at the REQ input parameter to
start a send job. The BUSY parameter is then set to 1 during processing. Completion of the
send job is indicated by either the DONE or ERROR parameters being set to 1 for one scan.
During this time, any low-to-high transition at the REQ input parameter is ignored.
S7-1200 Programmable controller
System Manual, 11/2011, A5E02486680-05
Data type Description
Bool Control parameter REQ starts the send job with the connection
described in CONNECT on a rising edge.
Bool Control parameter enabled to receive: When EN_R = 1,
TRCV_C is ready to receive. The receive job is processed.
Bool
0: Disconnect

1: Establish and hold connection

UInt Maximum number of bytes to be sent (TSEND_C) or received
(TRCV_C):
Default = 0: The DATA parameter determines the length of

the data to be sent (TSEND_C) or received (TRCV_C).
Ad hoc mode = 65535: A variable length of data is set for

reception (TRCV_C).
TCON_Param Pointer to the connection description
Variant
Contains address and length of data to be sent (TSEND_C)

Contains start address and maximum length of received

data (TRCV_C).
Bool Allows restart of the instruction:
0: Irrelevant

1: Complete restart of the function block, existing connection

will be terminated.
Bool
0: Job is not yet started or still running.

1: Job completed without error.

Bool
0: Job is completed.

1: Job is not yet completed. A new job cannot be triggered.

Bool Status parameters with the following values:
0: No error

1: Error occurred during processing. STATUS provides

detailed information on the type of error.
Word Status information including error information. (Refer to the
"Error and Status Parameters" table below.)
Int Amount of data actually received, in bytes
103BCommunication
10.2 PROFINET
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