Siemens SIMATIC S7-1200 - Page 852

Communication
11.2 PROFINET
S7-1200 Programmable controller
852 System Manual, V4.2, 09/2016, A5E02486680-AK
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. Comp
letion 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.
Note
The default setting of the LEN parameter (LEN = 0) uses the
DATA parameter to determine
the length of the data being transmitted. It is recommended that the data transmitted by the
TSEND_C instruction be the same size as the DATA parameter of the TRCV_C instruction.
If using the default setting of the LEN paramete
r and it is necessary to send the data in
segments smaller than the DATA parameter size, the following applies. If the size of the data
transmitted from TSEND_C does not equal the TRCV_C DATA parameter size, TRCV_C
remains in a busy status (status code: 70
06) until the overall size of the data transmitted
from TSEND_C equals the TRCV_C DATA parameter size.
The TRCV_C DATA parameter buffer does not display the new data received until the data
size equals the DATA parameter buffer size.
TSEND_C operations
The following functions describe the operation of the TSEND_C instruction:
● To establish a connection, execute TSEND_C with CONT = 1.
● After successful establishing of the connection, TSEND_C sets the DONE parameter for
one cycle.
● To terminate the communication connection, execute TSEND_C with CONT = 0. The
connection will be aborted immediately. This also affects the receiving station. The
connection will be closed there and data inside the receive buffer could be lost.
● To send data over an established connection, execute TSEND_C with a rising edge on
REQ. After a successful send operation, TSEND_C sets the DONE parameter for one
cycle.
● To establish a connection and send data, execute TSEND_C with CONT =1 and REQ =
1. After a successful send operation, TSEND_C sets the DONE parameter for one cycle.