Siemens S7-1200 - SEND_CFG (Configure Serial Transmission Parameters Dynamically) Instruction

Communication processor and Modbus TCP
12.3 Point-to-point (PtP) communication
S7-1200 Programmable controller
688 System Manual, 03/2014, A5E02486680-AG
12.3.3.3
SEND_CFG (Configure serial transmission parameters dynamically) instruction
Table 12- 10 SEND_CFG (Send Configuration) instruction
LAD / FBD
SCL
Description
"SEND_CFG_DB"(
REQ:=_bool_in_,
PORT:=_uint_in_,
RTSONDLY:=_uint_in_,
RTSOFFDLY:=_uint_in_,
BREAK:=_uint_in_,
IDLELINE:=_uint_in_,
DONE=>_bool_out_,
ERROR=>_bool_out_,
STATUS=>_word_out_);
SEND_CFG allows the dynamic configuration of serial
transmission parameters for a PtP communication port.
Any queued messages within a CM or CB are
discarded when SEND_CFG is executed.
1
STEP 7 automatically creates the DB when you insert the instruction.
You can set up the initial static configuration of the port in the device configuration
properties, or just use the default values. You can execute the SEND_CFG instruction in
your program to change the configuration.
The SEND_CFG configuration changes are not permanently stored in the CPU. The
parameters configured in the device configuration are restored when the CPU transitions
from RUN to STOP mode and after a power cycle. See Configuring transmit (send)
parameters (Page 675).
Table 12- 11 Data types for the parameters
Parameter and type
Data type
Description
REQ IN Bool Activate the configuration change on the rising edge of this input.. (Default
value: False)
PORT IN PORT After you install and configure a CM or CB communication device, the port
identifier appears in the parameter helper drop-list available at the PORT
box connection. The assigned CM or CB port value is the device
configuration property "hardware identifier". The port symbolic name is
assigned in the "System constants" tab of the PLC tag table. (Default value:
0)
RTSONDLY IN UInt Number of milliseconds to wait after enabling RTS before any Tx data
transmission occurs. This parameter is only valid when hardware flow
control is enabled. The valid range is 0 - 65535 ms. A value of 0 disables
the feature. (Default value: 0)
RTSOFFDLY IN UInt Number of milliseconds to wait after the Tx data transmission occurs before
RTS is disabled: This parameter is only valid when hardware flow control is
enabled. The valid range is 0 - 65535 ms. A value of 0 disables the feature.
(Default value: 0)
BREAK IN UInt This parameter specifies that a break will be sent upon the start of each
message for the specified number of bit times. The maximum is 65535 bit
times up to an eight second maximum. A value of 0 disables the feature.
(Default value: 12)