Siemens SIMATIC S7-1200 - Page 1227

Communication processor and Modbus TCP
13.6 Legacy PtP communication (CM/CB 1241 only)
S7-1200 Programmable controller
System Manual, V4.2, 09/2016, A5E02486680-AK
1227
Table 13- 105 Data types for the parameters
Parameter and type
Data type
Description
REQ IN Bool Activates the requested transmission on the rising edge of this transmission
enable input. This initiates transfer of the contents of the buffer to the Point-to-
Point communication interface. (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 "Sys-
tem constants" tab of the PLC tag table. (Default value: 0)
BUFFER IN Variant This parameter points to the starting location of the transmit buffer. (Default
value: 0)
Note: Boolean data or Boolean arrays are not supported.
LENGTH
1
IN UInt Transmitted frame length in bytes (Default value: 0)
When transmitting a complex structure, always use a length of 0.
PTRCL
IN
Bool
Reserved for future use
DONE
OUT
Bool
TRUE for one scan, after the last request was completed with no error
ERROR
OUT
Bool
TRUE for one scan, after the last request was completed with an error
STATUS
OUT
Word
Execution condition code (Default value: 0)
1
Optional parameter: Click the arrow at the bottom of a LAD/FBD box to expand the box and include this parameter.
While a transmit operation is in progress, the DONE and ERROR outputs are FALSE. When
a transmit operation is complete, either the DONE or the ERROR output will be set TRUE to
show the status of the transmit operation. While DONE or ERROR is TRUE, the STATUS
output is valid.
The instruction returns a status of 16#7001 if the communication interface accepts the
transmit data. Subsequent SEND_PTP executions return 16#7002, if the CM or CB is still
busy transmitting. When the transmit operation is complete, the CM or CB returns the status
of the transmit operation as 16#0000 (if no errors occurred). Subsequent executions of
SEND_PTP with REQ low return a status of 16#7000 (not busy).
The following diagrams show the relationship of the output values to REQ. This assumes
that the instruction is called periodically to check for the status of the transmission process.
In the diagram below, it is assumed that the instruction is called every scan (represented by
the STATUS values).