Communication processor and Modbus TCP
12.3 Point-to-point (PtP) communication
● Receive message start configuration: Configure the CM 1241 to start receiving a
message when the communication line is inactive for at least 50 bit times (about 5
milliseconds at 9600 baud = 50 * 1/9600):
● Receive message end configuration: Configure the CM 1241 to end a message when it
receives a maximum of 100 bytes or a linefeed character (10 decimal or a hexadecimal).
The end sequence allows up to five end characters in sequence. The fifth character in the
sequence is the linefeed character. The preceding four end sequence characters are
"don't care" or unselected characters. The CM 1241 does not evaluate the "don't care"
characters but looks for a linefeed character preceded by zero or more "don't care"
characters to indicate the message end.
706
S7-1200 Programmable controller
System Manual, 03/2014, A5E02486680-AG