Basic Principles of Serial Data Transmission
2.4 Data Transmission with the ASCII Driver
Point-to-point connection CP 440 Installation and Parameter Assignment
Manual, 09/2007, A5E00057742-03
35
End Criterion End-of-Text Character
When data is received, the end of the message frame is recognized when the configured
end-of-text character(s) arrive. The following options are available:
●
One end-of-text character
●
Two end-of-text characters, 1st and 2nd end-of-text characters
●
Two end-of-text characters, 1st or 2nd end-of-text character
The received data including the end-of-text character(s) is accepted from the CPU.
If the end-of-text character is missing in the received data, the character delay time elapses
during reception and results in a termination of the frame. The character delay time is used
in this instance as the monitoring time. An error message is issued and the message frame
fragment is discarded.
If you are working with end-of-text characters, transmission is not code-transparent, and you
must make sure that the end code(s) are not in the user data of the user.
Note the following when the last character in the received message frame is not the end-of-text
character.
●
End-of-text character elsewhere in the message frame:
All characters including the end-of-text character are entered in the receive DB. The
characters following the end-of-text character
–
Is discarded if the monitoring time expires at the end of the message frame.
–
Is merged with the next message frame if a new message frame is received before the
monitoring time expires.
●
End-of-text character not included in message frame:
The message frame
–
Is discarded if the monitoring time expires at the end of the message frame.
–
Is merged with the next message frame if a new message frame is received before the
monitoring time expires.
长沙工控帮教育科技有限公司
www.gkbpx.com
