Siemens Simatic S7-400

Protocol parameters
The table below describes the protocol parameters.
Table 5-5 Protocol Parameters (ASCII Driver)
Parameter Description Value Range Default Value
Indicator for end of
receive message
frame
De󹪝nes which criterion signals the end
of each message frame.
• After character delay time
expires
• On receipt of a 󹪝xed num‐
ber of characters
• On receipt of end-of-text
character
After character delay time
expires
Character delay
time
The character delay time de󹪝nes the
maximum permitted time between 2
consecutively received characters.
• 1 to 65530 ms
The shortest character delay
time depends on the transmis‐
sion rate
4 ms
Monitoring time for
missing end ID
The character delay time is used as the
monitoring time for a missing end code.
This applies to the following settings for
the end code
• On Receipt of Fixed Number of Char‐
acters
• On receipt of end-of-text character
Baud
• 300
• 600
• 1200
• 2400
• 4800
• 9600
• 19200
• 38400
• 57600
• 76800
• 115200
CDT (ms)
• 130
• 65
• 32
• 16
• 8
• 4
• 2
• 1
• 1
• 1
• 1
End-of-text charac‐
ter 1
(1)
First end code.
• with 7 data bits:
0 to 7FH (Hex)
(2)
• with 8 data bits:
0 to FFH (Hex)
(2)
3 (03H = ETX)
End-of-text charac‐
ter 2
(1)
Second end code, if speci󹪝ed.
You can con󹪝gure the following for the
end code:
• 1. end-of-text character AND 2nd
end-of-text character
• 1. end-of-text character OR 2nd end-
of-text character
• with 7 data bits:
0 to 7FH (Hex)
(2)
• with 8 data bits:
0 to FFH (hex)
(2)
0
Message frame
length when re‐
ceived
(3)
When the end criterion is "󹪝xed message
frame length", the number of bytes mak‐
ing up a message frame is de󹪝ned.
1 to 400 (bytes) (see chapter
"Overview of the Function
Blocks (Page 73)")
200
Con󹪝guring and Parameter Assignment the CP 440
5.4 Con󹪝guration data
Point-to-point connection CP 440 Installation and Parameter Assignment
Equipment Manual, 03/2022, A5E00057742-AE 59