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VIPA System 300S
Block check character
(BCC-Byte)
Initialization conflict
Data Link Escape
(DLE-character)
6.3.2 Proceeding
HB130 | CP | 341-1CH01 | en | 18-40
3964R appends a Block check character to safeguard the transmitted data. The BCC-
Byte is calculated by means of an XOR function over the entire data of the telegram,
including the DLE/ETX. When a BCC-Byte is received that differs from the calculated
BCC, a NAK is transmitted instead of the DLE.
If two stations should simultaneously attempt to issue a connection request within the
QVZ then the station with the lower priority will transmit the DLE and change to receive
mode.
The driver duplicates any DLE-character that is contained in a telegram, i.e. the
sequence DLE/DLE is sent. During the reception, the duplicated DLEs are saved as a
single DLE in the buffer. The telegram always terminates with the sequence
DLE/ETX/BCC (only for 3964R).
The control codes :
n
02h = STX
n
03h = ETX
n
10h = DLE
n
15h = NAK
1.
The parameter plugin "Point-to-Point-Communication, Parameter Assignment" is
started from the properties dialog of the CP by the button [Parameter...].
2.
Here the parameters for transfer protocol, data receipt and interface may be
adjusted.
3.
Set at Protocol the "3964(R)" protocol you want.
4.
For parameterization of the protocol click at
ð In the following these parameters are described. Information about this may
also be found in the online help of the parameter plugin.
Communication protocols
3964(R) > Proceeding
.
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