Siemens SIMATIC CP 440 Manual page 81

Transmission Rate/Character Frame
The following table describes the transmission rate/character frame.
Table 5-12 Transmission Rate/Character Frame (3964(R) Procedure)
Parameter
Transmission Rate Speed of data transmission in bps
Start Bit During transmission, a start bit is prefixed to
each character to be sent.
Data Bits Number of bits to which a character is mapped.
Stop Bits During transmission, a stop bit is appended to
every character to be sent to indicate the end of
the character.
Parity A sequence of information bits can be extended
to include another bit, the parity bit. The
addition of its value (0 or 1) brings the value of
all the bits up to a defined status. The data
integrity is thus enhanced.
If "none" is specified for parity, no parity bit is
sent.
It is not possible to specify "none" if 7 data
bits are set.
Priority A partner has high priority if its send job takes
precedence over the send job of the other
partner. A partner has low priority if its send job
must wait until the send job of the other partner
has been dealt with. With the 3964(R)
procedure, you must parameterize both
communication partners with different priorities,
i.e. one partner is assigned high priority, the
other low.
Point-to-point connection CP 440 Installation and Parameter Assignment
A5E00057742-02
Configuring and Parameterizing the CP 440
Description Value Range Default Value
300 9600
600
1200
2400
4800
9600
19200
38400
57600
76800
115200
1 (fixed 1
value)
7 8
8
1 1
2
None Even
Odd
Even
High Low
Low
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