Siemens SIMATIC S7-400 CP 440, Установка и настройка параметров

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Configuring and Parameter Assignment the CP 440
5.4 Configuration data
Point-to-point connection CP 440 Installation and Parameter Assignment
Manual, 09/2007, A5E00057742-03
79
Receive Buffer on CP
The following table describes the parameters for the CP receive buffer.
Table 5-13 Receive buffer on CP (3964(R) procedure)
Parameters Description Value Range Default Value
Delete CP receive
buffer at startup
During power up or during transition of the CPU from
STOP to RUN the CP receive buffer is deleted.
• Yes
•
No
No
Buffered receive
message frames
You can specify the number of receive message
frames to be buffered in the CP receive buffer or to
use the whole buffer. If you use the whole buffer of
2000 bytes, the number of buffered receive message
frames depends only on the length of the frames.
If you specify "1" here and deactivate the following
parameter "prevent overwrite" and cyclically read the
received data from the user program, a current
message frame will always be sent to the CPU.
• 1 to 10
• Use whole buffer
Use whole
buffer
Prevent overwrite You can use this parameter to prevent data in the
receive buffer being overwritten when the buffer is full.
• Yes
• No
Yes
Initial state of receive line
The table below contains a description of the initial state of the receive line for the X27
(RS 422) interface. RS 485 operation is not possible in conjunction with the 3964(R)
procedure.
Table 5-14 X27 (RS 422) Interface (3964(R) procedure)
Parameters Description Value Range Default Value
none: This setting only makes sense with bus-
capable drivers.
none
R(A) 5V/R(B) 0V: Break detection is possible
with this initial state.
R(A) 5V / R(B) 0V
(break detection)
Initial state of
receive line
R(A) 0V/R(B) 5V: Break detection is not possible
with this initial state.
R(A) 0V / R(B) 5V
R(A) 5V / R(B) 0V
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