Siemens SIMATIC CP 440, Руководство пользователя

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Configuring and Parameterizing the CP 440
5-11
Point-to-point connection CP 440 Installation and Parameter Assignment
A5E00057742-02
Receive Buffer on the CP
The table below describes the parameters for the CP receive buffer.
Table 5-8 Receive Buffer on the CP (ASCII Driver)
Parameter Description Value Range Default Value
Delete CP Receive
Buffer on 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 that are 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, disable the
“Prevent Overwriting” parameter 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
Overwriting You can use this parameter to prevent
data in the receive buffer being
overwritten when the buffer is full.
•
Yes
•
No
•
Yes
Further Information
You can find further information on handling the receive buffer under “Receive
Buffer on the CP 440” in Section 2.2.2.