Siemens SIMATIC S7-400 Equipment Manual page 64

Configuring and Parameter Assignment the CP 440
5.4 Configuration data
Configuration Data of the 3964(R) procedure
With the CP 440: Point-to-Point Communication, Parameter Assignment interface, specify
the parameters for the physical layer (layer 1) and the data-link layer (layer 2) of the 3964(R)
procedure. Below you will find a detailed description of the parameters.
Note
The 3964(R) procedure can only be used in four-wire mode.
Protocol
The following table describes the protocol.
Table 5-10 3964(R) Protocol
Parameter Description
3964 with default • The protocol parameters are set to default values.
values and no
• If the CP 440 recognizes the string DLE ETX, it stops receiving and
block check
sends a DLE to the communication partner if the block was re‐
ceived undamaged, or an NAK if it was damaged.
3964R with default
• The protocol parameters are set to default values.
values and block
• If the CP 440 recognizes the string DLE ETX BCC, it stops receiving.
check
The CP 440 compares the block check character (BCC) received
with the length parity calculated internally. If the BCC is correct and
no other receive errors have occurred, the CP 440 sends the code
DLE to the communication partner (the NAK code is sent if an error
occurs).
3964 assignable
• The protocol parameters are programmable.
without block
• If the CP 440 recognizes the string DLE ETX, it stops receiving and
check
sends a DLE to the communication partner if the block was re‐
ceived undamaged, or an NAK if it was damaged.
3964R assignable
• The protocol parameters are programmable.
with block check
• If the CP 440 recognizes the string DLE ETX BCC, it stops receiving.
The CP 440 compares the block check character (BCC) received
with the length parity calculated internally. If the BCC is correct and
no other receive errors have occurred, the CP 440 sends the code
DLE to the communication partner (the NAK code is sent if an error
occurs).
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Point-to-point connection CP 440 Installation and Parameter Assignment
Equipment Manual, 03/2022, A5E00057742-AE
Default Value
3964(R) with default values
and block check:
CDT = 220 ms
ADT = 2000 ms
Connection attempts = 6
Transmission attempts = 6