Siemens SIMATIC CP 340 User Manual page 63

Protocol
The table below describes the protocol.
Table 2- 2 3964(R) protocol
Parameter
3964 with default values and no block
check
3964R with default values and block
check
3964 assignable without block check
3964R assignable with block check
PtP coupling and configuration of CP 340
Manual, 04/2011, A5E00369892-03
Description
Default values are assigned to the

protocol parameters.
If the CP 340 recognizes the string

DLE ETX, it stops receiving and
sends a DLE to the communication
partner if the block was received
undamaged, or an NAK if it was
damaged.
Default values are assigned to the

protocol parameters.
If the CP 340 recognizes the string

DLE ETX BCC, it stops receiving. If
the BCC is correct and no other
receive errors have occurred, the
CP 340 sends the code DLE to the
communication partner. If the BCC
is correct and no other receive
errors have occurred, the CP 340
sends the DLE code to the
communication partner (the NAK
code is sent if an error occurs).
The protocol parameters are freely

programmable.
If the CP 340 recognizes the string

DLE ETX, it stops receiving and
sends a DLE to the communication
partner if the block was received
undamaged, or an NAK if it was
damaged.
The protocol parameters are freely

programmable.
If the CP 340 recognizes the string

DLE ETX BCC, it stops receiving. If
the BCC is correct and no other
receive errors have occurred, the
CP 340 sends the code DLE to the
communication partner. If the BCC
is correct and no other receive
errors have occurred, the CP 340
sends the DLE code to the
communication partner (the NAK
code is sent if an error occurs).
Basic Principles of Serial Data Transmission
2.7 Parameterization Data
Default value
3964R with default values and block
check:
CDT = 220 ms
ADT = 2000 ms
Connection attempts = 6
Transmission attempts = 6
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