Siemens SIMATIC CP 340, User Manual

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Basic Principles of Serial Data Transmission
2.7 Parameterization Data
PtP coupling and configuration of CP 340
Manual, 04/2011, A5E00369892-03
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Parameter Description Range of values Default value
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. This improves data
integrity. A parity of "none" means that no parity
bit is sent. "Any" parity indicates that the CP has
set the send parity to a value of "0". The parity bit
is not checked when data is received.

None
 Odd

Even
 Any

Even
Priority A partner has high priority if its send request
takes precedence over the other partner's send
request. A partner has low priority if its send
request has to wait until the other partner's send
request has been dealt with. With the 3964(R)
procedure, you must configure both
communication partners with different priorities,
i.e., one partner is assigned high priority, the
other low.

Low
 High

High
Activate
BREAK
monitoring
You can choose whether monitoring for an
interrupted receive line should be activated or
deactivated.
If BREAK monitoring is deactivated, in the event
of a BREAK

No entry will be made in the diagnostic buffer,
nor will the RECV FB be activated with set
ERROR bit and corresponding STATUS entry
 Activated send jobs will be sent without an
error message being generated for the user
 Yes

No
Depending on the HW
variant used and the
operating mode selected:
 RS 232: Yes

TTY: Yes
 RS 422 with
R(A)5V/R(B)0V:
Yes (cannot be
deactivated)

RS 422 with
R(A)0V/R(B)5V:
No (cannot be activated)
Receive buffer on CP
You will find a description of the parameters for the X27 (RS 422) interface in the table
below.
Table 2- 5 X27 (RS 422) interface (3964(R) procedure)
Parameter Description Range of values Default value
Delete CP receive
buffer on startup
You can specify whether the CP receive
buffer should be deleted on startup or an
existing (old) message frame should be
sent to the CPU.

Yes
 No

Yes
Receive line initial
state
R(A)5V/R(B)0V
This initial state supports BREAK
detection; it cannot be deactivated.
R(A)0V/R(B)5V
This initial state does not support break
detection.

R(A) 5V/R(B) 0V

R(A) 0V / R(B) 5V

R(A) 5V/R(B) 0V