Siemens SIMATIC CP 440 Manual page 83

Initial State of the 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)
Parameter
Initial State of the None: This setting only makes sense
Receive Line with bus-capable drivers.
R(A)5V/R(B)0V: Break evaluation is
possible with this initial state.
R(A)0V/R(B)5V: Break evaluation is not
possible with this initial state.
(See also Figure 5-2.)
The figure below shows the wiring of the recipient at the X27 (RS 422) interface:
none
R(A)5V/R(B)0V
R(A)0V/R(B)5V
Figure 5-2
Point-to-point connection CP 440 Installation and Parameter Assignment
A5E00057742-02
Description
Wiring of the Recipient at the X27 (RS 422) Interface (3964(R) Procedure)
Configuring and Parameterizing the CP 440
Value Range
None
Signal R(A)5
Volt (Break
Evaluation)
SignalR(B)0 Volt
SignalR(A)0 Volt
Signal R(B)5
Volt
0 V
5 V
5 V
0 V
Default Value
R(A)5V/R(B)0V
R(B) +
R(A) –
R(B) +
R(A) –
R(B) +
R(A) –
5-19