Siemens SIPART DR21 User Manual

2 Technical Description
2.5 Function principle
Manual
32
SIPART DR21
C73000-B7476-C143-08
6DR2803-8C Serial interface RS 232/RS 485
D Serial interface for RS 232 or RS 485 with electrical isolation
Can be used in slot 4, the structure switches S84 to S91 must be set for the transmission
procedure.
For connecting the controller SIPART DR21 to a master system for control and monitoring.
All process variables can be sent, the external setpoint, tracking variable, operating states,
parameters and structurings sent and received via the interface.
Interface communication can take place:
RS 232 as a point-to-point connection
SIPART Bus The SIPART bus driver is no longer availa ble.
Therefore, please realize multi--couplings via RS 485 or PROFIBUS DP.
RS 485 As a serial data bus with up to 32 users.
The interface module 6DR2803-8C offers electrical isolation between Rxd/Txd and the con-
troller. Switching can be performed between RS 232 and RS 485 with a plug-in bridge.
A detailed technical description of the data communication for creating a linking software is
available in Internet under www.fielddevices.com [Edition 05.2000].
Rxd/
Txd B
Rxd/
Txd A
24 V
0V
Txd
Rxd
-1
+1
+7.5 V
-7.5 V
+7.5V
-7.5 V
-7.5V
Rxd
Txd
2
3
7
8
Other connections: NC
24 V
0V
Txd
Rxd
Other connections: NC
Rxd/
Txd
3
NC2, 7
8
+7.5 V
+7.5 V
+7.5V
SIPART
bus
RS 485
RS 485+150R
RS 232
Figure 2-3 Block diagram serial interface in
RS 232/SIPART BUS
Figure 2-4 Block diagram serial interface at
Interface RS 485

Siemens SIPART DR21 Specifications

General

Brand	Siemens
Model	SIPART DR21
Category	Controller
Language	English