Siemens SINAUT ST7 - Page 134

Network Configurations
© Siemens AG 2002 All Rights Reserved 6NH7811-0AA22
MD2 Modem (07/2002) 5-41
Fig. 5-13 shows a configuration for multidrop line with fiber optic sections, 2-
wire half-duplex. All four MD2 modems represent 2-wire terminal points and are
set to the "With RS485 interface" operating mode. The multidrop line includes two
fiber optic sections that are connected through the RS485 interface of the MD2
modems.
All available baud rates and character recognition methods except for "MID off" can
be used in this configuration.
The DIL switch settings on the MD2 modem and the switch settings on the LTOP1
are the same at all terminal points (see Table 5-27).
Table 5-27 Settings for each 2-wire terminal point
Settings on the DIL switches accessible from above (see Fig. 2-3 and 2-4)
5-pin and 10-pin DIL switch Meaning
2-wire operation
channel 1
"With RS485 interface" operating mode
The baud rate must be selected with switches 4 and 5 on
the 5-pin DIL switch and the character recognition with
switches 5 to 7 on the 10-pin DIL switch.
Settings on the DIL switch accessible from below (termination resistors)
Type of
connection
Baud rate
Setting on
DIL switch
Note
1200 bps
2400 bps
The MD2 is located at the beginning or end of a 2-wire line
and is set to a transmission speed of 1200 or 2400 bps.
(see Fig. 2-6)
Terminal Point
2-wire
9600 bps
19200 bps
Terminal point as above but with transmission speed set to
9600 or 19200 bps.
(see Fig. 2-6)
Settings on the DIL switch accessible from below (port)
Interface type
Setting on
DIL switch
Note
RS485 interface
Activation of the RS485 interface
(see Fig. 2-6)
Settings on the LTOP1 switch
Switch
Switch
position
Note
Switch S1
2-wire channel (pins 2 and 5) activated
(see Fig. 2-18)
1
2
3
4
OFF
ON
1
2
OFF
ON
1
2
3
4
5
1
2
3
4
5
6
7
8
9
10
OFF
ON
1
2
3
4
OFF
ON
1
2
3
4
OFF
ON