Siemens SINAUT ST7 - 6.1 Function Plan of the MD2

Technical Data
6NH7811-0AA22 © Siemens AG 2002 All Rights Reserved
6-2 MD2 Modem (07/2002)
6.1 Function Plan of the MD2
The following illustration 6-1 shows the main function of the modem. The line
termination resistor, the transmission speed, the send level and the transmission
mode (2-wire or 4-wire) are set on DIL switches. The location and switch
assignments of these DIL switches are described in detail in Chapter 2 "Mounting
and Installation".
Fig. 6-1 Function Plan of the MD2 modem
Male
Sub-D 9-pin
0V+24V
RS485
DIL switch
5-pin
P12 M
P5 M
Digital
section
Transmission line connection
4-wire: Sender
2-wire: Sender +
Receiver
Insulation resistance to
continuous surge voltage
2.5kV acc. to DIN VDE0804
Transformer 1:1Transformer 1:1
150 Ohm
600 Ohm
FSK
demodulator
Input amplifier
with filter
FSK
modulator
Output
amplifier
LED’s: TxD, RxD
DTR, RTS
CTS, DCD
DIL switch
10-pin
TTL
TTL
V28 RS485
Female
Sub-D 9-pin
12V
DC
DC
24V
5V
DC
DC
24V
2
»
1
»
RTS RTS
RS485:
A
RS485:B
RS232
DT
R
RTS
TxD
DS
R
CTS
RxD
DCD
4-wire: Receiver
2-wire: Sender +
Receiver
150 Ohm
600 Ohm