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IM-ENG-116/GB
HART
PROTOCOL
AND 4-20mA
RS-232
Modem
Cable
A
B
GND
A
B
B
GND
A
GND
to
DCS
to
DCS
24 Vdc
CABLE PIN
ASSIGNMENT
2 TX
3 RX
5 GND
Female DB9
connector
Pin No.
Female DB9
connector
Pin No.
OPTIONAL DB9 to
DB25 ADAPTER
2 TX
3 RX
5 GND
DB9
Pin No.
DB25
Pin No.
2 TX
3 RX
5 GND
3 TX
2 RX
7 GND
PC
HOST STATION
RS 485
SHD
1
SHD
2
SPARE
FUSE
RS-485
Connections
RS-485
Connections
RS-485
Connections
WESTERMO switch settings
See the Westermo Mod. MD-44 DC
instruction manual for details
19200/9600
11
2-wire
No termination
Selection of data rate
Selection of bits
(8 bits odd parity - 1 stop bit)
Transmission
Termination
S2
S2
S2
S3
1-2-3
4-5
6-7
1-2-3-4
switch
bit
+
RS-232 IN
RS-485 IN
RS-485 OUT
Supply Line
Cord
A
B
GND
to PC
HOST STATION
54321
9876
F
IG
. 6
