- 33 -
RS232 SERIAL COMMUNICATION
DB9-F
5
3
2
WDESK - WINOX
WTAB
RS232 TXD
PC
RS232 RXD
-SUPPLY 12-24 VDC
RS485 SERIAL COMMUNICATION
WDESK
WINOX
WTAB
RS485 +
RS485 -
max 500 m
RS
48
5 +
3 2 5
PC
RS232
RX+
RX-
TX-
TX+
CONVLAU
24 Vcc
+
-
0
TX
RX
VIN
RS485 +
RS485 -
R
S
48
5 -
-S
UPP
L
Y
12
-24 V
D
C
RS
48
5 +
R
S
48
5 -
-S
UPP
L
Y
12
-24 V
D
C
RS
48
5 +
R
S
48
5 -
-S
UPP
L
Y
12
-24 V
D
C
WDESK
WINOX
WTAB
WDESK
WINOX
WTAB
If the RS485 network exceeds 100 metres in length or baud-rate over 9600 are
used, two terminating resistors are needed at the ends of the network. Two
120 ohm resistors must be connected between the “+” and “–” terminals of the
line, on the terminal strip of the furthest instruments
.
Should there be different
instruments or converters, refer to the specific manuals to determine whether it is
necessary to connect the above-mentioned resistors.
DIRECT CONNECTION BETWEEN RS485 AND RS232 WITHOUT CONVERTER
Since a two-wire RS485 output may be used directly on the RS-232 input of a PC or remote display,
it is possible to implement instrument connection to an RS-232 port in the following manner:
INSTRUMENT
RS232
RS485
–
→
RXD
RS485
+
→
GND
This type of connection allows A SINGLE instrument to be used in a ONE WAY
mode.
