2.2. DESCRIPTION
Many devices such as PLCs, measuring transducer, sensors, cash registers and electronic scales are equipped with RS232
communication port. However, the standard 232 has limitations on cable length (the distance at which transmission functioning
properly is 15m). Solution to this problem is to use the RS485/422 data transmission standard. It lets connect together distant devices
at 1200m.
ADA-1040 converts RS232 standard to RS485/RS422 without interfering with format of transmitted data. Converter does not require
power supply from RS232 port and support the asynchronous transmission data with baud rate 230,4 kbps.
ADA-1040 has DB-9F connector (DCE type) to connecting RS232 interface in use of RS232 extension cable (a typical modem cable)
without interleaving of Tx with Rx, RTS with CTS and DTR with DSR. Converter has also screw terminal block for connection of
RS485/422 network and power supply. This device use Rx, Tx and GND signals for operating and additionally DTR, DSR in extended
version. Galvanic isolation and optoisolation (in signal channel) separates RS232 interface from RS485/422 interface and protect a
device connected to RS232 port from overvoltage on RS485/422 network and power supply. Overvoltage protection was made on
base safety diodes and fuses on each RS485/RS422 lines.
ADA-1040 should be powered from stabilised power pack with minimum power output 2W and voltage form the scope 10 – 30VDC.
Fig 1. View and SW1 location
Fig 2. View with additional signals and SW1
2.3. CONVERSION OF TX, RX, DTR, DSR SIGNALS OF RS232 INTERFACE
In additional version ADA-1040(x-2-x-x) can convert DTR, DSR or RTS, CTS signals of RS232 interface to RS485/422 in POINT-TO-
POINT operating mode. Those additional signals are being connecting to ADA-1040 through DB-9 socket to
4-DTR and
6-DSR pins.
ATTENTION!
If the signals RTS and CTS need to be converted, should be solder wires at DB-9M plug as below:
RTS – PIN7 to PIN 4
CTS – PIN 8 to PIN6.
4
ADA-1040
(RS-232)
(SW1)
N
C
N
C
N
C
G
N
D
T
X
+
/A
T
X
-
/B
R
X
+
R
X
-
(RS485/RS422)
V
-
V
+
10 – 30
VDC
62mm
RS-232 interface
DB-9F connector
Power supply
10-24-30 VDC
53mm
10
m
m
6
m
m
90
m
m
RS-485
2-wires
RS-485 4-wires
or RS-422
Additional
signals in
RS422 standard
PWR
TX
RX
ADA-1040
RS-232 to RS-485/RS-422
CONVERTER
RS-485/422
(RS-232)
(SW1)
RS-232 interface
DB-9F connector
Power supply
10-24-30 VDC
PWR
TX
RX
ADA-1040
RS-232 to RS-485/RS-422
CONVERTER
RS-485/422
DSR DTR
D
T
R
+
D
T
R
-
D
S
R
-
D
S
R
+
T
X
+
/A
T
X
-
/B
R
X
+
R
X
-
(RS485/RS422)
V
-
V
+
10 – 30
VDC
RS-485 4-wires
or RS-422
RS-485
2-wires
