CEL-MAR ADA-1028L, User Manual

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2.2. DESCRIPTION
ADA-1028L converter allows connecting devices with two-wire Current Loop interface (CLO) to the RS232 interface (eg. the computer
or controller) for example, counters such LZQM without interfering with the format of transmitted data. ADA-1028L transmits data at
baud rate up to 19.2 kbps via one pair of the Current Loop twisted-pair cable.
The converter is equipped with screw terminals for connection Current Loop interface and power supply.
Device for operating uses signals:
a) Rx, Tx, GND - the RS232 interface,
b) TX +, TX-/ CLO-, RX +, RX * +, RX-/ CLO + Current Loop CLO interface.
It is possible to connect up to four devices operating in half duplex mode to the Current Loop bus. 1kVDC or 3kVDC galvanic isolation
and 2,5kVDC opto-isolation in the signal channel separates RS232 interface of converter from CLO interface and protects devices
connected to the RS232 interface from surges generated on line CLO and power circuit. The converter has an internal low-energy
surge protection for each line of Current Loop interface.
2.3. CURRENT LOOP TRANSMITTER AND RECEIVER
In ADA-1028L was used active transmitter of Current Loop, based on current source generating current 0-20mA and passive receiver
based on transoptors.
By the use of inside electronics, the converter controls Current Loop transmitter and receiver during data transmission, in order to
proper operation of Current Loop interface on two-wire data line. The transmitter and receiver have low-energy surge protection on
lines CLO+, CLO-.
Fig 1. Converter view
4
ADA-1028L
(RS-232)
N
C
N
C
N
C
N
C
C
L
O
-
R
d
N
C
C
L
O
+
(CURRENT LOOP CLO)
V
-
V
+
10 – 30
VDC
PWR TX RX
ADA-1028L
RS-232 to CLO
CONVERTER
CLO
62mm
RS-232 interface
DB-9F connector
Power supply
10-24-30 VDC
53mm
1
0
m
m
6
m
m
9
0
m
m
Current Loop (2W)
Interface