The converter ADA-4028L is produced with active or passive Current Loop
ADA-4028L with active transmitter allows to connect to RS485 Bus devices with passive interface of Current Loop (CLO) eg. energy meter LZQM type
, without interfering with the data format.
Connecting two ADA-4028L converters together (via Current Loop interfaces), one with passive transmitter and second with active transmitters, allows extension of RS485 bus by the use of 2-wire Current Loop.
ADA-4028L transmits data at baud rate up to 19,2 kbps, through one or two twisted-pair on the side of RS485 interface and one twisted-pair on the Current Loop side. The converter is equipped with screw terminal block for connection of RS485, CLO and power supply. Uses only the following signals:
The over-voltage protection on each RS485 line and Current Loop,
- RX+,RX-,TX+/A,TX-/B – for RS485 interface,
- CLO+, CLO-, Rd - for active Current Loop interface,
- CLO+, CLOR+ (connecting of CLO+ thought resistor R=1000W, Fig.10), CLO-, Rd - for passive Current Loop interface.
was made on the base 600W over-voltage LEDs and the fuses.
To RS485 bus created by the use ADA-4028L, it is possible to connect 32 devices, operating in half duplex mode (query /response) on 2 or 4 wires multipoint bus. To Current Loop bus it is possible to connect up to 4 devices with passive CLO interface, operating in half duplex mode.
The converter has an internal low-energy surge protection for each line of Current Loop interface. However, for the lightning protection should be used external lightning arresters such as the typical phone line protection.