RS-485 to Current Loop 2-wire CLO Converter
ADA-4028L

RS-485 to Current Loop 2-wire CLO Converter* The prices are given in the response to the offer.

The converter ADA-4028L is produced with active or passive Current Loop transmitter.
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:
  • 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.
The over-voltage protection on each RS485 line and Current Loop, 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.

Example of connection ADA-4028L converter