Isolated transmit/receive loop circuit (XTR105, RCV420)

As shown in the figure, after the RTD collects the temperature on site, it converts it into voltage, and the voltage is converted into 4-20mA current output by XTR105, and then transmitted through the twisted pair, received by RCV420, and amplified by isolation amplifier ISO122, and then output 0-5V voltage. The circuit has excellent anti-interference performance and can be used for long-distance transmission or occasions with large interference. The figure shows a three-wire RTD connection. If it is used for a two-wire RTD connection, remove RLIN2.