Current loops have become the standard for signal transmission
in the process control industry. Current loops are
insensitive to noise and are immune to errors from line
impedance. Adding isolation to the 4-20mA current loop
protects system electronics from electrical noise and transients.
It also allows transducers to be electrically separated
by hundreds of volts. Burr-Brown now offers all of the
integrated circuit building blocks needed to assemble complete
isolated 4-20mA current-loop systems. The product
line includes two-wire transmitters, two-wire receivers, low
cost isolation amplifiers, and low cost isolation power supplies.
Three two-wire transmitters are available: one is
general purpose, one designed for use with RTD temperature
sensors, and one designed for use with bridge circuits.