The Yokogawa UT155-AN is a single-channel intrinsically safe (IS) isolator designed for installation in Yokogawa UTSX Series rail-mounted housings. It functions as a repeater-type isolator, meaning it accepts an active 4-20 mA signal from an externally powered device (e.g., a 4-wire transmitter) in a hazardous area and provides an isolated 4-20 mA output to the safe area. The "AN" suffix indicates compliance with international intrinsic safety standards (e.g., ATEX, IECEx). Unlike rectifier-type isolators, the UT155-AN does not supply power to the field device; it only conditions and isolates the signal.
