The Yokogawa UT152-VN is a critical safety interface device. It is not just a signal converter but a certified safety barrier that protects industrial plants by ensuring signals to and from hazardous areas are energy-limited, thus preventing the risk of fire or explosion.

The Yokogawa UT155-VN is a repeater-type safety isolator. It is the preferred choice when the field device in the hazardous area has its own separate power source (4-wire configuration). Its role is to safely pass through and isolate the signal while maintaining the integrity of the intrinsic safety barrier.

The Yokogawa UT150-VN/AL/RES is a robust and reliable hardwired alarm and trip module. Its key differentiator is the manual reset (latching) function, making it indispensable for critical alarm and shutdown applications where an automatic return to normal operation without operator acknowledgment is unacceptable. It provides a simple, yet highly effective, layer of safety logic.

The Yokogawa UT150-RN/RS is a robust alarm trip module designed for 100V AC powered systems and featuring a critical remote reset capability. It combines the reliable process monitoring and latching alarm functions of the UT150 series with the flexibility of being reset from a distant location, making it ideal for distributed control systems and unmanned facilities. The key differences from the UT150-VN/AL/RES are its power supply requirement and the enhanced remote reset functionality.

The Yokogawa UT150-RR/RS is a robust alarm trip module designed for 120V AC, 60 Hz powered systems and featuring a critical remote reset capability. It is the functional equivalent of the UT150-RN/RS but tailored for the North American power standard. The key difference from other UT150 models (like the VN) is its AC power supply requirement and the enhanced remote reset functionality.

The Yokogawa UT150-RR/RS is a single-channel alarm trip module designed for rail mounting in Yokogawa UTSX Series housings. It monitors 4-20 mA DC signals and provides two configurable alarm setpoints with relay outputs. The "/RS" suffix denotes its remote reset functionality, allowing alarm conditions to be reset either locally via a front button or remotely via a dry contact signal. The "RR" designation indicates operation with a 120 V AC, 60 Hz power supply, making it suitable for North American and other 120V AC markets.

The Yokogawa UT152-AN/RET is a single-channel intrinsically safe (IS) isolator designed for installation in Yokogawa UTSX Series rail-mounted housings. It functions as a rectifier-type isolator with an additional retransmission output, providing both safety isolation and signal replication. The module accepts a 4-20 mA signal from a 2-wire transmitter in a hazardous area, supplies loop power to it, and outputs two isolated 4-20 mA signals: one for the control system and one for retransmission to secondary devices (e.g., recorders, displays). The "AN" suffix indicates compliance with specific safety standards (e.g., ATEX, IECEx), while "RET" denotes the retransmission output feature.

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.

The Yokogawa UT155-VR/RS is a specialized single-channel intrinsically safe (IS) isolator designed for installation in Yokogawa UTSX Series rail-mounted housings. It combines the functionality of a repeater-type isolator with a remote reset (RS) capability, making it suitable for critical safety applications where remote alarm management is required. The module 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 "VR" suffix indicates operation with a 24 V DC power supply, while "RS" denotes the remote reset functionality for alarm conditions.

The Yokogawa UT150L-RN is a 1/16 DIN size limit controller. It’s designed for safety / process limit control applications — e.g. to trigger alarms or shutdowns when temperature (or other measured variable) exceeds or falls below set limit(s). It features universal input, relay output (for control/limit), optional retransmission, alarms, etc.