Technical Specifications
Category Parameter Specification
General Model UT155-VR/RS
Type Intrinsically Safe Isolator (Repeater Type with Remote Reset)
Mounting DIN rail mount in Yokogawa UTSX Series housing
Input (Field Side - Hazardous Area) Signal 4-20 mA DC (from active device, e.g., 4-wire transmitter)
Input Impedance Approx. 50 Ω
Intrinsic Safety Parameters Ui ≈ 28 V DC, Ii ≈ 93 mA (compliant with ATEX/IECEx)
Output (System Side - Safe Area) Signal 4-20 mA DC
Load Resistance 0-750 Ω
Accuracy ±0.1% of span
Alarm & Reset Function Alarm Detection Configurable for signal fault (burn-out) or process alarm
Reset Type Local (front button) and remote (dry contact signal)
Remote Reset Signal Dry contact input (momentary short circuit)
Power Supply Voltage 20.4-31.2 V DC (24 V DC nominal)
Consumption Approx. 1.2 W
Isolation Between Input/Output/Power 1500 V AC
Performance Accuracy ±0.1% of span
Temperature Drift ±0.015% of span per °C
Response Time < 150 ms
Environment Operating Temperature -20°C to +60°C
Humidity 10-90% RH (non-condensing)
Key Features
Repeater Function: Accepts signals from externally powered field devices (4-wire transmitters).

Remote Reset (RS): Allows alarm conditions (e.g., signal faults) to be reset locally or remotely via a dry contact signal.

Intrinsic Safety: Complies with ATEX/IECEx standards for hazardous areas (Zone 0/1).

24 V DC Operation: Powered by 24 V DC, suitable for standard industrial control panels.

High Isolation: 1500 V AC isolation between input, output, and power supply.

Applications
Critical safety systems requiring remote alarm acknowledgment (e.g., shutdown systems).

Interfacing 4-wire transmitters in hazardous areas where remote reset functionality is needed.

Process industries (oil/gas, chemicals) with unmanned facilities or centralized control rooms