The Endress+Hauser RN42 active barrier is a loop-powered signal isolator designed for fast and accurate transmission of 0/4 to 20 mA and HART signals in industrial process applications. With a wide-range power supply of 24 to 230 V AC/DC, it simplifies inventory and installation across global facilities.

The RN42 accepts inputs from 2- or 4-wire transmitters via an active or passive current input, and its output can be configured for active or passive operation to match the connected control system. Bidirectional HART communication is fully supported, with easy-access front sockets for HART communicator connection. Transmission error is less than 0.1% of full scale, and response time is ≤1 ms, ensuring critical process data is accurately relayed.

Safety and hazardous area approvals include SIL2/SC3 for safety-instrumented systems, as well as ATEX, IECEx, CSA, and other certifications for use in Ex Zone 2 environments. The compact 17.5mm polycarbonate housing mounts on standard DIN rails, with pluggable screw or push-in terminals for fast wiring. Power supply terminals can be located at the top or bottom for flexible installation.

Typical applications include:

• Galvanic isolation of analog signals in process control loops
• Interface between hazardous area field devices and safe-area PLCs/DCS
• HART signal transmission in SIL-rated applications
• Signal conditioning for 2- and 4-wire transmitters

Features

• Single channel, loop-powered design
• Input: 0/4-20 mA / HART (feeding or non-feeding)
• Output: 0/4-20 mA / HART (active or passive, configurable)
• Wide-range power: 24 to 230 V AC/DC
• Transmission error: <0.1% FS (<20 µA)
• Response time: ≤1 ms
• SIL2/SC3 certified for safety applications
• Multiple hazardous area approvals (ATEX, IECEx, CSA, etc.)
• Compact 17.5mm housing, DIN rail mount
• Pluggable screw or push-in terminals
• Ambient temperature: -40 to 60°C