The Endress+Hauser RLN42 is a two-channel NAMUR isolating amplifier designed for operation of proximity switches according to EN 60947-5-6 (NAMUR), as well as mechanical contacts with resistive coupling elements. It provides a complete interface between hazardous area sensors and safe-area control systems, with intrinsically safe Ex i circuits approved for Zone 0 (gas) and Zone 20 (dust).

Each channel features a relay changeover output, with direction of action selectable via onboard DIP switches. The built-in line fault detection (LFD) continuously monitors input circuits for line breaks and short circuits, and can be disengaged if not required. If a fault is detected, the relay automatically de-energizes to ensure fail-safe operation.

The RLN42 accepts a universal power supply from 20 to 250 V AC/DC, simplifying installation across different regions and panel designs. With SIL2 certification, it is suitable for use in safety instrumented systems up to SIL2 per IEC61508.

Typical applications include:

• Intrinsically safe interfacing for NAMUR proximity switches
• Monitoring of mechanical switch contacts in hazardous areas
• Point level detection with Liquiphant FTL51B and similar sensors
• Safety-instrumented systems requiring SIL2-rated signal conditioning

Features

• Two independent channels
• Input for NAMUR proximity sensors, floating contacts, or contacts with resistive coupling
• Relay changeover output per channel
• Line fault detection (LFD) for wire break/short circuit; disengageable
• Direction of action selectable via DIP switches
• Universal power: 20 to 250 V AC/DC
• SIL2 certified per IEC61508
• ATEX, IECEx, DNV approvals for hazardous areas
• Ambient temperature: -40 to 60°C