The RKI S2 Series is a plug-in, field-replaceable gas sensor/transmitter built around catalytic bead, infrared, MOS, galvanic, or electrochemical sensing elements to cover combustible gas (LEL), hydrogen-specific detection, oxygen, and a wide range of toxic gases including AsH3, Cl2, ClO2, HCN, NH3, NO2, PH3, and SO2. Standard 4-20mA output pairs with RKI Beacon controllers, PLCs, or any compatible DCS.

Combustible, hydrogen-specific, oxygen, H2S, and CO2 versions are available in an explosion-proof housing with flame arrestors (Class I Division 1 Groups B, C, D) or a non-explosion-proof housing for Class I Division 2 installations; toxic sensor versions are rated for Division 2 service. An optional stainless steel junction box suits corrosive environments, and units are rated for indoor or outdoor mounting. A no-sensor base unit is also available for facilities specifying their own detector separately. Sensor service life runs 2-3 years for flammable sensors, 3-5 years for toxics, and 5+ years for O2, CO2, and IR sensors. The configurations listed here cover the most commonly ordered sensor types and housings; additional gas ranges and calibrations are available by quote.