RKI is located in Union City, California and began in 1994 with the belief that distributors and customers deserve a permanent reliable source for advanced gas detection instruments and advanced gas sensors.
The RKI S2 series gas sensor/transmitters are highly reliable and very cost effective for the detection of common gas hazards. The S2 series are available for LEL, H2 Specific (LEL, and ppm), Oxygen, H2S, CO, and for a variety of toxic gases. The transmitters for LEL, H2 Specific, Oxygen, H2S, CO2, and Carbon Monoxide are explosion-proof with flame arrestors, and approved for use in hazardous areas (Class l, Groups B, C, D). An optional non-explosion proof version is available for oxygen, H2S, CO, and CO2 in non-hazardous atmospheres. LEL sensors are available using catalytic bead and infrared technologies.
The toxic sensors are electrochemical type plug-in sensors, which provide high specificity, fast response, and long life. The plug-in design allows quick replacement in the field with no tools required. Toxic sensors are designed for use in Class I, Div. 2 hazardous locations. Sensors available for NH3, SO2, PH3, AsH3, and HCN.
The S2 transmitters can be used either indoors or outdoors. The flame arrestors for the explosion-proof versions utilize a patented coating which make them water repellent. Splash guards are also available for use in very wet environments. An optional stainless steel junction box is available for corrosive environments.
All of the S2 transmitters are designed to interface with RKI controllers, or with PLC/DCS systems.
Offshore Drilling Platforms
Water & wastewater treatment plants
Pulp & paper mills
Gas, telephone, & electric utilities
Chemical storage buildings
Explosion Proof Specifications
H2S Hydrogen Sulfide
CO Carbon Monoxide
0-100% LEL (H2 Specific)
Lower Detectable Limit (LDL)
2% of full scale
2% of full scale
Max Current Draw (24VDC)
200 mA (power wires) 25 mA (signal wires)
20 mA max, 2 wires
Response Time (T-90)
+/- 5% of full scale (0.5% volume for oxygen)
2 to 3 years with normal exposure to flammable gas
3-5 years with normal service
2-3 years with normal service
Indoor or outdoor. Explosion proof for Class I, Div. 1, Groups B, C, and D.
-40°F to 167°F -40°C to 75°C
-4°F to 113°F -20°C to 45°C
-40°F to 104°F -40°C to 40°C
23°F to 104°F -5°C to 40°C
0 – 99% RH, non condensing
Housing J Box
Cast aluminum explosion proof, optional stainless steel J-box available
Stainless steel explosion proof
Sets transmitter output to 4 mA with zero output from sensor
Sets transmitter output to proper level when span gas is applied
4 – 20 mA signal
11 VDC to 30 VDC
19-30VDC (250 OHMS impedance max)
C CSA US
C CSA US
Compatible with the following controllers: Beacon 110, Beacon 200, Beacon 410, and 800, also PLC and DCS systems