The FM and CSA approved Delphian Determinator (Fixed Point Infrared) sensor is a smart infrared hydrocarbon gas detector. It has no moving parts. It displays gas concentrations up to and above 100% LEL including over-range (above 120% LEL) concentrations up to 999% LEL. It can determine which hydrocarbon gas is being detected and transmit a 4-20 mA signal proportional to the LEL concentration of that gas or vapor. The Determinator displays the correct LEL as well as the gas detected on its five digit LED display. It can be set to show up to three gas alarm levels. An optional four-relay alarm module (SLAM) can be connected directly to the Determinator so that local alarms can be actuated in the event of a gas alarm or failure. The detector head is designed so that all normal operations, including checking calibration and changing alarm levels can be done in the field without declassifying the area. The built-in self test continuously monitors the hardware and software. Minor fault conditions are displayed on the LED display. Four informational and six possible critical malfunctions are transmitted on the 4-20 mA line. Standard RS 422/485 output is also available. Using a separate COMO module, the Determinator can be interfaced on Modbus RTU protocol highways.