The phx21 Flame Ionization Detection System is used in chemical refineries and industrial plants across the world to monitor hydrocarbons emissions. These working environments can have combustible hydrocarbon gases present in the atmosphere and devices that operate in these areas require intrinsically safe electronics design. The intrinsically safe design requirements create significant circuit design challenges that demand creative solutions to keep electrical and thermal energies low enough to prevent ignition of combustible materials.

Our customer, LDAR Tools of League City, Texas, came to us with a design challenge: build a compact, cost effective, safe device that can measure minute amounts of current. Indus Instruments designed the compact, ruggedized electronics of the phx21 to incorporate intrinsically safe design methodologies. The phx21 uses a novel charge digitization technique that is an improvement over the industry standard current to voltage amplifier designs in use for the past 30 years and can measure picoamperes of current from the chemical reaction in a flame ionization chamber. The phx21 has passed UL and FCC testing. Indus Instruments manufactures phx21 electronics assemblies for LDARtools under an OEM supply agreement.