FLEXIM’S FLUXUS F/G831 is a new ultrasonic system that measures liquids, gases and steam and is approved for operation in ATEX/IECEx Zone 1. The flow measurement is carried out nonintrusively with ultrasonic transducers mounted on the outside of the pipe. FLUXUS F/G831 has two intrinsically safe (Ex-ia) process inputs for connecting pressure and temperature sensors. This allows the transmitter to directly determine the output mass flow or standard volumetric flow rate. Inside the hermetically sealed enclosure, a digital signal processor ensures the highest measurement performance. The integrated disturbance correction ensures good measuring accuracy even at unfavorable measuring points. The high-performance processor supports fast switching between two measuring channels. Synchronized channel averaging enables immediate compensation of measured value fluctuations resulting from disturbances of the flow profile due to turbulence or difficult inlet conditions.