The Teledyne Hastings HFC-D-307A/B mass flow instruments have flow ranges from 0-1000 slm to 0-2500 slm; provide analog and digital outputs, and are constructed of stainless steel. Easy, user friendly digital communications with windows based software interface available. Available with a variety of elastomer seals for maximum flexibility. Self diagnostics of the sensor, valve and overflow are included in the digital features. Also of interest is the auto zero feature which detects when the valve is closed and automatically resets the zero. These mass flow meters and controllers can store up to 10 calibrations of different ranges and gases. Another feature is the built in totalizer for monitoring gas usage under user set conditions.