Differential Pressure Transducer converts a differential or gauge air pressure signal to a 4-20 mA signal. A signal conditioning circuit runs as a two wire 4-20mA devices. The input pressure signals are mechanically dampened to reduce sensitivity to turbulence and short duration pressure fluctuations. Integral zero and span adjustments are factory calibrated to specified output signal levels and may be field adjusted if required. The circuit design produces very little interaction between span and zero pots. It includes HVAC monitoring of filter differential pressures, fan static pressures, clean room pressures, variable air volume systems and velocity pressures. It provides total of 30 field-selectable variations that include unidirectional and bi-directional pressure ranges. They also provide auto-zero capability and include field-selectable port swap feature. With all cast aluminum housing, transducers are available with optional LCD for on-site indication of line and differential pressure.