The Series 616D Differential Pressure Transmitter senses the pressure of air and compatible gases and sends a standard 4-20 mA output signal. The 616D housing is specifically designed to mount on a 35 mm DIN rail in a panel. This mounting style allows for several units to be mounted closely together reducing required space. A wide range of models are available factory calibrated to specific ranges as listed in the Popular Models chart. The span and zero controls are for use when checking calibration. They are not intended for re-ranging to a significantly different span. Versatile circuit design enables operation in 2-wire current loops.