616W-4 is a series 616W differential pressure transmitter. The positive, negative and differential pressures can be measured within a full span accuracy of ±0.25 with the Series 616W differential pressure transmitter. Unit is enclosed in a polycarbonate case, rated NEMA 4X (IP66) and operate by sensing the pressure of air and compatible gases then sending a d 4-20 mA or selectable 0 to 5/0 to 10 VDC output signal. Design enables operation in 2-wire current loops. The span and zero controls are for use when checking calibration. It is not intended for re-ranging to a significantly different span. Typical applications include dust collection, outdoor HVAC and roof-top equipment.