Dwyer Pressure TransmitterDwyer Instruments’ Series 648C Differential-Pressure Transmitter is designed to be used with clean, dry air and other non-corrosive gases. These transmitters offer an accuracy of +/- 0.4 percent. Each unit features a push-activated zero function and an associated LED light indicator. With the push-button, zero calibration can be performed without any additional equipment. The dual-color LED indicates if the transmitter is at normal operation, overpressure, or in the process of zero calibration. The enclosure consists of a flame-retardant plastic top cover and a stainless steel bottom plate for ruggedness. The pressure ranges vary from 0.1 in w.c. to 25 in w.c. unidirectional and 0.25 in w.c. to 5 in w.c. bidirectional. Wiring time is reduced with the removable terminal block. Each unit features a two-wire 4-20 mA output that is fully protected against short circuiting and incorrect wiring. – www.dwyer-inst.com