During operation, the thin, flexible diaphragm and fill
fluid separate the pressure sensing element of the
transmitter from the process medium. The capillary
tubing or direct mount flange connects the
diaphragm to the transmitter.
When process pressure is applied, the diaphragm is
displaced, transferring the measured pressure
through the filled system, through the capillary
tubing, to the transmitter element. This transferred
pressure displaces the sensing diaphragm of the
pressure transmitter. This displacement is
proportional to the process pressure and is
converted electronically to an appropriate 4-20 mA,
digital HART, or FOUNDATION fieldbus output signal.