The ATEX certified AT2DH3 series Digihelic® differential pressure controller is a 3-in-1 instrument that consists of a digital differential pressure gauge, relay contacts for alarms, or on-off control and a transmitter output. The AT2DH3 can also be used to measure air velocities and flow in combination with a pitot tube. The AT2DH3 has an analogue 4-20 mA output and two SPDT relay contacts with adjustable deadband.