Dwyer Series DH3 Digihelic Differential Pressure Controller

The Series DH3 Digihelic® controller allows the selection of pressure, velocity or volumetric flow operation in several commonly used engineering units. 2 SPDT control relays with adjustable deadbands are provided along with a scalable 4-20 mA process output.


Programming is easy using the menu key to access 5 simplified menus which provide access to: security level; selection of pressure, velocity or flow operation; selection of engineering units; K-factor for use with flow sensors; rectangular or circular duct for inputting area in flow applications; set point control or set point and alarm operation; alarm operation as a high, low or high/low alarm; automatic or manual alarm reset; alarm delay; view peak and valley process reading; digital damping for smoothing erratic process applications; scaling the 4-20 mA process output to fit your applications range and field calibration.


Please see SERIES AT2DH3 for ATEX approved.


Service: Air and non-combustible, compatible gases.
Wetted Materials: Consult factory.
Housing Material: Die cast aluminum case and bezel.

< 5″ w.c. (except ±2.5″ w.c.): ±1%;

All other ranges: ±0.5% at 77°F (25°C) including hysteresis and repeatability (after 1 hour warm-up).
Stability: < ±1% per year.
Pressure Limits: Ranges ≤ 2.5″ w.c.: 25 psi; ±2.5″, 5″ w.c.: 5 psi; 10″ w.c.: 5 psi; 25″ w.c.: 5 psi; 50″ w.c.: 5 psi; 100″ w.c.: 9 psi.
Temperature Limits: 32 to 140°F (0 to 60°C).
Compensated Temperature Limits: 32 to 140°F (0 to 60°C).
Thermal Effects: 0.020%/°F (0.036/°C) from 77°F (25°C).
Power Requirements: 12-28 VDC, 12-28 VAC 50-400 Hz.
Power Consumption: 3 VA max.
Output Signal: 4-20 mA DC into 900 ohms max.
Zero & Span Adjustments: Accessible via menus.
Response Time: 250 ms (damping set to 1).
Display: Backlit 4 digit LCD 0.4″ height LED indicators for set point and alarm status.
Electrical Connections:

15 pin male high density D-Sub connection.

18″ (46 cm) cable with 10 conductors included. 4′ and 10′ cables available.
Process Connections: 1/8″ female NPT. Side or back connections.
Mounting Orientation: Mount unit in vertical plane.
Size: 5″ (127 mm) O.D. x 3-1/8″ (79.38 mm).
Weight: 1.75 lb (794 g).
Agency Approvals: CE.


Switch specifications

Switch Type: 2 SPDT relays.
Electrical Rating: 1 amp @ 30 VAC/VDC.
Set Point Adjustment: Adjustable via keypad on face.