DH3 Dwyer Digihelic Differential Pressure Controller

The Dwyer DH3 Digihelic® Differential Pressure Controller is a 3 in 1 instrument possessing a digital display gage, control relay switches, and a transmitter with current output all packed in the popular Photohelic® gage style housing. Combining these 3 features allows the reduction of several instruments with one product, saving inventory, installation time and money. The Digihelic® controller is the ideal instrument for pressure, velocity and flow applications,achieving a 1% full scale accuracy on ranges down to the extremely low 0.25" w.c. to 2.5" w.c. full scale. Ranges of 5" w.c. and greater maintain 0.5% F.S. accuracy. Bi-directional ranges are also available.

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.

DH3 Specifications

     Service: Air and non-combustible, compatible gases.
     Wetted Materials: Consult factory.
     Housing Material: Die cast aluminum case and bezel.
     Accuracy: ±1.5% for 0.25" and ±0.25" w.c. ranges. Ranges 0.5" to 5" w.c. and corresponding
          bi-directional (except ±2.5" w.c.) ±1%;  All other ranges: ±0.5% @ 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). For 0.25" and ±0.25" w.c. ranges:
          ±0.03%/°F (±0.054%/°C).
     Power Requirements: 12-24 VAC/VDC.
     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.
     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

DH3 Applications