Series-DHC

Supported Applications

The Dwyer Series DHC Digihelic® Differential Pressure Controller is a 3-in-1 instrument combining a digital display gage, control relay switches, and a transmitter with current and voltage outputs. The series supports pressure, velocity, and volumetric flow applications reading in several commonly used engineering units.

Available configurations include optional unidirectional or bidirectional ranges to accommodate specific measurement needs. Field calibration is supported for maintaining accuracy over time.

Operating Conditions & Performance

The Series DHC operates within an ambient temperature range of -4 to 158°F (-20 to 70°C). Accuracy specifications vary by range: ±0.5% FSO applies for all ranges except the 0.5 in w.c. model at ±1% FSO, and ranges at or below ±0.25 in w.c. at ±1.5% FSO.

Pressure limits are defined as follows:

• Ranges > 1 in w.c.: 6 psi max operation, 6 psi burst
• Ranges ≤ 1 in w.c.: 3.6 psi max operation, 6 psi burst

The instrument features a response time of 400 ms (damping set to 0) and stability of < ±1% / year FSO. Thermal effects are rated at 0.02% FS / °F (0.036% FS / °C). The unit is designed for service with air and non-combustible, compatible gases.

Configuration Options

The series offers a broad envelope of measurement ranges in inches water column (in w.c.), Pascals (Pa), and millimeters water column (mm w.c.). Unidirectional models include 0.25 to 100 in w.c., while bidirectional options range from ±0.25 to ±100 in w.c.

Output signals are configurable as:

• 4-20 mA (4-wire)
• 0-10 V, 0-5 V, 1-5 V
• 2-10 V (4-wire)

Communication options include selectable Modbus® or BACnet MS/TP. The unit includes a backlit LCD display and LED setpoint indicators.

Housing, Connections, and Mounting

• Enclosure: Polycarbonate housing with NEMA 4X (IP66) rating.
• Process Connection: Two sets of 1/8" female NPT ports located on the side and back; unused ports should be sealed with pipe plugs (Accessory A-330).
• Electrical Connection: 15 pin male high density D-sub connector with an included 18" (46 cm) cable containing 15 conductors.
• Mounting: Not position sensitive; surface mounting bracket (A-299), flat flush mounting bracket (A-300), and static pressure tips are available as accessories.

Control Features

The controller includes 2 SPDT control relays with adjustable deadbands. Set point adjustments, zero/span calibration, and menu navigation are accessible via the built-in interface using dedicated keys (SP/AL, MENU, UP/DOWN ARROW, ENTER, RESET).

Key Product Differences

Variants within the Series DHC differ primarily by measurement range directionality and unit scale. Models such as DHC-002 through DHC-012 provide unidirectional ranges (e.g., 0.25 in w.c. to 100 in w.c.), while models prefixed with 'DHC-2' offer bidirectional capabilities (e.g., ±0.25 in w.c. to ±100 in w.c.).

Additional variations include specific metric ranges such as DHC-053 (60 Pa), DHC-084 (25 mm w.c.), and their bidirectional counterparts. Optional suffixes allow for factory calibration certificates (-FC) or NIST traceable calibration certificates (-NIST). A 304 brushed stainless steel bezel is available via the -SS option.