Series AT2DH3 ATEX/IECEx Approved DH3 Differential Pressure Controller

3 in 1 Instrument: Gage, Switch, and Transmitter, Flame-Proof Enclosure

The ATEX/IECEx approved Series AT2DH3 Digihelic® Differential Pressure Controller is a 3-in-1 instrument possessing a digital display gage, control relay switches, and a transmitter with current output. Combining these three features allows the reduction of several instruments with one product, saving inventory, installation time and money. The ATEX/IECEx approved Digihelic® controller is the ideal instrument for hazardous area pressure, velocity and flow applications by allowing for the selection of pressure, velocity or volumetric flow operation in several commonly used engineering units. Two SPDT control relays with adjustable dead bands are provided along with a scalable 4 to 20 mA process output. In velocity or flow modes, a square root output is provided on the 4 to 20 mA signal to coincide with the actual flow curve. Flame-proof enclosures are available in aluminum and can include a glass window for viewing process information and set point status on digital display.

Important notes for installation:
• Cables must be fitted through 1/2" NPT cable gland or ATEX/IECEx conduit (not supplied with instrument).
• Make sure after cabling to close tight cover and cable gland, in order to keep IP66 rating (IP65 with option OPV, overpressure relief valve).
• Open cover only after de-energizing instrument.
• Attention: Check local safety rules and warnings on unit and manual for a correct use of the instrument in hazardous area.

Please see SERIES DH3 for non-ATEX/IECEx approved.

California Residents:  Click Here for Proposition 65 WARNING.

Product Applications

  • Hazardous area pressure measurement and switching

Models & Ordering

Shipping Information

All shipping times are dependent on product availability at time of shipment.

Although we make every effort to ensure a continuous supply of our products, occasional circumstances may force us to temporarily run out of a product, or have shipping delays. Should this occur, customers will be notified soon after placement of any orders for such products and, if applicable, items will be put on backorder. For orders requiring expedited shipment, our customer service team can be contacted to confirm product availability

COVID-19 Update: Due to high customer demand, lead time on some products may be up to two weeks. While this is a developing health situation, we are working continuously to take the necessary measures to ensure that the products you need are available with minimal interruption.

Build Your Custom Part. Use our Product Configurator


Air and non-combustible, compatible gases.
Wetted Materials:
Consult factory.
Housing Material:
Die cast aluminum case and bezel.
< 5 in w.c. (except ±2.5 in w.c.): ±1%; All other ranges: ±0.5% at 77°F (25°C) including hysteresis and repeatability (after 1 hour warm-up).
< ±1% per year.
Pressure Limits:
Ranges ≤ 2.5 in w.c.: 25 psi; ±2.5", 5 in w.c.: 5 psi; 10 in w.c.: 5 psi; 25 in w.c.: 5 psi; 50 in w.c.: 5 psi; 100 in w.c.: 9 psi.
Temperature Limits:
32 to 140°F (0 to 60°C)
(Note: Product temperature limits differ from case).
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 to 28 VDC, 12 to 28 VAC 50 to 400 Hz.
Power Consumption:
3 VA max.
Output Signal:
4 to 20 mA DC into 900 Ω max.
Zero & Span Adjustments:
Accessible via menus in safe zone only.
Response Time:
250 ms (damping set to 1).
Backlit 4 digit LCD 0.4" height LED indicators for set point and alarm status.
Electrical Wiring:
Screw terminal.
Mounting Orientation:
Mount unit in vertical plane.
Dial Size:
5" (127 mm) OD x 3-1/8" (79.38 mm).
Enclosure Rating:
(IP66). IP65 with option OPV, overpressure relief valve.
Housing Material:
Texture epoxy coat RAL7038.
Pressure Connections:
1/8" NPT female brass (SS optional). In presence of acetylene it is necessary to use SS.
Electrical Connections:
Two 1/2" FNPT. Cable gland not included.
12.3 lb (5.6 kg).
ATEX Certificate:
BVI 14ATEX0072.
Agency Approvals:
ATEX Compliant CE 1370 Ex II 2G Ex d IIC T6 Gb / II 2D Ex tb IIIC T85°C Db, -60°C=Tamb=+60°C IECEx Compliant: Ex d IIC T6 Gb / Ex tb IIIC T85°C Db
Switch Type:
2 SPDT relays.
Electrical Rating:
1 A @ 30 VAC/VDC.
Set Point Adjustment:
Adjustable via keypad on face in safe zone only.


  • 3-in-1 instrument allows the reduction of several instruments with one product, saving inventory, installation time and money
  • Flame-proof enclosure with optional glass window and aluminum housing protects the device in hazardous areas while giving local visibility to process pressure and set point status


Model Chart

EXAMPLE  AT2DH3 002 A 1 X T2 Series AT2DH3-002-AB1XT2  Pressure Gage with ATEX/IECEx Enclosure, range 0.25" wc, Aluminum housing material, Blind Top Cover, 1/8" npt female brass pressure port, Standard Plug without Overpressure Relief Valve, Stainless Steel Tag
SERIES  AT2DH3             Pressure Gage with ATEX/IECEx Enclosure



0.25" w.c.
0.5" w.c.
1" w.c.
2.5" w.c.
5" w.c.
10" w.c.
25" w.c.
50" w.c.
100" w.c.
-0.25 +/- 0.25" w.c.
-0.50 +/- 0.50" w.c.
-1.00 +/- 1.00" w.c.
-2.50 +/- 2.50" w.c.
-5.00 +/- 5.00" w.c.
-10.0 +/- 10.0" w.c.



COVER       B
      Blind Top Cover
Glass Top Cover
    1/8" npt femal Brass Pressure Port
1/8" npt femal Stainless Steel Port
  Standard without Overpressure Relief Valve
Overpressure Relief Valve Material, same as Port
TAG             T2  Stainless Steel Tag


Product Literature


Catalog Pages

Product Data Sheet



Photo Downloads

You must be logged in to view this content.
Click here to login to your account.

Product Reviews

Only registered users can write reviews. Please Sign in or create an account