The Series AT-DH3 ATEX/IECEx Approved 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 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 4-20 mA process output. In velocity or flow modes, a square root output is provided on the 4-20 mA signal to coincide with the actual flow curve. Flameproof enclosures are available in aluminum and can include a glass window for viewing process information and set point status on the 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 maintain IP66 rating. • 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.
Hazardous area pressure measurement and transmitter
±1.5% for 0.25 in w.c. and
±0.25 in w.c ranges. Ranges 0.5 in
w.c. to 5 in w.c. and corresponding
bi-directional (except ±2.5 in w.c.) ±1%;
all other ranges: ±0.5% @ 77°F (25°C)
including hysteresis and repeatability (after
1 hour warm-up).
< ±1% per year.
See pressure limit chart.
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).
0.020% /°F (0.036/°C)
from 77°F (25°C); For 0.25 in and ±0.25
in w.c. ranges: ±0.03%/°F (±0.054%/°C).
12-28 VDC, 12-28 VAC 50 to 400 Hz.
3 VA max.
4-20 mA DC into 900 Ω max.
Zero and Span Adjustments:
Accessible via menus in safe zone only.
250 ms (damping set
to 1). Without considering delay caused
by Exd flame arrestors (up to 30 s from
FS to zero depending model and ranges
with STD pressure ports) about 15 s with
LD pressure ports on very low ranges.
Backlit 4-digit LCD 0.4" height LED indicators for set point and alarm status.
1/8" NPT female brass (SS optional).
Two 1/2" NPT female. Cable gland not included.
Mount unit in vertical plane.
5" (127 mm) OD x 3-1/8" (79.38 mm).
12.3 lb (5.6 kg).
IECEx INE 21.0064X.
ATEX: 0080 II 2G Ex db IIC T5, T6 Gb -60°C ≤Ta ≤+50°C (T6) -60°C ≤Ta ≤+60°C (T5) II 2D Ex tb IIIC T75 °C Db;
IECEx: Ex db IIC T5, T6 Gb -60°C ≤Ta ≤+50°C (T6) -60°C ≤Ta ≤+60°C (T5) Ex tb IIIC T75°C Db.