Omega HHT User guide

1/2 NPT

1/2 NPT

SERIES HHT

HAZARDOUS AREA HUMIDITY/TEMPERATURE TRANSMITTER

Intrinsically Safe or Explosion-Proof Models

AIR QUALITY

4-9/32

[108.74]

3-29/32

[99.22]

4-15/32
[113.51]

13-23/32 [347.98]

2-23/32 [69.06]

1/2 NPT

The Series HHT Hazardous Area Humidity/Temperature Transmitter takes
accurate measurements in the harshest of environments. The explosion-proof model
is offered with 4-20 mA output for humidity only. The intrinsically safe version is offered
with 4-20 mA output for humidity and temperature, and do require an intrinsically safe
barrier to meet hazardous area approvals.

BENEFITS/FEATURES

• FM approved explosion-proof and intrinsically safe models

• Integral LCD option

• Dual temperature and relative humidity output models

APPLICATIONS

• Process monitoring

• Offshore HVAC monitoring

• Dust and grain handling

MODEL CHART
Model Protection Description Display

HHT-EU
HHT-IU
HHT-IT
HHT-EU-LCD
HHT-IT-LCD
HHT-IU-LCD

ACCESSORIES
Model Description
A-287

A-450
KFD0-SCS-EX1.55u

Explosion-proof
Intrinsically safe
Intrinsically safe
Explosion-proof
Intrinsically safe
Intrinsically safe

Mounting bracket for pipe or surface mounting (Includes

bracket and two 2˝ U-bolts)
Replacement sintered lter

Loop powered galvanic isolator

Humidity
Humidity
Humidity/temperature
Humidity
Humidity/temperature
Humidity

No
No
No
Yes
Yes
Yes

SPECIFICATIONS
Relative Humidity Range: 0 to 100% RH.

Temperature Range: -40 to 140°F (-40 to 60°C).
Accuracy: ±2% 10 to 90% RH, ±0.9°F at 77°F (±0.5°C at 25°C).
Hysteresis: ±1%.
Repeatability: ±0.1% typical.
Temperature Limits: -40 to 140°F (-40 to 60°C).
Storage Temperature: -40 to 176°F (-40 to 80°C).
Compensated Temperature: -40 to 140°F (-40 to 60°C).
Power Requirements: For intrinsically safe models HHT-IX, 9.5-28 VDC. For

explosion-proof models HHT-EX, 16.5-28 VDC.
Output Signal: 4-20 mA, 2 channels for humidity/temperature models (loop power
on RH).

Response Time: 15 s.
Electrical Connections: Screw terminal block.
Conduit Connection: 1/2 female NPT.
Drift: < 1% RH/year.
RH Sensor: Capacitance polymer.
Temperature Sensor: Solid state band gap.
Housing Material: Aluminum.
Display: Optional 2 line alpha numeric, 8 characters/line. Temperature display is

°F/°C selectable.

Display Resolution: RH: 0.1%; Temperature: 0.1°F (0.1°C).
Enclosure Rating: NEMA 4X (IP66). Models HHT-EX: FM Explosion- Proof, Class I

Div. 1 Group B, C, D, Class II Div. 1 Group E, F, G, Class III Div. 1; Models HHT-IX:
FM Intrinsically Safe, Class I Div. 1 Group A, B, C, D, Class II Div. 1 Group E, F, G,
Class III Div. 1 T4.

Weight: 2 lb 8 oz (1134 g).
Compliance: CE, FM.

uSee page 366 (Model KFD0)