Series HHT Hazardous Area Humidity/Temperature Transmitter

Intrinsically Safe or Explosion-Proof Models

The SERIES HHT Hazardous Area Humidity/Temperature Transmitter takes accurate measurements in the harshest of environments. The explosion-proof model is offered with 4 to 20 mA output for humidity only. The intrinsically safe version is offered with 4 to 20 mA output for humidity and temperature, and do require an intrinsically safe barrier to meet hazardous area approvals. It is important to develop a routine schedule for replacing the RH/temperature sensor (part number A-451). The sensor should be replaced annually or sooner depending on application conditions.

Product Applications

  • Process monitoring
  • Offshore HVAC monitoring
  • Dust and grain handling

Models & Ordering

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Model Description Usually Ships Price Order
HHT-EU
Ships: Same Day
Price: $761.00
Explosion-proof humidity transmitter. Same Day $761.00 Order
HHT-EU-LCD
Ships: Same Day
Price: $788.50
Explosion-proof humidity transmitter with LCD display. Same Day $788.50 Order
HHT-IT
Ships: Same Day
Price: $592.50
Intrinsically safe humidity/temperature transmitter. Same Day $592.50 Order
HHT-IT-LCD
Ships: Same Day
Price: $620.00
Intrinsically safe humidity/temperature transmitter with LCD display. Same Day $620.00 Order
HHT-IU
Ships: Same Day
Price: $563.00
Intrinsically safe humidity transmitter. Same Day $563.00 Order

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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 72°F (±0.3°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 instrinsically safe models HHT-IX, 9.5 to 28 VDC. For explosion-proof models HHT-EX, 16.5 to 28 VDC.
Output Signal:
4 to 20 mA, 2 channels for humidity/temperature models (loop power on RH).
Response Time:
15 seconds.
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).
Weight:
2 lb 8 oz (1134 g).
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 Instrinsically Safe, Class I Div. 1 Group A, B, C, D, Class II Div. 1 Group E, F, G, Class III Div. 1 T4.
Agency Approvals:
FM, CE.

Features

  • FM approved explosion-proof and intrinsically safe models
  • Integral LCD option
  • Replaceable calibrated sensor for long term use in harsh environments
  • Dual temperature and relative humidity output models

Accessories

Model Number Description Usually Ships Price Order
Loop powered galvanic barrier for use with intrinsically safe transmitters. KFD0-SCS-EX1.55 Loop powered galvanic barrier for use with intrinsically safe transmitters. Same Day $494.00 Order
A-287 Mounting bracket for pipe or surface mounting (includes bracket and two 2" U-bolts). Same Day $11.75 Order
A-451 Replacement 2% sensor. 1-2 Weeks $35.75 Order
A-450 Replacement sintered filter. 1-2 Weeks $8.00 Order

Videos

Model Chart

HHT-XX-OPT    HHT HUMIDITY HUMIDITY/TEMP TRANSMITTER
    
          1ST SYMBOL (1ST X) APPROVAL
             A     ATEX/IECEX FLAMEPROOF (NOT AVAILABLE)
             E     FM EXPLOSION PROOF   
             I     FM INTRINSICALLY SAFE
            
          2ND SYMBOL (2ND X) PROCESS CONNECTION AND OUTPUTS
             B     1/2 IN MALE BSPT HUMIDITY
             E     1/2 IN MALE BSPT HUMIDITY AND TEMPERATURE (I ONLY)
             T     1/2 IN MALE NPT HUMIDITY AND TEMPERATURE (I ONLY)
             U    1/2 IN MALE NPT HUMIDITY
            
          OPTION (OPT)
            -C5    C5-M HOUSING PAINT SPECIFICATION
            -LCD   LCD DISPLAY
            -M20   M20 CONDUIT HOUSING
            -FC    FACTORY CALIBRATION CERTIFICATE

Product Literature

Manuals

Catalog Pages

Approvals

Drawings

Questions

Question
I'm looking for a dual temp. and humidity gauge for an 8" duct. I'm wanting to remote read the temp and humidity on the incoming and outgoing air to an ERV unit. The RHP-3M11-LCD was recommended to me, however, it is a direct read. What would be the correct instrument to remote read the temperature and humidity from a distance of 8 feet. The 8" duct is in the attic and I want to read the result in the down-stair hall. I don't want to record nor program the unit, just read the performance.
Answer
The sensor recommended would be the best option we have for sensing temperature and relative humidity for your application. We do not have any options with a remote display that could stretch as far as you are asking, nor are there any on the market to my knowledge. In every case, you would need to utilize a process output, in this case 4-20 mA, to transmit the readings to a remote display(s) which would accept the process signal(s). If you are just looking for a remote readout to go with the RHP sensor with no control functionality, then you could look at one of our panel meters, possibly the SPPM, DPMA, DPMW, or DPMP & DPML series panel meters. For assistance selecting an appropriate panel meter, please contact our technical support group at 219-879-8000.

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