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

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 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).
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.

Product Literature
Catalog Pages

Models & Ordering
Model Description
HHT-EU Explosion-proof humidity transmitter.
HHT-EU-LCD Explosion-proof humidity transmitter with LCD display.
HHT-IT Intrinsically safe humidity/temperature transmitter.
HHT-IT-LCD Intrinsically safe humidity/temperature transmitter with LCD display.
HHT-IU Intrinsically safe humidity transmitter.