Loop-powered Dewpoint Transmitter

Fully Functional Instrument
Xentaur’s Model LPDT is the world’s smallest loop-powered (2-wire) dewpoint transmitter.
The LPDT is also a fully functional instrument, featuring the well proven and easy to use interface, familiar to many. Set-up functions, result display of dewpoint, temperature and optionally pressure are accommodated by a miniature custom LCD display and three programming buttons.
The LPDT is also the only loop-powered dewpoint transmitter featuring both analog and optional digital outputs.
Analog Output Loop
4 - 20 mA is drawn by the instrument from the power supply, with the current being linear to the selected engineering units. The range of the output is programmable. The output resolution is 0.1°C(dp)
Digital Output Loop (optional)
The instrument can supply digital output by modulating the 4 - 20 mA loop line. The timing and format of the data conforms to RS-232,and the output can be interfaced to a PC or other RS-232 devices with an optional adapter. In the digital mode, the LPDT can be remotely operated and dewpoint and temperature (and pressure if installed) can be read. In the digital mode, multiple units can operate on the same loop cable as a multi-channel instrument.
HTF™ High Capacitance Aluminum Oxide Sensor
The LPDT uses a Xentaur HTF™ high capacitance aluminum oxide sensor and provides a degree of accuracy, speed of response and stability unavailable from other instruments using conventional sensors.

LPDT Brochure

Technical Specifications
Dewpoint Sensor Element
Type: Hyper Thin Film high capacitance Al2O3
Dewpoint range: XTR-100: -148°F to +68°F (-100°C to +20°C)
XTR-65 -85°F to +68°F (-65°C to +20°C)
Capacitance: 15nF to 200nF
Accuracy: ±5.5°F (±3°C)
Repeatability: ±0.9°F(±0.5°C
Temperature Range: -14°F-158°F (-10°C to +70°C)
Sample flow range:
(linear vel. @ 1atm):
Static to 100 m/s
Storage temperature: -40°F to +176°F (-40°C to +80°C)
Calibration method: Autocal, sensor saturates at dewpoint above +68°F (+20°C). NIST/NPL traceable factory multipoint calibration available optionally
Temperature and Pressure Measurement
The instrument measures the sample temperature with a precision integrated circuit sensor. Units may be optionally fitted with a pressure sensor.
Electronics:
Input resolution: 0.1°C(dp)
Indicators: 3.5 digit LCD with custom legends
Engineering units: °C, °F, PPM, LBS H2O/mm scf, gm H2O/M3
Controls 3 push buttons, all settings stored in EPROM
Outputs: Analog: 4 - 20mA; Digital: RS-232 (bidirectional)
Alarms: The 4 - 20mA or the digital output may be used by an external device to operate relays
Isolation Sensor and case are isolated from the current loop and shunted with 33V transorbs.
Mechanical
Enclosure Stainless Steel
Weatherproof cover optionally available
Pressure operating range: Standard: 500 PSI (34 bar)
Optional: 5,000 PSI (340 bar)
Electrical connections: 2.1 mm power jack with retainer
Mechanical connections: 14 mm x 1.25 mm and 3/4” x 16 threads
Cable; Two conductor cable
Power requirements: 10 to 33 VDC, the instrument draws 4-20mA depending on measured dewpoint.
Warranty: 1 year
Product Overwiew
   Dewpoint Sensors     
Standard Dewpoint Transmitters
      Loop–powered     Dewpoint Transmitters
     Portable Dewpoint Instruments
Hazardous Area Products   
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