LPDT2 Dew Point Meter Transmitter

Ultra-Compact LPDT2 Dew Point Meter Transmitter

Loop-powered (2-wire) dew point meter with HTF aluminum oxide sensor transmitter

The LPDT2 is an ultra-compact, loop-powered (two-wire) dew point transmitter (with a display option available in June). The LPDT2 is a fully functional instrument operated through a miniature custom LCD display and four push buttons, using the same user-friendly interface of all COSA Xentaur hygrometers. The analog output is linear to the engineering units selected for display and is user configurable. The unit also provides for a 2-wire RS-485 Modbus Interface.

Loop-powered transmitter with integrated digital display; also available without display
Versatile and compatible with a wide range of gases and fits wide range of applications
Uses Hyper-Thin-Film HTF™ Sensor Technology
Available in standard version with display or no display option

Brochure

Manual

Hyper Thin Film Technology Overview

The LPDT2 uses a COSA Xentaur HTF aluminum oxide sensor. The breakthrough HTF moisture sensor technology represents advances in thin film and metal oxide sciences and offers significant performance advantages over all other aluminum oxide sensors. The operating principle of the HTF aluminum oxide sensors is that a hygroscopic layer of aluminum oxide adsorbs or releases water molecules within its pores, depending on the water vapor pressure in its environment. The electrical capacitance of the aluminum oxide layer changes with the surrounding water vapor pressure. The electrical capacitance is measured between the aluminum core of the sensor and a porous conductive gold layer on the outside. The advantages of the HTF sensor technology are a result of the proprietary manufacturing method in which the aluminum oxide layer is made to be hyper thin as well as extremely hygroscopic. This results in a very sensitive sensor with fast response.

Applications

Glove boxes
Clean room environments
Natural gas transmission
Hydrocarbon processing
Air dryers and compressors
Specialty air gases
Cryogenic
Air generators

Features and Benefits

Integrated HTF™ Sensor Technology
Display and no-display version available
Low-cost
Easy maintenance
Weatherproof NEMA 4X IP66
Convenient logging feature
RS-485 Modbus Interface
Adjustable analog outputs
Low cost of ownership and maintenance
Very low drift
Long sensor life

Electronics

The compact LPDT2 dew point meter is a fully functional instrument operated through a miniature custom LCD display and three push buttons, using the same user friendly interface of all COSA Xentaur hygrometers. The analog output is linear to the engineering units selected for display and is user configurable. A weatherproof cap is available for outdoor NEMA 4X (IP65) applications.

Sensor

The LPDT2 uses a COSA Xentaur Hyper-Thin-Film HTF™ aluminum oxide sensor. The breakthrough HTF sensor technology represents advances in thin film and metal oxide sciences and other significant performance advantages over all other aluminum oxide sensors. The operating principle of the HTF aluminum oxide sensors is that a hygroscopic layer of aluminum oxide adsorbs or releases water molecules within its pores, depending on the water vapor pressure in its environment. The electrical capacitance of the aluminum oxide layer changes with the surrounding water vapor pressure. The electrical capacitance is measured between the aluminum core of the sensor and a porous conductive gold layer on the outside. The advantages of the HTF sensor technology are a result of the proprietary manufacturing method in which the aluminum oxide layer is made to be hyper thin as well as extremely hygroscopic. This results in a very sensitive sensor with fast response.

High Capacitance Response

HTF sensors have a capacitance change, several orders of magnitude larger than that of conventional aluminum oxide sensors due to the hyper thin film, a sharp transition layer and a special pore geometry. Additionally, this change is quasi linear and its sensitivity to temperature is negligible. The advantages of a linear high capacitance response: better sensitivity, better repeatability and faster response times. Also, the measurement system is less prone to noise and drift, and signal conditioning is kept to a minimum.