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PTU-2000 METEOROLOGICAL THERMO-HYGROMETER

Description

The Model PTU-2000 is a complete precision pressure, ambient temperature, and humidity professional quality measuring system designed for the meteorologist, climatologist, or atmospheric scientist. It provides accurate and reliable measurements achieving an absolute accuracy of ± 0.2° C in measuring ambient temperature over the entire ± 50° C range, relative humidity accuracy of ± 2% and pressure accuracy of ± 0.03" Hg. The system consists of an aspirated double-shielded platinum resistance thermometer, polymer capacitance hygrometer sensor, and solid state pressure sensor.

Ambient temperature is highly variable in both time and space, and a single measurement reflects a limited space-time domain. Historically, techniques other than direct measurement of ambient temperature have provided support for the global warming issue, but precise knowledge of atmospheric ambient temperatures is a fundamental component to understanding the Earth's climatic mechanisms. As we continue collecting ambient temperature data for the climatological database, improvements in the basic measurement are required. While some of the problems of measuring ambient temperature cannot be easily eliminated, basic instrumental and observational errors in climatic temperature measurements can be reduced using the PTU-2000.

Features

High accuracy

Maximum sensor protection with double intake radiation shields plus canopy shade ring

Fully aspirated

Analog output

Reliable solid-state detection technology

Precision platinum resistance thermometer

Solid state pressure transducer

Low maintenance

 

 


PTU-2000 system

Applications

Professional grade meteorological stations

Educational institutions

Aviation weather systems

Agricultural

Mechanical Configuration

The PTU-2000 electronics are packaged in a weatherproof NEMA-type PVC enclosure. The radiation shields are manufactured with white UV-resistant materials. Electrical and mechanical components are designed to operate over a temperature span of ± 50° C. The system typically mounts two meters above the ground to a tower or support and aimed into the prevailing wind.



PTU-2000 sensor head.



Cross section identifying temperature sensor, double shielding, canopy shade ring, and air intake.

 


Detailed view of bottom of temperature sensor showing double intake radiation shields, canopy shade ring, and screen.

 

Electrical Connections

Two foil-shielded 10' (3m) long cables are supplied with pig tails for interface to the user's junction box:

DC power input; isolated return analog output

Power cable for + 12 Vdc

Twisted pair 4-20 mA or 0-1 Vdc for temperature

Twisted pair 4-20 mA or 0-1 Vdc for humidity

Twisted pair 4-20 mA or 0-1 Vdc for pressure

 

Available Options

Spare aspiration blower

Spare aspiration screen

 

 

 

 

 

Mechanical Interface, Dimensions in inches (cm)

 

Specifications

Power Requirement

11-14 Vdc, 250 mA

Environmental Operating Range

±50șC

Aspiration Rate

Approximately 400 FPM

Dimensions

45.5" long x 8.0" wide x 12.5" high (115 cm x 20 cm x 31.7 cm)

Weight

4.5 lb (2.0 kg)

Temperature Measurement

Type: Platinum resistance thermometer

Measuring Range: +50șC to -50șC

Accuracy: ±0.2șC

Analog Output: 1-5 Vdc

Humidity Measurement

Type: Polymer capacitance

Measuring Range: 0 to 100% RH

Operating Temperature: +60șC to -40șC

Accuracy: ±2% RH

Stability: ±1% over 5 years

Linearity: ±0.5% RH

Hysteresis: ±1.2% of RH span maximum

Repeatability: ±0.5% RH

Response time: 15 sec in slowly moving air at 25șC

Analog Output: 1-5 Vdc

Pressure Measurement

Type: Solid state

Range: 1100 mb to 600 mb (32.50 to 17.70 in Hg)

Operating Temperature: +60șC to -40șC

Accuracy: ±0.3 mb (0.01 in Hg) at 20șC

±1 mb (0.03 in Hg) over temperature range

Analog Output: 1-5 Vdc

 

 

 

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This page was last updated on Monday, September 11, 2006 .