|
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 |
| |
|
