WMS-16 Weather Station Operator’s Manual
2
Barometric Pressure
Barometric pressure is sensed using a piezoresistive sensing
element. This element responds to changes in barometric
pressure with a corresponding change in resistance. This
resistance is converted to a voltage from which the
microprocessor calculates the barometric pressure at the
elevation at which the barometer is located.
Since air pressure varies with elevation, the barometric
pressure must be set for the elevation at which the barometer
is installed. This value is set simply using a screwdriver.
Instructions are provided in the Installation Section of this
manual.
Temperature and Relative Humidity
The WMS-16 is designed to accommodate a combination
temperature/ relative humidity sensor. For maximum
accuracy, the sensor should be isolated from the effects of
sunlight a factor that can cause misleading temperature and
humidity measurements. The Model WMS-16-THS Naturally
Aspirated solar shield is provided to give this protection.
Temperature is sensed using a thermistor element whose
resistance changes in response to temperature fluctuations.
Relative humidity is sensed by changes in the dielectric
constant of a thin polymer film as it absorbs moisture or sheds
it to the surrounding air.
Rain
The rain gauge used with the WMS-16 is a traditional tipping
bucket design. Resolution is 0.01 inches.
Using the Data
Once the weather data generated by the WMS-16 has been
logged and saved-either within the control module or on an
external media-it can easily be manipulated by a number of
commercially available software packages. The format of the
columnar, coma-delimited data was carefully designed to
make it compatible with the most widely used spreadsheet
programs. The data can be imported easily into these programs
and from there analyzed or manipulated, making the
information generated by the WMS-16 much more than
simply a collection of numbers.
A number of enhancements to the WMS-16 are planned for
the future that will make the WMS-16 even more responsive
to your needs. The EEPROM in which the operating firmware
is stored can be electronically updated to simplify future
firmware upgrades.
