Glossary of Terms

8bit 16bit

In the decimal number system that we use in everyday life, numbers are represented using the digits 0 to 9. However computer data must be stored and processed as zeros and ones (binary system). The largest whole number that can be represented by 3 digits in the decimal system is 999. The largest whole number that can be represented by 3 digits in the binary system is 111 which is the same as 7 decimal.

We refer to the number of digits used in a computer binary number as the number of bits (from Binary digITs). If we use 8 bits in binary format the largest number we can have is 11111111 or 255 decimal. If we use 16 bits in binary the largest number we can have is 1111111111111111 or 65535 decimal. Processing and storing numbers in 16bit format uses more memory but gives us access to larger numbers. Processing and storing numbers in 8bit format uses less memory but gives us a much smaller number range.

In the Weather-Pro weather station the various sensors are read and converted in to digital data (Binary zeros and ones). This data can be stored in 8bit or 16bit format. If data is stored in 8bit format there is a maximum of only 255 steps from the smallest value that can be read to the largest value that can be read. The number of steps in a reading is referred to as resolution.

With 8bit resolution the readings are restricted to a maximum of 255 steps from smallest value to largest value. With 16bit resolution the readings are restricted to a maximum of 65535 steps from smallest value to largest value.

8bit format takes up less memory but has lower resolution

16bit format takes up more memory but has much higher resolution

Active Dataset

The Active Dataset is selected and displayed in the Dataset Selector on the Toolbar. The Values, Statistics and Graph views are views of the Active dataset at the time the view was started.


Instrument used for measuring wind speed

Barometric Pressure

Another term for Air or Atmospheric Pressure. The weight that a column of atmospheric air exerts in a surface area. It is measured in:

Comms Port

Refers to the physical RS232 communications port on the back of a Computer. One of these needs to be available to use the OmniLog software to control a Datalogger.

Configeration Area

In this document configuration area refers to the area within the Datalogger that controls the operation of the Logger. This area can be read and modified by the OmniLog program.

Connecter Logger

The logger that is currently connected to your computer. If Connected Logger is showing as the Active Dataset you can Control the logger and read its channels in Realtime.


A Dataset is a set of data available within the program. The current Dataset is selected using the Dataset selection tool in the main toolbar.

Derived Dataset

A Derived Datase tis created by joining one or more Datasets. The data in the Dataset has been derived from a number of different loggers. Derived datasets are also created when a derived channel is added to a dataset.

Dew Point

The temperature at which the relative humidity would reach 100% and dew would form.


The act of getting the saved data from the Datalogger and placing it into the current Logger Dataset.

Download Cable

A cable used to connect a Datalogger to a Computer. The 2 pin, 3 pin , microToT/SafeT and Multi-channel logger all require a different type of cable

Leaf Wetness

A percentage index indicating the relative wetness of a typical leaf. This wetness is the result of humidity and precipitation.

Light Energy

The energy produced by the sun and measured at the Light Energy sensor. This includes not only the energy from visible light but also energy from the infrared and ultraviolet areas of the spectrum either side of the visible light. The accumulated light energy can be used as a indication of the amount of photosynthesis that plants can perform in a given time period.

Log File

Downloaded data is saved in a Log file with a .log file extension. The Log file contains information on the logger and the logged data. This file can be reloaded at a later time to create a new dataset.

Logging Period

The period between each time the Datalogger reads the probes and saves the readings to memory.

OmniLog Assistant

The OmniLog Assistant is a dialog box designed to assist new users in the operation of the Omnilog Software. It can be disabled from the Program Tab of the Tools... Options... dialog box.


A Pager is a device that can be called up by telephone and it alerts the person carrying that someone or something is trying to contact them

Relative Humidity

The measure of amount of moisture held by the air expressed as a ratio of the total amount of water that the air could hold . As Air Temperature increases the amount of water that the air can hold also increases so the Relative Humidity is very temperature dependent. For a given amount of moisture in a given volume of air, the Relative Humidity will decrease as the temperature increases. The term is usually used to distinguish the readings from Absolute Humidity which is a measure of the actual amount of moisture in a given volume of air and is usually measured in millimeters of water per cubic meter of air.


Electronics Industry name given to the small plug used on the serial communications cable of the Weather-Pro


Strictly speaking, RS232 is an electrical specification for a serial communication system. It usually refers to the serial port of a computer or other device such as a Datalogger


Strictly speaking, RS485 is an electrical specification for a serial communication system. The Multi-Channel Plus and Weather-Pro Plus weather station uses an RS485 link to collect readings from remote sensors.


Normally refers to a single value within a Dataset but may also refer to a set of values within a Dataset that where recorded at the same time

Slow Pulse Input

A pulse input on the rain loggers, multi channel loggers and weather stations used for the connection of a Tipping Bucket Rain Gauge. The input can accept a maximum pulse rate of up to 5 pulses per second with a minimum pulse duration of 1ms).

Solar Radiation Shield

The solar radiation shield houses the temperature, humidity and pressure sensors. Fins on the shield encourage air flow through the housing so that the temperature, humidity and pressure sensors are kept at air temperature and are not warmed by direct exposure to solar radiation.


Brand of Battery used by the Weather-Pro Station. When purchasing specify 3.6Volt AA High Energy Lithium, Part Number TL-5903

Wind Chill Factor

When air moves over an object, energy (temperature) is transferred to the moving air and therefore lost from the object. The faster the air moves the more energy (temperature) is lost. This loss of temperature with air speed is referred to as Wind Chill. In the Omnilog software a derived Wind Chill channel can be added to any dataset that contained both Temperature and Windspeed. The Wind Chill is expressed as the heat loss that would occur e at the equivalent Temperature in relatively still but not stationary air.

Wind Vane

Instrument used to measure the direction of the wind.