Data Logging By Introduction The term data logging

Data Logging By: ----------& -----------

Introduction • The term 'data logging' refers to collecting or gathering data over a period of time.

How Data is Collected • Sensors are used to measure the data. • The sensors could be collecting data on a wide range of things such as temperature, wind speed, water currents etc. • As the sensor takes a reading, the data is sent though a cable or wireless link to the data logger. • The data logger usually stores the data for a period of time before sending it in a large batch to a computer which will process and analyse it.

Analogue or Digital? • The sensors may be either analogue or digital. If they take analogue readings, an Analogue to Digital Converter (ADC) will be needed to convert the signal into digital data which the computer can understand.

Data Logging Examples Data logging can be useful for a number of projects/professions: For water companies In hospitals Weather reporting • We will be concentrating on weather reporting Racing cars

Weather Reporting using a Data Logger • Weather reporting is an example which uses data logging. Most data loggers do not need to be connected to a computer all the time because the computer might be needed for other things. • A computer can be used to store all of the data from the sensors on the data logger.

The Sensors • Sensors act as the input devices into the computer. The sensors measure the following: Temperature Wind Speed Wind Direction (see notes for further information)

Advantages • Data logging has many advantages: • It can be used in remote or dangerous situations • It can be carried out 24 hours a day, 365 days a year • Time intervals for collecting data can be very frequent and regular, for example, hundreds of measurements per second • It can be set up to start at a time in the future • No need to have a person present • It is often more accurate because there is no likelihood of human error

Disadvantages • Data logging also has disadvantages: • If the data logging equipment breaks down or malfunctions, some data could be lost or not recorded • Equipment can be expensive for small tasks • The equipment will only take readings at the logging interval which has been set up. If something unexpected happens between recordings, the data will not be collected.

Logging Interval/Frequency • The 'Logging Interval' is the period of time over which measurements are taken by the sensors. • If the value you are measuring changes quickly then the time interval needs to be quick as well otherwise the logger might miss crucial events. • On the other hand, if the data is going to change very slowly, then you would take readings much less often so that you do not get too much data.

Typical intervals for the data

Logging Period The period is how long you will measure the data- e. g. log data for 4 hours each day.

Weather and Airplanes • Weather can be very unpredictable and if something happens 35, 000 feet in the air, there is not much a pilot can do to save his airplane from crashing due to storms, hurricanes etc. That is why weather satellites are very important to pilots and airline companies to ensure passenger safety. • Satellites are placed in space at around 36, 000 feet – the images captured by the satellites are then transmitted to the weather radar on the plane where the pilots are warned about any danger.

Weather Satellite Image

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