Data Logging GCSE ICT

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

How Data is Collected Sensors are used to take readings or measurements at regular intervals of their environment. (Tactile, audible, visible) The sensors could be collecting data on a wide range of things such as temperature, humidity, pressure, wind speed, water currents, electrical voltage, pH readings etc. (Progress Leisure?) 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.

As the sensor takes a reading, the data is sent through 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. A data logger is often a hand-held battery-operated device which has a large amount of memory.

Remote Data Logging The data might need to be collected at all times of the day and night or during weekends when people might be away from work. Data might also need to be collected from dangerous places such as volcanoes or from places where it is not practical or safe for a human. Remote data logging means that the sensors collect data 'out in the field' and pass it to a portable data logger. The data logger then relays the data either wirelessly, by fibre-optic cables or possibly even by satellite, back to a computer ready for analysis.

Logging Interval & Period The 'Logging Interval' is the time between measurements which are taken by the sensors e.g. 2 seconds, 1 minute The 'Logging Period' is the total amount of time data is being read e.g. a year

Data Logging Typical Interval Sound recording Thousandth of a second Heart beat Tenths of a second Oven temperature Minutes Outdoor temperature Hours Soil dampness Days Growth of plants Weeks Destruction of the rain forest Months Growth of cities Years Global warming Decades

Advantages of Data Logging Data Logging can be used in remote or dangerous situations. Data logging can be carried out 24 hours a day, 365 days of the year. Time intervals for collecting data can be very frequent and regular. Can be set up to start at a time in the future. No need to have a person present. Data logging is often more accurate because there is no likelihood of human error.

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.