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Data Logging & ControlICT GCSE
Data Logging
The automated collection of data over a period of time
Sensors Sensors are used to
take readings or measurements
They record things such as: Wind Speed Temperature pH Pressure Voltage Heart Rate
Analogue and Digital Data Digital
Made up of 0s and 1s
Each 1 or 0 is a bit Groups of bits can be
coded together to represent data
Analogue An analogue signal
can be any value An example of
analogue data is a sound wave such as the human voice
An interface box is used to convert analogue signals from sensors into digital signals which can be
processed by a computer
Example Hospitals
When a patient has had a major operation or is very ill they may be put in the intensive care unit (ICU)
Several sensors are used to monitor their condition:
Heart Rate Oxygen levels Temperature
This data is displayed as digital numbers or in the form of a graph
Other Uses
Taking readings during science experiments
Weather stations Recording traffic levels Recording pollution levels Central heating systems
Advantages and DisadvantagesAdvantages Can be used in remote
or dangerous locations 24/7 Automated Often more accurate No need for a human
to be present
Disadvantages Equipment could
break down Can be expensive The recordings will
only be taken at the intervals set up, if something unexpected happens it may not be recorded
Control
Using a computer to control the actions and movement of an object
Sensors are also used in control, these are known as inputs
Input
Control
Once the input data has been received by the computer it can begin to process it
ProcessProcessInput
Control
Once the data has been processed and a decision has been made the computer will send a signal to the output device
ProcessProcess OutputInput
Example
Central Heating System
Is it too cold
?
Is it too cold
?
BB
AA
Is it too hot?
Is it too hot?
CC
A = Temperature Sensor (Input)B = Heating On (Output)C = Heating Off (Output)
Too Hot
Example
Central Heating System
Is it too cold
?
Is it too cold
?
BB
AA
Is it too hot?
Is it too hot?
CC
A = Temperature Sensor (Input)B = Heating On (Output)C = Heating Off (Output)
Too Cold
Example
Central Heating System
Is it too cold
?
Is it too cold
?
BB
AA
Is it too hot?
Is it too hot?
CC
A = Temperature Sensor (Input)B = Heating On (Output)C = Heating Off (Output)
Too Hot
Instructions
You write sequences of instructions in order to control devices, for example a robot which is designed to draw designs
Instructions
StopForward 40Instruction
Right 90Forward 40Right 90Forward 40Right 90Forward 40