data logging and control

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