Post on 09-Jun-2015
Control Systems
A control system typically comprises of a computer or microprocessor, a control program which handles
data from sensors and sends signals to output devices and an interface box to convert signals
between the sensors and the processor.
http://www.bbc.co.uk/schools/gcsebitesize/ict/measurecontrol/0computercontrol_act.shtml
A control system is a set of devices to manage, command, direct or regulate the behavior of systems.
In most systems there will be an input and an output. This block diagram represents that.
Signals flow from the input, through the system and produce an output.
Example
Example of Manual Input Devices
Example of Automatic Input Devices
Example of Output Devices
Sensors
Example of Sensors
Control System Examples
Input device: Hardware devices that allow
information to be input in to a computer.
Sensor collects data to a
computer.
It measure physical quantities such a noise, light and moisture in its environment.
The data captured from a sensor is downloaded to a PC
ADC: Convert analog in digital signals
Data Logging. The automatic collection of data over a period of time.
Logging Period. Period of time over which measurements are automatically taken by sensors. A Program is a
set of instructions which arewritten to control something and comes after data is collected from an input.
When Data is analyzed, spreadsheets are used.
Actuator: Device or motor whose movement is controlled by a
computer.
Output: Action that arise after processing. e.g. Turn up the heat,
turn off the light.
Feedback: Continuous process of monitoring
something in a Control System
Flowcharts
To understand what a system flowchart is, it helps to know that the most basic definition of a system is: a connection of parts that does something useful.
System flowcharts are a way of displaying how data flows
To illustrate this, symbols are used. They are connected together to show what happens to data and where it goes. The basic ones include:
Example
The flowchart shows what the outcome is if the car is going too fast or too slow. The system is designed to add fuel, or take it away and so keep the car's speed constant. The output (the car's new speed) is then fed back into the system via the speed sensor.