Unit 7 Control Flashcards
Control system
A device (or set of devices) that manages; commands; directs or regulates the behaviour of other devices or systems. (IPO)
How a control system works
Sensor - Processor - Transducer - Feedback
Embedded system
Performs a specific function within a larger system
Microprocessor
An integrated circuit that contains all the functions of a CPU of a computer
Sensor
A device which detects or measures a physical property and records; indicates; or otherwise responds to it
Analog data
Data accepted by continuous variable
Output transducers
Turn the digital data into analogue signals to power ‘real world’ devices
Advantage of output transducers
- Compatible with microprocessors and computers - Remote controllability and easy data transmission capability - Ease of convertability from analog to digital
Feedback
Modification or control of a process or system by its results or effects
Centralized system
Computing done at a central location; using terminals that are attached to central computer
Distributed system
System in which components located on networked computers communicate and coordinate their actions by passing messages.
Advantages of centralized system
Easier to administrate More control
Advantages of distributed system
Quicker access Shared load Response more specific to environment
Automated doors
Input: Access sensor; movement Process: Sends message to processor (triggered) Output: Doors on pulley system that rotates to pull door open; with timer that closes after a few seconds
Movement on automated doors
Interrupt on OS to stop door from closing
House heating
Input: Thermometer Process: Sends message to boiler; switches pump and water goes through house. Output: Radiates heat until the thermometer comes to required heat
Taxi Meter types
Timer based; Pay by mile
Timer based taxi meter
Input: Clock Process: Checks how much time has gone by Output: Amount of money on screen
Pay by mile
Process: Odometer; calculates cash; GPS receiver to calculate number of miles Output: Amount of money
All outputs of taxi meter
Light on top of taxi Printer of receipt Card input device Payment to driver
Elevator
Input: Button to call Process: Motor lifts up and down ; pressure and door sensors Output: Light inside elevator; Comes to floor
Washing machine
Input: Settings - Button; how long Process: Spins Output: Done
GPS
Input: User enters address/ place Process: Sends messages to satellites which would access the given location using trilateration. Sends result to client Output: Client receives directions
Traffic light
Input: Vehicle detector Process: Check 7.1.1
Device drivers
Program -> OS -> Device drivers (interprets instructions from sensors) -> ROM
Device driver (definition)
Translation software used by the OS so that it can communicate with peripheral devices
Types of sensors
Motion Heat Speedometer GPS Timer Compass
Accessibility input devices
Wide range of input devices can be used to allow people with a range of disabilities operating computer hardware and software
Examples of accessibility input devices
Joystick Switch Keyboard alternatives
Input devices
Mouse Keyboard Joystick Light pen Touch pad Microphone Scanner Track Ball Digital Camera
In a system; the feedback
becomes the input
Social impacts and ethical considerations associated with the use of embedded systems
Tagging prisoners Surveillance CCTV
Evaluating systems
For and against argument Evaluation Costs Hardware and software Which is best for that scenario
Autonomous agents
Autonomy Reactive behavior Concurrency Persistence
Autonomy (AA)
Activates alone for tasks Selects tasks themselves - no human intervention needed
Reactive behavior (AA)
Sense the environment Reacts based on perceptions
Concurrency/Sociality (AA)
Interact with other agents through communication
Persistence (AA)
Runs continuously; not executed on demand
Ethical issues of computers replacing workers
Labor cost Quality of work Retraining Productivity Safety
Function of OS in control system
Controls hardware components Reading input devices Sends feedback
