7.1.2 Real-World Examples of Control System Notes

Examples of Control Systems

Here are some examples of control systems you should be aware of.

Automatic Doors

1. Functionality: Open and close doors automatically when motion is detected.
2. Components:
   1. Motion Sensors: Detect movement using infrared or microwave signals.
   2. Processors: Decide when to open or close the doors.
   3. Actuators: Physically move the doors.
3. Benefits:
   1. Energy Efficiency: Prevents doors from being left open, reducing heating or cooling loss.
   2. Accessibility: Offers easy access for the elderly and individuals with disabilities.

Heating Systems

1. Functionality: Maintain a desired temperature by automatically adjusting heating or cooling.
2. Components:
   1. Temperature Sensors: Measure the current temperature.
   2. Processors: Compare the current temperature to the desired setpoint.
   3. Actuators: Turn the heating or cooling system on or off.
3. Benefits:
   1. Energy Conservation: Automatically adjusts to maintain the desired temperature, reducing waste.
   2. Remote Control: Smart systems can be controlled via the internet, allowing users to adjust settings from anywhere.

Taxi Meters

1. Functionality: Calculate fares based on distance and time.
2. Components:
   1. GPS Sensors: Track the vehicle's location and distance travelled.
   2. Processors: Calculate the fare using predefined rates.
   3. Output Devices: Display the fare and print receipts.
3. Benefits:
   1. Accuracy: Reduces errors and prevents fraud.
   2. Convenience: Supports credit card payments and provides automatic receipts.

Elevators

1. Functionality: Transport people and goods between floors safely and efficiently.
2. Components:
   1. Human Interaction Device (HID): Detect which buttons are pressed.
   2. Position Sensors: Detect the elevator's current location.
   3. Load Sensors: Measure the weight of passengers to prevent overloading.
   4. Processors: Control the elevator's movement and door operations.
3. Benefits:
   1. Safety: Motion sensors prevent doors from closing on passengers.
   2. Efficiency: Algorithms optimise the elevator's route based on demand.

Washing Machines

1. Functionality: Automate the washing process by adjusting settings based on load size and fabric type.
2. Components:
   1. Load Sensors: Determine the weight of the laundry.
   2. Temperature Sensors: Monitor water temperature.
   3. Processors: Select the appropriate wash cycle and duration.
3. Benefits:
   1. Efficiency: Optimises water and energy usage.
   2. Safety: Locks the door during operation to prevent accidents.

Traffic Lights

1. Functionality: Regulate traffic flow and ensure pedestrian safety.
2. Types:
   1. Fixed Time: Change signals at regular intervals without feedback.
   2. Dynamic Control: Use sensors to adjust signals based on traffic conditions.
3. Components:
   1. Motion Sensors: Detect vehicles and pedestrians.
   2. Processors: Determine the optimal signal timing.