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Monitoring & Controlling Systems & Bitwise Operations


What you need to know?

Controlling systems are systems which measure a physical properties and alerts the user if the system is out of range.

There is very little difference between a monitoring process and a controlling software. The only difference is that the controlling does an extra role and sends signals to an actuator to alter the system

You will need to know the hardware used in monitoring and controlling systems. Also we need to remember the steps when the process occurs.

Usually these points are the same in every marksheme and will help you to score the marks.


Sensors

It is an input device which measures a physical property of the environment and sends digital signals to the processor

There are many types of sensors you have to know and identify

  • Temperature sensor
  • To measure the temperature of a system or to keep a chemical process at a constant temperature. To maintain a constant temperature is a controlling system

  • Ph sensor
  • Usually used in testing water or liquids or the soil

  • Infrared sensor
  • To detect motion - used in security systems

  • Pressure sensor
  • This measures the pressure of a gas or a system

  • Sound sensors and more..
  • These sensors are rarely asked but it's good to know

    Sound sensors- used to measure the intensity of the sound

    Light sensor - used to measure the light intensity

    Magnetic sensor - used to detect magnetic fields(compass apps) and for ABS systems in cars

    How to answer a general question

    They will ask:

    Explain the monitoring process in detail

    1. Indentify the type of sensor used such as Temperature sensor

    2. The sensor measures the physical properties and send electrical signals, these signals are then converted form analogue signals to digital(binary) signals using an ADC convertor.

    3. These signals are sent to a microproccesor where they are compared with the desired or stored values

    4. If the measured values are not within the desired range a signal is sent to an alarm to alert the user and the data is stored in a system

    5. If it is within the range the process doesn't do anything and continuues to operate the system until the system is terminated


    Infact the only difference between a monitoring and controlling systems is the 4th point.


    Controlling Systems

    A system which measures the physical properties of a system and send signals to an actuator to alter the system depending on the readings


    Actuator

    A hardware or device which receives signals from the processor to alter the system.

    A good example is a cooler or a fan on your CPU, the fan spins faster when you're gaming.

    How to answer a general question

    1. Indentify the type of sensor used such as Temperature sensor

    2. The sensor measures the physical properties and send electrical signals, these signals are then converted form analogue signals to digital(binary) signals using a ADC convertor.

    3. These signals are sent to a microproccesor where they are compared with the desired or stored values

    4. If the results are not within the desired range then a digital signal is sent to an actuator. The digital signal must be converted to analogue signals using DAC convertor.The actuator will be switched on to alter the system.

    5. If within the range, the process continously compares the readings to make sure the readings are within the desired range.



    Closed loop feedback system

    This is quite easy to understand. This is a system or an environment which when the actuator operates , the next reading it measures will be directly altered by the controlling system

    Think of a closed room and the A.C is switched on. The A.C will controll the temperature of the room but if the room is open the reading measured wouldn't be directly altered by the actuator.

    So the readings which the controlling system measures are actually feedbacks if whether the actuator is operating properly and doing its function.


    Bitwise Operations

    Bitwise operator are heavily used in assembly language. It compares two binary numbers or denary(must be converted to binary) and outputs a result depending on the operator used

    When dealing with bitwise operations. The individual bits are considered

    01100101 AND 01110111
    

    Usually when representing a binary number we use b01100101

    So the individual bits are compared

    01100101 AND
    01110111
    ________
    01100101
    
    
    

    Each corresponding bits are compared depending on the operator used. So in this case, we use AND, so both bits must be 1 for the final value to be 1

    This can be applied for different boolean operators such as OR and XOR

    Bitwise operations are used heavily in python but it is not in your syllabus





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