Control System

Discussion in 'Homework Help' started by nikon, Sep 27, 2007.

  1. nikon

    Thread Starter Member

    May 3, 2007
    17
    0
    Hi you all,

    I learned a week ago the basics about Control Systems,
    I learned that any Control Sys. consist:

    *Input\Output
    *CPU
    *Memory

    and for home work I got those questions:

    1.Is there any Control System without Input? give an example.
    2.Is there any Control System without Output? give an example.
    3.Is there any Control System without CPU? give an example.
    4.Is there any Control System without Memory? give an example.

    I tought about it for 3 days and I didnt found nothing.
    Waiting for Help-Thanks,
    nikon
    ****************

    I didnt knew where to write this help topic so please forgive me
    if its not the correct place.
     
  2. beenthere

    Retired Moderator

    Apr 20, 2004
    15,815
    282
    Have you had any thoughts on the subject? What is the definition of a control system? Going from that, why is an input or an output necessary? What is the function of the CPU and/or memory in a control system?

    See if you can't think some more about this and come back with some answers or at least articulated thoughts.
     
  3. nikon

    Thread Starter Member

    May 3, 2007
    17
    0
    The memory remember all the inputs in order to use them in a later step.
    The memory is also the OS,Operation System that consist the actions
    that the system needs to do.

    The CPU take the input and following the OS actions.

    The input in those kinds of systems ,is usually a digital information.
    Its can be a press on a button or for example an oven , where you can
    select the time and tempature.

    The output can be also an energy.
    for example , in the oven, the output is the heat waves that comes out.

    Its seems that there is not such system that works with out one of them.
     
  4. thingmaker3

    Retired Moderator

    May 16, 2005
    5,072
    6
    What is the definition of "control system" in this context? Does an AGC or a simple thermostat count as a "control system?"
     
  5. beenthere

    Retired Moderator

    Apr 20, 2004
    15,815
    282
    Don't forget than in almost every case of a control system where a CPU mediates the outputs depending on the inputs, the same function was done by purely analog means not too long in the past.

    In the case of the oven, turning the heat up changed a resistance that caused a programmable unijunction transistor to fire. That current caused a wire to sag, closing the contacts that passed current through the oven 's heat elements. The temperature sensor had it's resistance change with heat in a manner that changed the operating point of the PUJT, eventually shutting off the heat as the set temperature was reached.
     
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