What to implement for gaining experience in control loop?

Discussion in 'General Electronics Chat' started by atferrari, May 24, 2015.

  1. atferrari

    Thread Starter AAC Fanatic!

    Jan 6, 2004
    I intend to gain hands-on experience in control loops (of the PID type). At this stage, op amps to be used.

    I am looking for suggestions (the easiest / simplest / cheapest / quickest) on two concrete points:

    1) a "plant" that I could implement on my bench.

    2) way of tracking ( eventually recording) set point - system output - error - time. If things go not too fast, I guess I could do it manually but not really sure.

    After reading a lot, starting with Bob Pease, I concluded that something related to temperature control or motor speed are the best candidates. Have read about a pendulum but sounds complex to start with so I discarded it already.

    Suggestions appreciated.
  2. MaxHeadRoom


    Jul 18, 2013
    If you search in Mit.Edu they have some brief on line courses outlining motor control and PID loop using op amps.
  3. Sensacell

    Senior Member

    Jun 19, 2012
    A thermal system is a really easy choice.
    Get a nice big aluminum heatsink, bolt some big power resistors to it (heaters) and attach a temp sensor.

    You can play around with fans and such to change the characteristics of the 'plant'.
  4. alfacliff

    Well-Known Member

    Dec 13, 2013
    if controling a motor, you need a form of feedback for rpm. a tach generator, or rotary scale. the rotary scale could also be used to control the position of the motor shaft. then the usual comparator and amplifier.
  5. atferrari

    Thread Starter AAC Fanatic!

    Jan 6, 2004
    Thanks to you all for replying.

    I decided to go the temperature-control way. Simpler to start. Now, I am implementing the sensor/s (DS1820) Dearly expensive but available. >8USD ea!!! Nice country this, eh?

    Something I do not know how to manage yet: say I want to fix the setpoint for 30ºC. What I will be having is just a pot able to span from +XxV to -XxV. How to make voltage there to correspond to actual 30ºC (or whatever)?

    Is much easier to say I am working on a certain temperature range than a certain voltage range, otherwise I risk to be confused. Any simple idea to solve this?
    Last edited: May 27, 2015
  6. atferrari

    Thread Starter AAC Fanatic!

    Jan 6, 2004
    Hola Max,

    I cannot quote your message. :(

    I tried the MIT site but found impossible to spot them. Too much offer and I seem to lack the magic words to do the right search. Maybe I will reread Bob Pease even twice again. :D