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  • katsaronas
    Participant
    September 21, 2012 at 7:12 pm
    Post count: 3
    #3570

    Hello,
    I have an inverter which has one capacitor as a power source, and I want to keep the voltage of the capacitor’s pins at 400VDC. The best choice to do this, is a PID controller, I think. And my question is:
    Will the osPID do the job? What input and output cards should I use ? Thank you.

    Brett
    Keymaster
    September 21, 2012 at 9:15 pm
    Post count: 101
    #3927

    Will the osPID do the job?

    I’m skeptical that it will. the osPID has a sample time of 250mS. this is more than adequate for things like temperature, level, and pressure, but it’s likely WAY to slow for electricity.

    katsaronas
    Participant
    September 22, 2012 at 5:59 am
    Post count: 3
    #3928

    So it’s better a PID loop running in arduino instead? I’m not sure but I think that arduino can sample at ~88kHz with some modifications.

    Brett
    Keymaster
    September 22, 2012 at 10:44 am
    Post count: 101
    #3929

    even using the PID library on the arduino may not be an option: http://brettbeauregard.com/blog/2011/04/how-fast-is-the-arduino-pid-library/

    because it uses floating point math, it’s not terribly fast. if your program did NOTHING but pid (no analogRead, no analogWrite) the fastest you could get would be ~12kHz.

    katsaronas
    Participant
    September 22, 2012 at 4:54 pm
    Post count: 3
    #3930

    So what is your suggestion? What can I do? Should I try a different controller, maybe more powerful-> 32bit pic?

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