pid control configuration

[Vijay Khemka]

On 5/6/19, 9:20 AM, "Ed Tanous" <ed.tanous at intel.com> wrote:

    On 5/2/19 4:24 PM, Vijay Khemka wrote:
    >  My understanding here is pid data are only defined for temp sensors which will generate pwm values for fan.
    > 
    
    The above is not how phosphor pid control operates.  The temperature
    controllers "request" a given fan RPM, then the fan PID controller
    (which is scanned much more quickly than the temperature controllers)
    attempts to drive the fan to that speed.  This ends up being a two stage
    feedback loop that can perform better than a single PID loop.
Where would I get data for Fan pid whatever data  we get from thermal team are 
Only for temperature pids.
    
    In control theory, this is called a "Cascade" control scheme
    
    https://urldefense.proofpoint.com/v2/url?u=https-3A__en.wikipedia.org_wiki_PID-5Fcontroller-23Cascade-5Fcontrol&d=DwICaQ&c=5VD0RTtNlTh3ycd41b3MUw&r=v9MU0Ki9pWnTXCWwjHPVgpnCR80vXkkcrIaqU7USl5g&m=gRrQtSejyIRsjuPS0GfqwX6bOmjSCOqs7BU5oina6oM&s=o56OqsqtJgiAeHSyp3Zd4yb8oFO8lzH-DIYsokTyc48&e=

Thanks for this.
    
    -Ed