Re: pid control configuration

[Vijay Khemka <vijaykhemka@fb.com>]

On 5/13/19, 10:32 AM, "Ed Tanous" <ed.tanous@intel.com> wrote:

    On 5/13/19 9:32 AM, Patrick Venture wrote:
    > On Fri, May 10, 2019 at 2:21 PM Vijay Khemka <vijaykhemka@fb.com> wrote:
    >>
    >>
    >>
    >> On 5/6/19, 9:20 AM, "Ed Tanous" <ed.tanous@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.
    >>
    >> Ed, we are not using cascade control here in facebook. We only use outer loop which gives data for fan to drive.
    >> Is it possible to still run Phosphor pid controller with single loop?
    > 
    > Your cascade PID could be a pass-through -- so that it receives the
    > set-point from the sensor PID and then just sets it directly within
    > that loop..  It may require a new PID controller that is just a
    > pass-through to explicitly exist -- i haven't dove into
    > phosphor-pid-control in a while, but you probably need to write a
    > basically empty PID controller object type.
    > 
    
    +1  That is an option for you.
Ed, please see if following declaration in entity manager would work as I am not defining any pid values here.
        {
            "Class": "fan",
            "Inputs": [
                "MB_FAN0_TACH"
            ],
            "Name": "MB_FAN0_TACH",
            "Outputs": [
                "Pwm 1"
            ],
            "Type": "Pid",
            "Zones": [
                "Pid 1"
            ]
        },
    
    >>
    >> Regards
    >> -Vijay
    >>