On Sun, Sep 27, 2020 at 6:27 AM 周 远清 <zhouyuanqing8@outlook.com> wrote:
Hi everyone,

          For the parameters of the following table, does the PID code of openbmc have a clearer transfer function corresponding to this table? By adjusting the following parameters, fancontrol has taken effect. I set 5000 rpm, but the fan will change back and forth between 4500-5500. The change in this range is still relatively large. If there is a transfer function, the adjustment will be more accurate and faster.


https://github.com/openbmc/phosphor-pid-control/blob/master/configure.md
openbmc/phosphor-pid-control
OpenBMC PID-based Thermal Control Daemon. Contribute to openbmc/phosphor-pid-control development by creating an account on GitHub.
github.com

field type meaning
samplePeriod double How frequently the value is sampled. 0.1 for fans, 1.0 for temperatures.
proportionalCoeff double The proportional coefficient.
integralCoeff double The integral coefficient.
feedFwdOffsetCoeff double The feed forward offset coefficient.
feedFwdGainCoeff double The feed forward gain coefficient.
integralLimit_min double The integral minimum clamp value.
integralLimit_max double The integral maximum clamp value.
outLim_min double The output minimum clamp value.
outLim_max double The output maximum clamp value.
slewNeg double Negative slew value to dampen output.
slewPos double Positive slew value to accelerate output.

+Josh Lehan for input. 


发件人: 周 远清 <zhouyuanqing8@outlook.com>
发送时间: 2020年9月27日 11:17
收件人: openbmc <openbmc@lists.ozlabs.org>
抄送: uperic@163.com <uperic@163.com>
主题: about pid speed control
 
Hi everyone,

    I added the phophor-pid-control module to my project. After the PID module was started, the pwm value oscillated between 12 and 153. I deleted other configurations and only kept one fan and one temp. I have debugged various PID parameter values of fan, and there is no obvious change in the phenomenon. Please take a look at it, thank you.

   The configuration is as follows: 

   4611 root      7616 S    /usr/bin/swampd -t -l /tmp/

   root@starlake-sn:~# cat /etc/thermal.d/setpoint
   3000

   config.json as follow:
   {
    "sensors" : [
        {
            "name": "Fan0_Speed",
            "type": "fan",
            "readPath": "/xyz/openbmc_project/sensors/fan_tach/Fan0_Speed",  
            "writePath": "/xyz/openbmc_project/sensors/fan_tach/Fan0_Speed",  
            "min": 0,
            "max": 255,
            "timeout": 0
        },
        {
            "name": "inlet_Temp",
            "type": "temp",
            "readPath": "/xyz/openbmc_project/sensors/temperature/inlet_Temp",
            "writePath": "",
            "min": 0,
            "max": 0,
            "ignoreDbusMinMax": true,
            "timeout": 0
        }
    ],
  "zones" : [
        {
            "id": 1,
            "minThermalOutput": 3000.0,
            "failsafePercent": 75.0,
            "pids": [
                {
                    "name": "Fan0_Speed",
                    "type": "fan",
                    "inputs": ["Fan0_Speed"],
                    "setpoint": 50.0,
                    "pid": {
                        "samplePeriod": 0.1,
                        "proportionalCoeff": 20.0,
                        "integralCoeff": 0.1,    
                        "feedFwdOffsetCoeff": 0.0,
                        "feedFwdGainCoeff": 1.0,  
                        "integralLimit_min": 0.0,
                        "integralLimit_max": 5.0,
                        "outLim_min": 5.0,        
                        "outLim_max": 60.0,      
                        "slewNeg": 0.0,
                        "slewPos": 0.0
                    }
                },
                {
                    "name": "inlet_Temp",
                    "type": "temp",
                    "inputs": ["inlet_Temp"],    
                    "setpoint": 50.0,
                    "pid": {                      amplePeriod": 0.1,      
                        "samplePeriod": 1.0,      
                        "proportionalCoeff": -0.1,
                        "integralCoeff": 1.0,     36;34Hin": 5.0,
                        "feedFwdOffsetCoeff": 0.0,
                        "feedFwdGainCoeff": 0.0,  
                        "integralLimit_min": 0.0,
                        "integralLimit_max": 0.0,
                        "outLim_min": 3000.0,    
                        "outLim_max": 16000.0,    
                        "slewNeg": 0.0,
                        "slewPos": 0.0,
                        "positiveHysteresis": 1.0,
                        "negativeHysteresis": 1.0
                    }
           }
            ]
        }
    ]
}