# \[Attachment Removed\] Some Simple Questions **URL:** \ **Category:** CSG2016\ **Created:** [October 2, 2016, 12:32pm UTC](http://discourse.iapct.org/t/attachment-removed-some-simple-questions/12683 "2016-10-02T12:32:55Z")\ **Posts on this page:** 3\ **Page:** 1
**Author:** ![FredNickols](http://discourse.iapct.org/user_avatar/discourse.iapct.org/frednickols/32/2645_2.png) [@FredNickols](http://discourse.iapct.org/u/FredNickols)\ **Post date:** [October 2, 2016, 12:32pm UTC](http://discourse.iapct.org/t/attachment-removed-some-simple-questions/12683/1 "2016-10-02T12:32:55Z")
[From Fred Nickols (2016.10.02.0826 ET)] The diagram below is essentially the same one that appears on page 286 in B:CP (2nd Edition). The only changes I have made were to remove the annotations Bill used for linear analysis purposes. I have a few simple questions: ![image00187.png](http://discourse.iapct.org/uploads/default/original/1X/2ef896a450777946a9ac9e9ff65c90e32a426771.png) Is _qo_ the controlled quantity? Is _p_ the perceptual signal that corresponds to _qo_? In terms of my coffee cup example, is _qo_ the amount of coffee in the cup? In terms of my coffee cup example, is _p_ my perception of the amount of coffee in the cup? Regards, Fred Nickols, Knowledge Worker My Objective is to Help You Achieve Yours **[DISTANCE CONSULTING LLC](https://urldefense.proofpoint.com/v2/url?u=http-3A__www.nickols.us_&d=DQMFAg&c=8hUWFZcy2Z-Za5rBPlktOQ&r=-dJBNItYEMOLt6aj_KjGi2LMO_Q8QB-ZzxIZIF8DGyQ&m=t2iSxOD1jHpdv_I7TT7tZ5SSuIaD67T_VAithLY5UZE&s=b7euZMFwrRqi3LLnV40_pSkZb8hhWh64MV1pvcGGuzg&e=)** _“Assistance at a Distance”_SM [image0015.emz](http://discourse.iapct.org/uploads/short-url/2S3li1Fco0LuFPYjPLAwhzTkngV.emz) (7.1 KB) ---
**Author:** ![rsmarken](http://discourse.iapct.org/user_avatar/discourse.iapct.org/rsmarken/32/3553_2.png) [@rsmarken](http://discourse.iapct.org/u/rsmarken)\ **Post date:** [October 2, 2016, 4:12pm UTC](http://discourse.iapct.org/t/attachment-removed-some-simple-questions/12683/2 "2016-10-02T16:12:01Z")
[From Rick Marken (2016.10.02.0910)] ![image00187.png](http://discourse.iapct.org/uploads/default/original/1X/2ef896a450777946a9ac9e9ff65c90e32a426771.png) > **···** > > >  Fred Nickols (2016.10.02.0826 ET) > > >  > > > FN: The diagram below is essentially the same one that appears on page 286 in B:CP (2nd Edition). The only changes I have made were to remove the annotations Bill used for linear analysis purposes. I have a few simple questions: > > >  > > >  > > > Is _qo_ the controlled quantity? > > RM: No, qi is the controlled quantity. > >  > > > FN:  Is _p_ the perceptual signal that corresponds to _qo_? > > RM: No, p is the perceptual signal that corresponds to qi. > >  > > >  FN: In terms of my coffee cup example, is _qo_ the amount of coffee in the cup? > > RM: qo is the output variable.  qi corresponds to whatever variable aspect of the environment the system is controlling. It would correspond to the amount of coffee in the cup if this were the system controlling for the amount of coffee in the cup. > >  > > > FN:  In terms of my coffee cup example, is _p_ my perception of the amount of coffee in the cup? > >  RM: If that’s what this system is controlling then, yes. The perceptual signal in a control loop corresponds to whatever variable aspect of the environment the system is controlling. Think of it in terms of a thermostat. qi is the aspect of the environment that is sensed and controlled. So in the thermostat qi is a measure of molecular motion; this measure is converted into an electrical current, equivalent to the perceptual signal, p. So variations in p in a thermostat correspond to the rate of molecular motion at the thermostat’s sensor (the bimetallic coil). If instead of a thermostat the device is a humidity controller then qi is some measure of the ratio of molecular motion to vapor content of the air. And variations in p correspond to variations in this ratio. > > Best > > Rick > > >  > > >  > > > Regards, > > >  > > > Fred Nickols, Knowledge Worker > > > My Objective is to Help You Achieve Yours > > > **[DISTANCE CONSULTING LLC](https://urldefense.proofpoint.com/v2/url?u=http-3A__www.nickols.us_&d=DQMFAg&c=8hUWFZcy2Z-Za5rBPlktOQ&r=-dJBNItYEMOLt6aj_KjGi2LMO_Q8QB-ZzxIZIF8DGyQ&m=t2iSxOD1jHpdv_I7TT7tZ5SSuIaD67T_VAithLY5UZE&s=b7euZMFwrRqi3LLnV40_pSkZb8hhWh64MV1pvcGGuzg&e=)** > > > _“Assistance at a Distanceâ€?_SM > > >  > > – > Richard S. Marken > > “The childhood of the human race is far from over. We > have a long way to go before most people will understand that what they do for > others is just as important to their well-being as what they do for > themselves.” – William T. Powers ---
**Author:** ![FredNickols](http://discourse.iapct.org/user_avatar/discourse.iapct.org/frednickols/32/2645_2.png) [@FredNickols](http://discourse.iapct.org/u/FredNickols)\ **Post date:** [October 2, 2016, 5:01pm UTC](http://discourse.iapct.org/t/attachment-removed-some-simple-questions/12683/3 "2016-10-02T17:01:57Z")
[From Fred Nickols (2016.10.02.1259 ET)] Oops. My bad. I transposed _qo_ and \*qi. \* Sorry about that. That said, Rick, your answers do confirm what I thought was the case. Sorry again for the confusion. Fred Nickols ![image00187.png](http://discourse.iapct.org/uploads/default/original/1X/2ef896a450777946a9ac9e9ff65c90e32a426771.png) > **···** > > **From:** Richard Marken [[mailto:rsmarken@gmail.com](mailto:rsmarken@gmail.com)] > **Sent:** Sunday, October 02, 2016 12:12 PM > **To:** csgnet@lists.illinois.edu > **Subject:** Re: [Attachment Removed] Some Simple Questions > > [From Rick Marken (2016.10.02.0910)] > > > Fred Nickols (2016.10.02.0826 ET) > > > FN: The diagram below is essentially the same one that appears on page 286 in B:CP (2nd Edition). The only changes I have made were to remove the annotations Bill used for linear analysis purposes. I have a few simple questions: > > > ![]() > > > Is _qo_ the controlled quantity? > > RM: No, qi is the controlled quantity. > > > FN: Is _p_ the perceptual signal that corresponds to _qo_? > > RM: No, p is the perceptual signal that corresponds to qi. > > > FN: In terms of my coffee cup example, is _qo_ the amount of coffee in the cup? > > RM: qo is the output variable. qi corresponds to whatever variable aspect of the environment the system is controlling. It would correspond to the amount of coffee in the cup if this were the system controlling for the amount of coffee in the cup. > > > FN: In terms of my coffee cup example, is _p_ my perception of the amount of coffee in the cup? > > RM: If that’s what this system is controlling then, yes. The perceptual signal in a control loop corresponds to whatever variable aspect of the environment the system is controlling. Think of it in terms of a thermostat. qi is the aspect of the environment that is sensed and controlled. So in the thermostat qi is a measure of molecular motion; this measure is converted into an electrical current, equivalent to the perceptual signal, p. So variations in p in a thermostat correspond to the rate of molecular motion at the thermostat’s sensor (the bimetallic coil). If instead of a thermostat the device is a humidity controller then qi is some measure of the ratio of molecular motion to vapor content of the air. And variations in p correspond to variations in this ratio. > > Best > > Rick > > > Regards, > > > Fred Nickols, Knowledge Worker > > > My Objective is to Help You Achieve Yours > > > **[DISTANCE CONSULTING LLC](https://urldefense.proofpoint.com/v2/url?u=http-3A__www.nickols.us_&d=DQMFAg&c=8hUWFZcy2Z-Za5rBPlktOQ&r=-dJBNItYEMOLt6aj_KjGi2LMO_Q8QB-ZzxIZIF8DGyQ&m=t2iSxOD1jHpdv_I7TT7tZ5SSuIaD67T_VAithLY5UZE&s=b7euZMFwrRqi3LLnV40_pSkZb8hhWh64MV1pvcGGuzg&e=)** > > > _“Assistance at a Distanceâ€?_SM > > – > > Richard S. Marken > > “The childhood of the human race is far from over. We have a long way to go before most people will understand that what they do for others is just as important to their well-being as what they do for themselves.” – William T. Powers