That is, a control system adjusts the relationship between an input and an output, often by counteracting it completely—thus we would see the absence of a relationship that we would normally expect to see.
The words “input” and “output” are not right here. A controller has two signals coming into it and one coming out of it. What you above called the “output” is actually one of the input signals, the perception. This is fundamental to understanding control systems.
The two signals going into the controller are the reference and the perception. The reference is the value at which the control system is trying to bring the perception to. The signal coming out of the controller is the output, action or behaviour of the controller. The action is being emitted in order to bring the perception towards the reference. The controller is controlling the relationship between its two input signals, trying to make that relationship the identity. The italicised words are somewhere between definitions and descriptions. They are the usual words used to name these signals in PCT, but this usage is an instance of their everyday meanings.
In concrete terms, a thermostat’s perception is (some measure of) the actual temperature. Its reference signal is the setting of the desired temperature on a dial. Its output or behaviour is the signal it sends to turn the heat source on and off. In a well-functioning control system, one observes that as the reference changes, the perception tracks it very closely, while the output signal has zero correlation with both of them. The purpose of the behaviour is to control the perception—hence the title of William Powers’ book, “Behavior: The Control of Perception”. All of the behaviour of living organisms is undertaken for a purpose: to bring some perception close to some reference.
The words “input” and “output” are not right here.
Yeah, that paragraph was sloppy and the previous sentence didn’t add much, so I deleted it and reworded the sentence you quoted. I’m used to flipping my perspective around a system, and thus ‘output’ and ‘input’ are more like ‘left’ and ‘right’ to me than invariant relationships like ‘clockwise’ and ‘counterclockwise’—with the result that I’ll sometimes be looking at something from the opposite direction of someone else. “Left! No, house left!”
(In this particular case, the system output and the controller input are the same thing, and the system input is the disturbance that the controller counteracts, and I assumed you didn’t have access to the controller’s other input, the reference.)
The words “input” and “output” are not right here. A controller has two signals coming into it and one coming out of it. What you above called the “output” is actually one of the input signals, the perception. This is fundamental to understanding control systems.
The two signals going into the controller are the reference and the perception. The reference is the value at which the control system is trying to bring the perception to. The signal coming out of the controller is the output, action or behaviour of the controller. The action is being emitted in order to bring the perception towards the reference. The controller is controlling the relationship between its two input signals, trying to make that relationship the identity. The italicised words are somewhere between definitions and descriptions. They are the usual words used to name these signals in PCT, but this usage is an instance of their everyday meanings.
In concrete terms, a thermostat’s perception is (some measure of) the actual temperature. Its reference signal is the setting of the desired temperature on a dial. Its output or behaviour is the signal it sends to turn the heat source on and off. In a well-functioning control system, one observes that as the reference changes, the perception tracks it very closely, while the output signal has zero correlation with both of them. The purpose of the behaviour is to control the perception—hence the title of William Powers’ book, “Behavior: The Control of Perception”. All of the behaviour of living organisms is undertaken for a purpose: to bring some perception close to some reference.
Yeah, that paragraph was sloppy and the previous sentence didn’t add much, so I deleted it and reworded the sentence you quoted. I’m used to flipping my perspective around a system, and thus ‘output’ and ‘input’ are more like ‘left’ and ‘right’ to me than invariant relationships like ‘clockwise’ and ‘counterclockwise’—with the result that I’ll sometimes be looking at something from the opposite direction of someone else. “Left! No, house left!”
(In this particular case, the system output and the controller input are the same thing, and the system input is the disturbance that the controller counteracts, and I assumed you didn’t have access to the controller’s other input, the reference.)