Adjustable proportional response for balanceable system

Claim 2

In a balanceable system for controlling the position of an element to maintain an adjustable proportional relationship between the change in the position and the change in the magnitude of an input signal; the combination comprising, an amplifier for producing a control signal in response to an unbalance between its inputs, said input signal being applied as a first of the inputs of said amplifier, means responsive to said control signal for changing the position of said element in sense corresponding to the sense of said control signal, said change continuing until said control signal has been reduced substantially to zero, means responsive to the position of said element for producing a first feedback signal representative of, said position means responsive to said control signal for producing a second feedback signal representative of, a portion of the magnitude of said control signal an adjustable signal divider operable to sum said first and second feedback signals and to supply a total feedback signal responsive to an adjustable part of the sum of said first and second feedback signals as a second input to said amplifier so that an adjustment of said signal divider is effective to change said proportional relationship while maintaining unchanged the sensitivity of said balanceable system.

Claim 3

A balanceable system as set forth in claim 1 in which the portion of the magnitude of said control signal of which the second feedback signal is representative is adjustable to determine the effective gain of the amplifier.

Claim 4

A process controller for varying the state of a control element in response to the deviation between a controlled variable and its set point for controlling the manipulated variable so that the magnitude of the controlled variable is caused to change toward its set point comprising means for producing a first feedback signal indicative of the state of the control element, amplifying means for producing a control signal in response to the difference between the magnitude of an error signal established as the deviation between the magnitude of the controlled variable and its set point and the magnitude of a total feedback signal derived from said first feedback signal, means for changing the state of the control element in response to the control signal so as to cause resulting variations in the manipulated variable to change the controlled variable so as to change said error signal towards zero, means responsive to said first feedback signal for producing said total feedback signal, said means including a potentiometer providing an adjustable tap for setting the proportional response of the controller, said potentiometer being connected at one end to said first mentioned means so as to provide, between said variable tap and the other end of said potentiometer, a signal which is a predetermined proportion of said first feedback signal, a series connected capacitor and variable resistor connected to shunt that portion of said potentiometer producing said predetermined proportion of said first signal to provide a reset response to said controller, means for connecting a circuit point between said capacitor and said variable resistor to one input of said amplifying means as the total feedback signal with a polarity such that it tends to oppose the error signal so as to reduce the control signal toward zero as the state of the control element is varied in a direction tending to reduce the error signal toward zero, and an adjustable gain determining potentiometer for connecting a portion of the control signal to that end of the proportional response potentiometer connected to said first mentioned means so as to determine the proportional gain of the controller in a way which provides for a substantially constant sensitivity for said controller to variations of said error signal.

Claim 5

A process controller for varying the state of a control element in response to the deviation between a controlled variable and its set point for controlling the manipulated variable so that the magnitude of the controlled variable is caused to change toward its set point comprising means for producing a first feedback signal indicative of the state of the control element, amplifying means for producing a control signal in response to the difference between the magnitude of an error signal established as the deviation between the magnitude of the controlled variable and its set point and the magnitude of a total feedback signal derived from said first feedback signal, means for changing the state of the control element in response to the control signal so as to cause resulting variations in the manipulated variable to change the controlled variable so as to change said error signal towards zero, means responsive to said first feedback signal for producing said total feedback signal, said means including a potentiometer providing an adjustable tap for setting the proportional response of the controller, said potentiometer being connected at one end to said first mentioned means so as to provide, between said variable tap and the other end of said potentiometer, a signal which is a predetermined proportion of said first feedback signal, a series connected capacitor and variable resistor connected to shunt that portion of said potentiometer producing said predetermined proportion of said first signal to provide a reset response to said controller, means for connecting a circuit point between said capacitor and said variable resistor to one input of said amplifying means as the total feedback signal with a polarity such that it tends to oppose the error signal so as to reduce the control signal toward zero as the state of the control element is varied in a direction tending to reduce the error signal toward zero, and an adjustable gain determining potentiometer for connecting a portion of the control signal to that end of the proportional response potentiometer connected to said first mentioned means so as to determine the proportional gain of the controller in a way which provides for a substantially constant sensitivity for said controller to variations of said error signal.