US5481453A — Dual loop PID configuration

Claim 1

Independent Claim 190 words

A process controller for controlling a process in relation to a process variable signal representative of a variable of the process to be controlled and a setpoint signal representative of a desired value for said process variable, said controller comprising: (a) means for producing a difference signal representative of a difference between said process variable signal and said setpoint signal; (b) an inner loop comprising amplifying means for applying an adjustable gain to at least one of said difference and setpoint signals to thereby produce at least one corresponding amplified signal; (c) an outer loop comprising: means for integrating said difference signal to produce an integral signal; and amplifying means for applying an adjustable gain to said integral signal to produce an outer-loop output signal; and (d) means for combining i) said at least one amplified signal and ii) said outer-loop output signal into a process control signal applied to said process in view of controlling said process; wherein adjustment of said gain of the inner loop affects input/output characteristics of the controller and adjustment of said gain of the outer loop influences the sensitivity of said controller to perturbations.

Claim 2

Dependent Claim 190 words

A process controller for controlling a process in relation to a process variable signal representative of a variable of the process to be controlled and a setpoint signal representative of a desired value for said process variable, said controller comprising: (a) means for producing a difference signal representative of a difference between said process variable signal and said setpoint signal; (b) an inner loop comprising amplifying means for applying an adjustable gain to at least one of said difference and setpoint signals to thereby produce at least one corresponding amplified signal; (c) an outer loop comprising: means for integrating said difference signal to produce an integral signal; and amplifying means for applying an adjustable gain to said integral signal to produce an outer-loop output signal; and (d) means for combining i) said at least one amplified signal and ii) said outer-loop output signal into a process control signal applied to said process in view of controlling said process; wherein adjustment of said gain of the inner loop affects input/output characteristics of the controller and adjustment of said gain of the outer loop influences the sensitivity of said controller to perturbations.

Claim 3

Dependent Claim 54 words

A process controller as defined in claim 1, wherein said inner loop amplifying means comprise: first amplifying means for applying a first adjustable gain to said difference signal to produce an amplified difference signal; and second amplifying means for applying a second adjustable gain to said setpoint signal to produce an amplified setpoint signal.

Claim 4

Dependent Claim 67 words

A process controller as defined in claim 1, wherein said outer loop further comprises amplifying means for applying an adjustable gain to said process variable signal to produce an amplified process variable signal, and means for combining said amplified process variable signal and said integral signal into a combination signal applied to the amplifying means of the outer loop in view of producing the outer-loop output signal.

Claim 5

Independent Claim 180 words

A method for controlling a process in relation to a process variable signal representative of a variable of the process to be controlled and a setpoint signal representative of a desired value for said process variable, said method comprising the steps of: (a) producing a difference signal representative of a difference between said process variable signal and said setpoint signal; (b) in an inner loop, applying an adjustable gain to at least one of said difference and setpoint signals to thereby produce at least one corresponding amplified signal; (c) in an outer loop, integrating said difference signal to produce an integral signal; and applying an adjustable gain to said integral signal to produce an outer-loop output signal; and (d) combining i) said at least one amplified signal and ii) said outer-loop output signal into a process control signal applied to said process in view of controlling said process; wherein adjustment of said gain of the inner loop affects input/output characteristics of the controller and adjustment of the gain of the outer loop influences the sensitivity of said controller to perturbations.

Claim 6

Independent Claim 180 words

A method for controlling a process in relation to a process variable signal representative of a variable of the process to be controlled and a setpoint signal representative of a desired value for said process variable, said method comprising the steps of: (a) producing a difference signal representative of a difference between said process variable signal and said setpoint signal; (b) in an inner loop, applying an adjustable gain to at least one of said difference and setpoint signals to thereby produce at least one corresponding amplified signal; (c) in an outer loop, integrating said difference signal to produce an integral signal; and applying an adjustable gain to said integral signal to produce an outer-loop output signal; and (d) combining i) said at least one amplified signal and ii) said outer-loop output signal into a process control signal applied to said process in view of controlling said process; wherein adjustment of said gain of the inner loop affects input/output characteristics of the controller and adjustment of the gain of the outer loop influences the sensitivity of said controller to perturbations.

Claim 7

Dependent Claim 58 words

The method of claim 4, wherein the step of applying an adjustable gain to at least one of said difference and setpoint signals comprises the steps of: applying a first adjustable gain to said difference signal to produce an amplified difference signal; and applying a second adjustable gain to said setpoint signal to produce an amplified setpoint signal.

Claim 8

Dependent Claim 64 words

The method of claim 4, further comprising, in the outer loop, the step of applying an adjustable gain to said process variable signal to produce an amplified process variable signal, and combining said amplified process variable signal and said integral signal into a combination signal to which the adjustable gain of the outer loop is applied in view of producing the outer-loop output signal.

Claim 9

Dependent Claim 203 words

A proportional-integral-derivative controller for controlling a process in relation to a process variable signal representative of a variable of the process to be controlled, a derivative signal representative of the derivative of said process variable, and a setpoint signal representative of a desired value for said process variable, said proportional-integral-derivative controller comprising: (a) means for producing a difference signal representative of a difference between said process variable signal and said setpoint signal; (b) an inner loop comprising amplifying means for applying respective adjustable gains to at least two of said difference, derivative and setpoint signals to thereby produce at least two corresponding amplified signals; (c) an outer loop comprising: means for integrating said difference signal to produce an integral signal; and amplifying means for applying an adjustable gain to said integral signal to produce an outer-loop output signal; and (d) means for combining i) said at least two amplified signals and ii) said outer-loop output signal into a process control signal applied to said process in view of controlling said process; wherein adjustment of the gains of the inner loop affects input/output characteristics of the controller and adjustment of the gain of the outer loop influences the sensitivity of said controller to perturbations.

Claim 10

Dependent Claim 203 words

A proportional-integral-derivative controller for controlling a process in relation to a process variable signal representative of a variable of the process to be controlled, a derivative signal representative of the derivative of said process variable, and a setpoint signal representative of a desired value for said process variable, said proportional-integral-derivative controller comprising: (a) means for producing a difference signal representative of a difference between said process variable signal and said setpoint signal; (b) an inner loop comprising amplifying means for applying respective adjustable gains to at least two of said difference, derivative and setpoint signals to thereby produce at least two corresponding amplified signals; (c) an outer loop comprising: means for integrating said difference signal to produce an integral signal; and amplifying means for applying an adjustable gain to said integral signal to produce an outer-loop output signal; and (d) means for combining i) said at least two amplified signals and ii) said outer-loop output signal into a process control signal applied to said process in view of controlling said process; wherein adjustment of the gains of the inner loop affects input/output characteristics of the controller and adjustment of the gain of the outer loop influences the sensitivity of said controller to perturbations.

Claim 11

Dependent Claim 73 words

A proportional-integral-derivative controller as defined in claim 7, wherein said inner loop amplifying means comprise: first amplifying means for applying a first adjustable gain to said difference signal to produce an amplified difference signal; second amplifying means for applying a second adjustable gain to said derivative signal to produce an amplified derivative signal; and third amplifying means for applying a third adjustable gain to said setpoint signal to produce an amplified setpoint signal.

Claim 12

Dependent Claim 123 words

A proportional-integral-derivative controller as defined in claim 8, wherein the amplifying means of the outer loop is a fourth amplifying means for applying a fourth adjustable gain to said integral signal in view of producing the outer-loop output signal, and wherein said outer loop further comprises: fifth amplifying means for applying a fifth adjustable gain to said process variable signal to produce an amplified process variable signal; sixth amplifying means for applying a sixth adjustable gain to said derivative signal to produce a second amplified derivative signal; and means for combining said amplified process variable signal, said second amplified derivative signal and said integral signal into a combination signal applied to said fourth amplifying means in view of producing said outer-loop output signal.

Claim 13

Dependent Claim 103 words

A proportional-integral-derivative controller as defined in claim 9, wherein said process control signal is expressed as follows in Laplace transform notation: ##EQU20## where: U(s) is the Laplace transform of the control signal; K 1 is the first adjustable gain; K 2 is the second adjustable gain; K 3 is the third adjustable gain; K 4 is the fourth adjustable gain; α 1 is the fifth adjustable gain; α 2 is the sixth adjustable gain; P s (s) is the Laplace transform of the setpoint signal; P v (s) is the Laplace transform of the process variable signal; and s is the Laplace operator.

Claim 14

Dependent Claim 92 words

A proportional-integral-derivative controller as defined in claim 7, wherein said outer loop further comprises: first amplifying means for applying a first adjustable gain to said process variable signal to produce an amplified process variable signal; second amplifying means for applying a second adjustable gain to said derivative signal to produce an amplified derivative signal; and means for combining said amplified process variable signal, said amplified derivative signal and said integral signal into a combination signal applied to said amplifying means of the outer loop in view of producing said outer-loop output signal.

Claim 15

Dependent Claim 67 words

A proportional-integral-derivative controller as defined in claim 7, wherein said outer loop further comprises amplifying means for applying an adjustable gain to said process variable signal to produce an amplified process variable signal, and means for combining said amplified process variable signal and said integral signal into a combination signal applied to said amplifying means of the outer loop in view of producing said outer-loop output signal.

Claim 16

Dependent Claim 64 words

A proportional-integral-derivative controller as defined in claim 7, wherein said outer loop further comprises amplifying means for applying an adjustable gain to said derivative signal to produce an amplified derivative signal, and means for combining the amplified derivative signal and said integral signal into a combination signal applied to said amplifying means of the outer loop in view of producing said outer-loop output signal.

Claim 17

Dependent Claim 194 words

A proportional-integral-derivative method for controlling a process in relation to a process variable signal representative of a variable of the process to be controlled, a derivative signal representative of the derivative of said process variable, and a setpoint signal representative of a desired value for said process variable, said proportional-integral-derivative method comprising the steps of: (a) producing a difference signal representative of a difference between said process variable signal and said setpoint signal; (b) in an inner loop, applying respective adjustable gains to at least two of said difference, derivative and setpoint signals to thereby produce at least two corresponding amplified signals; (c) in an outer loop, integrating said difference signal to produce an integral signal; and applying an adjustable gain to said integral signal to produce an outer-loop output signal; and (d) combining i) said at least two amplified signals and ii) said outer-loop output signal into a process control signal applied to said process in view of controlling said process; wherein adjustment of the gains of the inner loop affects input/output characteristics of the controller and adjustment of the gain of the outer loop influences the sensitivity of said controller to perturbations.

Claim 18

Dependent Claim 194 words

A proportional-integral-derivative method for controlling a process in relation to a process variable signal representative of a variable of the process to be controlled, a derivative signal representative of the derivative of said process variable, and a setpoint signal representative of a desired value for said process variable, said proportional-integral-derivative method comprising the steps of: (a) producing a difference signal representative of a difference between said process variable signal and said setpoint signal; (b) in an inner loop, applying respective adjustable gains to at least two of said difference, derivative and setpoint signals to thereby produce at least two corresponding amplified signals; (c) in an outer loop, integrating said difference signal to produce an integral signal; and applying an adjustable gain to said integral signal to produce an outer-loop output signal; and (d) combining i) said at least two amplified signals and ii) said outer-loop output signal into a process control signal applied to said process in view of controlling said process; wherein adjustment of the gains of the inner loop affects input/output characteristics of the controller and adjustment of the gain of the outer loop influences the sensitivity of said controller to perturbations.

Claim 19

Dependent Claim 77 words

The proportional-integral-derivative method of claim 14, further comprising, in the outer loop, the steps of: applying a first adjustable gain to said process variable signal to produce an amplified process variable signal; applying a second adjustable gain to said derivative signal to produce an amplified derivative signal; and combining said amplified process variable signal, said amplified derivative signal and said integral signal into a combination signal to which the adjustable gain of the outer loop is applied.

Claim 20

Dependent Claim 57 words

The proportional-integral-derivative method of claim 14, further comprising, in the outer loop, the step of applying an adjustable gain to said process variable signal to produce an amplified process variable signal, and combining said amplified process variable signal and said integral signal into a combination signal to which said adjustable gain of the outer loop is applied.

Claim 21

Dependent Claim 54 words

The proportional-integral-derivative method of claim 14, further comprising, in the outer loop, the step of applying an adjustable gain to said derivative signal to produce an amplified derivative signal, and combining said amplified derivative signal and said integral signal into a combination signal to which the adjustable gain of the outer loop is applied.

Claim 22

Dependent Claim 75 words

The proportional-integral-derivative method of claim 14, wherein the step of applying respective adjustable gains to at least two of said difference, derivative and setpoint signals comprises the steps of: applying a first adjustable gain to said difference signal to produce an amplified difference signal; applying a second adjustable gain to said derivative signal to produce an amplified derivative signal; and applying a third adjustable gain to said setpoint signal to produce an amplified setpoint signal.

Claim 23

Dependent Claim 97 words

The proportional-integral-derivative method of claim 18, wherein the adjustable gain of the outer loop is a fourth adjustable gain, and wherein said outer loop further comprises the steps of: applying a fifth adjustable gain to said process variable signal to produce an amplified process variable signal; applying a sixth adjustable gain to said derivative signal to produce a second amplified derivative signal; and combining said amplified process variable signal, said second amplified derivative signal and said integral signal into a combination signal to which said fourth gain is applied in view of producing said outer-loop output signal.

Claim 24

Dependent Claim 100 words

The proportional-integral-derivative method of claim 19, wherein said control signal is expressed as follows in Laplace transform notation: ##EQU21## where: U(s) is the Laplace transform of the control signal; K 1 is the first adjustable gain; K 2 is the second adjustable gain; K 3 is the third adjustable gain; K 4 is the fourth adjustable gain; α 1 is the fifth adjustable gain; α 2 is the sixth adjustable gain; P s (s) is the Laplace transform of the setpoint signal; P v (s) is the Laplace transform of the process variable signal; and s is the Laplace operator.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1999-01-01	1999-07-03	2000-01-02	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	2003-01-01	2003-07-03	2004-01-02	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	2007-01-01	2007-07-03	2008-01-02	$7700.00	Window Closed / Lapsed

Dual loop PID configuration

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