Coarse-fine digital servo indicator with continuous rotation potentiometer feedback in fine mode

Claim 2

Linear control apparatus for positioning a controlled element in accordance with a single input signal, said apparatus including a servo loop having a motor, a controlled element positioned by said motor, a single summing point to receive said input signal, feedback means movable with the controlled element to supply to said summing point a feedback signal correlated in predetermined relation to the input signal in accordance with the position of the controlled element, and an amplifier connected to said summing point and responsive to said input signal and said feedback signal to produce an output signal which controls the response of the motor, the improvement wherein said feedback means comprises; first and second signal dividing means each having an electrical path comprised of a continuous portion and a discontinuous portion and movable in ganged relation with said controlled element so that when either signal dividing means is at its continuous portion; a switching circuit connected to said first and second signal dividing means for selectively switching only one or only the other of said signal dividing means into said servo loop; and switching logic means automatically responsive to the input signal to actuate the switching circuit at an operating point at which each of said signal dividing means is at its continuous portion, said switching logic means simultaneously switching to another operating point at which each of said signal dividing means is at its continuous portion, the lastnamed operating point being spaced from the first-named operating point to prevent transients due to fluctuations of the input signal.

Claim 3

Apparatus as in claim 1 wherein said switching logic means to control the switching circuit also operates to simultaneously switch the input signal to a corrected input signal with a value correlated with the value of the active feedback signal.

Claim 4

Apparatus as in claim 1 wherein said signal dividing means are voltage dividers.

Claim 5

Apparatus as in claim 3 wherein said voltage dividers are connected across a common source.

Claim 6

Apparatus as in claim 3 wherein said voltage dividers are each connected to their own source.

Claim 7

Apparatus as in claim 3 wherein said voltage dividers have a cyclical electrical path

Claim 8

Linear control apparatus for positioning a controlled element in accordance with a single linear input signal, said apparatus including a servo loop having a motor, a controlled element positioned by said motor, a single summing point to receive said input signal, feedback means movable with the controlled element to said summing point a feedback signal correlated in predetermined relation to the input signal in accordance with the position of the controlled element, and an amplifier responsive to said input signal and said feedback signal to produce an output signal which controls the response of the motor, the improvement wherein said feedback means comprises: first and second potentiometers each having a cyclical electrical path comprised of a continuous portion and a discontinuous portion, said potentiometers connected in parallel across a common source and movable in ganged relation with said controlled element so that one potentiometer is in its continuous portion, when the other is in its discontinuous portion; a switching circuit connected to said first and second potentiometers for selectively switching only one or only the other of said potentiometers into said servo loop; and switching logic means automatically responsive to the input signal to actuate the switching circuit at an operating point at which each of said potentiometers is at its continuous portion, said switching logic means simultaneously switching to another operating point at which each of said potentiometers is at its continuous portion, the last-named operating point being spaced from the first-named operating point to prevent transients due to fluctutations of the input signal.

Claim 9

Linear control apparatus for positioning a controlled element in accordance with a single linear input signal, said apparatus including a servo loop having a motor, a controlled element positioned by said motor, a single summing point to receive said input signal, feedback means movable with the controlled element to said summing point a feedback signal correlated in predetermined relation to the input signal in accordance with the position of the controlled element, and an amplifier responsive to said input signal and said feedback signal to produce an output signal which controls the response of the motor, the improvement wherein said feedback means comprises: first and second potentiometers each having a cyclical electrical path comprised of a continuous portion and a discontinuous portion, said potentiometers connected in parallel across a common source and movable in ganged relation with said controlled element so that one potentiometer is in its continuous portion, when the other is in its discontinuous portion; a switching circuit connected to said first and second potentiometers for selectively switching only one or only the other of said potentiometers into said servo loop; and switching logic means automatically responsive to the input signal to actuate the switching circuit at an operating point at which each of said potentiometers is at its continuous portion, said switching logic means simultaneously switching to another operating point at which each of said potentiometers is at its continuous portion, the last-named operating point being spaced from the first-named operating point to prevent transients due to fluctutations of the input signal.

Claim 10

Control apparatus for positioning a controlled element in accordance with a linear input signal said apparatus including: two storage units one of which stores a pre-selected high order portion of the input data, while the other stores the resulting cyclically repeating low order portion of the input data; a first feedback loop responsive to the high order input data signal and the first feedback signal to produce a first difference signal; a second feedback loop responsive to the low order portion of the input data and including a second feedback control means for producing a second feedback signal; a second summing point responsive to the low order input data signal and the second feedback signal to produce a second difference signal; said second summing point comprising the sole summing point of said second loop, a controlled element included in said second loop; a motor drivingly connected to said element; switching means responsive to the difference signals developed by said first and second summing points to selectively apply one of said last-named signals to control the motor; said second feedback control has first and second signal dividing means each having a cyclical electrical path comprised of a continuous portion and a discontinuous portion and movable in ganged with said controlled element so that when either signal dividing means is at its discontinuous portion the other signal dividing means is at its continuous portion; a switching circuit connected to said first and second signal dividing means for selectively switching only one or only the other of said signal dividing means into said second feedback loop; and switching logic means automatically responsive to the low order portion input data to actuate the switching circuit at an operating point at which each of said signal dividing means is at its continuous portion and to simultaneously cause a corrected input signal to be generated with a value correlated with the value of the active feedback signal, said switching logic means simultaneously switching to another operating point at which each of said signal dividing means is at its continuous portion, the last-named operating point being spaced from the first-named operating point to prevent transients due to fluctuations of the low order portion input data.

Claim 11

Control apparatus for positioning a controlled element in accordance with a linear input signal said apparatus including: two storage units one of which stores a pre-selected high order portion of the input data, while the other stores the resulting cyclically repeating low order portion of the input data; a first feedback loop responsive to the high order input data signal and the first feedback signal to produce a first difference signal; a second feedback loop responsive to the low order portion of the input data and including a second feedback control means for producing a second feedback signal; a second summing point responsive to the low order input data signal and the second feedback signal to produce a second difference signal; said second summing point comprising the sole summing point of said second loop, a controlled element included in said second loop; a motor drivingly connected to said element; switching means responsive to the difference signals developed by said first and second summing points to selectively apply one of said last-named signals to control the motor; said second feedback control has first and second signal dividing means each having a cyclical electrical path comprised of a continuous portion and a discontinuous portion and movable in ganged with said controlled element so that when either signal dividing means is at its discontinuous portion the other signal dividing means is at its continuous portion; a switching circuit connected to said first and second signal dividing means for selectively switching only one or only the other of said signal dividing means into said second feedback loop; and switching logic means automatically responsive to the low order portion input data to actuate the switching circuit at an operating point at which each of said signal dividing means is at its continuous portion and to simultaneously cause a corrected input signal to be generated with a value correlated with the value of the active feedback signal, said switching logic means simultaneously switching to another operating point at which each of said signal dividing means is at its continuous portion, the last-named operating point being spaced from the first-named operating point to prevent transients due to fluctuations of the low order portion input data.

Claim 12

Apparatus as in claim 8 wherein said signal dividers are potentiometers.