Proportional motor circuit

In a control system, a control circuit responsive to an input signal indicative of a condition being monitored for providing first and second control outputs indicating an increase or a decrease, respectively, in said input signal, said control circuit comprising sensing means responsive to said input signal to provide an error signal which varies in amplitude and polarity in accordance with changes in the condition being monitored, first differential detecting means having a first input connected to an output of said sensing means to receive said error signal, and a second input connected to an output of a first reference source means to receive a first reference signal, said first differential detecting means being responsive to said error signal and said first reference signal to provide a first output signal at an output thereof, second differential detecting means having a first input connected to said output of said first differential detecting means to receive said first output signal, and a second input connected to an output of a second reference source means to receive a second reference signal, said second differential detecting means being responsive to said first output signal and said second reference signal to provide a second output signal at an output thereof, load means connected between said outputs of said first and second detecting means to permit one of said detecting means to source current to said load means and the other of said detecting means to sink current from said load means in response to an increase in said error signal, and to permit said other detecting means to source current to said load means and said one detecting means to sink current from said load means in response to a decrease in said error signal, first switching means enabled in response to the output signals provided by said first and second detecting means in response to a predetermined increase in said error signal to provide said first control output, and second switching means enabled in response to the output signals provided by said first and second detecting means in response to a predetermined decrease in said error signal to provide said second control output.

In a control system, a control circuit responsive to an input signal indicative of a condition being monitored, for providing first and second control outputs indicating an increase or a decrease, respectively, in said input signal, said control circuit comprising sensing means responsive to said input signal to provide an error signal at an output thereof which varies in amplitude and polarity in accordance with changes in the condition being monitored, differential detecting means including first and second differential amplifier means, load means connected between respective first and second outputs of said first and second differential amplifier means, said first differential amplifier means being responsive to an increase in said error signal to provide current flow from said first output over said load means and said second differential amplifier means, said second differential amplifier means being responsive to a decrease in said error signal to provide current flow from said second output over said load means and said first differential amplifier means, and output means including first and second switching means controlled by said differential detecting means to provide said first and second control outputs in accordance with the direction of current flow over said load means, said first switching means being enabled to provide said first control output in response to current flow over said load means in one direction, and said second switching means being enabled to provide said second control output in response to current flow over said load means in the opposite direction.

In a control system including a motor having a shaft connected to apparatus of the system for controlling said apparatus to maintain a system parameter at a set point value, a sensing device for monitoring the parameter, and a motor control circuit responsive to the sensing device to supply bi-directional drive signals to the motor in response to changes in the value of the parameter relative to a set-point value as sensed by the sensing device, said motor control circuit comprising sensing means controlled by said sensing device to provide an error signal which varies in accordance with changes in said parameter, first differential detecting means responsive to said error signal and a first reference signal to provide a first control output, second differential detecting means responsive to said first control output and a second reference signal to provide a second control output, and output means including first switching means coupled to and controlled by at least one of said differential detecting means for applying an energizing signal of one polarity to said motor whenever the difference between said first and second control outputs indicates a predetermined increase in the error signal relative to said first reference signal, and second switching means coupled to and controlled by at least the other one of said differential detecting means for applying an energizing signal of the opposite polarity to said motor whenever the difference between said first and second control outputs indicates a predetermined decrease in the error signal relative to said first reference signal.

In a control system including a motor having a shaft connected to apparatus of the system for controlling said apparatus to maintain a system parameter at a set point value, a sensing device for monitoring the parameter, and a motor control circuit responsive to the sensing device to supply drive signals to the motor in response to changes in the value of the parameter relative to a setpoint value as sensed by the sensing device, said motor control circuit comprising sensing means controlled by said sensing device to provide an error signal which varies from a reference value in accordance with changes in said parameter, differential detecting means including first and second differential amplifier means, said first differential amplifier means having a first input connected to an output of said sensing means to receive said error signal, and a second input connected to an output of a first reference source means to receive a first reference signal, said first differential amplifier means providing a first output signal at an output thereof which varies with changes in said error signal, and said second differential amplifier means having a first input connected to said output of said first differential amplifier means to receive said first output signal, and a second input connected to a second reference source means to receive a second reference signal, said second differential amplifier means providing a second output signal at an output thereof which varies with changes in said first output signal, and thus said error signal, load means interconnecting said output of said first differential amplifier means and said output of said second differential amplifier means, the output signals provided by said differential amplifier means in response to an increase in said error signal causing current to flow over said load means in one direction, and the output signals provided by said differential amplifier means in response to a decrease in said error signal causing current to flow over said load means in the opposite direction, and output means including first and second drive means controlled by said first and second differential amplifier means for energizing said motor to drive said motor shaft in respective first and second directions as a function of the direction of current flow over said load means.