US 5,153,493 A · Non-bridge type electronic actuator control

Abstract

A quick-calibrate control module for use in a heating and cooling system is provided which responds to setpoint signals from a control potentiometer to drive a remote actuator to corresponding positions. The control module comprises a motor coupled to the actuator and a feedback potentiometer coupled to the motor for producing a feedback signal relating to the actuator position. Operational amplifiers combine the setpoint signal and the feedback signal to produce an error signal, and a comparator responds to the error signal and drives the motor to minimize the error signal. A reference supply is connected to the control potentiometer, the reference supply having a zero setting potentiometer which calibrates the closed position of the actuator to a corresponding zero setting of the control potentiometer. A stroke adjustment potentiometer scales the feedback signal to calibrate a desired open position of the actuator with a corresponding setting of the control potentiometer. The amplifiers also prevent cross-loading of the reference supply and the stroke adjustment potentiometer, so that stroke adjustments can be made without altering the zero setting of the actuator.

Claims17

Dependent claims

In a heating and cooling system having a control potentiometer disposed for manipulation by a user to control the position of a remote actuator in the system between open and closed positions, a quick-calibrate control module for responding to setpoint signals from the control potentiometer to drive the actuator to corresponding positions, the control module comprising, in combination:

a motor coupled to the actuator and a feedback potentiometer coupled to the motor for producing a feedback signal relating to the actuator position;
summing means for combining the setpoint signal and the feedback signal to produce an error signal;
means responsive to the error signal for driving the motor to minimize the error signal;
a reference supply connected to the control potentiometer, the reference supply including zero setting means for adjusting the setpoint signal to produce an error signal which calibrates the closed position of the actuator to a corresponding setting of the control potentiometer;
scaling means for scaling the feedback signal to produce an error signal which calibrates a desired open position of the actuator with a corresponding setting of the control potentiometer;
and
means for establishing a common reference related to the setpoint signal to prevent cross loading between the reference supply and the scaling means, so that the scaling means can be adjusted without altering the zero setting of the actuator.

4 more elements

A replacement control module for a heating and cooling system having a control potentiometer for establishing a setpoint signal, the control potentiometer being of the type having at least two terminals connectable in a bridge circuit adapted to be balanced to control the position of an actuator, the replacement control module controlling the position of an actuator between closed and open positions in response to settings of the control potentiometer, the replacement control module comprising, in combination:

a pair of constant current sources connected to the respective terminals of the control potentiometer to produce a differential first and second signal having levels dependent on the setting of the control potentiometer, and zero setting means associated with the constant current sources for calibrating the closed position of the actuator to a corresponding setting of the control potentiometer;
means for establishing a common reference related to the level of the first signal;
a feedback circuit being connected to the common reference for receiving a feedback signal and producing a referenced feedback signal;
summing means connected to the common reference for combining the referenced feedback signal and the first and second signals to produce an error signal;
a motor coupled to a feedback potentiometer for producing the feedback signal which corresponds to the actuator position, the motor being coupled to the actuator and responsive to the error signal for positioning the actuator in response to settings of the control potentiometer;
and
scaling means for scaling the referenced feedback signal to produce an error signal which calibrates a desired open position of the actuator with a corresponding setting of the control potentiometer.

4 more elements

Dependencies are inferred from the claim text.

Non-bridge type electronic actuator control

Life of this patent

Non-bridge type electronic actuator control

Life of this patent

Abstract

Claims17