Barber Colman Company

Eugene R Jornod

Lary L Field

Gerald R Parsons

James G Mueller

Fred Fauerbach

Steven D Siden

Matthew S Solar

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.

Non-bridge type electronic actuator control

The piston of a reciprocating hydraulic actuator carries a pump which is driven by an electric motor and which supplies oil from the low pressure chamber of a cylinder to the high pressure chamber thereof in order to advance the piston. An exhaust valve in the piston is normally held in a closed position by magnetic force created by energizing a coil and, when closed, enables pressurization of the high pressure chamber of the cylinder. When a second coil is energized, the magnetic field of the first coil is negated and the valve is opened by a spring to permit oil to exhaust from the high pressure chamber to the low pressure chamber and permit a second spring to retract the piston. If both the pump motor and the second coil are de-energized, the first coil keeps the valve closed and causes the piston to remain in a commanded position. The actuator may be controlled by a floating single pole, double throw switch and its piston is automatically shifted to its fully retracted position by the second spring if electrical power to the actuator is lost.

Floating fluid-operated actuator

Methods and apparatus by which a transducer is employed to create a digital signal representing numerically the value of a changeable physical parameter. The signal from the transducer is subject to large and unpredictable amounts of offset due to either or both (i) manufacturing tolerance departures from the desired target of creating a zero output signal value when the sensed parameter is zero and (ii) changes in offset due to changes in one or more physical conditions (other than the sensed parameter) to which the transducer and its associated electrical components are subjected. A bistate device is associated with the transducer and controlled so as (a) to first apply substitutionally to the transducer a known, and preferably zero, value of the parameter--with the output signal value being stored so as to represent the then-existing offset, and then (b) to apply the changeable physical parameter to the transducer. The stored value of the transducer output signal is, in effect, subtracted from the output signal obtained in the second instance, to produce an accurate final signal numerically representing the existing actual value of the sensed parameter. A programmed microcomputer is preferably employed to carry out the necessary steps in the sequence, and apparatus of that character is described.

Method and apparatus for automatic offset compensation in

A lockout control system locks out the lag load upon occurrence of a predetermined condition in a dual load system set up in a lead-lag configuration. The lockout control system utilizes a lead-lag memory circuit for insuring that only the lag load is locked out when the lockout condition exists irrespective of which load is lead and which load is lag.

Lead-lag load lockout control

Fanfold paper is progressively withdrawn from the bottom of a container, fed past a printing mechanism, transported upwardly and deposited in fanfold configuration at the top of the container.

Fanfold paper transport

A thermal printhead has heating elements arranged for multiplexing so as to limit the number of leads required to selectively energize the heating elements. Current diverting resistors are utilized to act as a shunt path to divert current from certain of the heating elements to prevent unwanted shadows from being produced on the thermal sensitive paper.

Growing community of inventors

Caledonia, IL, United States of America

Eugene R Jornod