Abstract: A thermostat with a single control to establish the quantity of set back during heating and set up during cooling.

Abstract: A time proportional control means, shown as a temperature control system, utilizes an expanded time constant arrangement with a unidirectional type of digital counter. The control system also utilizes a pulse generating means that is linked to the set point control for the system. Any substantial change of the set point causes the pulse generating means to generate pulses that are used by a pulse responsive circuit to insure that the counter for the system is adjusted to cause the output of the system to correspond with the new set point position.

Abstract: A condition responsive time proportional control means which has a relatively fast time constant when operating in its proportional band has the time constant expanded by means of a digital counter. The counter is repetitively switched by the condition responsive means and counts the switched operation. During the period that the switched operation is occurring, the time constant is expanded by simultaneously counting pulses from a pulse generating means.

Abstract: A multi-stage condition control system of the time proportional type is shown. The control system utilizes a counting means as part of the anticipation for system control. The counting means counts during the time the control system is within its proportional band. When the control system moves outside of the proportional band, the counting stops. A count detection circuit senses the absence of counts thereby indicating that the system is outside of the proportional band. The absence of counts is then used to increase or decrease multiple stages of condition control equipment to bring the system back within the proportional band.

Abstract: A proportional temperature control system using a linear time delay circuit provides an output voltage that is similar to the output voltage of a thermostat but delayed in time. The delay circuit is a linear rate time delay system that compares a called for voltage shift at its input to the output voltage of an integrator circuit to provide a substantially linear rate of time delay. The comparator circuit and the integrator circuit are separated by a limiter so that regardless of the amount of the initial offset in voltage at the comparator, the rate of integration is always maintained the same.

Abstract: Circuitry associated with a self-contained abnormal condition sensing and alarm annunciating unit for supervising or monitoring leads interconnecting a plurality of such units and for responding to an open circuit condition of such leads so as to actuate an annunciator in a distinctive fashion to signal the open circuit condition.