Abb Inc.

Ssac, Inc.

Entrelec-ssac, Inc.

Kenneth C Volz

Robert C Morris, Jr

Jerome R Mullaly

Dan S Carroll

Donald D Martell

Robert A Southworth

Richard W Shutt

In the present invention, several timer functions (e.g. delay on make, delay on break, recycle, single shot, etc.) are expressed in terms of a series of timer subfunctions, and code segments are developed for each identified subfunction. A program of a timer is established to include a plurality of subfunction code segments and a subfunction ordering table for determining the ordering of execution for the subfunction code segments. The ordering of subfunctions of the subfunction ordering table may be selectable in accordance with a model number input received at a program builder system adapted for use in programming the programmable timer. In one embodiment, the programming method provides for reprogramming of a timer including a control circuit having a one-time programmable processor.

Method for programming timer to execute timing operations

A safety circuit according to the invention controls operation of an equipment load. A manual control switch of the safety circuit is connected in series with the equipment load for controlling the flow of electrical current to the equipment load. The equipment load and control switch series combination are further in communication with a relay contact switch of the safety circuit, which, like the manual control switch controls the flow of electrical current to the equipment load. Arranged in this configuration the equipment load operates only if both the mechanical switch and relay contact are closed. If either the manual control switch or the relay contact are open, the equipment load does not operate.

Equipment load safety circuit

The invention is an improved timer circuit for operating a heating or air conditioning unit which utilizes a single time delay generating circuit for delaying operation of both a compressor and a unit fan under certain operating conditions. A logic circuit for operating a fan relay is made responsive to the thermostat output and a time delay generating circuit output so that the fan relay is de-energized only in the case that the compressor has been turned off for at least the duration of a time delay generator timing period, and is in a state commensurate with a satisfactory building temperature. When the timer circuit is used in large-scale heating or air conditioning systems, the timing period of each timing circuit can be adjusted to a different duration so that a voltage lag problem on start up is avoided.

Timer circuit for heating or air conditioner unit

Growing community of inventors

West Monroe, NY, United States of America

Kenneth C Volz