Abstract: A structure for supporting a loop-gap resonator includes a cylindrical housing which defines a space into which microwave energy is injected. The resonator is mounted to a support element which is inserted into the space through an opening at one end of the housing. The support element and attached resonator form an interchangeable module.

Abstract: A microwave resonator is formed by a cylindrical conductive loop and one or more gaps which extend along its length. The loop forms an inductive element and the gaps form capacitive elements which determine the resonant frequency. The loop is surrounded by a conductive shield which improves the quality factor (Q) of the resonator and high frequency radio signals are coupled to the resonator by an inductive loop positioned at one of its ends.

Abstract: A numerical control system executes part programs which contain parameters and arithmetic expressions containing parameters. A parameter table containing parameter values is employed to evaluate parameters and arithmetic expressions during the execution of a part program, and means is provided which enables parameter values to be changed by part program instructions or manual data entry. Macroprograms, such as canned cycles, are stored in the numerical control system in a generalized form in which their instructions contain parameters and arithmetic expressions in lieu of constants. Prior to calling such a macroprogram, the part program assigns suitable values to the parameters employed in the macroprogram.

Abstract: A programmable controller is formed by connecting separate functional modules to a common backplane bus. A bus arbitration scheme and a message handling technique are disclosed to tightly couple the functional modules together to form an efficient programmable controller. A number of improvements to the CPU module and I/O scanner module are disclosed to further improve the performance of the resulting system.

Abstract: A plurality of remote stations are sequentially addressed by a master controller to ascertain the status of associated sensing devices. The addresses are each comprised of a sequence of sinusoidal waveforms which are counted by the remote stations and compared with a preselected station number. Each addressed station responds by driving a communication line to a low voltage level for a time interval determined by the status of its associated sensing device.

Abstract: A microwave resonator is formed by a cylindrical loop and one or more gaps which extend along its length. The loop is formed from a machineable insulating material and a layer of electrically conductive material is deposited over its surfaces.

Abstract: A U-shaped heater unit is surrounded by a U-shaped bimetal, the legs of which move in response to temperature variations. The motion of the bimetal is conveyed through a wall by a slidable pin which acts to rotate an L-shaped compensator element. This rotation lifts a link element which operates a switch when the trip point is reached. A reset mechanism includes a plunger which when manually depressed rotates a reset arm first in one direction to reset the switch after it has been tripped and then in the opposite direction to a neutral station in which it will not reset the switch. The reset mechanism thus cannot be defeated by jamming the plunger in its fully depressed position.