Abstract: A beam splitter for transmitting and deflecting light comprises a foil having a top surface and at least one hole therethrough. A highly reflective finish is provided on the top surface of the foil. Light is transmitted through the holes in the foil while other light is reflected from the reflective finish on the top surface.

Abstract: A process control operator workstation ergonomically designed to provide a plurality of consoles integrally mountable in a substantially semi-circular configuration wherein the individual operator console provides a variable height keyboard countertop, a video display monitor that is adjustable vertically horizontally and rotationally as well as being tiltable, and an integral rotatable side-panel or monitor wing station mounted to the video display monitor for containing various control modules within easy reach of the operator while viewing the monitor to thus provide a comfortable workstation adaptable to operators in the range of 5% female to 95% male as defined in the anthropometric tables of THE HUMAN FACTORS SOCIETY INC.

Abstract: A sigma-delta technique is used to generate a digital representation of the incoming analog signal amplitude. The integration stage of the converter holds an analog error term relative to the ratio of an incoming analog input signal to a reference voltage. The incoming analog signal is disconnected at the end of the conversion. The error term is monitored through a comparator as charge packets are applied to the input of the integration stage. The number of charge packets needed to have the error term cross zero provides information which can be used to extend the resolution of the analog to digital converter.

Abstract: A peak amplitude detector for use in a synchronized position demodulator associated with a linear variable differential transformer. The peak amplitude detector adjusts for phase shift in the transformer and maintains the full bandwidth of the transformer. The detector obtains the maximum positive or negative amplitude of the sinusoidal signal at one of the secondary windings of the transformer by first counting either a positive or negative half cycle of the signal and then while down counting one half of the counted half cycle sampling the amplitude of the sinusoidal signal. The sampling ends when the count reaches zero.

Abstract: A method for compensating for the differences in temperature across a cell used to sense pressure. A microprocessor calculates a dynamic temperature factor signal by multiplying a signal representative of temperature change across the cell by a coefficient based on measurements made of the effect of temperature change on the cell. The dynamic temperature factor signal is then subtracted from the signal representative of the differential pressure sensed by the cell to thereby provide the dynamic temperature compensation.

Abstract: A method for filtering digital signals in a pressure transmitter. The transmitter includes a microprocessor. In each operating cycle of the microprocessor included in the transmitter, the method determines if there are any noise spikes in the signal at the input to the microprocessor representative of pressure and provides rejection for such spikes. The method also provides for a faster response to a step change in pressure than is provided by conventional filtering methods and also dampens small fluctuations in the filtered output signal.

Abstract: An electrochemical sensor wherein the salt bridge is a unitary plug of semipermeable material which is saturated with an electrolyte. The plug has a spiral cut from its outer surface to the central bore of the plug. The spiral has at least one complete turn and starts at or near one end of the plug and stops at or near the other end of the plug. A layer of impermeable material is deposited in the plug to thereby form an ion impermeable spiral barrier.