Abstract: A bargraph with a single set of light emitting diode (LED) segments creates a display showing a parameter level by the number of segments illuminated and a separate condition by the color of all illuminated segments. For example, an input parameter in a normal data range results in all segments below and at the data level being illuminated in a first color. Satisfaction of a first set point condition by that or another input results in all segments below and at the data level being illuminated, but all illuminated in a second color; and satisfaction of a second set point condition results in all segments below and at the data level being illuminated, but all illuminated in a third color. All of the segments below the data level change color with passage of the set point. The bargraph combines present data value, alarm set points, and indication of set point exceedance in a single bargraph through use of multi-color activated segments.

Abstract: A proximity detection system having two eddy current probes, one a measurement and the other a reference probe. In one embodiment, one probe is energized by a high frequency AC signal and the other by a DC signal. The energizing signals are periodically switched between the two probes and the difference between responses of the probes when AC energized is detected. The difference eliminates drift and variations in the probe outputs from environmental effects like temperature, one of the probes measures the proximity of a selected material, and the other probe is set-up with a target of the same material at a constant distance, as a reference. The DC constant current signal which alternately energizes each probe when not energized by the AC signal, prevents each probe from being dead when not energized by the AC signal. The probes are operated in a resonant mode to increase both the system linearity and sensitivity to target position.

Abstract: An extent of travel detection system particularly adapted for measuring piston bottom excursion in an internal combustion engine. Two eddy-current position transducer probes are provided for each piston, the first being positioned to sense piston bottom travel position and the second being operated as a reference probe, mounted in close proximity to the first probe. The first probe of each pair is only operated to measure piston travel within the cylinder during the brief moment that the piston is near its bottom. The actual point of the bottom travel is detected, using the reference probe to compensate for environment effects such as temperature. The measured bottom point for each piston is displayed either by a separate or shared display. Changes in the displays over time indicate engine wear or impending failure. The measured bottom points are typically averaged over a selected number of engine cycles.

Abstract: A remote reading crankshaft alignment tool utilizes a differential transformer and live centers to measure the deflection of crankshaft webs as a function of crankshaft angle. The tool is positioned between adjacent webs to measure the difference in spacing between preset points on the crankshaft webs as the crankshaft is rotated, with any misalignment resulting in a difference in output as the crankshaft is rotated. The live centers are in the form of conical-shaped feelers mounted in bearings, with the live centers fitting into punch marks in opposing webs. In one embodiment, one feeler is fixed with respect to the tool body and the other is spring-loaded and slidably mounted in the tool body. An extension of the slidably mounted feeler includes a ferromagnetic coupling slug which is initially centered in a split-winding differential transformer within the tool.

Abstract: A system for monitoring misalignment between two in-line rotating shafts and for indicating the direction of shaft misalignment wherein alignment sensors are mounted directly to and rotate with the shafts. The sensors are mounted to detect position or stress variations between elements on coupled shafts as a function of the rotational position of the shaft and thus errors normally encountered where the sensor is positioned off the shaft are avoided. A coupling system such as a rotary transformer is employed to apply power to the sensors and associated circuitry on the shaft and to receive from the shaft signals indicative of sensed misalignment. A signal representative of relative phasing between the rotating shaft and surrounding equipment is provided and is used in electronically processing the misalignment signals to provide output signals indicative of the direction and orientation of misalignment between the rotating shafts on orthogonal axes.