Abstract: A system for detecting a fault, e.g. a liquid leak from a pipe or vessel containing an electrolyte or a hydrocarbon. In one embodiment, the system comprises a central unit and a plurality of sub-units; each of the sub-units is powered in turn from a power source in the central unit, and the sub-unit generates a signal which is observed by the central unit and which identifies the presence of a fault. In another embodiment, signals generated by a detection system at different times are compared and the decision whether to generate a fault alarm is based on that comparison.

Abstract: A printer/plotter incorporates four individual microprocessor-based print stations, each for printing on a print media a separate color image for superimposition with one another, forming a final full-color image. The four print stations are located along a transport path for single-pass operation, and each print station includes a transport system that allows the media to traverse a print station with controlled forces exerted on the media by that station. The invention further includes a precise registration system wherein each print station monitors registration marks to detect variations of the media (i.e., stretching or shrinkage) during the printing process and to correct for such variations on obtaining accurate registration of the individual images for a full-color result.