Abstract: A graphical logic computer is formed by apertured parameter slides that are moved back and forth in an envelope between an apertured cover member and a back panel. The cover member has an event network with paths that branch from and connect event windows formed by the apertures in the cover member. Event indicators are disposed on the back panel in position to be observed through the event windows provided none of the parameter slides obstructs its view. The parameter slides have logic windows, and the position of each parameter slide with a logic window or solid portion aligned with an event window corresponds to a logical input, the combination of two or more such imputs providing a logical output. For each combination of slide positions, a single path is observed through the event network to a logically determined result.

Abstract: A protective enclosure for an instrument comprising a pair of housings connected to a support ring. An external bracket for securing the enclosure to a mounting structure is attached to the outside of the support ring and an internal bracket for supporting an instrument inside the enclosure is attached to the inside of the support ring. Instrument lines, fluid or electrical, to and from the instrument lead through the support ring.