GB1453195A - Industrial logic systems - Google Patents

Abstract

1453195 Circuit assemblies SQUARE D CO 9 Nov 1973 [9 Nov 1972] 51710/72 Heading H1R A circuit module 10 constituting a logic device comprises circuit components and printed circuitry in insulating case 12 parallel terminal pins 18 connected to the various logic functions through decoupling capacitors and extending from case 12 in rows, bores 24 extending from one face 16 of the case to the opposite face, the bores receiving mounting screws which may be inserted from either end whereby the module may be secured either to a panel and have wirewrapped or the like connection made to the terminals, or to a frame in a plug-in mode. Pins 18 may pass through a transparent plate (20) (Figs. 2, 6, not shown) through which a marking label may be seen. Screws 28 also secure the circuit board carrying the components and plate 20 in place. As shown, screws 28 are inserted from face 16 and are sufficiently long to be received in openings 72 in a connector unit 64 into which module 10 may be plugged, and the assembly mounted in frame 46 (Fig. 5) by screws 78 passing through apertures 76 into tapped bushes 62 in flanges of frame members 54, 56. The power supply to the modules comprises a laminated bus system (Fig. 3) consisting of neutral and line conductors 34, 36 respectively, separated by dielectric film 38 and protected by insulation 40 except where terminal members 42 extend. In the plug-in arrangement, the bus system is secured to the underside of frame member 56. The frame is detachably secured to a support at 52, the other end being hingedly mounted in relation to the support. A multilevel frame may be constructed (Fig. 7, not shown). The laminated bus system provides low inductance and together with the capacitive decoupling minimizes noise. Moreover overvoltage protection may be provided by limiting the impedance of the power source, e.g. by connecting across it a Zener diode with a sufficiently high breakdown voltage. The modules may include light emitting diodes visible from the exterior for indicating the condition of output components, and the various modules may be colour coded. For panel-mounting of the modules, the laminated bus system has a bracket secured thereto (Fig. 4, not shown) so that it can be mounted alongside.