I/o unit terminal base with external connection terminals, socket for

Abstract

This terminal base for an I/O unit includes a socket unit adapted for being mounted with several relays comprising several relay terminals. This socket unit includes several socket terminals which, when the relays are mounted to this socket unit, are contacted to the relay terminals. The terminal base also includes several I/O terminals, exposed to the outside for external connection, and connected to some of the socket terminals, and a multi wire connector, adapted to be connected to several wires for leading to a central processing unit, and having several connector terminals which are connected to some of the socket terminals. It may further include a printed circuit base board on which the I/O terminals and the socket terminals are mounted. Thereby, the manufacture and assembly of the terminal base, and of the I/O unit as a whole, are simplified and reduced in cost, while the servicability and ease of diagnosis of the I/O unit are good.