Abstract: A controller of the data processing type including a memory programmable to adapt it to a wide variety of industrial machine and process control applications includes terminals permitting a hardwired logic circuit to be connected with the controller to supplement or improve its control functions. In particular, the hardwired logic backup may act as a redundant safety circuit responding to certain danger signals from the controlled process or may be used to enhance the response time or other characteristics of the controller in certain situations.

Abstract: Disclosed is a random access memory particularly adapted for use in a programmable controller or other similar application wherein some data is preferably handled in the form of multi-bit words or bytes and other data is preferably handled in the form of single bits (one-bit words). The memory is comprised of at least one bank of chips or similar memory units each capable of storing one bit at each of a plurality (2.sup.N) of locations addressed through N address terminals. Through the agency of control signals, the chips of the bank may be accessed either in parallel to read or write a multi-bit word or individually to read or write a single bit.