UN CONTROLADOR PROGRAMABLE PARA RESOLVER UN CIRCUITO DE RE- DES EN ESCALERA Y METODO CORRESPONDIENTE.

摘要

A programmable controller of the type used to solve relay ladder diagrams includes a memory into which is placed a digital representation of the rungs of the ladder diagram. The dispositions of various switches and coils are periodically sampled by portions of the programmable controller and stored in known memory locations. At appropriate times between sampling intervals, the various memory information are combined and provided to a relay line solver which updates the status of the relay ladder diagram and restores the updated information in a memory. The programming portion of the programmable controller includes UP, OPEN and RETURN keys which may be manipulated by an operator in an appropriate manner for entering the ladder diagram initially into the programmable controller memory or for updating or charging the status of the various rungs of the ladder diagram. The entry keys are such that contact interconnection information is entered into the memory at the same time and by the same keys that are utilized to enter the contact information; no separate memory words are required for contact interconnection information. Very complex rungs of ladder diagrams may be entered using the three previously-mentioned keys. The sequence of ladder-diagram entry into the memory of the programmable controller is decided by contact-interconnection information which is displayed to a key operator to facilitate which contact is to be entered next in sequence.