Multi-level state language controller for multi-threaded machine control

Abstract

A control system for an NC machine incorporates a personal computer and an auxiliary control having an auxiliary microprocessor connected together and with the machine, via communication channels The personal computer and auxiliary controller are both provided with apparatus for controlling operations in a plurality of sequences, all of which run simultaneously, without requiring any modification in the normal operating system of the personal computer. The control program of the auxiliary controller is downloaded from the personal computer, and the sequences in both contain a number of consecutive states for each sequence, with each state characterized by one or more instructions and an operational time. One state of each sequence is designated the current state and the instruction of the current state of each sequence is performed in consecutive order, except when a priority instruction is recognized, after which the instruction of consecutive states of a single sequence are performed successively until a priority halt instruction is recognized. The auxiliary controller can operate autonomously to facilitate time-critical control operations without delays imposed by the need to communicate with the personal computer, but the personal computer can communicate with the auxiliary controller on demand for supervision and control when necessary or desired.