Abstract: An apparatus and method for controlling the operation of a system are provided. The overall system operation is described by a plurality of mechanism cycles of operation each defined by a sequence of instructions relating sensed conditions of input devices, selectable conditions of output devices and variable values. Instruction signals representing the instructions of the sequences are stored together with mechanism cycle status signals each representing the executability of the associated mechanism cycle. Only instructions associated with cycles for which the status signal represent an executable condition are executed. Instructions for cycles for which the status signals represent a nonexecutable condition are modifiable during execution of the other instruction sequence. The instruction signals include variable name signals associated with unique interface circuits connected to the input and output devices.

Abstract: A method is disclosed for modifying coordinate data in a machining program in response to workpiece measurements made by a programmably controlled surface sensing element. The location of the workpiece and position of workpiece characteristics are determined by a series of programmed scanning cycles. The maximum, minimum and average measured positions of points on a workpiece surface are stored and may be used to calculate position offsets which may be used to modify a machining program. Further, the measured positions and offsets may be tested against programmed maximum and minimum limits to determine if the measured positions are within a tolerance band. In one embodiment, the positions of points on the workpiece surface are measured by a cutting tool operating in conjunction with a torque measuring circuit.

Abstract: A method is disclosed for detecting the presence of a workpiece characteristic and controlling the sequence of execution of operational steps in a machining program. First instructions in a machining program cause a sensing element to execute a scanning cycle to detect workpiece characteristics. Second instructions in the machining program test for the presence of the workpiece characteristics to determine the next operational step to be executed. The next operational step may be sequentially located in the program or may be identified by third instructions which define a nonsequential program location. Jump instructions are also provided to execute an unconditional jump to operational steps defined by a jump location instruction in the program.