Patent ID: 6466827
Filing Date: 2002-10-15
Classification: G05B

Abstract:
An industrial control system for controlling interconnected equipment of equipment types, the equipment having electrical sensors and actuators, the control system comprising:(a) a programmable logic controller including: (i) I/O circuits communicating electrical signals with the actuators and sensors of the equipment; (ii) a relay ladder processing unit; and (iii) a controller memory holding multiple, predefined relay ladder objects for different equipment types, the relay ladder objects having rungs with contacts representing signals from the sensors and output coils representing signals to the actuators, the rungs joining the contacts and output coils to provide intra-machine control logically relating operation of the actuators and sensors; (b) at least one general purpose computer including: (i) a processing unit and (ii) a computer memory, the memory holding: (1) an instancing table matching particular equipment with particular ones of the relay ladder objects having matching equipment types; (2) a stored control program executable by the processing unit to provide inter-machine control of the equipment, the control program logically coordinating operation of different interconnected equipment by exchanging data with the predefined relay ladder objects according to the instancing table; whereby a writing of control programs may be simplified by using predefined relay ladder objects for intra-machine control.