초록 ▼

A method of operating an industrial control system converts relay ladder logic programs into flow type programs expressed as ‘logical gates’connected with ‘wires’representing variables. This formulation is converted to an efficient code structure in which changes in state of the variables are evalua

A method of operating an industrial control system converts relay ladder logic programs into flow type programs expressed as ‘logical gates’connected with ‘wires’representing variables. This formulation is converted to an efficient code structure in which changes in state of the variables are evaluated and only changes are propagated in evaluating program outputs. The net effect is many steps of evaluation in the control program are avoided during real-time operation of the program connected to controlled equipment.

대표청구항 ▼

A method of compiling relay ladder logic comprising the steps of: (a) receiving a relay ladder diagram providing: (i) a plurality of virtual contacts and coils, the virtual contacts representing data from the industrial process and the virtual coils representing data to the industrial process; and (

A method of compiling relay ladder logic comprising the steps of: (a) receiving a relay ladder diagram providing: (i) a plurality of virtual contacts and coils, the virtual contacts representing data from the industrial process and the virtual coils representing data to the industrial process; and (ii) a plurality of interconnections between contacts and coils in rungs, the interconnections representing a control logic for the industrial process; (b) translating the relay ladder diagram into a data flow form, the data flow form providing: (i) a plurality of Boolean elements having inputs and outputs, the Boolean elements representing the control logic for the industrial process, and; (ii) a plurality of data paths between inputs and outputs of Boolean elements; the data paths corresponding to the data to and from the industrial process; (c) associating each data path with a transition routine determining the effect of a transition in data of the given data path on the outputs of any directly connected Boolean elements having inputs connected to that data path; (d) combining the transition routines of step (c) into a control program by having each given transition routine call transition routines associated with data paths connected to outputs of the given transition routine\s directly connected Boolean elements.