<P> Ladder logic has evolved into a programming language that represents a program by a graphical diagram based on the circuit diagrams of relay logic hardware . Ladder logic is used to develop software for programmable logic controllers ( PLCs ) used in industrial control applications . The name is based on the observation that programs in this language resemble ladders , with two vertical rails and a series of horizontal rungs between them . While ladder diagrams were once the only available notation for recording programmable controller programs , today other forms are standardized in IEC 61131 - 3 ( For example , as an alternative to the graphical ladder logic form , there is also a more assembly language like format called Instruction list within the IEC 61131 - 3 standard . ) . </P>
<P> Ladder logic has evolved into a programming language that represents a program by a graphical diagram based on the circuit diagrams of relay logic hardware . Ladder logic is used to develop software for programmable logic controllers ( PLCs ) used in industrial control applications . The name is based on the observation that programs in this language resemble ladders , with two vertical rails and a series of horizontal rungs between them . While ladder diagrams were once the only available notation for recording programmable controller programs , today other forms are standardized in IEC 61131 - 3 ( For example , as an alternative to the graphical ladder logic form , there is also a more assembly language like format called Instruction list within the IEC 61131 - 3 standard . ) . </P>
what type of control system logic did plc ladder logic replace
what type of control system logic did plc ladder logic replace
relay
relay