IEC 61131-3 is the international standard for programmable logic controller (PLC) programming languages and specifies the syntax, semantics and display for five languages. Multiple language support in IEC 61131-3 enables the control program developer to select the language that is best suited to a particular task. Tasks and languages include:
Graphic Programming Interfaces
Ladder Diagrams (LD): traditional PLC “Ladder Logic”
Function Block Diagrams (FBD): uses “functions” between input variables and output variables
Text-based Programming Interfaces
Structured Text (ST): a text-based high level language that syntactically resembles Pascal. Complex statements and nested instructions are supported:
Iteration loops (REPEAT-UNTIL; WHILE-DO)
Conditional execution (IF-THEN-ELSE; CASE)
Functions (SQRT(), SIN())
Instruction List (IL): an efficient, text-based, low level language that resembles assembly
Flow-Chart based ProgrammingInterface
Sequential Flow Charts (SFC): a language to model complex programs such as DA scenarios with second contingencies, load-checking and multiple alternate sources.
Full Integration with NCD
IEC 61131-3 is now available in the OrionLX along with the other four Math & Logic tools.
Orion IEC 61131-3 is fully integrated in the Orion NCD (NovaTech Automation Communications Director) confi guration software.
All points and records accessed from IEDs by Orion (SCADA data, fault data from SEL® Short Event Summaries, etc.) or points generated internally (diagnostic data, comms data, etc.) are available for use in OrionLX IEC 61131-3 math and logic schemes.
Offl ine Simulation and Secure OnlineViewing of Logic Execution
OrionLX IEC 61131-3 includes an o ffline simulator to view logic execution exactly as it will appear when running online in the OrionLX.
