2.2. Fundamental concepts

2.2.1. Memory Overview

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Memory layout and addressing

2.2.1.1. Input and Output

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S7-1200 integrated IO mapping

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PLC tags organization

2.2.1.2. Merker

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Merker

2.2.1.3. Data Block

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Create new Data Block

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Using DB variables

2.2.2. POU: Program Organization Unit

2.2.2.1. Organization Block

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Organization Blocks

2.2.2.2. Function

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Create and use a function as code organization

2.2.2.3. Function Block

2.2.3. PLC programming languages

The standard IEC 61131-3 define 5 programming languages for PLC:
  • IL: Instruction List (STL in Step7)
  • LD: Ladder Diagram (LAD in step7)
  • ST: Strucured Text (SCL in Siemens)
  • SFC : Sequential Fucntion Chart
  • FBD: Fucntion Block Diagram
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