siemens-awl-stl-programmer

name: siemens-awl-stl-programmer description: Generate Siemens S7-300/S7-400/S7-1500 Statement List (STL/AWL) programs compatible with Step7 Classic and TIA Portal. Use this skill whenever the user asks to write, generate, create, or modify any PLC logic, function blocks, organization blocks, data blocks, or control programs in STL/AWL format. Also trigger for any questions about Siemens S7 memory addressing, timers, counters, accumulators, block structure, or Step7/TIA Portal imports. Always use this skill even if the user just mentions "STL", "AWL", "Step7", "TIA Portal", "S7-300", "S7-400", "S7-1500", "PLC block", "OB", "FB", "FC", or "DB". metadata: version: "1.0"

Siemens S7 STL (AWL) Programming Skill

Overview

Generate Siemens S7-300 / S7-400 / S7-1500 Statement List (STL / AWL) programs compatible with Step7 Classic and TIA Portal.

Core model knowledge:

Accumulator-based execution (ACCU1 / ACCU2)
RLO (Result of Logic Operation) for boolean logic
S5 timers, IEC timers (TON/TOF/TP), counters, INT and REAL arithmetic
OB / FB / FC / DB block hierarchy
Standard scan cycle model (Read → Execute → Write)

For full instruction syntax, see references/STL_Core_Instructions.md.

Critical Rule: Omit Block Number (`NAME`) Line

Always omit the NAME : '<number>' line unless the user specifically requests a fixed block number. TIA Portal automatically assigns the next available unused block number on import.

Block Structure

Organization Block (OB)

ORGANIZATION_BLOCK "OB1"
TITLE = Main Program Cycle
{ S7_Optimized_Access := 'TRUE' }
VERSION : 0.1

VAR_TEMP
      TempVar : Int;
END_VAR

BEGIN
NETWORK
TITLE = Example Network
      L     PIW256;
      T     #TempVar;
END_ORGANIZATION_BLOCK

Function (FC) — Stateless

FUNCTION "FC_Name" : Void
{ S7_Optimized_Access := 'TRUE' }
VERSION : 0.1

VAR_INPUT
    IN : Int;
END_VAR

VAR_OUTPUT
    OUT : Real;
END_VAR

BEGIN
NETWORK
TITLE = Convert and Scale
      L     #IN;
      ITD;
      DTR;
      T     #OUT;
END_FUNCTION

Function Block (FB) — Stateful

FUNCTION_BLOCK "FB_Name"
{ S7_Optimized_Access := 'TRUE' }
VERSION : 0.1

VAR_INPUT
    StartPB : BOOL;
    StopPB  : BOOL;
END_VAR

VAR_OUTPUT
    MotorOut : BOOL;
END_VAR

VAR
    RunLatch : BOOL;
    Delay    : TON;
END_VAR

BEGIN
NETWORK
TITLE = Start Latch
      A     #StartPB;
      AN    #StopPB;
      S     #RunLatch;

NETWORK
TITLE = Output
      A     #RunLatch;
      =     #MotorOut;
END_FUNCTION_BLOCK

Data Block (DB)

DATA_BLOCK "DB_Name"
{ S7_Optimized_Access := 'TRUE' }
VERSION : 0.1
NON_RETAIN

VAR
    Value : Int;
END_VAR

BEGIN
END_DATA_BLOCK

Key Formatting Rules

Always include { S7_Optimized_Access := 'TRUE' } after block keyword
Use symbolic quoted names ("BlockName") — never numeric references
Prefix local variables with # (e.g., #StartPB)
Each instruction ends with ;
Use NETWORK + TITLE = ... + // comment for each logical group

Timer Selection:

Inside FC: Use S5 timers (SE, SP, SD, SA, SS)
Inside FB: Use IEC timers (TON, TOF, TP)

Code Generation Constraints

MUST:

Use symbolic quoted names for all block references
Generate complete, compilable blocks
Separate logical groups into individual NETWORKs
Use uppercase STL mnemonics (A, AN, O, =, S, R, L, T, FP, ITD, DTR, etc.)
Generate matching instance DB when generating an FB

MUST NOT:

Mix LAD, SCL, or non-STL syntax
Use numeric-only block references unless user explicitly requests
Include NAME : '<number>' in generated blocks

When to Consult Documentation

If the user's request involves instructions or patterns not covered here, consult:

TIA Portal STL Reference: https://docs.tia.siemens.cloud/r/en-us/v21/creating-stl-programs-s7-300-s7-400-s7-1500
Full instruction reference: references/STL_Core_Instructions.md
Block templates: references/REFERENCE.md
Formatting rules: references/FORMATTING.md

Typical cases requiring documentation lookup:

Interrupt OBs (OB35, OB40, OB80) and their startup VAR_TEMP
System function calls (SFC, SFB) such as CALL SFC14
String handling, DATE_AND_TIME types
BLKMOV, FILL, UBLKMOV block move instructions
Less common accumulator operations (CAD, CAW, TAK, PUSH, POP)