Generate SCL Code with AI
for Siemens TIA Portal
Stop writing boilerplate Structured Text by hand. Describe your automation logic in plain English and get production-ready SCL code — written directly into your TIA Portal project.
Why Generate SCL with AI?
SCL (Structured Control Language) is the most powerful IEC 61131-3 language for Siemens PLCs. But writing complex SCL — PID controllers, state machines, alarm handlers, data processing — is time-consuming and error-prone. A typical motor control FB takes 30-60 minutes to write manually.
With T-IA Connect, AI models like Claude or GPT read your TIA Portal project context (existing UDTs, naming conventions, block structure) and generate SCL that fits your codebase. The code is written directly into TIA Portal, compiled, and validated — no copy-paste workflow.
SCL Generation Examples
Real prompts engineers use and the SCL code they get
Motor Control with Star-Delta
“Create an FB for a 3-phase motor with star-delta starter. Include: start/stop inputs, star-delta transition timer (configurable, default 5s), thermal overload protection, running hours counter, and alarm output for failed start.”
Complete FB with 8 inputs, 6 outputs, 3-state machine (STOPPED/STAR/DELTA), configurable timer, runtime counter as TIME type, and startup monitoring with timeout alarm.
PID Temperature Controller
“Generate an FB for PID temperature control of an oven. Use Siemens PID_Compact as sub-block. Add manual/auto mode switch, setpoint ramping, high/low temperature alarms with deadband, and output limiting 0-100%.”
FB wrapping PID_Compact with mode switching, linear ramp generator, configurable alarm thresholds with hysteresis, output clamping, and trending data output for HMI.
Valve Sequence Controller
“Create a sequence controller for a CIP (Clean-in-Place) system with 6 valves. Steps: rinse (V1+V2, 30s), caustic wash (V3+V4, 120s), rinse again (V1+V2, 30s), acid wash (V5+V6, 60s), final rinse (V1+V2, 30s). Include pause/resume and step skip.”
FB with GRAPH-like step sequencer, 5-step CIP cycle, pause/resume logic, step skip capability, current step output for HMI, and total cycle time tracking.
Data Logger to DB
“Write an FC that logs process data (10 REAL values) to a ring buffer DB with 1000 entries. Include timestamp, trigger on value change > 1%, and overflow handling.”
FC with ring buffer management, configurable deadband per channel, timestamp from OB1 cycle, write pointer management, buffer full flag, and statistics (min/max/avg per channel).
SCL Patterns the AI Masters
Common industrial automation patterns that AI generates reliably
State Machines
CASE-based state machines with entry/exit actions, transition conditions, timeout monitoring, and fault states. The most common pattern in industrial SCL.
PID Control Wrappers
Wrappers around Siemens PID_Compact or PID_3Step with auto-tuning triggers, manual mode, cascade control, and anti-windup logic.
Alarm Management
Alarm generation with configurable delays, acknowledgment logic, alarm classes (warning/fault/critical), and structured alarm output for HMI integration.
Communication Handlers
Modbus RTU/TCP frame builders, PROFINET IO status handling, PUT/GET blocks for S7 communication, and TCP/UDP socket management.
Recipe Management
Recipe data structures with parameter validation, recipe selection/loading, parameter comparison, and batch tracking with recipe versioning.
Motion Control
Position control with acceleration ramps, homing sequences, axis coordination, position tracking, and jog mode with speed selection.
SCL vs Other PLC Languages
Why Structured Text is the best fit for AI code generation
| Language | AI Generation | Best For |
|---|---|---|
| SCL / Structured Text | Excellent — text-based, AI generates it natively | Complex logic, math, data processing, state machines |
| LAD / Ladder Diagram | Poor — graphical language, AI can't generate directly | Simple boolean logic, electrical schematics |
| FBD / Function Block Diagram | Poor — graphical, requires visual editor | Analog processing, PID, continuous control |
| GRAPH / Sequential Function Chart | Limited — AI can generate equivalent SCL state machines | Sequential processes, batch control |
Industrial-Grade SCL Output
Generated code follows Siemens standards and IEC 61131-3
REGION Blocks
Code organized with #REGION / #ENDREGION pragmas for collapsible sections in TIA Portal. Clean, navigable source.
Proper Interface
Well-defined Input, Output, InOut, Static, and Temp sections. Correct data types, default values, and interface comments.
Error Handling
TRY/CATCH blocks for runtime errors, status codes on outputs, and defensive programming patterns for robust industrial code.
Inline Documentation
Block comments, section headers, variable descriptions. Generated code is self-documenting and maintainable by your team.
Frequently Asked Questions
Can AI generate SCL as well as an experienced PLC programmer?
For standard patterns (motor control, PID, sequences, data handling), AI-generated SCL is comparable to experienced programmer output. For highly specialized or safety-critical code, AI serves as a fast first draft that an engineer reviews and refines. The key advantage is speed: 30 seconds vs 30 minutes for a typical FB.
Does the AI understand Siemens-specific SCL syntax?
Yes. Claude and GPT-4o understand Siemens SCL specifics: REGION pragmas, DB access syntax ("DB".variable), multi-instance FB patterns, AT overlay, PEEK/POKE, and TIA Portal naming conventions. The generated code compiles in TIA Portal without syntax modifications.
Can I generate SCL for safety PLCs (F-CPUs)?
AI can generate the logic for safety-related functions, but safety PLC programming has strict certification requirements (IEC 62061, IEC 13849). Always validate AI-generated safety code through your formal safety review process before deploying to F-CPUs.
What about Ladder (LAD) or FBD code generation?
AI generates text natively, so SCL/Structured Text is the natural fit. LAD and FBD are graphical languages that can't be directly generated as text. However, any logic that can be expressed in LAD/FBD can also be expressed in SCL — often more concisely. T-IA Connect focuses on SCL generation for this reason.