Understand any PLC code in seconds.
AI-powered analysis, documentation, and optimization for industrial automation code. Siemens, Allen-Bradley, Mitsubishi & more.
How it works
Three simple steps to understand any PLC program.
Paste your code
Copy your PLC code from any environment — TIA Portal, Studio 5000, GX Works or plain text.
Choose an action
Select Explain, Document, Optimize or Migrate to tell the AI what you need.
Get results
Receive a detailed analysis in seconds. Export as PDF, Markdown or share with your team.
Four powerful modes
Everything you need to work with legacy and modern PLC code.
Understand legacy code instantly
Get a clear, structured breakdown of any PLC program — variable roles, logic flow, safety patterns and potential issues.
Generate audit-ready documentation in seconds
Produce professional documentation with I/O tables, flowcharts and block descriptions. Ready for compliance audits.
Find bugs, bottlenecks and improvements
Detect unused variables, inefficient logic, missing error handling and safety gaps. Get actionable recommendations.
Convert S5→S7, SLC→ControlLogix and more
Translate PLC code between platforms and languages. Handles instruction mapping, address conversion and syntax differences.
Free PLC Tools
View All Tools →S5 Timer Calculator
Convert KT timer values to seconds, IEC format, and S7 code.
Open →S5→S7 Address Converter
Convert S5 addresses to S7 equivalents with ×2 rule for data blocks.
Open →AWL Command Lookup
Search all 40 S5 AWL commands with S7 equivalents and SCL.
Open →S5→S7 Command Converter
Paste S5 AWL code, get S7 STL + SCL instantly.
Open →PLC Code Validator
Paste AWL or SCL code and get instant syntax and logic checks.
Open →Migration Estimator
Estimate migration effort, cost, and timeline for your plant.
Open →Popular Migration Guides
Browse All Guides →S5 to S7 Migration: The Complete Guide
Step-by-step guide for migrating Siemens S5 PLC programs to S7-1500.
Read Guide →S7-300 End-of-Life: Migration Planning Guide
What the S7-300 phase-out means for your plant and how to plan the migration.
Read Guide →PLC-5 to ControlLogix Migration Guide
Complete guide for migrating Allen-Bradley PLC-5 to ControlLogix.
Read Guide →PLC Reference Library
Browse Full Reference →S5 AWL Command Reference
Complete reference of all 40 S5 AWL instructions with S7 equivalents, syntax, and examples.
S7 SCL Reference
SCL syntax, timers, counters, math operators, data types, and best practices.
S5→S7 Address Mapping
I/O, markers, data blocks, periphery, and counter format conversion tables.
Timer Conversion
S5 KT timer format to IEC timers (TON/TOF/TP). Time base reference and BCD encoding.
IEC 61131-3
Programming languages, data types, and standard function blocks.
Simple, transparent pricing
Start free. Upgrade when you're ready.
Free
For evaluation and small tasks.
- 3 analyses per month
- All 4 modes
- Up to 500 lines per analysis
- Community support
Pro
For professional automation engineers.
- Unlimited analyses
- All 4 modes
- Up to 10,000 lines per analysis
- Priority support
- PDF & Markdown export
- API access
Team
For engineering teams and integrators.
- Everything in Pro
- 5 team members included
- Shared project library
- Admin dashboard
- SSO integration
- Dedicated support
Trusted by automation engineers
See what engineers are saying about PLCcheck.
“PLCcheck saved us weeks of work on a legacy S5 migration project. The code explanations were spot-on.”
“Finally a tool that understands industrial automation. The documentation feature alone is worth the subscription.”
“We use PLCcheck for every commissioning project now. It cuts our code review time in half.”
Frequently asked questions
- What PLC languages are supported?
- PLCcheck supports Structured Text (ST/SCL), Ladder Diagram (LD/KOP), Function Block Diagram (FBD/FUP), Instruction List (IL/AWL), and Statement List (STL). We support code from Siemens (S5, S7, TIA Portal), Allen-Bradley (SLC 500, ControlLogix, CompactLogix), Mitsubishi (GX Works), Schneider (Unity Pro), and more.
- Is my code secure?
- Absolutely. Your code is encrypted in transit (TLS 1.3) and at rest (AES-256). We never store your code after analysis is complete. Our infrastructure runs in EU data centers (Frankfurt) and we are fully GDPR compliant. We never use your code for AI training.
- How accurate is the AI analysis?
- PLCcheck uses models specifically fine-tuned for industrial automation code. Accuracy varies by code complexity, but typical results are above 95% for code explanation and documentation. We always recommend human review for safety-critical applications.
- Can I use PLCcheck offline?
- PLCcheck is currently a cloud-based tool. An on-premise version for enterprise customers with strict data policies is planned for Q3 2026. Contact our sales team for early access.
- What is the difference between Explain and Document?
- Explain gives you a conversational, human-readable breakdown of what the code does — ideal for understanding unfamiliar programs. Document generates structured, formal documentation with I/O tables, block descriptions and flowcharts — ready for audits and project handovers.