Codesys-MCP/python_scripting/what-you-can-do.md

What You Can Do with Python in CODESYS

Python in CODESYS is mainly for engineering automation (IDE/project automation), not for PLC runtime logic execution.

Typical use cases

• Project scaffolding
  • Create project structures, folders, and naming templates automatically.
• Bulk edits
  • Create or modify many POUs/objects consistently.
• Consistency checks
  • Enforce naming conventions, library versions, and structure rules.
• Build/export automation
  • Trigger exports and produce repeatable build artifacts.
• Documentation generation
  • Extract project metadata and generate docs/reports.
• Pre-release validation
  • Run scripted checks before handing over a project.

Practical examples

• Generate standard folder trees and placeholder POUs for new machines.
• Scan all variables and report naming/style violations.
• Export project data for review and commit audit trails.
• Produce release notes from project metadata.

What Python in CODESYS is NOT

• Not a replacement for IEC 61131-3 application logic running on the PLC.
• Not typically used for hard real-time control loops on the target runtime.

Good practices

• Keep scripts idempotent where possible (safe to run multiple times).
• Add a dry-run mode for scripts that change project data.
• Write action logs (what changed, where, and when).
• Use one script per purpose (small, focused scripts are easier to maintain).
• Test against project copies before production use.

Suggested first automation tasks

1. A read-only project inventory script (devices, POUs, libraries).
2. A naming-convention checker script.
3. A release/export helper script.

These three give immediate value while keeping risk low.