IronPLC Visual Studio Code Extension

IronPLC brings IEC 61131-3 support to Visual Studio Code.

⚠ This project's capabilities are limited to a parser, semantic analyzer, and Visual Studio Code Extension that are building blocks for a complete IEC 61131-3 runtime and development environment.

Quick Start

Step 1. Install the IronPLC compiler and Visual Studio Code extension on your system.
Step 2. Open or create an IEC 61131-3 file and start coding.

Supported File Types

File Type	Extensions	Description
Structured Text	`.st`, `.iec`	IEC 61131-3 Structured Text source files
PLCopen XML	Auto-detected	PLCopen TC6 XML project files with embedded Structured Text

Features

Syntax Highlighting

Full syntax highlighting for IEC 61131-3 Structured Text including:

Keywords (PROGRAM, FUNCTION, FUNCTION_BLOCK, VAR, IF, FOR, WHILE, etc.)
Data types (BOOL, INT, REAL, STRING, TIME, etc.)
Operators and literals
Comments ((* block comments *))

PLCopen XML files are also highlighted with embedded Structured Text support.

Real-Time Analysis

As you type, IronPLC analyzes your code and reports:

Syntax errors
Semantic errors (type mismatches, undefined variables, etc.)
Warnings for potential issues

Diagnostics appear inline and in the Problems panel.

Auto-Closing Pairs

The extension automatically closes:

Brackets and strings: [], (), '', ""
Comments: (* *)
Control structures: IF/END_IF, FOR/END_FOR, WHILE/END_WHILE, CASE/END_CASE, REPEAT/END_REPEAT
Program units: PROGRAM/END_PROGRAM, FUNCTION/END_FUNCTION, FUNCTION_BLOCK/END_FUNCTION_BLOCK
Variable blocks: VAR/END_VAR, VAR_INPUT/END_VAR, VAR_OUTPUT/END_VAR, and other VAR types
Other blocks: STRUCT/END_STRUCT, ACTION/END_ACTION, CONFIGURATION/END_CONFIGURATION

Bracket Colorization

Matching brackets are colorized to help visualize nesting levels.

Commands

Open the Command Palette (Command+Shift+P on macOS and Ctrl+Shift+P on Windows) and type in one of the following commands:

Command	Description
`IronPLC: New Structured Text File`	Create a new IEC 61131-3 structured text file

Extension Settings

Setting	Description	Default
`ironplc.path`	Path to the IronPLC compiler executable. If empty, discovers based on PATH.	(empty)
`ironplc.logLevel`	Log level for the compiler: ERROR, WARN, INFO, DEBUG, or TRACE	ERROR
`ironplc.logFile`	Path to write compiler logs. If empty, logs are not written to file.	(empty)

Platform Support

The extension works on:

Windows
macOS
Linux

Learn More

Visit ironplc.com for documentation, tutorials, and guides.