IronPLC Visual Studio Code Extension
IronPLC brings IEC 61131-3 support to your development environment, providing
real-time code analysis, syntax highlighting, build tasks, and a bytecode
viewer for programs written in the IEC 61131-3 Structured Text language.
Quick Start
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 |
| TwinCAT |
.TcPOU, .TcGVL, .TcDUT |
Beckhoff TwinCAT 3 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.
Build Tasks
The extension integrates with the build system to compile IEC 61131-3
projects into bytecode container (.iplc) files without leaving the
development environment.
- Press
Ctrl+Shift+B (or Cmd+Shift+B on macOS) and select ironplc: compile
- Output is written to a
.iplc file in the workspace root
Bytecode Viewer
Opening an .iplc bytecode file displays a human-readable disassembly of
the compiled program, including the file header, constant pool, task table,
and function instructions with color-coded opcodes.
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) |
The extension works on:
Supported Development Environments
This extension is published to both the Visual Studio Code Marketplace and the
Open VSX Registry. It works with any development environment that supports
VS Code extensions, including:
Learn More
Visit ironplc.com for documentation, tutorials, and guides.
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