How Version Link Works

Version Link compares two versions of a Rockwell Automation PLC program export (L5X file) and produces a structured breakdown of every change: routines added or removed, rung-level diffs, tag changes, module differences, and more.

Export your before and after programs from Studio 5000 as L5X files, drop them on the compare page, and you’ll have a full report in seconds. Files are parsed in memory and never stored.

Step by Step

Upload Files

Export two versions of your program from Studio 5000 as L5X files, then drop them on the compare page.

Parse Structure

Each file’s XML is parsed into programs, routines, tags, modules, AOIs, UDTs, and tasks.

Compare

Every element is diffed: rung-level logic changes, tag additions and removals, module differences.

Review Report

Interactive report with colour-coded diffs, collapsible sections, and filtering.

Export

Download the full report as a PDF, or export tag values as a CSV spreadsheet.

What Gets Compared

Routines & Rungs

Rung-level comparison for Ladder Logic routines. Added, removed, and modified rungs are highlighted individually.

I/O Modules

Detects added, removed, or changed I/O modules including catalog numbers and parent module assignments.

Add-On Instructions

AOI additions, removals, and parameter changes between versions.

User-Defined Types

UDT structure changes including member additions, removals, and type modifications.

Tasks & Programs

Task configuration changes including type, rate, priority, and program assignments. Program additions and removals.

Frequently Asked Questions

What is an L5X file?

An L5X file is Rockwell Automation’s XML-based export format for PLC programs. You can export one from Studio 5000 (or RSLogix 5000) via File → Save As and selecting the L5X format. It contains the complete project: controller configuration, programs, routines, tags, modules, and more.

What file size is supported?

Free users can compare files up to 50 MB each. Pro accounts support files up to 100 MB. Most projects, even large ones with tens of thousands of tags, fall well within these limits.

Is my data stored?

For anonymous (free) comparisons, no. Files are parsed in memory and discarded immediately after the comparison completes. Nothing is written to disk or stored in a database. Pro users can optionally save files to their library for future comparisons.

What PLC platforms are supported?

Currently Rockwell Automation / Allen-Bradley controllers that export to L5X format (ControlLogix, CompactLogix, GuardLogix). Support for Siemens TIA Portal and Omron Sysmac exports is planned for a future release.

What routine types are compared?

Ladder Logic (RLL), Structured Text (ST), Function Block Diagram (FBD), and Sequential Function Chart (SFC) routines are all detected and listed. Rung-level diff highlighting is available for RLL routines. ST routines show a text-based diff.

Ready to compare?

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