PLC Program Comparison Tool
Compare PLC
Program Versions
Identify every change between program versions instantly. See added rungs, removed logic, modified instructions, and tag changes side by side.
- PLC program comparison identifies every change between versions at the rung and instruction level.
- Added, removed, and modified rungs are color-coded for instant visibility.
- Works with all Allen-Bradley formats: ACD, L5X, and RSS files.
- No Studio 5000 license required — perfect for change management and compliance documentation.
Why Compare Program Versions?
When you modify a PLC program, knowing exactly what changed is critical for troubleshooting, compliance, and safety. The standard workflow — manually reviewing each rung in Studio 5000 — is slow, error-prone, and requires expensive software licenses.
- Change Management: Understand what was modified between releases
- Troubleshooting: Quickly identify what changed when a problem appears
- Compliance: Document every change to safety-critical logic
- Knowledge Transfer: Show team members exactly what was updated
- Version Control: Track program history without expensive version control systems
- Backup Validation: Confirm your backup matches your production version
Everything You Need to
Track Program Changes
Side-by-Side Comparison
View two program versions next to each other with synchronized scrolling. Navigate through routines and rungs with differences highlighted in context.
Instruction-Level Diff
See exactly which instructions changed within each rung. Added instructions are highlighted in green, removed in red, and modified instructions show both old and new values.
Identify Added & Removed Logic
Quickly find new rungs that were added, old rungs that were deleted, and routines or programs that were created or removed between versions.
Tag & Type Changes
Track changes to tag definitions, data types, UDTs, and AOIs. See what new tags were created and what tag properties were modified.
Change Summary Report
Get a high-level overview showing total rungs added, removed, and modified. Understand the scope of changes at a glance.
Version Control Without Studio 5000
No Studio 5000 license needed. Perfect for change management, compliance documentation, and team collaboration across locations.
Supported File Formats
Studio 5000 Project
Native binary format. Contains complete project state, online edit history, and pending changes. The most common format for production programs.
Studio 5000 Export
XML-based export format. Portable and portable across systems. Ideal for sharing and version control.
SLC Export
Legacy RSLogix 5000 export format. Supported for comparing older programs and legacy systems.
Start Comparing PLC Programs
Upload your base program version and then your updated version to see all changes
Drop your PLC file here
or browse to select
How to Compare Programs
Upload your base program
Start by uploading the original version of your PLC program. This is the 'before' file you'll compare against.
Upload the revised version
Upload the updated version of your program. This is the 'after' file with the changes you want to review.
Review the diff
The comparison tool instantly identifies every change: added rungs (green), removed rungs (red), and modified instructions. Navigate through differences with full context.
Export the report
Generate a detailed change report showing all modifications. Use this for change management, regulatory documentation, and team communication.
Frequently Asked Questions
How do I compare two PLC programs?
Upload your Allen-Bradley PLC file (ACD, L5X, or RSS) to PLC Company. The system parses every program, routine, and rung automatically. You can then upload a second version of the same file to compare them side by side. The diff tool highlights added, removed, and modified rungs so you can see exactly what changed between versions.
Can I compare PLC programs without Studio 5000?
Yes. PLC Company provides program comparison capabilities without requiring Studio 5000, RSLogix 5000, or any Rockwell software license. Upload two versions of your ACD or L5X file and the tool identifies all differences at the rung level, including changes to instructions, tag references, and program structure.
What types of changes does the diff tool detect?
The comparison tool detects added rungs (new logic that was not in the original), removed rungs (logic that was deleted), modified rungs (changes to instructions, conditions, or tag references), and structural changes such as added or removed programs and routines. It also identifies changes to tag definitions, data types, and controller properties.
Why is comparing PLC program versions important?
Comparing PLC program versions is critical for change management, troubleshooting, and safety. When a machine stops working after a program change, comparing the current version to a known-good backup reveals exactly what was modified. It also supports regulatory compliance by documenting every change made to safety-critical control logic.
Compare Your PLC Programs Today
No Studio 5000 license required. See exactly what changed between program versions in seconds.
Upload Your Programs