PLC Program
Compare Tool
Compare two versions of your Allen-Bradley PLC program side by side. Instantly identify added, removed, and modified rungs with a visual diff tool. Track changes and maintain version control without Studio 5000.
Detailed Program Comparison
Every tool you need to understand what changed between program versions
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.
Rung-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.
Version Tracking
Keep multiple versions of your PLC program organized. Compare any two uploads to understand the evolution of your control logic over time.
How It Works
Three steps to compare your PLC program versions
Upload First Version
Upload the baseline version of your ACD, L5X, or RSS file. This becomes the reference point for comparison. The system parses all programs, routines, and tags.
Upload Second Version
Upload the updated version of the same program. The comparison engine analyzes both versions and identifies every difference at the rung, instruction, and tag level.
Review the Differences
Browse through the highlighted changes. Added logic appears in green, removed logic in red. Click any change to see the full rung context and understand the modification.
Upload Your First PLC File
Start by uploading the base version of your program
Drop your PLC file here
or browse to select
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.