FreertosHow-ToBeginner · 4 min read

How to Version Control PLC Programs: Best Practices and Examples

To version control PLC programs, export your PLC code to a text-based format like XML or structured text and store it in a Git repository. This allows tracking changes, collaboration, and rollback just like software code.

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Syntax

Version controlling PLC programs involves these key steps:

Export: Save your PLC program in a text-based format (e.g., XML, ST, or CSV) from your PLC software.
Initialize Git: Create a Git repository to track changes.
Commit: Add and commit exported files to Git with meaningful messages.
Push: Upload changes to a remote repository for backup and collaboration.

bash

git init
git add program.xml
git commit -m "Initial commit of PLC program"
git push -u origin main

Output

Initialized empty Git repository in /path/to/repo/.git/ [main (root-commit) abc1234] Initial commit of PLC program 1 file changed, 100 insertions(+) create mode 100644 program.xml

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Example

This example shows exporting a PLC program as XML and version controlling it with Git commands.

bash

echo "<PLCProgram>\n  <Name>ConveyorControl</Name>\n  <Logic>\n    // Ladder logic or structured text here\n  </Logic>\n</PLCProgram>" > ConveyorControl.xml

git init

# Add the exported PLC program file
git add ConveyorControl.xml

git commit -m "Add initial ConveyorControl PLC program"

# Simulate a change
sed -i 's/ConveyorControl/ConveyorControlV2/' ConveyorControl.xml

git add ConveyorControl.xml

git commit -m "Update program name to ConveyorControlV2"

Output

[main (root-commit) abc1234] Add initial ConveyorControl PLC program 1 file changed, 5 insertions(+) create mode 100644 ConveyorControl.xml [main def5678] Update program name to ConveyorControlV2 1 file changed, 1 insertion(+), 1 deletion(-)

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Common Pitfalls

Common mistakes when version controlling PLC programs include:

Not exporting programs as text files, making diffs and merges impossible.
Committing binary project files directly, which are hard to track and merge.
Forgetting to commit regularly, losing change history.
Not using meaningful commit messages, making history unclear.

Always export to text formats and commit often with clear messages.

bash

## Wrong: Committing binary project file directly
# git add project.plcproj
# git commit -m "Add PLC project"

## Right: Export to XML and commit
# export project to program.xml
# git add program.xml
# git commit -m "Add exported PLC program as XML"

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Quick Reference

Summary tips for version controlling PLC programs:

Always export PLC code to a text-based format before versioning.
Use Git or similar tools to track changes and collaborate.
Commit changes frequently with clear messages.
Keep backups and use branches for experimental changes.
Document your version control process for your team.

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Key Takeaways

Export PLC programs to text formats like XML or structured text before version control.

Use Git to track changes, collaborate, and rollback PLC program versions.

Avoid committing binary project files directly as they are hard to manage.

Commit changes frequently with clear, descriptive messages.

Maintain backups and use branching strategies for safe development.