Project Documentation And Analysis Service

Understanding what your PLC code actually does shouldn’t require the original programmer.

I provide comprehensive documentation and analysis services for CODESYS and TIA Portal projects, transforming undocumented or poorly documented code into clear, structured technical documentation that your team can actually use.

Whether you’re inheriting a legacy system, need proper handover documentation, or want to understand the logic behind critical industrial processes, I deliver professional documentation that bridges the gap between the code and the people who need to maintain it.

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My Approach

I read and analyze your PLC code directly, understanding what’s happening with minimal supporting context. While knowing what the system controls is helpful, I can work effectively even without detailed background information – the code tells its own story when you know how to read it.

This means you don’t need to spend hours briefing me or digging up old commissioning documents. Send me your project files, give me a brief overview of what the system does, and I’ll take it from there.

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What You’ll Receive

I deliver a comprehensive Word or PDF document that becomes the definitive reference for your PLC project. This isn’t a superficial overview – it’s an in-depth analysis that covers everything your maintenance team, project engineers, or future programmers need to understand the system.

Comprehensive Program Walkthrough

At the heart of the documentation is a complete walkthrough of your PLC program. Every program organization unit, function block, function, and data structure is individually documented and explained. This means each object in your project gets its own dedicated section covering what it does, how it works, what inputs it expects, what outputs it produces, and how it fits into the overall system.

You’ll understand not just that a function block exists, but what problem it solves, how it’s called, what happens inside it, and what edge cases or special behaviors to watch for. State machines are documented with their states and transitions explained. Complex calculations are broken down into understandable steps. Safety interlocks are explained with their purpose and triggering conditions.

This granular level of documentation means your team can jump directly to any part of the code and understand it without needing to trace through the entire program first.

Project Structure Analysis

I document how your project is organized, identifying the hierarchy of programs, function blocks, and functions. You’ll understand which parts of the code handle specific system functions, how different program components relate to each other, and the overall architectural approach the original programmer took.

Program Flow and Execution Order

Understanding when code executes is crucial. I map out the scan cycle, task priorities, and execution sequences so you know exactly what happens when, and in what order. This includes identifying cyclic tasks, event-driven logic, and interrupt handling where applicable.

Program Areas

Your PLC code likely handles multiple distinct functions – conveyor control, mixing sequences, safety interlocks, alarm handling, and more. I break down these functional areas, explaining what each section does and how they interact with each other. This gives you a clear mental model of the system’s operation.

Comprehensive Input and Output Documentation

Every physical input and output is catalogued with its function, location, and role in the control system. You’ll know what each I/O point does, where it’s used in the code, and what happens when it changes state. No more tracing signal names through thousands of lines of ladder logic to figure out what “M_Conv_3_Run” actually controls.

Configuration Overview

Hardware configuration, network settings, communication parameters, and device setup are all documented. This includes PROFINET/PROFIBUS configurations, HMI connections, fieldbus settings, and any special hardware features being used. When you need to replicate the setup or troubleshoot communication issues, you’ll have everything documented in one place.

Critical Analysis – Pitfalls and Problem Areas

This is where my documentation goes beyond simple description. I identify and highlight areas of concern that could cause maintenance headaches or operational issues:

I flag complex areas where the logic is particularly intricate or non-obvious. These sections get extra attention in the documentation, with detailed explanations and flowcharts to make them understandable. You’ll know which parts of the code require careful handling during modifications.

Undocumented and uncommented sections are called out explicitly. If the original programmer left no comments or explanation, I document what the code is doing and why it might be structured that way. You’ll understand the logic even if the original developer provided no guidance.

I identify areas that are difficult to maintain – code that’s tightly coupled, uses obscure programming patterns, or relies on implicit assumptions. These sections are documented with warnings and suggestions for how to handle future changes carefully.

Errors and potential issues don’t get glossed over. If I find logic that could cause problems, incorrect assumptions in the code, or potential failure modes, I document them clearly. You’ll know what needs fixing and why it matters.

Areas for improvement are highlighted throughout the documentation. I’ll point out where the code could be simplified, where modern programming patterns could improve maintainability, or where refactoring would reduce future headaches. This gives you a roadmap for technical debt reduction.

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Who Is This For?

This service is designed for anyone who needs to understand, maintain, or modify a PLC system but lacks the documentation to do so confidently.

You’ve Acquired an Existing System

You’ve purchased equipment, taken over a facility, or acquired a company with installed automation systems. The PLC code runs the production line, but there’s no documentation explaining how it works. The original integrator is no longer available, or their knowledge has walked out the door. You need to understand what you own before you can maintain it, modify it, or integrate it with other systems.

You’re Inheriting a Contractor’s Work

A contractor delivered a functioning system but provided minimal or no documentation. The code works, but when something needs changing or when a fault occurs, your team is left guessing. You need proper documentation to take ownership of the system and manage it going forward without being dependent on the original contractor for every modification or troubleshooting session.

You’re Dealing with Legacy Systems

The system was installed years or decades ago. The original programmer has retired or moved on. Comments in the code are sparse or non-existent. The system is critical to your operation, but nobody fully understands how it works anymore. You need documentation before someone can confidently make modifications or respond to breakdowns effectively.

You’re Planning System Modifications

You need to add new functionality, upgrade equipment, or integrate with other systems. Before you can plan modifications safely, you need to understand the existing code structure, identify the best integration points, and assess the risks. Proper documentation prevents new code from breaking existing functionality and helps scope the work accurately.

You’re Conducting a System Audit or Assessment

You need to evaluate the current state of your automation systems – perhaps for compliance, for risk assessment, or to plan future upgrades. You need an independent technical review that identifies potential issues, maintenance risks, and improvement opportunities. Documentation becomes the foundation for your improvement roadmap.

You’re Preparing for Handover or Sale

You’re handing over a system to a client, selling equipment, or transferring responsibility to a different team. Professional documentation adds value, reduces handover risks, and demonstrates the quality and professionalism of your work. It protects both you and the receiving party by ensuring knowledge transfer happens properly.

You’re Reducing Key Person Dependency

One person on your team understands the PLC system intimately, but that knowledge exists only in their head. If they leave, go on extended leave, or are unavailable during a breakdown, you’re in trouble. Documentation distributes that knowledge across your team and creates resilience.

You’re Supporting Multiple Sites with Similar Systems

You have standardized equipment across multiple locations, but each installation has site-specific modifications. You need documentation that captures both the common platform and the site variations, making it easier to train maintenance staff, order spare parts, and replicate successful modifications across sites.

You’re Dealing with Compliance or Audit Requirements

Regulatory requirements, quality standards, or client contracts require documented control systems. You need professional technical documentation that demonstrates you understand and can maintain your critical control systems.

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Beyond Documentation – Modification Support

If you’re planning modifications to the system, the documentation can be extended to include specific guidance on where and how changes should be implemented. I’ll analyze the existing code structure to identify the best integration points for new functionality, explain how the current architecture can support your planned changes, and highlight any constraints or dependencies you’ll need to work around.

This saves significant time during the development phase and reduces the risk of new code breaking existing functionality.

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Ongoing Support

For clients who find ongoing technical support beneficial, we can discuss retainer arrangements or on-call support options. This might include answering questions about the documented system, providing guidance during modifications, or reviewing proposed changes before implementation. The goal is to ensure you get maximum value from the documentation and have expert backup when you need it.

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Deliverables

You’ll receive professional documentation as a Word document (fully editable for your internal updates) or PDF (polished and ready for client handover or archival). The documentation includes PlantUML diagrams where helpful, flowcharts for complex sequences, and clear technical writing that your team can actually use.

For ongoing projects or situations where stakeholder feedback is valuable, I can provide living documentation through OneDrive with commenting enabled. This allows your team to ask questions, request clarifications, or provide additional context during the documentation development process.

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Investment

Starting from £800 – Every project is unique, and I provide fixed-price quotes based on your specific requirements.

Understanding your project’s scope helps me provide accurate pricing. Here’s what typically influences the investment:

How It Works:

Send me your PLC project files and a brief overview of what the system does. I’ll review the project and provide you with a fixed-price quote within 48 hours – no obligation, no surprise costs later. The quote will include a specific delivery timeline for your project.

Not sure where your project fits? The free assessment will tell you exactly what the investment will be before you commit to anything.

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Why Choose Me

I’m not just a technical writer – I’m an automation engineer who works daily with SCADA systems, PLC programming, and industrial control systems. I document and develop projects involving wastewater treatment plants, conveyor systems, and complex industrial processes for clients.

When I read your PLC code, I understand the engineering decisions behind it. I know why a particular state machine structure was chosen, what the interlocks are protecting against, and where the tricky edge cases hide. I document projects the way an experienced engineer explains them to a colleague – with context, reasoning, and practical insights.

I also create Asset Oriented Programming training content, so I’m constantly thinking about how to make complex automation concepts understandable. That teaching mindset carries through into every documentation project I deliver.

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