An 18-Step Workflow for PC-Based Automation Equipment Control
A step-by-step walkthrough of how we develop C-based equipment control software — from first-pass mechanical review all the way to long-term post-deployment maintenance.
This article walks through the development workflow we typically follow when building C-based equipment control software for automation lines.
The order below is the most common one, but if you have multiple developers, several steps can run in parallel or even start earlier. Treat it as a rough sequence and adapt it to your project's scope, the team's experience and the headcount you actually have.
Assumptions
- Basic IO and motor libraries are already in place.
- Common GUI screens have been built and reusable.
1. Understand the Machine Structure
Start by reviewing the machine with the mechanical designer.
You need to understand the entire motion structure. Every machine, in the end, uses actuators (motors, cylinders) to move or process material — so you have to understand how the material flows and how each actuator participates in that flow before you can design the control structure.
- Number of motor axes, motion direction and target positions for each.
- Cylinder positions, directions and motion structure.
- For each sensor: when does it trigger, why was it placed there, and is anything missing that the control side actually needs?
- Boards installed in the control PC, communication and interface types.
Ideally the software engineer is involved from the original quote/concept stage, not just brought in after the machine is mechanically assembled — that way control-friendly design choices and risks can be addressed before they become expensive.
2. Design and Review the Control Structure
Based on the mechanical understanding above, sketch out how the machine will be controlled at a high level.
Decide which parts run concurrently, what data the material payload should carry, and what the main screen should display. Reviewing this with another developer once before going into code pays off.
3. Create the Project
Once the control concept is locked, create a fresh project — either a brand new Visual Studio project or a stripped-down clone of an existing one with everything machine-specific removed.
Each individual machine project should contain only that machine's source. Anything reused across machines should live in a separate DLL library. The collection of common libraries used to control your equipment is what some teams call a framework.
4. Author the Base Data
Author the foundational data files:
- IO Map
- Cylinder Data
- Motor Data
Use whatever format your in-house framework expects.
You can technically code without configuration files, but the moment you do, every parameter tweak forces a rebuild and a redeployed binary, and a slightly different hardware variant requires a separate executable. Make sure your framework lets the basic control objects be configured from data files.
5. IO · Cylinder · Motor Check
Once the machine and control PC are powered on, verify that IO, cylinders and motors actually behave correctly.
- Are the sensors detecting material correctly?
- Do cylinders move in the correct direction, and do their sensors come on as expected?
- Motor drive direction, sensor states, travel distance.
6. Interlocks (Develop the Check Functions)
Before any real sequence work, write strict interlock checks that prevent motors and cylinders from colliding by accident.
Start strict and loosen them later as needed. If you start loose, the inevitable bugs, mistakes and accidental jog moves during sequence development will end in collisions. A motor alarm is the lucky outcome — the unlucky one is broken hardware. And the financial damage is usually less painful than the schedule damage: production deadlines don't move. Worse, an unexpected motion can injure an operator. Interlocks deserve the time you spend on them.
Take interlocks seriously.
7. Author Teaching Parameters
As the motion structure firms up, capture the teaching values each motor needs.
- Build a screen that lets the operator set the values in GUI and jog motors to fine-tune them.
- Define the data structure on the sequence-side that consumes those GUI values.
8. Develop Sequences
Now the real sequence work begins.
Develop sequences as modules that run concurrently, with each module backed by one or more threads. Sequence code drives motors, cylinders and IO outputs to move/process material and updates the relevant data along the way.
Most teams structure sequences with if/else or switch/case plus an error-handling scaffold.
The control structure varies wildly between companies and engineers — without standardization, every machine ends up with its own ad-hoc sequence code. The senior engineer's job is to establish the common structure as a shared library so every developer in the company writes sequences the same way.
9. Build the Main GUI
Lay out the main screen with the information operators actually need. Some of this can run in parallel with sequence development.
10. Vision Algorithm and Teaching Screens
Machines that include vision align or inspection need vision algorithm work plus a vision teaching screen.
If a separate vision engineer owns a separate program (or even runs it on a separate PC), the equipment control program just communicates with it and consumes the result.
11. Sequence Debugging
Once sequences are stable enough, run them in IDLE RUN (DRY RUN) to verify each module behaves correctly and that the connection conditions between modules work as expected.
This is where most accidental collisions happen during development. Strict interlocks pay off here.
12. MES Development and Testing
If you have multiple developers and bandwidth to spare, MES work can start in parallel with everything else.
Read the spec, understand the protocol and data structures, then implement scenario-by-scenario. Send/receive data per scenario or event — and keep this synced with sequence and GUI development.
A typical MES rollout:
- Spec analysis
- Base protocol implementation
- Per-event data send/receive testing
- Scenario implementation
- Local server protocol/scenario testing
- Production server testing
13. Full Auto Run Test & Debug
After the sequences are in place, feed real material in and run the full cycle.
Real material exposes a flood of edge cases — sensors, timing, mechanical interactions — that you simply don't see in dry runs. Work them out together with the mechanical, hardware and CS engineers. Fix the software bugs, and where software alone can compensate for a non-software issue, do that too.
Software is the cheapest place to fix a control problem. (Just don't abuse it.)
14. Manual Mode and Operator Conveniences
Build manual operation features early — they make on-site setup much faster.
Watch the setup process closely (or run it yourself) and ship convenience features as quickly as possible. The first setup of newly developed software is best done by the developer who built it.
Eat your own dog food.
15. Error and Message Data
Ideally you maintain error data alongside sequence work. In practice everyone is heads-down on sequence logic, so error codes get organized late. Once sequence debugging is stable, sit down and clean up the error codes and messages so operators can read them. Make sure the structure supports multiple languages.
XMachineStudio lets you author ERROR data while you write sequences — they live next to each other.
16. Localization Data
Author the localization data for the error/message data above, plus translations for the GUI.
17. Software User Manual
Write the setup and operation manual. If the customer needs it in another language, request a translation.
18. Production Support · Bug Fixes · Maintenance
After delivery, support the production line — fix bugs found during qualification or live operation, and keep maintaining the software long-term.