Virtual commissioning is the practice of testing control logic, sequences and process changes against a digital twin of the equipment or line before they are applied to the physical system, so that errors are found in software rather than on site.
Commissioning is where design meets reality. On a physical line, logic errors, missing interlocks and sequence timing problems usually appear during start-up — when time is shortest and the cost of a mistake is highest. Virtual commissioning moves much of that testing earlier, onto a model of the line.
Why commissioning is a high-risk phase
- Schedule pressure. Commissioning sits at the end of a project, after delays elsewhere have used up the slack.
- Late discovery. Many logic errors only show up once equipment is moving.
- Risk to equipment and people. Untested sequences on real machines can cause collisions, jams or unsafe states.
- Limited test coverage. Rare faults and abnormal conditions are hard, or unsafe, to reproduce on real plant.
How virtual commissioning works
The principle is simple: the control system should not be able to tell whether it is driving the real line or its digital twin.
- Build the model. Create a digital twin of the equipment or line — geometry, movement, sensors, actuators and process behaviour — at the fidelity the tests require.
- Connect the control logic. The PLC program reads simulated sensor signals and drives simulated actuators, as it would on site.
- Run the scenarios. Test normal sequences, start-up and shut-down, interlocks, operator actions and fault conditions.
- Fix and repeat. Correct errors in software and re-run the tests until the behaviour is right.
- Commission on site. Physical commissioning then focuses on verifying wiring, mechanics and real-world behaviour.
Who is involved
Virtual commissioning brings together people who often meet for the first time on site: mechanical designers, controls engineers, process engineers and operations. Working against a shared model, they can resolve interface questions — which sensor confirms which movement, what happens when a step times out — while changes are still easy to make.
Software-in-the-loop and hardware-in-the-loop
| Approach | Controller | What it tests |
|---|---|---|
| Software-in-the-loop | Control program on an emulated controller | Logic, sequences and interlocks, early in the project |
| Hardware-in-the-loop | Real controller connected to the simulated plant | Logic plus I/O mapping, communication and timing |
Many projects use both: software-in-the-loop while logic is being written, and hardware-in-the-loop once the real controller is available. The choice depends on the project stage, when the controller hardware arrives and how much of the timing behaviour needs to be proven before site work.
Virtual commissioning does not remove site commissioning; it changes what is left to find on site — from logic errors to physical verification.
Physical-only vs virtual commissioning
| Dimension | Physical commissioning only | With virtual commissioning |
|---|---|---|
| When logic is tested | On site, after installation | Before installation, in parallel with the build |
| Fault scenarios | Hard or unsafe to reproduce | Simulated repeatedly |
| Cost of an error | Rework on site, delayed start-up | Corrected in software |
| Operator familiarity | Built on the live line | Can be built on the twin first |
Process changes on existing lines
Virtual commissioning is not only for new plants. On a running line, a new product variant, an added station or a modified sequence can be tested against the twin before the planned shutdown. The shutdown is then spent installing and verifying, not debugging.
For this kind of work, the model must reflect the line as it is, not as it was originally drawn. Checking drawings and I/O lists against the installed equipment is often the first task.
What a useful model needs
A virtual commissioning model is judged by whether the control logic behaves the same way on the model as it will on the line. That depends on:
- An accurate I/O list. Every signal the controller expects must exist in the model.
- Realistic timing. Movements and sensor responses close enough to reality for sequences to be meaningful.
- Fault modelling. The ability to simulate jams, failed sensors and abnormal states, not just the normal sequence.
- Good source information. Layout drawings, equipment data and a clear control narrative.
How detailed should the model be?
A common mistake is to over-build. Logic testing rarely needs realistic graphics; it needs correct signals, sensible timing and credible faults. Detailed physics may matter for a robot cell or a complex transfer, and much less for a simple conveyor sequence. The level of detail should follow the tests the model has to support.
In the NIVOSK Industrial Intelligence Stack, virtual commissioning links Simulate — digital twin and simulation — to Act, where automation, PLC and SCADA connect intelligence with real operations.
Understand before you act.
Getting started
The best time to plan virtual commissioning is early: at the design stage of a new line, a retrofit or a major control change. Starting late limits the benefit, because the model needs time to build and validate. A useful first step is to list the sequences and fault scenarios that caused the most trouble on previous projects; they make a good initial test plan.
Deployment follows Discover → Assess → Design → Develop → Integrate → Deploy → Scale. Assessment covers the equipment, the available design data and the control platform; integration connects the model to the control system under test. The approach applies wherever automated lines are built or changed, from manufacturing to automotive plants.
If you are commissioning a new line or planning a major change, request a technical assessment.
Frequently asked questions
What is virtual commissioning?
Testing control logic, sequences and process changes against a digital twin of the equipment or line before applying them to the physical system, so that errors are found in software rather than on site.
Does virtual commissioning replace site commissioning?
No. Physical commissioning is still needed to verify wiring, mechanics and real-world behaviour. Virtual commissioning reduces what is left to find on site.
What is the difference between software-in-the-loop and hardware-in-the-loop?
In software-in-the-loop testing the control program runs on an emulated controller. In hardware-in-the-loop testing the real controller is connected to the simulated plant, which also tests I/O mapping and timing.
Is virtual commissioning only for new lines?
No. It is also useful for changes to existing lines, such as a new product variant, an added station or a modified sequence, where logic can be tested before a planned shutdown.
What information is needed to start?
Typically layout or 3D data for the equipment, the I/O list, the control narrative or sequence description, and the control program or its specification.