Simulation as a basis for decision-making when emulating the control system
Whether a new plant will actually operate as planned after commissioning is often only determined on site, when rectification work is at its most expensive. A real-life case study from the round timber yard of plant manufacturer HOLTEC demonstrates how emulating the PLC mitigates precisely this risk before construction begins.
Initial situation: PLC programme untested before construction began
For one section of the new round timber yard, the PLC programme had to be tested and validated before the actual plant went into operation. The focus was on a material flow involving ejection into a bypass and subsequent re-feeding – a control logic that is almost impossible to verify fully on the drawing board.
Three questions that needed to be clarified before construction began
- Does the PLC logic also work in edge cases, such as when material is discharged into the bypass and then reintroduced?
- Which errors only become apparent when the control system and material flow interact, rather than during isolated testing of individual programme components?
- How much time can be saved on site if these errors are rectified in advance?
The simulation approach: emulation rather than relying on paper
SimPlan fully modelled the material flow of the round timber yard in Plant Simulation 16.0 and linked the model directly to the real PLC software from TIA Portal (Step 7) v16 via PLCSIM Advanced 3.0. As a result, the material flow in the model was not controlled by a simplified test script, but by the exact PLC programme that was later to run on the actual plant. Selected errors in the PLC were logged and made traceable.
Results: Errors rectified before the plant went live
The simulation uncovered several errors in the PLC programme and enabled them to be rectified before the actual plant went into operation.
- The system was configured entirely virtually.
- The specific section of the PLC under investigation was fully validated.
- The actual commissioning on site was ultimately completed three days sooner.
The overarching lesson: emulation pays off across projects
This pattern is not unique to HOLTEC. At an intralogistics system integrator, an emulation linked to SAP/EWM confirmed the exception handling of a new system before the actual software commissioning began, and remained in use thereafter as a test and training system. At a manufacturer of security and sensor technology, an emulation of the higher-level control units revealed protocol assumptions and errors that would not have become apparent in isolated software tests.
Three questions recur in almost every project:
- Has the control logic really been tested in full, or just the part that is easy to test?
- How many errors only become apparent when the system interacts with other systems?
- And how much time could be saved on site if these errors had been rectified beforehand?
Anyone who only answers these questions during actual commissioning pays the price in the form of downtime on site, delayed start-ups or rework carried out under time pressure.
Are you planning an emulation for your plant?
Speak to our experts before your PLC software runs on the actual plant. SimPlan supports plant manufacturers and operators from the modelling of material flow right through to validated control logic.
You can find further case studies, technical articles and practical examples on the SimPlan blog.
